1
|
Möller FN, Fan JL, Futral JE, Hodgman CF, Kayser B, Lovering AT. Cardiopulmonary haemodynamics in Tibetans and Han Chinese during rest and exercise. J Physiol 2024; 602:3893-3907. [PMID: 38924564 DOI: 10.1113/jp286303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024] Open
Abstract
During sea-level exercise, blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) in humans without a patent foramen ovale (PFO) is negatively correlated with pulmonary pressure. Yet, it is unknown whether the superior exercise capacity of Tibetans well adapted to living at high altitude is the result of lower pulmonary pressure during exercise in hypoxia, and whether their cardiopulmonary characteristics are significantly different from lowland natives of comparable ancestry (e.g. Han Chinese). We found a 47% PFO prevalence in male Tibetans (n = 19) and Han Chinese (n = 19) participants. In participants without a PFO (n = 10 each group), we measured heart structure and function at rest and peak oxygen uptake (V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ ), peak power output (W ̇ p e a k ${{\dot{W}}_{peak}}$ ), pulmonary artery systolic pressure (PASP), blood flow through IPAVA and cardiac output (Q ̇ T ${{\dot{Q}}_{\mathrm{T}}} $ ) at rest and during recumbent cycle ergometer exercise at 760 Torr (SL) and at 410 Torr (ALT) barometric pressure in a pressure chamber. Tibetans achieved a higherW peak ${W}_{\textit{peak}}$ than Han, and a higherV ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ at ALT without differences in heart rate, stroke volume orQ ̇ T ${{\dot{Q}}_{\mathrm{T}}} $ . Blood flow through IPAVA was generally similar between groups. Increases in PASP and total pulmonary resistance at ALT were comparable between the groups. There were no differences in the slopes of PASP plotted as a function ofQ ̇ T ${{\dot{Q}}_{\mathrm{T}}} $ during exercise. In those without PFO, our data indicate that the superior aerobic exercise capacity of Tibetans over Han Chinese is independent of cardiopulmonary features and more probably linked to differences in local muscular oxygen extraction. KEY POINTS: Patent foramen ovale (PFO) prevalence was 47% in Tibetans and Han Chinese living at 2 275 m. Subjects with PFO were excluded from exercise studies. Compared to Han Chinese, Tibetans had a higher peak workload with acute compression to sea level barometric pressure (SL) and acute decompression to 5000 m altitude (ALT). Comprehensive cardiac structure and function at rest were not significantly different between Han Chinese and Tibetans. Tibetans and Han had similar blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) during exercise at SL. Peak pulmonary artery systolic pressure (PASP) and total pulmonary resistance were different between SL and ALT, with significantly increased PASP for Han compared to Tibetans at ALT. No differences were observed between groups at acute SL and ALT.
Collapse
Affiliation(s)
- Fabian N Möller
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Boston, MA, USA
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
- German Sport University Cologne, Institute for Professional Sport Education and Qualification, Cologne, Germany
| | - Jui-Lin Fan
- Department of Physiology, Manaaki Manawa - The Centre for Heart Research, University of Auckland, Faculty of Medical and Health Sciences, Auckland, New Zealand
| | - Joel E Futral
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
- Oregon Heart & Vascular Institute, Springfield, Oregon, USA
| | - Charles F Hodgman
- Department of Health and Human Performance, University of Houston, Houston, TX, USA
| | - Bengt Kayser
- University of Lausanne, Institute of Sports Sciences, Lausanne, Switzerland
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| |
Collapse
|
2
|
McPhail S, Steed D, Holdsworth D, Nicol E, Bennett A, Phillips S. Development, design and experience of the UK Military's return to diving pathway following SARS-CoV-2 infection. BMJ Mil Health 2024; 170:365-369. [PMID: 36581498 DOI: 10.1136/military-2022-002327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/31/2022]
Abstract
After the emergence of the SARS-CoV-2 virus in early 2020, it quickly became clear that symptomatic or asymptomatic infection had the potential to negatively impact on an individual's fitness to dive through effects on the respiratory, cardiovascular or neurological systems. The significance of these effects in the military diving environment was initially unclear due to an absence of data concerning incidence, chronology or severity. In order to safely return divers to the water and maintain operational capability, the UK Military developed a pathway for SARS-CoV-2 positive divers that stratified risk of sequelae and extent of required clinical investigation, while minimising reliance on viral testing and hospital-based investigations. We present this process, provide rationale and support for its design and detail the number of SARS-CoV-2 positive divers who have been returned to full diving fitness following infection of varying degrees of severity.
Collapse
Affiliation(s)
- Stuart McPhail
- Underwater Medicine Division, Institute of Naval Medicine, Alverstoke, UK
- Department of Anaesthesia, University Hospitals Plymouth NHS Trust, Plymouth, Devon, UK
| | - D Steed
- Underwater Medicine Division, Institute of Naval Medicine, Alverstoke, UK
| | - D Holdsworth
- Academic Department of Military Medicine, Royal Centre for Defence Medicine (Research and Clinical Innovation), Birmingham, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - E Nicol
- Royal Brompton Hospital, London, UK
- King's College London School of Biomedical Engineering and Imaging Sciences, London, UK
| | - A Bennett
- Academic Department of Military Rehabilitation, Defence Medical Rehabilitation Centre Headley Court, Epsom, UK
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, UK
| | - S Phillips
- Underwater Medicine Division, Institute of Naval Medicine, Alverstoke, UK
| |
Collapse
|
3
|
Kim G, Ji Y, Jeong HG, Lee T, Lee K, Yoon H. Case report: Imaging features of aorta-right atrial tunnel in a dog using two-dimensional echocardiography and computed tomography. Front Vet Sci 2023; 10:1160390. [PMID: 37465274 PMCID: PMC10352079 DOI: 10.3389/fvets.2023.1160390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/19/2023] [Indexed: 07/20/2023] Open
Abstract
A 7-year-old castrated male Pomeranian dog weighing 5 kg presented with a right-sided continuous murmur without any clinical signs. Thoracic radiographs indicated cardiomegaly and right atrial (RA) bulging. Echocardiography revealed a tunnel originating from the right coronary sinus of Valsalva and terminating in the RA. Contrast echocardiography revealed pulmonary arteriovenous anastomoses. Computed tomography (CT) demonstrated a tortuous shunting vessel that originated from the aorta extending in a ventral direction, ran along the right ventricular wall, and was inserted into the RA. Based on these diagnostic findings, the dog was diagnosed with the aorta-RA tunnel. At the 1-year follow-up visit without treatment, the dog showed no significant change except for mild left ventricular volume overload and mildly decreased contractility. To the best of our knowledge, this is the first case report of an aorta-RA tunnel that has been described in detail using echocardiography and CT in a dog. In conclusion, the aorta-RA tunnel should be included in the clinical differential diagnoses if a right-sided continuous murmur is heard or shunt flow originating from the aortic root is identified.
Collapse
Affiliation(s)
- Geunha Kim
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Jeonbuk National University, Iksan-si, Republic of Korea
| | - Yewon Ji
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Jeonbuk National University, Iksan-si, Republic of Korea
| | | | - Taekwon Lee
- Animal Medical Center, Jeonju, Republic of Korea
| | - Kichang Lee
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Jeonbuk National University, Iksan-si, Republic of Korea
| | - Hakyoung Yoon
- Department of Veterinary Medical Imaging, College of Veterinary Medicine, Jeonbuk National University, Iksan-si, Republic of Korea
| |
Collapse
|
4
|
Davis JT, Elliott JE, Duke JW, Cristobal A, Lovering AT. Hyperoxia-induced stepwise reduction in blood flow through intrapulmonary, but not intracardiac, shunt during exercise. Am J Physiol Regul Integr Comp Physiol 2023; 325:R96-R105. [PMID: 37184225 PMCID: PMC10292968 DOI: 10.1152/ajpregu.00014.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 05/16/2023]
Abstract
Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) (QIPAVA) increases during exercise breathing air, but it has been proposed that QIPAVA is reduced during exercise while breathing a fraction of inspired oxygen ([Formula: see text]) of 1.00. It has been argued that the reduction in saline contrast bubbles through IPAVA is due to altered in vivo microbubble dynamics with hyperoxia reducing bubble stability, rather than closure of IPAVA. To definitively determine whether breathing hyperoxia decreases saline contrast bubble stability in vivo, the present study included individuals with and without patent foramen ovale (PFO) to determine if hyperoxia also eliminates left heart contrast in people with an intracardiac right-to-left shunt. Thirty-two participants consisted of 16 without a PFO; 8 females, 8 with a PFO; 4 females, and 8 with late-appearing left-sided contrast (4 females) completed five, 4-min bouts of constant-load cycle ergometer exercise (males: 250 W, females: 175 W), breathing an [Formula: see text] = 0.21, 0.40, 0.60, 0.80, and 1.00 in a balanced Latin Squares design. QIPAVA was assessed at rest and 3 min into each exercise bout via transthoracic saline contrast echocardiography and our previously used bubble scoring system. Bubble scores at [Formula: see text]= 0.21, 0.40, and 0.60 were unchanged and significantly greater than at [Formula: see text]= 0.80 and 1.00 in those without a PFO. Participants with a PFO had greater bubble scores at [Formula: see text]= 1.00 than those without a PFO. These data suggest that hyperoxia-induced decreases in QIPAVA during exercise occur when [Formula: see text] ≥ 0.80 and is not a result of altered in vivo microbubble dynamics supporting the idea that hyperoxia closes QIPAVA.
Collapse
Affiliation(s)
- James T Davis
- Indiana University School of Medicine, Department of Anatomy, Cell Biology and Physiology Bloomington, Indiana, United States
| | - Jonathan E Elliott
- Veterans Affairs Portland Health Care Systeme, Research Servic, Portland, Oregon, United States
- Department of Neurology, Oregon Health & Science University, Portland, Oregon, United States
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States
| | - Alberto Cristobal
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| |
Collapse
|
5
|
Quantification of shunt fraction using contrast ultrasound and indicator dilution in an in vitro model. Respir Physiol Neurobiol 2023; 310:104013. [PMID: 36639005 DOI: 10.1016/j.resp.2023.104013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/12/2023]
Abstract
Transthoracic saline contrast echocardiography is commonly used to assess intrathoracic shunt flow in vivo. Though the technique has many advantages (safe, simple, repeatable), the measurement technique lacks specificity, and the contrast agent has limited stability. This study sought to determine if the indicator dilution modeling technique could be applied to ultrasound contrast data to quantify shunt fraction and to determine if buoyant force has a significant effect on microbubble pathway determination at a "vascular" bifurcation. A model of the pulmonary circuit was perfused with blood at three distinct flow rates (low, medium and high) over shunt fractions ranging from ∼2-10 %. The buoyancy effect on contrast was quantified using a simplified in vitro model of a vascular bifurcation that had an upper and lower outflow tract where saline contrast formed from carbon monoxide (CO) gas passed through the bifurcation, was collected and quantified. The indicator dilution model was found to have a mean bias of - 3.2 % for the low flow stage, - 2.6 % for the medium flow stage and - 1.4 % for the high flow stage compared to volumetric measurements, suggesting agreement increases with increasing flow rate. Investigations of the buoyant effects revealed that at lower flow rates, contrast bubbles that encounter a bifurcation will favor the upper outflow tract over the lower. However, this effect is reduced by increasing the flow rate two-fold. These data identify that application of indicator dilution theory to contrast ultrasound data and the pathway ultrasound contrast travels in a network of tubules is flow dependent.
Collapse
|
6
|
Hou H, Guo C, Que C, Nie L, Zhang Q, Zhao H, Nong L, Ma W, Wang Q, Liang Z, Wang B, Ma J, Wang G. Diffuse large B-cell lymphoma presenting as reversible intrapulmonary arteriovenous shunts with hypoxia, fever and progressive jaundice: a case report and literature review. BMC Pulm Med 2022; 22:89. [PMID: 35292006 PMCID: PMC8922084 DOI: 10.1186/s12890-022-01881-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/07/2022] [Indexed: 11/16/2022] Open
Abstract
Background Intrapulmonary arteriovenous shunts is rare seen in a patient without lung involvement. Case presentation This is the first report of reversible intrapulmonary arteriovenous shunts secondary to extrapulmonary lymphoma as one initial symptom. The patient presented as fever of unknown origin and dyspnea, and examinations of infection were negative. Diagnosis of DLBCL was finally confirmed through bone marrow and splenic biopsies. Intrapulmonary arteriovenous shunts were diagnosed through 100% oxygen inhalation test and transthoracic contrast echocardiography (TTCE). After the treatment of lymphoma, his respiratory failure was relieved. We rechecked the 100% oxygen inhalation test and TTCE, which both indicated that his intrapulmonary arteriovenous shunts had resolved. Conclusions We speculated the prominent inflammation from active DLBCL was the most possible mechanism associated with the reversible intrapulmonary shunt in this patient. These findings will assist us to better understand the mechanism of intrapulmonary shunts.
Collapse
Affiliation(s)
- Huan Hou
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Cuiyan Guo
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Chengli Que
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Ligong Nie
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Qi Zhang
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| | - Hong Zhao
- Department of Infectious Diseases, Center for Liver Disease, Peking University First Hospital, Beijing, China
| | - Lin Nong
- Department of Pathology, Peking University First Hospital, Beijing, China
| | - Wei Ma
- Department of Cardiology, Peking University First Hospital, Beijing, China
| | - Qian Wang
- Department of Hematology, Peking University First Hospital, Beijing, China
| | - Zeyin Liang
- Department of Hematology, Peking University First Hospital, Beijing, China
| | - Bingjie Wang
- Department of Hematology, Peking University First Hospital, Beijing, China
| | - Jing Ma
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.
| | - Guangfa Wang
- Department of Respiratory and Critical Care Medicine, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China
| |
Collapse
|
7
|
Lovering AT, Kelly TS, DiMarco KG, Bradbury KE, Charkoudian N. Implications of a patent foramen ovale on environmental physiology and pathophysiology: Do we know the hole story? J Physiol 2022; 600:1541-1553. [PMID: 35043424 DOI: 10.1113/jp281108] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/14/2022] [Indexed: 11/08/2022] Open
Abstract
The foramen ovale is an essential component of the foetal circulation contributing to oxygenation and carbon dioxide elimination that remains patent under certain circumstances, in ∼ 30% of the healthy adult population, without major negative sequelae in most. Adults with a patent foramen ovale (PFO) have a greater tendency to develop symptoms of acute mountain sickness and high-altitude pulmonary oedema upon ascent to high altitude, and PFO presence is associated with worse cardiopulmonary function in chronic mountain sickness. This increase in altitude illness prevalence may be related to dysregulated cerebral blood flow associated with altered respiratory chemoreflex sensitivity; however, the mechanisms remain to be elucidated. Interestingly, men with a PFO appear to have a shift in thermoregulatory control to higher internal temperatures, both at rest and during exercise, and they have blunted thermal tachypnea. The teleological "reason" for this thermoregulatory shift is unclear, but the shift of ∼0.5°C in core body temperature does not appear to be sufficient to have any significant negative consequences in terms of risk of heat illness. Further work in this area is needed, particularly in women, to evaluate mechanisms of heat storage and dissipation in these individuals as compared to people without a PFO. Consequences of a PFO in SCUBA divers include a greater incidence of unprovoked decompression sickness, but whether PFO is beneficial or detrimental to breath hold diving remains unexplored. Whether PFO presence will explain interindividual variability in responses to, and consequences from, other environmental stressors such as spaceflight remain entirely unknown. Abstract figure legend Associations between PFO and altitude illnesses, core body temperature and diving. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
| | - Tyler S Kelly
- University of Oregon, Department of Human Physiology, Eugene, OR
| | | | - Karleigh E Bradbury
- University of Oregon, Department of Human Physiology, Eugene, OR.,United States Army Research Institute of Environmental Medicine, Thermal & Mountain Medicine Division, Natick, MA
| | - Nisha Charkoudian
- United States Army Research Institute of Environmental Medicine, Thermal & Mountain Medicine Division, Natick, MA
| |
Collapse
|
8
|
DiMarco KG, Beasley KM, Shah K, Speros JP, Elliott JE, Laurie SS, Duke JW, Goodman RD, Futral JE, Hawn JA, Roach RC, Lovering AT. No effect of patent foramen ovale on acute mountain sickness and pulmonary pressure in normobaric hypoxia. Exp Physiol 2021; 107:122-132. [PMID: 34907608 DOI: 10.1113/ep089948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/08/2021] [Indexed: 11/08/2022]
Abstract
What is the central question to this study? Is there a relationship between a patent foramen ovale and the development of acute mountain sickness and an exaggerated increase in pulmonary pressure in response to 7-10 hours of normobaric hypoxia? What is the main finding and its importance? Patent foramen ovale presence did not increase susceptibility to acute mountain sickness or result in an exaggerated increase in pulmonary artery systolic pressure with normobaric hypoxia. This data suggest hypobaric hypoxia is integral to the increased susceptibility to acute mountain sickness previously reported in those with patent foramen ovale, and patent foramen ovale presence alone does not contribute to the hypoxic pulmonary pressor response. ABSTRACT: Acute mountain sickness (AMS) develops following rapid ascent to altitude, but its exact causes remain unknown. A patent foramen ovale (PFO) is a right-to-left intracardiac shunt present in ∼30% of the population that has been shown to increase AMS susceptibility with high altitude hypoxia. Additionally, high altitude pulmonary edema (HAPE), is a severe type of altitude illness characterized by an exaggerated pulmonary pressure response, and there is a greater prevalence of PFO in those with a history of HAPE. However, whether hypoxia, per se, is causing the increased incidence of AMS in those with a PFO and whether a PFO is associated with an exaggerated increase in pulmonary pressure in those without a history of HAPE is unknown. Participants (n = 36) matched for biological sex (18 female) and the presence or absence of a PFO (18 PFO+) were exposed to 7-10 hours of normobaric hypoxia equivalent to 4755 m. Presence and severity of AMS was determined using the Lake Louise AMS scoring system. Pulmonary artery systolic pressure, cardiac output, and total pulmonary resistance were measured using ultrasound. We found no significant association of PFO with incidence or severity of AMS and no association of PFO with arterial oxygen saturation. Additionally, there was no effect of a PFO on pulmonary pressure, cardiac output, or total pulmonary resistance. These data suggest that hypobaric hypoxia is necessary for those with a PFO to have increased incidence of AMS and that presence of PFO is not associated with an exaggerated pulmonary pressor response. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Kaitlyn G DiMarco
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Kara M Beasley
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Karina Shah
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Julia P Speros
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Jonathan E Elliott
- VA Portland Health Care System, Portland, OR, USA.,Oregon Health and Science University, Department of Neurology, Portland, OR, USA
| | - Steven S Laurie
- KBR, Cardiovascular and Vision Laboratory, NASA Johnson Space Center, Houston, TX, USA
| | - Joseph W Duke
- Northern Arizona University, Department of Biological Sciences, Flagstaff, AZ, USA
| | | | | | - Jerold A Hawn
- Oregon Heart and Vascular Institute, Springfield, OR, USA
| | - Robert C Roach
- University of Colorado Anschutz Medical Campus, Altitude Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Aurora, CO, USA
| | - Andrew T Lovering
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| |
Collapse
|
9
|
Kohshi K, Denoble PJ, Tamaki H, Morimatsu Y, Ishitake T, Lemaître F. Decompression Illness in Repetitive Breath-Hold Diving: Why Ischemic Lesions Involve the Brain? Front Physiol 2021; 12:711850. [PMID: 34539434 PMCID: PMC8446421 DOI: 10.3389/fphys.2021.711850] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/28/2021] [Indexed: 12/03/2022] Open
Abstract
Nitrogen (N2) accumulation in the blood and tissues can occur due to breath-hold (BH) diving. Post-dive venous gas emboli have been documented in commercial BH divers (Ama) after repetitive dives with short surface intervals. Hence, BH diving can theoretically cause decompression illness (DCI). “Taravana,” the diving syndrome described in Polynesian pearl divers by Cross in the 1960s, is likely DCI. It manifests mainly with cerebral involvements, especially stroke-like brain attacks with the spinal cord spared. Neuroradiological studies on Ama divers showed symptomatic and asymptomatic ischemic lesions in the cerebral cortex, subcortex, basal ganglia, brainstem, and cerebellum. These lesions localized in the external watershed areas and deep perforating arteries are compatible with cerebral arterial gas embolism. The underlying mechanisms remain to be elucidated. We consider that the most plausible mechanisms are arterialized venous gas bubbles passing through the lungs, bubbles mixed with thrombi occlude cerebral arteries and then expand from N2 influx from the occluded arteries and the brain. The first aid normobaric oxygen appears beneficial. DCI prevention strategy includes avoiding long-lasting repetitive dives for more than several hours, prolonging the surface intervals. This article provides an overview of clinical manifestations of DCI following repetitive BH dives and discusses possible mechanisms based on clinical and neuroimaging studies.
Collapse
Affiliation(s)
- Kiyotaka Kohshi
- Division of Neurosurgery, Nishinihon Hospital, Kumamoto, Japan.,Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan
| | | | - Hideki Tamaki
- Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan.,Division of Surgery and General Medicine, Tamaki Hospital, Hagi, Japan
| | - Yoshitaka Morimatsu
- Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Tatsuya Ishitake
- Department of Environmental Medicine, Kurume University School of Medicine, Kurume, Japan
| | - Frédéric Lemaître
- Faculty of Sport Sciences, University of Rouen, Mont-Saint-Aignan, France.,CRIOBE USR 3278, CNRS-EPHE-UPVD, PSL, Moorea, France
| |
Collapse
|
10
|
Implication of Blood Rheology and Pulmonary Hemodynamics on Exercise-Induced Hypoxemia at Sea Level and Altitude in Athletes. Int J Sport Nutr Exerc Metab 2021; 31:397-405. [PMID: 34303308 DOI: 10.1123/ijsnem.2021-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 11/18/2022]
Abstract
This study aimed to investigate the changes in blood viscosity, pulmonary hemodynamics, nitric oxide (NO) production, and maximal oxygen uptake (V˙O2max) during a maximal incremental test conducted in normoxia and during exposure to moderate altitude (2,400 m) in athletes exhibiting exercise-induced hypoxemia at sea level (EIH). Nine endurance athletes with EIH and eight without EIH (NEIH) performed a maximal incremental test under three conditions: sea level, 1 day after arrival in hypoxia, and 5 days after arrival in hypoxia (H5) at 2,400 m. Gas exchange and oxygen peripheral saturation (SpO2) were continuously monitored. Cardiac output, pulmonary arterial pressure, and total pulmonary vascular resistance were assessed by echocardiography. Venous blood was sampled before and 3 min after exercise cessation to analyze blood viscosity and NO end-products. At sea level, athletes with EIH exhibited an increase in blood viscosity and NO levels during exercise while NEIH athletes showed no change. Pulmonary hemodynamics and aerobic performance were not different between the two groups. No between-group differences in blood viscosity, pulmonary hemodynamics, and V˙O2max were found at 1 day after arrival in hypoxia. At H5, lower total pulmonary vascular resistance and greater NO concentration were reported in response to exercise in EIH compared with NEIH athletes. EIH athletes had greater cardiac output and lower SpO2 at maximal exercise in H5, but no between-group differences occurred regarding blood viscosity and V˙O2max. The pulmonary vascular response observed at H5 in EIH athletes may be involved in the greater cardiac output of EIH group and counterbalanced the drop in SpO2 in order to achieve similar V˙O2max than NEIH athletes.
Collapse
|
11
|
Durand F, Raberin A. Exercise-Induced Hypoxemia in Endurance Athletes: Consequences for Altitude Exposure. Front Sports Act Living 2021; 3:663674. [PMID: 33981992 PMCID: PMC8107360 DOI: 10.3389/fspor.2021.663674] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/25/2021] [Indexed: 11/26/2022] Open
Abstract
Exercise-induced hypoxemia (EIH) is well-described in endurance-trained athletes during both maximal and submaximal exercise intensities. Despite the drop in oxygen (O2) saturation and provided that training volumes are similar, athletes who experience EIH nevertheless produce the same endurance performance in normoxia as athletes without EIH. This lack of a difference prompted trainers to consider that the phenomenon was not relevant to performance but also suggested that a specific adaptation to exercise is present in EIH athletes. Even though the causes of EIH have been extensively studied, its consequences have not been fully characterized. With the development of endurance outdoor activities and altitude/hypoxia training, athletes often train and/or compete in this stressful environment with a decrease in the partial pressure of inspired O2 (due to the drop in barometric pressure). Thus, one can reasonably hypothesize that EIH athletes can specifically adapt to hypoxemic episodes during exercise at altitude. Although our knowledge of the interactions between EIH and acute exposure to hypoxia has improved over the last 10 years, many questions have yet to be addressed. Firstly, endurance performance during acute exposure to altitude appears to be more impaired in EIH vs. non-EIH athletes but the corresponding physiological mechanisms are not fully understood. Secondly, we lack information on the consequences of EIH during chronic exposure to altitude. Here, we (i) review research on the consequences of EIH under acute hypoxic conditions, (ii) highlight unresolved questions about EIH and chronic hypoxic exposure, and (iii) suggest perspectives for improving endurance training.
Collapse
Affiliation(s)
- Fabienne Durand
- Images Espace Dev, Université de Perpignan Via Domitia, Perpignan, France
| | | |
Collapse
|
12
|
The Value of Contrast-Enhanced Transesophageal Echocardiography in the Detection of Cardiac Right-to-Left Shunt Related with Cryptogenic Stroke and Migraine. BIOMED RESEARCH INTERNATIONAL 2020; 2020:8845652. [PMID: 33415164 PMCID: PMC7752281 DOI: 10.1155/2020/8845652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/26/2020] [Accepted: 11/28/2020] [Indexed: 12/17/2022]
Abstract
Purpose To analyze the characteristics of right-to-left shunt (RLS) in patients with cryptogenic stroke and migraine by contrast-enhanced transesophageal echocardiography (c-TEE). Methods The study population consisted of 330 patients with cryptogenic stroke and 330 patients with migraine who suspected PFO. All of them received c-TEE examination successfully. In terms of c-TEE analyses, RLS could be diagnosed when microbubbles were visualized in the transition from the right atrium to the left atrium. For semiquantitative analysis, a small amount of RLS was grade 1, indicating 1-10 microvesicles per frame could be seen in the left atrium, a moderate amount of RLS was grade 2, indicating 11-30 microvesicles per frame could be seen in the left atrium, and a large amount of RLS was grade 3, indicating more than 30 microvesicles per frame, or the left atrium is filled with microvesicles. Results A total of 660 patients were analyzed in the study. PFO-RLS was detected in 348 (348/660, 52.7%) cases by TEE, while in 392 (392/660, 59.3%) cases by c-TEE. Simultaneously, P-RLS was detected in 239 (239/660, 36.2%) cases by c-TEE. Among 330 patients with cryptogenic stroke, PFO-RLS was detected in 198 cases; according to the c-TTE method (198/330, 60.0%), concurrently, 83 participants suffered from PFO-RLS and P-RSL (83/330, 25.1%), including 1 case with PFO and pulmonary arteriovenous fistula. Among 330 patients with migraine, PFO-RLS was detected in 194 cases; according to the c-TTE method (194/330, 58.7%), specifically, 90 participants suffered from PFO-RLS and P-RSL (90/330, 27.2%). There was no statistical significance between the two groups. P-RLS singly was detected in 28 cases with cryptogenic stroke, while in 38 cases with migraine, excluding from pulmonary arteriovenous fistula by CTA examination. In addition, semiquantitative results on c-TTE grading of RLS were compared between the two groups: grade 1 RLS in the migraine group (144/322) was significantly higher than that in the cryptogenic stroke group (71/309) (P < 0.05). Grade 3 RLS in the cryptogenic stroke group (113/309) was significantly higher than that in the migraine group (67/322) (P < 0.05). For grade 2 RLS, there was no statistical difference between the two groups (P = 0.12). Conclusions c-TEE can increase the positive rate of PFO diagnosis compared with TEE color Doppler. There is no significant difference in the incidence of PFO-PLS and P-RLS between the cryptogenic stroke group and the migraine group. The grades 2-3 RLS are mainly detected in the cryptogenic stroke group, while grades 1-2 RLS are mostly detected in the migraine group.
Collapse
|
13
|
Boulet LM, Vermeulen TD, Cotton PD, Foster GE. Influence of blood Po 2 on the stability of agitated saline contrast. J Appl Physiol (1985) 2020; 129:1341-1347. [PMID: 33054656 DOI: 10.1152/japplphysiol.00488.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The utility of transthoracic saline contrast echocardiography (TTSCE) to assess blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) in humans is limited due to the potential destabilizing effects of the gas concentration gradients established in varied blood-gas environments. This study assessed the specific effect of a hyperoxic and mixed venous blood-gas environment on the stability of saline contrast. We hypothesized that the rate of contrast mass lost in hyperoxic blood would be similar to mixed venous due to the establishment of equal and opposing gas gradients (O2, N2, CO2) created when the partial pressure of dissolved gases is manipulated. Using an in vitro model of the pulmonary circulation perfused with defibrinated sheep blood and a membrane oxygenator to control blood gases, we assessed the percent contrast conserved (an index of contrast stability) between inflow and outflow sites at multiple flow rates (1.8, 2.8, 4.3, and 6.8 L/min) in a hyperoxic (Po2: 646 ± 16 mmHg; Pco2: 0 ± 0 mmHg) and a mixed venous blood gas condition (Po2: 35 ± 3 mmHg; Pco2: 40 ± 0 mmHg). We found significant contrast decay with time in both conditions, with slightly higher contrast conservation in the hyperoxia trials (64 ± 32%) versus the mixed venous trials (55 ± 21%). These findings suggest that contrast stability is not likely a factor affecting the interpretation of TTSCE performed in healthy humans breathing hyperoxia and lends support to the existence of a local O2-dependent mechanism contributing to the regulation of Q̇IPAVA.NEW & NOTEWORTHY Hyperoxic blood has a small stabilizing effect on agitated saline contrast compared with mixed venous blood, lending support to studies that show the reversal of exercise-induced blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) with hyperoxia. These data support the possible presence of a local O2-dependent regulatory mechanism within the pulmonary vasculature that may play a role in Q̇IPAVA regulation.
Collapse
Affiliation(s)
- Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Tyler D Vermeulen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Paul D Cotton
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| |
Collapse
|
14
|
Park S, Oh JK, Song JK, Kwon B, Kim BJ, Kim JS, Kang DW, Chang JY, Lee JS, Kwon SU. Transcranial Doppler as a Screening Tool for High-Risk Patent Foramen Ovale in Cryptogenic Stroke. J Neuroimaging 2020; 31:165-170. [PMID: 32896963 DOI: 10.1111/jon.12783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/29/2020] [Accepted: 08/22/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The identification of high-risk patent foramen ovale (PFO) is important for selecting suitable patients for PFO closure to prevent recurrent stroke in those with cryptogenic stroke. We aimed to evaluate the predictability of transcranial Doppler (TCD) in diagnosing high-risk PFO compared with that of transesophageal echocardiography (TEE), which is not feasible for some stroke patients. METHODS We retrospectively reviewed the data of 461 cryptogenic stroke patients who underwent TEE and TCD for PFO evaluation. High-risk PFO on TEE was defined as PFO with atrial septal aneurysm (phasic septal excursion ≥10 mm) or large PFO (≥2 mm). Spencer grading of right-to-left shunt was used to classify the amount of shunt on TCD. RESULTS PFO on TEE was observed for 242 (52.5%) patients, and high-risk PFO was detected for 123 (26.7%) patients. However, PFO on TCD was observed for 336 (72.9%) patients. Among patients with significant shunt (Spencer grade III or higher) who underwent TCD after Valsalva maneuver (VM), 60.0% of patients had high-risk PFO. However, only 5.3% of patients had high-risk PFO among those without significant shunt. Receiver operating characteristic curves showed that significant shunt after VM had higher predictability (AUC = .876, 95% CI: .843-.905) for detecting the high-risk PFO compared with the predictability based on significant shunt at rest (AUC = .718, 95% CI: .674-.759). (P<.0001 for the differences between two AUCs). CONCLUSIONS TCD is a good screening tool for evaluating high-risk PFO. VM is important for the evaluation of PFO. Patients with minimal or no shunt on TCD after VM are unlikely to have high-risk PFO.
Collapse
Affiliation(s)
- Seongho Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Jin Kyung Oh
- Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.,Division of Cardiology, Department of Internal Medicine, Sejong Chungnam National University Hospital, Chungnam National University College of Medicine, Daejeon, Korea
| | - Jae-Kwan Song
- Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Boseong Kwon
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Bum Joon Kim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jong S Kim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Dong-Wha Kang
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jun Young Chang
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Ji Sung Lee
- Clinical Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sun U Kwon
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| |
Collapse
|
15
|
Duke JW, Beasley KM, Speros JP, Elliott JE, Laurie SS, Goodman RD, Futral E, Hawn JA, Lovering AT. Impaired pulmonary gas exchange efficiency, but normal pulmonary artery pressure increases, with hypoxia in men and women with a patent foramen ovale. Exp Physiol 2020; 105:1648-1659. [PMID: 32627890 DOI: 10.1113/ep088750] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/30/2020] [Indexed: 01/07/2023]
Abstract
NEW FINDINGS What is the central question of this study? Do individuals with a patent foramen ovale (PFO+ ) have a larger alveolar-to-arterial difference in P O 2 ( A - a D O 2 ) than those without (PFO- ) and/or an exaggerated increase in pulmonary artery systolic pressure (PASP) in response to hypoxia? What is the main finding and its importance? PFO+ had a greater A - a D O 2 while breathing air, 16% and 14% O2 , but not 12% or 10% O2 . PASP increased equally in hypoxia between PFO+ and PFO- . These data suggest that PFO+ may not have an exaggerated acute increase in PASP in response to hypoxia. ABSTRACT Patent foramen ovale (PFO) is present in 30-40% of the population and is a potential source of right-to-left shunt. Accordingly, those with a PFO (PFO+ ) may have a larger alveolar-to-arterial difference in P O 2 ( A - a D O 2 ) than those without (PFO- ) in normoxia and with mild hypoxia. Likewise, PFO is associated with high-altitude pulmonary oedema, a condition known to have an exaggerated pulmonary pressure response to hypoxia. Thus, PFO+ may also have exaggerated pulmonary pressure increases in response to hypoxia. Therefore, the purposes of the present study were to systematically determine whether or not: (1) the A - a D O 2 was greater in PFO+ than in PFO- in normoxia and mild to severe hypoxia and (2) the increase in pulmonary artery systolic pressure (PASP) in response to hypoxia was greater in PFO+ than in PFO- . We measured arterial blood gases and PASP via ultrasound in healthy PFO+ (n = 15) and PFO- (n = 15) humans breathing air and 30 min after breathing four levels of hypoxia (16%, 14%, 12%, 10% O2 , randomized and balanced order) at rest. The A - a D O 2 was significantly greater in PFO+ compared to PFO- while breathing air (2.1 ± 0.7 vs. 0.4 ± 0.3 Torr), 16% O2 (1.8 ± 1.2 vs. 0.7 ± 0.8 Torr) and 14% O2 (2.3 ± 1.2 vs. 0.7 ± 0.6 Torr), but not 12% or 10% O2 . We found no effect of PFO on PASP at any level of hypoxia. We conclude that PFO influences pulmonary gas exchange efficiency with mild hypoxia, but not the acute increase in PASP in response to hypoxia.
Collapse
Affiliation(s)
- Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kara M Beasley
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Julia P Speros
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Jonathan E Elliott
- VA Portland Health Care System, Portland, OR, USA.,Department of Neurology, Oregon Health and Science University, Portland, OR, USA
| | - Steven S Laurie
- KBR, Cardiovascular and Vision Laboratory, NASA Johnson Space Center, Houston, TX, USA
| | | | - Eben Futral
- Oregon Heart and Vascular Institute, Springfield, OR, USA
| | - Jerold A Hawn
- Oregon Heart and Vascular Institute, Springfield, OR, USA
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| |
Collapse
|
16
|
Lichtblau M, Furian M, Aeschbacher SS, Bisang M, Sheraliev U, Mademilov M, Marazhapov NH, Ulrich S, Sooronbaev T, Bloch KE, Ulrich S. Right-to-left shunts in lowlanders with COPD traveling to altitude: a randomized controlled trial with dexamethasone. J Appl Physiol (1985) 2019; 128:117-126. [PMID: 31751183 DOI: 10.1152/japplphysiol.00548.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Right-to-left shunts (RLS) are prevalent in patients with chronic obstructive pulmonary disease (COPD) and might exaggerate oxygen desaturation, especially at altitude. The aim of this study was to describe the prevalence of RLS in patients with COPD traveling to altitude and the effect of preventive dexamethasone. Lowlanders with COPD [Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades 1-2, oxygen saturation assessed by pulse oximetry (SpO2) >92%] were randomized to dexamethasone (4 mg bid) or placebo starting 24 h before ascent from 760 m and while staying at 3,100 m for 48 h. Saline-contrast echocardiography was performed at 760 m and after the first night at altitude. Of 87 patients (81 men, 6 women; mean ± SD age 57 ± 9 yr, forced expiratory volume in 1 s 89 ± 22% pred, SpO2 95 ± 2%), 39 were assigned to placebo and 48 to dexamethasone. In the placebo group, 19 patients (49%) had RLS, of which 13 were intracardiac. In the dexamethasone group 23 patients (48%) had RLS, of which 11 were intracardiac (P = 1.0 vs. dexamethasone). Eleven patients receiving placebo and 13 receiving dexamethasone developed new RLS at altitude (P = 0.011 for both changes, P = 0.411 between groups). RLS prevalence at 3,100 m was 30 (77%) in the placebo and 36 (75%) in the dexamethasone group (P = not significant). Development of RLS at altitude could be predicted at lowland by a higher resting pulmonary artery pressure, a lower arterial partial pressure of oxygen, and a greater oxygen desaturation during exercise but not by treatment allocation. Almost half of lowlanders with COPD revealed RLS near sea level, and this proportion significantly increased to about three-fourths when traveling to 3,100 m irrespective of dexamethasone prophylaxis.NEW & NOTEWORTHY The prevalence of intracardiac and intrapulmonary right-to-left shunts (RLS) at altitude in patients with chronic obstructive pulmonary disease (COPD) has not been studied so far. In a large cohort of patients with moderate COPD, our randomized trial showed that the prevalence of RLS increased from 48% at 760 m to 75% at 3,100 m in patients taking placebo. Preventive treatment with dexamethasone did not significantly reduce the altitude-induced recruitment of RLS. Development of RLS at 3,100 m could be predicted at 760 m by a higher resting pulmonary artery pressure and arterial partial pressure of oxygen and a more pronounced oxygen desaturation during exercise. Dexamethasone did not modify the RLS prevalence at 3,100 m.
Collapse
Affiliation(s)
- Mona Lichtblau
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Michael Furian
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Sayaka S Aeschbacher
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Maya Bisang
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Ulan Sheraliev
- National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyzstan
| | - Maamed Mademilov
- National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyzstan
| | | | - Stefanie Ulrich
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Talant Sooronbaev
- National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyzstan
| | - Konrad E Bloch
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Pulmonary Division and Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| |
Collapse
|
17
|
Carter EA, Koch S, O'Donovan JP, Sheel AW, Milsom WK, Koehle MS. Perfusion of Intrapulmonary Arteriovenous Anastomoses Is Not Related to VO 2max in Hypoxia and Is Unchanged by Oral Sildenafil. High Alt Med Biol 2019; 20:399-406. [PMID: 31618060 DOI: 10.1089/ham.2019.0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Perfusion of intrapulmonary arteriovenous anastomoses (IPAVA) is increased during exercise and in hypoxia and is associated with variations in oxygen saturation (SPO2), resulting in blood bypassing the pulmonary microcirculation. Sildenafil is a pulmonary vasodilator that improves SPO2 and endurance performance in hypoxia. The purpose of this study was to determine if 50 mg sildenafil would reduce IPAVA perfusion (QIPAVA) and if the decrement in maximal exercise capacity (VO2max) in hypoxia is related to QIPAVA. We hypothesized that during progressive levels of hypoxia at rest (FIO2 = 0.21, 0.14, 0.12), sildenafil would increase SPO2 and reduce bubble score (estimate of QIPAVA) compared to placebo, and that the decrement in VO2max in hypoxia would be positively correlated with bubble score at rest in hypoxia. Materials and Methods: Fourteen endurance-trained men performed a graded maximal exercise test at sea level and at a simulated altitude of 3000 m, followed by two experimental visits where, after randomly ingesting sildenafil or placebo, they underwent agitated saline contrast echocardiography during progressive levels of hypoxia at rest. Results: All participants experienced a decrement in power output in hypoxia that ranged from 9% to 19% lower than sea level values. Compared to normoxia, bubble score increased significantly in hypoxia (p < 0.001) with no effect of sildenafil (p = 0.580). There was a negative correlation between SPO2 and bubble score (p < 0.001). The decrement in peak power output at VO2max in hypoxia was unrelated to IPAVA perfusion in resting hypoxia (p = 0.32). Several participants demonstrated QIPAVA greater than zero in room air, indicating that arterial hypoxemia may not be the sole mechanism for QIPAVA. Conclusion: These results indicate that the VO2max decrement caused by hypoxia is not related to QIPAVA and that sildenafil does not improve VO2max in hypoxia through modulation of QIPAVA.
Collapse
Affiliation(s)
- Eric A Carter
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Sarah Koch
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - James P O'Donovan
- Sports Medicine Department, Sports Surgery Clinic, Santry, Ireland.,Division of Sport and Exercise Medicine, Department of Family Practice, University of British Columbia, Vancouver, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Michael S Koehle
- School of Kinesiology, University of British Columbia, Vancouver, Canada.,Division of Sport and Exercise Medicine, Department of Family Practice, University of British Columbia, Vancouver, Canada
| |
Collapse
|
18
|
Corda A, Carta S, Varcasia A, Tamponi C, Evangelisti MA, Scala A, Pinna Parpaglia ML. Pulmonary arterial response to Angiostrongylus vasorum in naturally infected dogs: echocardiographic findings in two cases. Parasit Vectors 2019; 12:286. [PMID: 31164175 PMCID: PMC6549332 DOI: 10.1186/s13071-019-3544-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 05/29/2019] [Indexed: 12/21/2022] Open
Abstract
Background Angiostrongylus vasorum is a nematode living in the pulmonary arteries of canids. Infected dogs develop severe pulmonary lesions which can potentially lead to pulmonary hypertension (PH). However, reports of PH in natural infected dogs are scant. One of the possible causes of the low prevalence of PH in A. vasorum-infected dogs could be the establishment of large diameter intrapulmonary arteriovenous anastomoses (IPAVAs), which attenuate pulmonary vascular resistance, thus reducing the pulmonary arterial pressure. The present report describes the pulmonary arterial pressure (PAP) response to A. vasorum natural infection in two dogs, assessed by echocardiography and by the saline contrast echocardiographic test (SCE). Results Both dogs showed clinical signs of respiratory disease. At presentation, case 1 did not show echocardiographic signs of PH and the SCE test was positive proving the presence of IPAVAs. However, at the follow-up visit, despite A. vasorum infection resolution, the same dog showed PH and the SCE test resulted negative, which ruled out the presence of IPAVAs. Case 2 suffered from severe pulmonary arterial hypertension and right-side congestive heart failure since the day of presentation. Saline contrast echocardiography was negative both at the time of presentation and at the follow-up visit. Conclusions In the two cases described above, the PH was not associated with IPAVAs. During A. vasorum infection, IPAVAs recruitment mechanism is able to contrast the rise of PAP until a certain level. It probably represents an initial escape mechanism of PH that, over time, exhausts its compensatory capacities allowing PAP to rise and to be detectable on echocardiography. Electronic supplementary material The online version of this article (10.1186/s13071-019-3544-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Andrea Corda
- Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Sassari, Italy
| | - Silvia Carta
- Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Sassari, Italy
| | - Antonio Varcasia
- Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Sassari, Italy.
| | - Claudia Tamponi
- Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Sassari, Italy
| | | | - Antonio Scala
- Dipartimento di Medicina Veterinaria, Università degli Studi di Sassari, Sassari, Italy
| | | |
Collapse
|
19
|
Schipke JD, Lemaitre F, Cleveland S, Tetzlaff K. Effects of Breath-Hold Deep Diving on the Pulmonary System. Respiration 2019; 97:476-483. [PMID: 30783070 DOI: 10.1159/000495757] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/24/2018] [Indexed: 11/19/2022] Open
Abstract
This short review focuses on pulmonary injury in breath-hold (BH) divers. When practicing their extreme leisure sport, they are exposed to increased pressure on pulmonary gas volumes, hypoxia, and increased partial gas pressures. Increasing ambient pressures do present a serious problem to BH deep divers, because the semi-rigid thorax prevents the deformation required by the Boyle-Mariotte law. As a result, a negative-pressure barotrauma (lung squeeze) with acute hemoptysis is not uncommon. Respiratory maneuvers such as glossopharyngeal insufflation (GI) and glossopharyngeal exsufflation (GE) are practiced to prevent lung squeeze and to permit equalizing the paranasal sinuses and the middle ear. GI not only impairs venous return, thereby provoking hypotension and even fainting, but also produces intrathoracic pressures likely to induce pulmonary barotrauma that is speculated to induce long-term injury. GE, in turn, further increases the already negative intrapulmonary pressure, thereby favoring alveolar collapse (atelectasis). Finally, hypoxia seemingly not only induces brain injury but initiates the opening of intrapulmonary shunts. These pathways are large enough to permit transpulmonary passage of venous N2 bubbles, making stroke-like phenomena in deep BH divers possible.
Collapse
Affiliation(s)
- Jochen D Schipke
- Research Group Experimental Surgery, University Hospital Düsseldorf, Düsseldorf, Germany,
| | - Frederic Lemaitre
- UFR Sciences du Sport et de l'Éducation Physique, Université de Rouen, Mont-Saint-Aignan, France
| | - Sinclair Cleveland
- Institute of Neuro- and Sensory Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Kay Tetzlaff
- Department of Sports Medicine, Medical Clinic, Eberhard Karls University of Tübingen, Tübingen, Germany
| |
Collapse
|
20
|
Feng C, Luo T, Luo Y, Zhao N, Huang K, Xiao C. Contrast-enhanced transthoracic echocardiography applied in evaluation of pulmonary right-to-left shunt: A preliminary study. Comput Med Imaging Graph 2018; 68:55-60. [PMID: 30056290 DOI: 10.1016/j.compmedimag.2018.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/13/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To investigate the detection rate of patent foramen ovale-right to left shunt (PFO-RLS) and/or pulmonary-right to left shunt (P-RLS) via contrast-enhanced transthoracic echocardiography (c-TTE) in healthy participants, patients suffering from cryptogenic stroke and migraine with aura. METHODS Initially, 20 healthy volunteers, 21 cases with cryptogenic stroke, and 18 cases with migraine aura were randomly selected, and all of them received c-TTE and transesophageal echocardiography (TEE) examinations. First of all, 0.9% sodium chloride solution was rapidly injected into upper extremiry vein, when these volunteers and patients were at rest or following a Valsalva maneuver with 40 mm Hg pressure exerted against a manometer. Secondly, c-TTE detection was carried out in order to distinguish PFO-RLS and P-RLS and make semi-quantitative classification of RLS from many different sources, according to the occurrence and duration time of microvesicles in left atrial after the developing of left atrium. In terms of c-TTE analyses, RLS could be diagnosed when micro bubbles were visualized in transition from the right atrium to the left atrium. Particularly, a small amounts of RLS was 1 level, indicating 1-10 microvesicles per frame could be seen in left atrium, moderate amounts of RLS was 2 level, indicating 11-30 microvesicles per frame could be seen in left atrium, and a large amounts of RLS was 3 level, indicating more than 30 microvesicles per frame, or the left atrium is filled with micro vesicles. RESULTS A total of 20 healthy adult volunteers were identified into this research. RLS was detected in 7 cases, according to c-TTE method (7/20, 35%). In detail, 3 participants suffered from PFO-RLS and P-RSL (3/20, 15%) simultaneously, 5 cases suffered from PFO-RLS (5/20, 25%), and 5 cases suffered from P-RLS (5/20, 25%). Among 21 patients with cryptogenic stroke, RLS was detected in 14 cases, according to cTTE method (14/20, 67%), and then compared with healthy participants group, the difference between them was significant (χ2 = 4.11, P = 0.04). Specifically, 2 participants suffered from PFO-RLS and P-RSL (2/21, 9.5%), 11 cases suffered from PFO-RLS (11/21, 52.4%), and 5 cases suffered from P-RLS (5/21, 23.8%). Among 21 patients suffering from migraine with aura, RLS was detected in 13 cases, according to c-TTE method (13/18, 72%), and then compared with healthy participants group, the difference of detection rate between them was significant (χ2 = 5.2, P = 0.02). In detail, 3 participants suffered from PFO-RLS and P-RSL (3/18, 16.7%), 8 cases suffered from PFO-RLS (8/18, 44.4%), and 8 cases suffered from P-RLS (8/18, 44.4%). In addition, the grading of PFO-RLS in patients suffering from cryptogenic stroke and migraine with aura was mostly grade 2-grade 3. On the contrary, the grading of PFO-RLS in healthy adult volunteers was mostly grade 1-2. Besides, the semi-quantitative grading of P-RLS in each group was mostly grade 1 to grade 2, and difference between healthy volunteer group and cryptogenic stroke group was significant (Z = -2.77, P = 0.006). CONCLUSION P-RLS with lower semiquantitative grade is common in healthy individuals, patients with cryptogenic stroke and migraine aura. And P-RLS can be considered as a significant influencing factor in the pathogenesis of migraine with aura.
Collapse
Affiliation(s)
- Cheng Feng
- Department of Ultrasound, The Third People's Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| | - Tingting Luo
- Department of Ultrasound, The Third People's Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| | - Yongfang Luo
- Department of Ultrasound, The Third People's Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| | - Ningbo Zhao
- Department of Ultrasound, The Third People's Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| | - Kun Huang
- Department of Ultrasound, The Third People's Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| | - Chang Xiao
- Department of Ultrasound, The Third People's Hospital of Shenzhen, Shenzhen, 518116, Guangdong, China.
| |
Collapse
|
21
|
Petrassi FA, Davis JT, Beasley KM, Evero O, Elliott JE, Goodman RD, Futral JE, Subudhi A, Solano-Altamirano JM, Goldman S, Roach RC, Lovering AT. AltitudeOmics: effect of reduced barometric pressure on detection of intrapulmonary shunt, pulmonary gas exchange efficiency, and total pulmonary resistance. J Appl Physiol (1985) 2018; 124:1363-1376. [PMID: 29357511 PMCID: PMC6008081 DOI: 10.1152/japplphysiol.00474.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 12/06/2017] [Accepted: 12/10/2017] [Indexed: 11/22/2022] Open
Abstract
Blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA) occurs in healthy humans at rest and during exercise when breathing hypoxic gas mixtures at sea level and may be a source of right-to-left shunt. However, at high altitudes, QIPAVA is reduced compared with sea level, as detected using transthoracic saline contrast echocardiography (TTSCE). It remains unknown whether the reduction in QIPAVA (i.e., lower bubble scores) at high altitude is due to a reduction in bubble stability resulting from the lower barometric pressure (PB) or represents an actual reduction in QIPAVA. To this end, QIPAVA, pulmonary artery systolic pressure (PASP), cardiac output (QT), and the alveolar-to-arterial oxygen difference (AaDO2) were assessed at rest and during exercise (70-190 W) in the field (5,260 m) and in the laboratory (1,668 m) during four conditions: normobaric normoxia (NN; [Formula: see text] = 121 mmHg, PB = 625 mmHg; n = 8), normobaric hypoxia (NH; [Formula: see text] = 76 mmHg, PB = 625 mmHg; n = 7), hypobaric normoxia (HN; [Formula: see text] = 121 mmHg, PB = 410 mmHg; n = 8), and hypobaric hypoxia (HH; [Formula: see text] = 75 mmHg, PB = 410 mmHg; n = 7). We hypothesized QIPAVA would be reduced during exercise in isooxic hypobaria compared with normobaria and that the AaDO2 would be reduced in isooxic hypobaria compared with normobaria. Bubble scores were greater in normobaric conditions, but the AaDO2 was similar in both isooxic hypobaria and normobaria. Total pulmonary resistance (PASP/QT) was elevated in HN and HH. Using mathematical modeling, we found no effect of hypobaria on bubble dissolution time within the pulmonary transit times under consideration (<5 s). Consequently, our data suggest an effect of hypobaria alone on pulmonary blood flow. NEW & NOTEWORTHY Blood flow through intrapulmonary arteriovenous anastomoses, detected by transthoracic saline contrast echocardiography, was reduced during exercise in acute hypobaria compared with normobaria, independent of oxygen tension, whereas pulmonary gas exchange efficiency was unaffected. Modeling the effect(s) of reduced air density on contrast bubble lifetime did not result in a significantly reduced contrast stability. Interestingly, total pulmonary resistance was increased by hypobaria, independent of oxygen tension, suggesting that pulmonary blood flow may be changed by hypobaria.
Collapse
Affiliation(s)
- Frank A Petrassi
- Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute, Indiana
| | - James T Davis
- Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute, Indiana
| | - Kara M Beasley
- Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute, Indiana
| | - Oghenero Evero
- Altitude Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus , Denver, Colorado
| | - Jonathan E Elliott
- Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute, Indiana
| | - Randall D Goodman
- Oregon Heart and Vascular Institute, Echocardiography, Springfield, Oregon
| | - Joel E Futral
- Oregon Heart and Vascular Institute, Echocardiography, Springfield, Oregon
| | - Andrew Subudhi
- Altitude Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus , Denver, Colorado
| | | | - Saul Goldman
- Department of Chemistry, University of Guelph , Guelph, Ontario , Canada
| | - Robert C Roach
- Altitude Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus , Denver, Colorado
| | - Andrew T Lovering
- Department of Kinesiology, Recreation, and Sport, Indiana State University, Terre Haute, Indiana
| |
Collapse
|
22
|
Brugniaux JV, Coombs GB, Barak OF, Dujic Z, Sekhon MS, Ainslie PN. Highs and lows of hyperoxia: physiological, performance, and clinical aspects. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1-R27. [PMID: 29488785 DOI: 10.1152/ajpregu.00165.2017] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Molecular oxygen (O2) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content ([Formula: see text]), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds, including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e.g., brain ischemia, traumatic brain injury, carbon monoxide poisoning, etc.) and chronic hypoxemia (e.g., severe COPD, etc.) and to help with wound healing, necrosis, or reperfusion injuries (e.g., compromised grafts). Hyperoxia has also been used liberally by athletes in a belief that it offers performance-enhancing benefits; such benefits also extend to hypoxemic patients both at rest and during rehabilitation. This review aims to provide a comprehensive overview of the effects of hyperoxia in humans from the "bench to bedside." The first section will focus on the basic physiological principles of partial pressure of arterial O2, [Formula: see text], and barometric pressure and how these changes lead to variation in regional O2 delivery. This review provides an overview of the evidence for and against the use of hyperoxia as an aid to enhance physical performance. The final section addresses pathophysiological concepts, clinical studies, and implications for therapy. The potential of O2 toxicity and future research directions are also considered.
Collapse
Affiliation(s)
| | - Geoff B Coombs
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| | - Otto F Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.,Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Zeljko Dujic
- Department of Integrative Physiology, School of Medicine, University of Split , Split , Croatia
| | - Mypinder S Sekhon
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada.,Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia , Vancouver, British Columbia , Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| |
Collapse
|
23
|
Norris HC, Mangum TS, Kern JP, Elliott JE, Beasley KM, Goodman RD, Mladinov S, Barak OF, Bakovic D, Dujic Z, Lovering AT. Intrapulmonary arteriovenous anastomoses in humans with chronic obstructive pulmonary disease: implications for cryptogenic stroke? Exp Physiol 2018; 101:1128-42. [PMID: 27339093 DOI: 10.1113/ep085811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/20/2016] [Indexed: 12/13/2022]
Abstract
What is the central question of this study? Do individuals with chronic obstructive pulmonary disease have blood flow through intrapulmonary arteriovenous anastomoses at rest or during exercise? What is the main finding and its importance? Individuals with chronic obstructive pulmonary disease have a greater prevalence of blood flow through intrapulmonary arteriovenous anastomoses at rest than age-matched control subjects. Given that the intrapulmonary arteriovenous anastomoses are large enough to permit venous emboli to pass into the arterial circulation, patients with chronic obstructive pulmonary disease and an elevated risk of thrombus formation may be at risk of intrapulmonary arteriovenous anastomosis-facilitated embolic injury (e.g. stroke or transient ischaemic attack). The pulmonary capillaries prevent stroke by filtering venous emboli from the circulation. Intrapulmonary arteriovenous anastomoses are large-diameter (≥50 μm) vascular connections in the lung that may compromise the integrity of the pulmonary capillary filter and have recently been linked to cryptogenic stroke and transient ischaemic attack. Prothrombotic populations, such as individuals with chronic obstructive pulmonary disease (COPD), may be at increased risk of stroke and transient ischaemic attack facilitated by intrapulmonary arteriovenous anastomoses, but the prevalence and degree of blood flow through intrapulmonary arteriovenous anastomoses in this population has not been fully examined and compared with age-matched healthy control subjects. We used saline contrast echocardiography to assess blood flow through intrapulmonary arteriovenous anastomoses at rest (n = 29 COPD and 19 control subjects) and during exercise (n = 10 COPD and 10 control subjects) in subjects with COPD and age-matched healthy control subjects. Blood flow through intrapulmonary arteriovenous anastomoses was detected in 23% of subjects with COPD at rest and was significantly higher compared with age-matched healthy control subjects. Blood flow through intrapulmonary arteriovenous anastomoses at rest was reduced or eliminated in subjects with COPD after breathing hyperoxic gas. Sixty per cent of subjects with COPD who did not have blood flow through the intrapulmonary arteriovenous anastomoses at rest had blood flow through them during exercise. The combination of blood flow through intrapulmonary arteriovenous anastomoses and potential for thrombus formation in individuals with COPD may permit venous emboli to pass into the arterial circulation and cause stroke and transient ischaemic attack. Breathing supplemental oxygen may reduce this risk in COPD. The link between blood flow through intrapulmonary arteriovenous anastomoses, stroke and transient ischaemic attack is worthy of future investigation in COPD and other populations.
Collapse
Affiliation(s)
- H Cameron Norris
- Department of Human Physiology, University of Oregon, Eugene, OR, UK
| | - Tyler S Mangum
- Department of Human Physiology, University of Oregon, Eugene, OR, UK
| | - Julia P Kern
- Department of Human Physiology, University of Oregon, Eugene, OR, UK
| | | | - Kara M Beasley
- Department of Human Physiology, University of Oregon, Eugene, OR, UK
| | | | - Suzana Mladinov
- Clinical Department for Pulmonary Diseases, University Hospital Center Split, Split, Croatia
| | - Otto F Barak
- Department of Physiology, University of Novi Sad, Novi Sad, Serbia
| | - Darija Bakovic
- Division of Cardiology, Department of Internal Medicine, University Hospital Center Split, Split, Croatia.,Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, UK
| |
Collapse
|
24
|
Duke JW, Elliott JE, Laurie SS, Voelkel T, Gladstone IM, Fish MB, Lovering AT. Bubble and macroaggregate methods differ in detection of blood flow through intrapulmonary arteriovenous anastomoses in upright and supine hypoxia in humans. J Appl Physiol (1985) 2017; 123:1592-1598. [PMID: 28970204 DOI: 10.1152/japplphysiol.00673.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) increases in healthy humans breathing hypoxic gas and is potentially dependent on body position. Previous work in subjects breathing room air has shown an effect of body position when Q̇IPAVA is detected with transthoracic saline contrast echocardiography (TTSCE). However, the potential effect of body position on Q̇IPAVA has not been investigated when subjects are breathing hypoxic gas or with a technique capable of quantifying Q̇IPAVA. Thus the purpose of this study was to quantify the effect of body position on Q̇IPAVA when breathing normoxic and hypoxic gas at rest. We studied Q̇IPAVA with TTSCE and quantified Q̇IPAVA with filtered technetium-99m-labeled macroaggregates of albumin (99mTc-MAA) in seven healthy men breathing normoxic and hypoxic (12% O2) gas at rest while supine and upright. On the basis of previous work using TTSCE, we hypothesized that the quantified Q̇IPAVA would be greatest with hypoxia in the supine position. We found that Q̇IPAVA quantified with 99mTc-MAA significantly increased while subjects breathed hypoxic gas in both supine and upright body positions (ΔQ̇IPAVA = 0.7 ± 0.4 vs. 2.5 ± 1.1% of cardiac output, respectively). Q̇IPAVA detected with TTSCE increased from normoxia in supine hypoxia but not in upright hypoxia (median hypoxia bubble score of 2 vs. 0, respectively). Surprisingly, Q̇IPAVA magnitude was greatest in upright hypoxia, when Q̇IPAVA was undetectable with TTSCE. These findings suggest that the relationship between TTSCE and 99mTc-MAA is more complex than previously appreciated, perhaps because of the different physical properties of bubbles and MAA in solution. NEW & NOTEWORTHY Using saline contrast bubbles and radiolabeled macroaggregrates (MAA), we detected and quantified, respectively, hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) in supine and upright body positions in healthy men. Upright hypoxia resulted in the largest magnitude of Q̇IPAVA quantified with MAA but the lowest Q̇IPAVA detected with saline contrast bubbles. These surprising results suggest that the differences in physical properties between saline contrast bubbles and MAA in blood may affect their behavior in vivo.
Collapse
Affiliation(s)
- Joseph W Duke
- Department of Biological Sciences, Northern Arizona University , Flagstaff, Arizona
| | | | | | - Thomas Voelkel
- Department of Nuclear Medicine, Sacred Heart Medical Center , Springfield, Oregon
| | - Igor M Gladstone
- Department of Pediatrics, Oregon Health and Sciences University , Portland, Oregon
| | - Mathews B Fish
- Department of Nuclear Medicine, Sacred Heart Medical Center , Springfield, Oregon
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon , Eugene, Oregon
| |
Collapse
|
25
|
Duke JW, Elliott JE, Laurie SS, Voelkel T, Gladstone IM, Fish MB, Lovering AT. Relationship between quantitative and descriptive methods of studying blood flow through intrapulmonary arteriovenous anastomoses during exercise. Respir Physiol Neurobiol 2017; 243:47-54. [PMID: 28536067 DOI: 10.1016/j.resp.2017.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 10/19/2022]
Abstract
Several methods exist to study intrapulmonary arteriovenous anastomoses (IPAVA) in humans. Transthoracic saline contrast echocardiography (TTSCE), i.e., bubble scores, is minimally-invasive, but cannot be used to quantify the magnitude of blood flow through IPAVA (QIPAVA). Radiolabeled macroaggregates of albumin (99mTc-MAA) have been used to quantify QIPAVA in humans, but this requires injection of radioactive particles. Previous work has shown agreement between 99mTc-MAA and TTSCE, but this has not been tested simultaneously in the same group of subjects. Thus, the purpose of this study was to determine if there was a relationship between QIPAVA quantified with 99mTc-MAA and bubble scores obtained with TTSCE. To test this, we used 99mTc-MAA and TTSCE to quantify and detect QIPAVA at rest and during exercise in humans. QIPAVA significantly increased from rest to exercise using 99mTc-MAA and TTSCE and there was a moderately-strong, but significant relationship between methods. Our data suggest that high bubble scores generally correspond with large QIPAVA quantified with 99mTc-MAA during exercise.
Collapse
Affiliation(s)
- Joseph W Duke
- Northern Arizona University, Department of Biological Sciences, Flagstaff, AZ, USA.
| | | | | | - Thomas Voelkel
- Sacred Heart Medical Center, Department of Nuclear Medicine, Springfield, OR, USA
| | - Igor M Gladstone
- Oregon Health and Sciences University, Department of Pediatrics, Portland, OR, USA
| | - Mathews B Fish
- Sacred Heart Medical Center, Department of Nuclear Medicine, Springfield, OR, USA
| | - Andrew T Lovering
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| |
Collapse
|
26
|
Boulet LM, Lovering AT, Tymko MM, Day TA, Stembridge M, Nguyen TA, Ainslie PN, Foster GE. Reduced blood flow through intrapulmonary arteriovenous anastomoses during exercise in lowlanders acclimatizing to high altitude. Exp Physiol 2017; 102:670-683. [PMID: 28370674 DOI: 10.1113/ep086182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/27/2017] [Indexed: 12/13/2022]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to determine, using the technique of agitated saline contrast echocardiography, whether exercise after 4-7 days at 5050 m would affect blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) compared with exercise at sea level. What is the main finding and its importance? Despite a significant increase in both cardiac output and pulmonary pressure during exercise at high altitude, there is very little Q̇IPAVA at rest or during exercise after 4-7 days of acclimatization. Mathematical modelling suggests that bubble instability at high altitude is an unlikely explanation for the reduced Q̇IPAVA. Blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) is elevated during exercise at sea level (SL) and at rest in acute normobaric hypoxia. After high altitude (HA) acclimatization, resting Q̇IPAVA is similar to that at SL, but it is unknown whether this is true during exercise at HA. We reasoned that exercise at HA (5050 m) would exacerbate Q̇IPAVA as a result of heightened pulmonary arterial pressure. Using a supine cycle ergometer, seven healthy adults free from intracardiac shunts underwent an incremental exercise test at SL [25, 50 and 75% of SL peak oxygen consumption (V̇O2 peak )] and at HA (25 and 50% of SL V̇O2 peak ). Echocardiography was used to determine cardiac output (Q̇) and pulmonary artery systolic pressure (PASP), and agitated saline contrast was used to determine Q̇IPAVA (bubble score; 0-5). The principal findings were as follows: (i) Q̇ was similar at SL rest (3.9 ± 0.47 l min-1 ) compared with HA rest (4.5 ± 0.49 l min-1 ; P = 0.382), but increased from rest during both SL and HA exercise (P < 0.001); (ii) PASP increased from SL rest (19.2 ± 0.7 mmHg) to HA rest (33.7 ± 2.8 mmHg; P = 0.001) and, compared with SL, PASP was further elevated during HA exercise (P = 0.003); (iii) Q̇IPAVA was increased from SL rest (0) to HA rest (median = 1; P = 0.04) and increased from resting values during SL exercise (P < 0.05), but was unchanged during HA exercise (P = 0.91), despite significant increases in Q̇ and PASP. Theoretical modelling of microbubble dissolution suggests that the lack of Q̇IPAVA in response to exercise at HA is unlikely to be caused by saline contrast instability.
Collapse
Affiliation(s)
- Lindsey M Boulet
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Michael M Tymko
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Mike Stembridge
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UK
| | - Trang Anh Nguyen
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada.,Department of Biomedical Engineering, International University, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Philip N Ainslie
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| |
Collapse
|
27
|
Bates ML, Jacobson JE, Eldridge MW. Beta Adrenergic Regulation of Intrapulmonary Arteriovenous Anastomoses in Intact Rat and Isolated Rat Lungs. Front Physiol 2017; 8:218. [PMID: 28469578 PMCID: PMC5396286 DOI: 10.3389/fphys.2017.00218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/27/2017] [Indexed: 11/18/2022] Open
Abstract
Intrapulmonary arteriovenous anastomoses (IPAVA) allow large diameter particles of venous origin to bypass the pulmonary capillary bed and embolize the systemic arterial circulation. IPAVA have been routinely observed in healthy humans with exercise, hypoxia, and catecholamine infusion, but the mechanism by which they are recruited is not well-defined. We hypothesized that beta-adrenergic receptor stimulation recruits IPAVA and that receptor blockade would limit hypoxia-induced IPAVA recruitment. To test our hypothesis, we evaluated the transpulmonary passage of microspheres in intact rats and isolated rats lung infused with the beta-adrenergic receptor agonist isoproterenol. We also evaluated IPAVA recruitment in intact rats with hypoxia and the beta-adrenergic receptor blocker propranolol. We found that IPAVA are recruited in the intact rat by isoproterenol and their recruitment by hypoxia can be minimized by propranolol, suggesting a role for the adrenergic system in the recruitment of IPAVA by hypoxia. IPAVA recruitment is completely abolished by ventilation with 100% oxygen. Isoproterenol also recruits IPAVA in isolated rat lungs. The fact that isoproterenol can recruit IPAVA in isolated lungs, without increased pulmonary flow, suggests that elevated cardiac output is not required for IPAVA recruitment.
Collapse
Affiliation(s)
- Melissa L Bates
- Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, Department of Pediatrics, University of IowaIowa City, IA, USA.,Department of Health and Human Physiology, University of IowaIowa City, IA, USA
| | - Joseph E Jacobson
- Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, Department of Pediatrics, University of IowaIowa City, IA, USA.,Michigan State University College of Human MedicineEast Lansing, MI, USA
| | - Marlowe W Eldridge
- Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, Department of Pediatrics, University of IowaIowa City, IA, USA.,Departments of Biomedical Engineering and Kinesiology, University of WisconsinMadison, WI, USA
| |
Collapse
|
28
|
Romac R, Barak O, Glavas D, Susilovic Grabovac Z, Lozo P, Roje I, Caljkusic K, Drmic-Hofman I, Davis JT, Dujic Z, Lovering AT. Characterization of blood flow through intrapulmonary arteriovenous anastomoses and patent foramen ovale at rest and during exercise in stroke and transient ischemic attack patients. Echocardiography 2017; 34:676-682. [DOI: 10.1111/echo.13519] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Rinaldo Romac
- Department of Neurology; University Hospital Center Split; Split Croatia
| | - Otto Barak
- Department of Integrative Physiology; University of Split School of Medicine; Split Croatia
- Faculty of Medicine; University of Novi Sad; Novi Sad Serbia
| | - Duska Glavas
- Division of Cardiology; Department of Internal Medicine; University Hospital Center Split; Split Croatia
| | - Zora Susilovic Grabovac
- Division of Cardiology; Department of Internal Medicine; University Hospital Center Split; Split Croatia
| | - Petar Lozo
- Division of Cardiology; Department of Internal Medicine; University Hospital Center Split; Split Croatia
| | - Igor Roje
- Department of Neurology; University Hospital Center Split; Split Croatia
| | - Kresimir Caljkusic
- Department of Anesthesiology; University Hospital Center Split; Split Croatia
| | - Irena Drmic-Hofman
- Department of Pathology, Forensic Medicine and Cytology; University Hospital Center Split; Split Croatia
- Department of Medical Chemistry and Biochemistry; University of Split School of Medicine; Split Croatia
| | - James T. Davis
- Department of Kinesiology, Recreation and Sport; Indiana State University; Terre Haute IN USA
| | - Zeljko Dujic
- Department of Integrative Physiology; University of Split School of Medicine; Split Croatia
| | | |
Collapse
|
29
|
Aoki T, Sugimura K, Nochioka K, Miura M, Tatebe S, Yamamoto S, Yaoita N, Suzuki H, Sato H, Kozu K, Miyata S, Satoh K, Shimokawa H. Effects of Balloon Pulmonary Angioplasty on Oxygenation in Patients With Chronic Thromboembolic Pulmonary Hypertension - Importance of Intrapulmonary Shunt. Circ J 2016; 80:2227-34. [PMID: 27581344 DOI: 10.1253/circj.cj-16-0254] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Although balloon pulmonary angioplasty (BPA) improves the hemodynamics and prognosis of patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH), the mechanisms of improvement in oxygenation remain to be elucidated. METHODS AND RESULTS From August 2013 to May 2015, we performed a total of 113 BPA procedures in 24 patients with inoperable CTEPH (mean 4.7 procedures per patient). Median age was 70 [60, 74] years and 18 were female (75%). We examined hemodynamics, respiratory functions, and intrapulmonary shunt before and after the BPA procedure. Mean pulmonary arterial pressure (37 [28, 45] to 23[19, 27] mmHg, P<0.01), pulmonary vascular resistance (517 [389, 696] to 268 [239, 345] dyne/s/cm(5)) and 6-min walk distance (390 [286, 484] to 490 [411, 617] m, P<0.01) were significantly improved after BPA therapy. Furthermore, arterial oxygen partial pressure (PaO2, 54.8 [50.0, 60.8] to 65.2 [60.6, 73.2] %, P<0.01) and intrapulmonary shunt (23.4±6.0% to 19.3±5.0%, P<0.01) were also significantly ameliorated. In the multivariate analysis, decrease in intrapulmonary shunt after BPA was significantly correlated with improvement of both PaO2(r(2)=0.26, P<0.01) and SaO2(r(2)=0.49, P<0.01) after BPA. CONCLUSIONS These results indicated that BPA improved not only pulmonary hemodynamics but also oxygenation with a resultant decrease in intrapulmonary shunt. (Circ J 2016; 80: 2227-2234).
Collapse
Affiliation(s)
- Tatsuo Aoki
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Hackett HK, Boulet LM, Dominelli PB, Foster GE. A methodological approach for quantifying and characterizing the stability of agitated saline contrast: implications for quantifying intrapulmonary shunt. J Appl Physiol (1985) 2016; 121:568-76. [PMID: 27365283 DOI: 10.1152/japplphysiol.00422.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/27/2016] [Indexed: 12/26/2022] Open
Abstract
Agitated saline contrast echocardiography is often used to determine blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA). We applied indicator dilution theory to time-acoustic intensity curves obtained from a bolus injection of hand-agitated saline contrast to acquire a quantitative index of contrast mass. Using this methodology and an in vitro model of the pulmonary circulation, the purpose of this study was to determine the effect of transit time and gas composition [air vs. sulphur hexafluoride (SF6)] on contrast conservation between two detection sites separated by a convoluted network of vessels. We hypothesized that the contrast lost between the detection sites would increase with transit times and be reduced by using contrast bubbles composed of SF6 Changing the flow and/or reducing the volume of the circulatory network manipulated transit time. Contrast conservation was measured as the ratio of outflow and inflow contrast masses. For air, 53.2 ± 3.4% (SE) of contrast was conserved at a transit time of 9.25 ± 0.02 s but dropped to 16.0 ± 1.0% at a transit time of 10.17 ± 0.06 s. Compared with air, SF6 contrast conservation was significantly greater (P < 0.05) with 114.3 ± 2.9% and 73.7 ± 3.3% of contrast conserved at a transit time of 10.39 ± 0.02 s and 13.46 ± 0.04 s, respectively. In summary, time-acoustic intensity curves can quantify agitated saline contrast, but loss of contrast due to bubble dissolution makes measuring Q̇IPAVA across varying transit time difficult. Agitated saline composed of SF6 is stabilized and may be a suitable alternative for Q̇IPAVA measurement.
Collapse
Affiliation(s)
- Heather K Hackett
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada; and
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada; and
| | - Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada; and
| |
Collapse
|
31
|
Duke JW, Davis JT, Ryan BJ, Elliott JE, Beasley KM, Hawn JA, Byrnes WC, Lovering AT. Decreased arterial PO2, not O2 content, increases blood flow through intrapulmonary arteriovenous anastomoses at rest. J Physiol 2016; 594:4981-96. [PMID: 27062157 DOI: 10.1113/jp272211] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/23/2016] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS The mechanism(s) that regulate hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) are currently unknown. Our previous work has demonstrated that the mechanism of hypoxia-induced QIPAVA is not simply increased cardiac output, pulmonary artery systolic pressure or sympathetic nervous system activity and, instead, it may be a result of hypoxaemia directly. To determine whether it is reduced arterial PO2 (PaO2) or O2 content (CaO2) that causes hypoxia-induced QIPAVA , individuals were instructed to breathe room air and three levels of hypoxic gas at rest before (control) and after CaO2 was reduced by 10% by lowering the haemoglobin concentration (isovolaemic haemodilution; Low [Hb]). QIPAVA , assessed by transthoracic saline contrast echocardiography, significantly increased as PaO2 decreased and, despite reduced CaO2 (via isovolaemic haemodilution), was similar at iso-PaO2. These data suggest that, with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA , although where and how this is detected remains unknown. ABSTRACT Alveolar hypoxia causes increased blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) in healthy humans at rest. However, it is unknown whether the stimulus regulating hypoxia-induced QIPAVA is decreased arterial PO2 (PaO2) or O2 content (CaO2). CaO2 is known to regulate blood flow in the systemic circulation and it is suggested that IPAVA may be regulated similar to the systemic vasculature. Thus, we hypothesized that reduced CaO2 would be the stimulus for hypoxia-induced QIPAVA . Blood volume (BV) was measured using the optimized carbon monoxide rebreathing method in 10 individuals. Less than 5 days later, subjects breathed room air, as well as 18%, 14% and 12.5% O2 , for 30 min each, in a randomized order, before (CON) and after isovolaemic haemodilution (10% of BV withdrawn and replaced with an equal volume of 5% human serum albumin-saline mixture) to reduce [Hb] (Low [Hb]). PaO2 was measured at the end of each condition and QIPAVA was assessed using transthoracic saline contrast echocardiography. [Hb] was reduced from 14.2 ± 0.8 to 12.8 ± 0.7 g dl(-1) (10 ± 2% reduction) from CON to Low [Hb] conditions. PaO2 was no different between CON and Low [Hb], although CaO2 was 10.4%, 9.2% and 9.8% lower at 18%, 14% and 12.5% O2 , respectively. QIPAVA significantly increased as PaO2 decreased and, despite reduced CaO2, was similar at iso-PaO2. These data suggest that, with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA . Whether the low PO2 is detected at the carotid body, airway and/or the vasculature remains unknown.
Collapse
Affiliation(s)
- Joseph W Duke
- Ohio University, Division of Exercise Physiology, Athens, OH, USA
| | - James T Davis
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Benjamin J Ryan
- University of Colorado at Boulder, Department of Integrative Physiology, Boulder, CO, USA
| | | | - Kara M Beasley
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Jerold A Hawn
- Oregon Heart and Vascular Institute, Springfield, OR, USA
| | - William C Byrnes
- University of Colorado at Boulder, Department of Integrative Physiology, Boulder, CO, USA
| | - Andrew T Lovering
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| |
Collapse
|
32
|
Novo Matos J, Malbon A, Dennler M, Glaus T. Intrapulmonary arteriovenous anastomoses in dogs with severe Angiostrongylus vasorum infection: clinical, radiographic, and echocardiographic evaluation. J Vet Cardiol 2016; 18:110-24. [DOI: 10.1016/j.jvc.2015.10.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 10/08/2015] [Accepted: 10/14/2015] [Indexed: 11/25/2022]
|
33
|
Lovering AT, Lozo M, Barak O, Davis JT, Lojpur M, Lozo P, Čaljkušić K, Dujić Ž. Resting arterial hypoxaemia in subjects with chronic heart failure, pulmonary hypertension and patent foramen ovale. Exp Physiol 2016; 101:657-70. [DOI: 10.1113/ep085657] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/14/2016] [Indexed: 01/09/2023]
Affiliation(s)
| | - Mislav Lozo
- Department of Cardiology; University Hospital Centre Split; Split Croatia
| | - Otto Barak
- Department of Integrative Physiology; University of Split, School of Medicine; Split Croatia
- Department of Physiology; University of Novi Sad; Novi Sad Serbia
| | - James T. Davis
- Department of Human Physiology; University of Oregon; Eugene OR USA
| | - Mihajlo Lojpur
- Department of Anesthesiology; University Hospital Centre Split; Split Croatia
| | - Petar Lozo
- Department of Cardiology; University Hospital Centre Split; Split Croatia
| | - Krešimir Čaljkušić
- Department of Neurology; University Hospital Centre Split; Split Croatia
| | - Željko Dujić
- Department of Integrative Physiology; University of Split, School of Medicine; Split Croatia
| |
Collapse
|
34
|
Schipke JD, Tetzlaff K. Why predominantly neurological decompression sickness in breath-hold divers? J Appl Physiol (1985) 2016; 120:1474-7. [PMID: 26796755 DOI: 10.1152/japplphysiol.00840.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/20/2016] [Indexed: 11/22/2022] Open
Affiliation(s)
- J D Schipke
- Research Group Experimental Surgery, University Hospital Düsseldorf, Düsseldorf Germany; and
| | - K Tetzlaff
- Sportmedizin Tübingen Universitätsklinikum Tübingen, Tübingen, Germany
| |
Collapse
|
35
|
Tymko MM, Hoiland RL, Kuca T, Boulet LM, Tremblay JC, Pinske BK, Williams AM, Foster GE. Measuring the human ventilatory and cerebral blood flow response to CO2: a technical consideration for the end-tidal-to-arterial gas gradient. J Appl Physiol (1985) 2016; 120:282-96. [DOI: 10.1152/japplphysiol.00787.2015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 10/19/2015] [Indexed: 11/22/2022] Open
Abstract
Our aim was to quantify the end-tidal-to-arterial gas gradients for O2 (PET-PaO2) and CO2 (Pa-PETCO2) during a CO2 reactivity test to determine their influence on the cerebrovascular (CVR) and ventilatory (HCVR) response in subjects with (PFO+, n = 8) and without (PFO−, n = 7) a patent foramen ovale (PFO). We hypothesized that 1) the Pa-PETCO2 would be greater in hypoxia compared with normoxia, 2) the Pa-PETCO2 would be similar, whereas the PET-PaO2 gradient would be greater in those with a PFO, 3) the HCVR and CVR would be underestimated when plotted against PETCO2 compared with PaCO2, and 4) previously derived prediction algorithms will accurately target PaCO2. PETCO2 was controlled by dynamic end-tidal forcing in steady-state steps of −8, −4, 0, +4, and +8 mmHg from baseline in normoxia and hypoxia. Minute ventilation (V̇E), internal carotid artery blood flow (Q̇ICA), middle cerebral artery blood velocity (MCAv), and temperature corrected end-tidal and arterial blood gases were measured throughout experimentation. HCVR and CVR were calculated using linear regression analysis by indexing V̇E and relative changes in Q̇ICA, and MCAv against PETCO2, predicted PaCO2, and measured PaCO2. The Pa-PETCO2 was similar between hypoxia and normoxia and PFO+ and PFO−. The PET-PaO2 was greater in PFO+ by 2.1 mmHg during normoxia ( P = 0.003). HCVR and CVR plotted against PETCO2 underestimated HCVR and CVR indexed against PaCO2 in normoxia and hypoxia. Our PaCO2 prediction equation modestly improved estimates of HCVR and CVR. In summary, care must be taken when indexing reactivity measures to PETCO2 compared with PaCO2.
Collapse
Affiliation(s)
- Michael M. Tymko
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Ryan L. Hoiland
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Tomas Kuca
- Department of Anesthesia, Pain and Perioperative Medicine, Department of Critical Care Medicine, Dalhousie University, Halifax, Canada
| | - Lindsey M. Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Joshua C. Tremblay
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Bryenna K. Pinske
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Alexandra M. Williams
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| | - Glen E. Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada; and
| |
Collapse
|
36
|
Histologic Evidence of Intrapulmonary Bronchopulmonary Anastomotic Pathways in Neonates with Meconium Aspiration Syndrome. J Pediatr 2015; 167:1445-7. [PMID: 26421487 DOI: 10.1016/j.jpeds.2015.08.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/17/2015] [Accepted: 08/24/2015] [Indexed: 11/22/2022]
Abstract
We examined lung histology from 8 infants who died with meconium aspiration syndrome in order to determine the presence of intrapulmonary bronchopulmonary anastomotic pathways. Each infant required mechanical ventilation to treat hypoxemic respiratory distress. Lung histology from each infant shows evidence of prominent bronchopulmonary vascular connections.
Collapse
|
37
|
Duke JW, Elliott JE, Lovering AT. Clinical consideration for techniques to detect and quantify blood flow through intrapulmonary arteriovenous anastomoses: lessons from physiological studies. Echocardiography 2015; 32 Suppl 3:S195-204. [PMID: 25693624 DOI: 10.1111/echo.12839] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Intrapulmonary arteriovenous anastomoses (IPAVA) are large diameter (>50 μm) vascular conduits, present in >95% of healthy humans. Because IPAVA are large diameter pathways that allow blood flow to bypass the pulmonary capillary network, blood flow through IPAVA (QIPAVA) can permit the transpulmonary passage of particles larger than pulmonary capillaries. IPAVA have been known to exist for over 50 years, but their physiological and clinical significance are still being established; although, currently suggested roles for QIPAVA include allowing emboli to reach the systemic circulation and providing a source of shunt. Studying QIPAVA is an important area of research and as the suggested roles become better established, detecting and quantifying QIPAVA may become significantly more important in the clinic. Several techniques that can be used to quantify and/or detect QIPAVA in animals, ex vivo human/animal lungs, and intact healthy humans; microspheres, radiolabeled macroaggregated albumin particles, and saline contrast echocardiography, are reviewed with limitations and advantages to each. The current body of literature using these techniques to study QIPAVA in animals, ex vivo lungs, and healthy humans has established conditions when QIPAVA is present, such as during exercise or with arterial hypoxemia and conditions when QIPAVA is absent, such as at rest or during exercise breathing 100% O2 . Many of these physiological studies have direct application to patient populations and we discuss each of these findings in the context of their potential to influence the clinical utility, and interpretation, of the results from these techniques highlighted in this review.
Collapse
Affiliation(s)
- Joseph W Duke
- Division of Exercise Physiology, Ohio University, Athens, Ohio
| | | | | |
Collapse
|
38
|
Boissier F, Razazi K, Thille AW, Roche-Campo F, Leon R, Vivier E, Brochard L, Brun-Buisson C, Mekontso Dessap A. Echocardiographic detection of transpulmonary bubble transit during acute respiratory distress syndrome. Ann Intensive Care 2015; 5:5. [PMID: 25859416 PMCID: PMC4388070 DOI: 10.1186/s13613-015-0046-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022] Open
Abstract
Background Transpulmonary bubble transit (TPBT) detected with contrast echocardiography is reported as a sign of intrapulmonary shunt during cirrhosis or exercise in healthy humans. However, its physiological meaning is not clear during acute respiratory distress syndrome (ARDS). Our aim was to determine the prevalence, significance, and prognosis of TPBT detection during ARDS. Methods This was a prospective observational study in an academic medical intensive care unit in France. Two hundred and sixteen consecutive patients with moderate-to-severe ARDS underwent transesophageal echocardiography with modified gelatine contrast. Moderate-to-large TPBT was defined as right-to-left passage of at least ten bubbles through a pulmonary vein more than three cardiac cycles after complete opacification of the right atrium. Patients with intra-cardiac shunt through patent foramen ovale were excluded. Results The prevalence of moderate-to-large TPBT was 26% (including 42 patients with moderate and 15 with large TPBT). Patients with moderate-to-large TPBT had higher values of cardiac index and heart rate as compared to those without TPBT. There was no significant difference in PaO2/FIO2 ratio between groups, and TPBT was not influenced by end-expiratory positive pressure level in 93% of tested patients. Prevalence of septic shock was higher in the group with moderate-to-large TPBT. Patients with moderate-to-large TPBT had fewer ventilator-free days and intensive care unit-free days within the first 28 days, and higher in-hospital mortality as compared to others. Conclusions Moderate-to-large TPBT was detected with contrast echocardiography in 26% of patients with ARDS. This finding was associated with a hyperdynamic and septic state, but did not influence oxygenation.
Collapse
Affiliation(s)
- Florence Boissier
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; INSERM, Unité U955 (IMRB), 8 rue du Général Sarrail, Créteil, 94010 France ; Faculté de Médecine, Université Paris Est Créteil, 8, rue du Général Sarrail, Créteil, 94010 France
| | - Keyvan Razazi
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France
| | - Arnaud W Thille
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; CHU de Poitiers, Réanimation médicale, Poitiers, France; INSERM CIC 1402 (équipe 5 ALIVE), Université de Poitiers, 2 Rue de la Milétrie, 86021 Poitiers, France
| | - Ferran Roche-Campo
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; Servei de Medicina Intensiva, Hospital Verge de la Cinta, Carrer de les Esplanetes, 14, 43500 Tortosa, Tarragona Spain
| | - Rusel Leon
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; Centre Hospitalier Intercommunal de Créteil, Réanimation polyvalente, 40 avenue de Verdun, 94010 Créteil, France
| | - Emmanuel Vivier
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; Centre Hospitalier Saint Luc Saint Joseph, Réanimation Polyvalente, 20, quai Claude Bernard, 69007 Lyon, France
| | - Laurent Brochard
- Saint Michael's Hospital, 30 Bond Street, ON M5B 1 W8 Toronto, Canada
| | - Christian Brun-Buisson
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; INSERM, Unité U955 (IMRB), 8 rue du Général Sarrail, Créteil, 94010 France ; Faculté de Médecine, Université Paris Est Créteil, 8, rue du Général Sarrail, Créteil, 94010 France
| | - Armand Mekontso Dessap
- AP-HP, Hôpital Henri Mondor, DHU A-TVB, Service de Réanimation Médicale, Groupe de recherche CARMAS, 51 Av Mal de Lattre de Tassigny, Créteil, 94010 France ; INSERM, Unité U955 (IMRB), 8 rue du Général Sarrail, Créteil, 94010 France ; Faculté de Médecine, Université Paris Est Créteil, 8, rue du Général Sarrail, Créteil, 94010 France
| |
Collapse
|
39
|
McMullan DM, Riemer RK. Embryology and Anatomy of Intrapulmonary Shunts. Echocardiography 2015; 32 Suppl 3:S190-4. [DOI: 10.1111/echo.12888] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
| | - R. Kirk Riemer
- Department of Cardiothoracic Surgery; Pediatric Cardiac Surgery Division; Stanford University School of Medicine; Stanford California
| |
Collapse
|
40
|
Elliott JE, Laurie SS, Kern JP, Beasley KM, Goodman RD, Kayser B, Subudhi AW, Roach RC, Lovering AT. AltitudeOmics: impaired pulmonary gas exchange efficiency and blunted ventilatory acclimatization in humans with patent foramen ovale after 16 days at 5,260 m. J Appl Physiol (1985) 2015; 118:1100-12. [PMID: 25678698 DOI: 10.1152/japplphysiol.00879.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/08/2015] [Indexed: 12/29/2022] Open
Abstract
A patent foramen ovale (PFO), present in ∼40% of the general population, is a potential source of right-to-left shunt that can impair pulmonary gas exchange efficiency [i.e., increase the alveolar-to-arterial Po2 difference (A-aDO2)]. Prior studies investigating human acclimatization to high-altitude with A-aDO2 as a key parameter have not investigated differences between subjects with (PFO+) or without a PFO (PFO-). We hypothesized that in PFO+ subjects A-aDO2 would not improve (i.e., decrease) after acclimatization to high altitude compared with PFO- subjects. Twenty-one (11 PFO+) healthy sea-level residents were studied at rest and during cycle ergometer exercise at the highest iso-workload achieved at sea level (SL), after acute transport to 5,260 m (ALT1), and again at 5,260 m after 16 days of high-altitude acclimatization (ALT16). In contrast to PFO- subjects, PFO+ subjects had 1) no improvement in A-aDO2 at rest and during exercise at ALT16 compared with ALT1, 2) no significant increase in resting alveolar ventilation, or alveolar Po2, at ALT16 compared with ALT1, and consequently had 3) an increased arterial Pco2 and decreased arterial Po2 and arterial O2 saturation at rest at ALT16. Furthermore, PFO+ subjects had an increased incidence of acute mountain sickness (AMS) at ALT1 concomitant with significantly lower peripheral O2 saturation (SpO2). These data suggest that PFO+ subjects have increased susceptibility to AMS when not taking prophylactic treatments, that right-to-left shunt through a PFO impairs pulmonary gas exchange efficiency even after acclimatization to high altitude, and that PFO+ subjects have blunted ventilatory acclimatization after 16 days at altitude compared with PFO- subjects.
Collapse
Affiliation(s)
| | - Steven S Laurie
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Julia P Kern
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Kara M Beasley
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Randall D Goodman
- Oregon Heart and Vascular Institute, Echocardiography, Springfield, Oregon
| | - Bengt Kayser
- University of Lausanne, Department of Physiology and Institute of Sports Sciences, Lausanne, Switzerland
| | - Andrew W Subudhi
- Altitude Research Center, University of Colorado Anschutz Medical Campus, Denver, Colorado; and Department of Biology, University of Colorado, Colorado Springs, Colorado
| | - Robert C Roach
- Altitude Research Center, University of Colorado Anschutz Medical Campus, Denver, Colorado; and
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon;
| |
Collapse
|
41
|
Lovering AT, Duke JW, Elliott JE. Intrapulmonary arteriovenous anastomoses in humans--response to exercise and the environment. J Physiol 2015; 593:507-20. [PMID: 25565568 DOI: 10.1113/jphysiol.2014.275495] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 12/05/2014] [Indexed: 12/17/2022] Open
Abstract
Intrapulmonary arteriovenous anastomoses (IPAVA) have been known to exist in human lungs for over 60 years. The majority of the work in this area has largely focused on characterizing the conditions in which IPAVA blood flow (Q̇IPAVA ) is either increased, e.g. during exercise, acute normobaric hypoxia, and the intravenous infusion of catecholamines, or absent/decreased, e.g. at rest and in all conditions with alveolar hyperoxia (FIO2 = 1.0). Additionally, Q̇IPAVA is present in utero and shortly after birth, but is reduced in older (>50 years) adults during exercise and with alveolar hypoxia, suggesting potential developmental origins and an effect of age. The physiological and pathophysiological roles of Q̇IPAVA are only beginning to be understood and therefore these data remain controversial. Although evidence is accumulating in support of important roles in both health and disease, including associations with pulmonary arterial pressure, and adverse neurological sequelae, there is much work that remains to be done to fully understand the physiological and pathophysiological roles of IPAVA. The development of novel approaches to studying these pathways that can overcome the limitations of the currently employed techniques will greatly help to better quantify Q̇IPAVA and identify the consequences of Q̇IPAVA on physiological and pathophysiological processes. Nevertheless, based on currently published data, our proposed working model is that Q̇IPAVA occurs due to passive recruitment under conditions of exercise and supine body posture, but can be further modified by active redistribution of pulmonary blood flow under hypoxic and hyperoxic conditions.
Collapse
Affiliation(s)
- Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | | | | |
Collapse
|
42
|
Moses KL, Beshish AG, Heinowski N, Baker KR, Pegelow DF, Eldridge MW, Bates ML. Effect of body position and oxygen tension on foramen ovale recruitment. Am J Physiol Regul Integr Comp Physiol 2015; 308:R28-33. [PMID: 25394826 PMCID: PMC4281682 DOI: 10.1152/ajpregu.00263.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 11/10/2014] [Indexed: 01/09/2023]
Abstract
While there is an increased prevalence of stroke at altitude in individuals who are considered to be low risk for thrombotic events, it is uncertain how venous thrombi reach the brain. The patent foramen ovale (PFO) is a recruitable intracardiac shunt between the right and left atrium. We aimed to determine whether body position and oxygen tension affect blood flow through the PFO in healthy adults. We hypothesized that hypoxia and body positions that promote right atrial filling would independently recruit the PFO. Subjects with a PFO (n = 11) performed 11 trials, combining four different fractions of inhaled oxygen (FiO₂) (1.0, 0.21, 0.15, and 0.10) and three positions (upright, supine, and 45° head down), with the exception of FiO₂ = 0.10, while 45° head down. After 5 min in each position, breathing the prescribed oxygen tension, saline bubbles were injected into an antecubital vein and a four-chamber echocardiogram was obtained to evaluate PFO recruitment. We observed a high incidence of PFO recruitment in all conditions, with increased recruitment in response to severe hypoxia and some contribution of body position at moderate levels of hypoxia. We suspect that increased pulmonary vascular pressure, secondary to hypoxia-induced pulmonary vasoconstriction, increased right atrial pressure enough to recruit the PFO. Additionally, we hypothesize that the minor increase in breathing resistance that was added by the mouthpiece, used during experimental trials, affected intrathoracic pressure and venous return sufficiently to recruit the PFO.
Collapse
Affiliation(s)
- Kayla L Moses
- Department of Pediatrics, Critical Care Division, and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin; Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Arij G Beshish
- Department of Pediatrics, Critical Care Division, and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Nicole Heinowski
- Department of Pediatrics, Critical Care Division, and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Kim R Baker
- Adult Echocardiography Laboratory, University of Wisconsin Hospital and Clinics, Madison, Wisconsin; and
| | - David F Pegelow
- Department of Pediatrics, Critical Care Division, and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Marlowe W Eldridge
- Department of Pediatrics, Critical Care Division, and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin; Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin
| | - Melissa L Bates
- Department of Pediatrics, Critical Care Division, and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin; Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| |
Collapse
|
43
|
Calbet JAL, Boushel R. Assessment of cardiac output with transpulmonary thermodilution during exercise in humans. J Appl Physiol (1985) 2015; 118:1-10. [DOI: 10.1152/japplphysiol.00686.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The accuracy and reproducibility of transpulmonary thermodilution (TPTd) to assess cardiac output (Q̇) in exercising men was determined using indocyanine green (ICG) dilution as a reference method. TPTd has been utilized for the assessment of Q̇ and preload indexes of global end-diastolic volume and intrathoracic blood volume, as well as extravascular lung water (EVLW) in resting humans. It remains unknown if this technique is also accurate and reproducible during exercise. Sixteen healthy men underwent catheterization of the right femoral vein (for iced saline injection), an antecubital vein (ICG injection), and femoral artery (thermistor) to determine their Q̇ by TPTd and ICG concentration during incremental one- and two-legged pedaling on a cycle ergometer and combined arm cranking with leg pedaling to exhaustion. There was a close relationship between TPTd-Q̇ and ICG-Q̇ ( r = 0.95, n = 151, standard error of the estimate: 1.452 l/min, P < 0.001; mean difference of 0.06 l/min; limits of agreement −2.98 to 2.86 l/min), and TPTd-Q̇ and ICG-Q̇ increased linearly with oxygen uptake with similar intercepts and slopes. Both methods had mean coefficients of variation close to 5% for Q̇, global end-diastolic volume, and intrathoracic blood volume. The mean coefficient of variation of EVLW, assessed with both indicators (ICG and thermal) was 17% and was sensitive enough to detect a reduction in EVLW of 107 ml when changing from resting supine to upright exercise. In summary, TPTd with bolus injection into the femoral vein is an accurate and reproducible method to assess Q̇ during exercise in humans.
Collapse
Affiliation(s)
- José A. L. Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira, Las Palmas de Gran Canaria, Spain
- Research Institute of Biomedical and Health Sciences, IUIBS, University of Las Palmas de Gran Canaria, Canary Island, Spain
- Copenhagen Muscle Research Center, Heart & Circulatory Section, Department of Biomedical Sciences, University of Copenhagen, and Department of Anaesthesia, Bispebjerg Hospital, Copenhagen, Denmark; and
| | - Robert Boushel
- Copenhagen Muscle Research Center, Heart & Circulatory Section, Department of Biomedical Sciences, University of Copenhagen, and Department of Anaesthesia, Bispebjerg Hospital, Copenhagen, Denmark; and
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| |
Collapse
|
44
|
Tremblay JC, Lovering AT, Ainslie PN, Stembridge M, Burgess KR, Bakker A, Donnelly J, Lucas SJE, Lewis NCS, Dominelli PB, Henderson WR, Dominelli GS, Sheel AW, Foster GE. Hypoxia, not pulmonary vascular pressure, induces blood flow through intrapulmonary arteriovenous anastomoses. J Physiol 2014; 593:723-37. [PMID: 25416621 DOI: 10.1113/jphysiol.2014.282962] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 11/10/2014] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased by acute hypoxia during rest by unknown mechanisms. Oral administration of acetazolamide blunts the pulmonary vascular pressure response to acute hypoxia, thus permitting the observation of IPAVA blood flow with minimal pulmonary pressure change. Hypoxic pulmonary vasoconstriction was attenuated in humans following acetazolamide administration and partially restored with bicarbonate infusion, indicating that the effects of acetazolamide on hypoxic pulmonary vasoconstriction may involve an interaction between arterial pH and PCO2. We observed that IPAVA blood flow during hypoxia was similar before and after acetazolamide administration, even after acid-base status correction, indicating that pulmonary pressure, pH and PCO2 are unlikely regulators of IPAVA blood flow. ABSTRACT Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased with exposure to acute hypoxia and has been associated with pulmonary artery systolic pressure (PASP). We aimed to determine the direct relationship between blood flow through IPAVA and PASP in 10 participants with no detectable intracardiac shunt by comparing: (1) isocapnic hypoxia (control); (2) isocapnic hypoxia with oral administration of acetazolamide (AZ; 250 mg, three times a day for 48 h) to prevent increases in PASP; and (3) isocapnic hypoxia with AZ and 8.4% NaHCO3 infusion (AZ + HCO3 (-) ) to control for AZ-induced acidosis. Isocapnic hypoxia (20 min) was maintained by end-tidal forcing, blood flow through IPAVA was determined by agitated saline contrast echocardiography and PASP was estimated by Doppler ultrasound. Arterial blood samples were collected at rest before each isocapnic-hypoxia condition to determine pH, [HCO3(-)] and Pa,CO2. AZ decreased pH (-0.08 ± 0.01), [HCO3(-)] (-7.1 ± 0.7 mmol l(-1)) and Pa,CO2 (-4.5 ± 1.4 mmHg; P < 0.01), while intravenous NaHCO3 restored arterial blood gas parameters to control levels. Although PASP increased from baseline in all three hypoxic conditions (P < 0.05), a main effect of condition expressed an 11 ± 2% reduction in PASP from control (P < 0.001) following AZ administration while intravenous NaHCO3 partially restored the PASP response to isocapnic hypoxia. Blood flow through IPAVA increased during exposure to isocapnic hypoxia (P < 0.01) and was unrelated to PASP, cardiac output and pulmonary vascular resistance for all conditions. In conclusion, isocapnic hypoxia induces blood flow through IPAVA independent of changes in PASP and the influence of AZ on the PASP response to isocapnic hypoxia is dependent upon the H(+) concentration or Pa,CO2.
Collapse
Affiliation(s)
- Joshua C Tremblay
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Elliott JE, Friedman JM, Futral JE, Goodman RD, Lovering AT. Sildenafil, nifedipine and acetazolamide do not allow for blood flow through intrapulmonary arteriovenous anastomoses during exercise while breathing 100% oxygen. Exp Physiol 2014; 99:1636-47. [DOI: 10.1113/expphysiol.2014.081562] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
46
|
Elliott JE, Duke JW, Hawn JA, Halliwill JR, Lovering AT. Increased cardiac output, not pulmonary artery systolic pressure, increases intrapulmonary shunt in healthy humans breathing room air and 40% O2. J Physiol 2014; 592:4537-53. [PMID: 25085889 DOI: 10.1113/jphysiol.2014.274829] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Blood flow through intrapulmonary arteriovenous anastomoses (IPAVAs) has been demonstrated to increase in healthy humans during a variety of conditions; however, whether or not this blood flow represents a source of venous admixture (Q̇ VA /Q̇T) that impairs pulmonary gas exchange efficiency (i.e. increases the alveolar-to-arterial PO2 difference (A-aDO2)) remains controversial and unknown. We hypothesized that blood flow through IPAVAs does provide a source of Q̇ VA /Q̇T. To test this, blood flow through IPAVAs was increased in healthy humans at rest breathing room air and 40% O2: (1) during intravenous adrenaline (epinephrine) infusion at 320 ng kg(-1) min(-1) (320 ADR), and (2) with vagal blockade (2 mg atropine), before and during intravenous adrenaline infusion at 80 ng kg(-1) min(-1) (ATR + 80 ADR). When breathing room air the A-aDO2 increased by 6 ± 2 mmHg during 320 ADR and by 5 ± 2 mmHg during ATR + 80 ADR, and the change in calculated Q̇ VA /Q̇T was +2% in both conditions. When breathing 40% O2, which minimizes contributions from diffusion limitation and alveolar ventilation-to-perfusion inequality, the A-aDO2 increased by 12 ± 7 mmHg during 320 ADR, and by 9 ± 6 mmHg during ATR + 80 ADR, and the change in calculated Q̇ VA /Q̇T was +2% in both conditions. During 320 ADR cardiac output (Q̇T) and pulmonary artery systolic pressure (PASP) were significantly increased; however, during ATR + 80 ADR only Q̇T was significantly increased, yet blood flow through IPAVAs as detected with saline contrast echocardiography was not different between conditions. Accordingly, we suggest that blood flow through IPAVAs provides a source of intrapulmonary shunt, and is mediated primarily by increases in Q̇T rather than PASP.
Collapse
Affiliation(s)
| | - Joseph W Duke
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Jerold A Hawn
- Oregon Heart and Vascular Institute, Cardiology, Springfield, OR, USA
| | - John R Halliwill
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| | - Andrew T Lovering
- University of Oregon, Department of Human Physiology, Eugene, OR, USA
| |
Collapse
|
47
|
Lozo M, Lojpur M, Madden D, Lozo P, Banic I, Dujic Z. The effects of nitroglycerin, norepinephrine and aminophylline on intrapulmonary arteriovenous anastomoses in healthy humans at rest. Respir Physiol Neurobiol 2014; 199:19-23. [DOI: 10.1016/j.resp.2014.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/22/2014] [Accepted: 04/24/2014] [Indexed: 10/25/2022]
|
48
|
Bates ML, Farrell ET, Drezdon A, Jacobson JE, Perlman SB, Eldridge MW. Hypoxia and exercise increase the transpulmonary passage of 99mTc-labeled albumin particles in humans. PLoS One 2014; 9:e101146. [PMID: 25013985 PMCID: PMC4094383 DOI: 10.1371/journal.pone.0101146] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 06/03/2014] [Indexed: 11/19/2022] Open
Abstract
Intrapulmonary arteriovenous anastomoses (IPAVs) are large diameter connections that allow blood to bypass the lung capillaries and may provide a route for right-to-left embolus transmission. These anastomoses are recruited by exercise and catecholamines and hypoxia. Yet, whether IPAVs are recruited via direct, oxygen sensitive regulatory mechanisms or indirect effects secondary to redistribution pulmonary blood flow is unknown. Here, we hypothesized that the addition of exercise to hypoxic gas breathing, which increases cardiac output, would augment IPAVs recruitment in healthy humans. To test this hypothesis, we measured the transpulmonary passage of 99mTc-macroaggregated albumin particles (99mTc-MAA) in seven healthy volunteers, at rest and with exercise at 85% of volitional max, with normoxic (FIO2 = 0.21) and hypoxic (FIO2 = 0.10) gas breathing. We found increased 99mTc-MAA passage in both exercise conditions and resting hypoxia. However, contrary to our hypothesis, we found the greatest 99mTc-MAA passage with resting hypoxia. As an additional, secondary endpoint, we also noted that the transpulmonary passage of 99mTc-MAA was well-correlated with the alveolar-arterial oxygen difference (A-aDO2) during exercise. While increased cardiac output has been proposed as an important modulator of IPAVs recruitment, we provide evidence that the modulation of blood flow through these pathways is more complex and that increasing cardiac output does not necessarily increase IPAVs recruitment. As we discuss, our data suggest that the resistance downstream of IPAVs is an important determinant of their perfusion.
Collapse
Affiliation(s)
- Melissa L. Bates
- Department of Pediatrics, Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Emily T. Farrell
- Department of Pediatrics, Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Alyssa Drezdon
- Department of Pediatrics, Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Joseph E. Jacobson
- Department of Pediatrics, Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
- Michigan State University College of Human Medicine, East Lansing, Michigan, United States of America
| | - Scott B. Perlman
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Marlowe W. Eldridge
- Department of Pediatrics, Critical Care Division and the John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
- Departments of Biomedical Engineering and Kinesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| |
Collapse
|
49
|
Intrapulmonary arteriovenous anastomoses. Physiological, pathophysiological, or both? Ann Am Thorac Soc 2014; 10:504-8. [PMID: 24161053 DOI: 10.1513/annalsats.201308-265ed] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Large-diameter, intrapulmonary arteriovenous anastomoses exist in human lungs. In developing fetuses, blood flows physiologically through pulmonary arteriovenous channels that appear to regress during lung maturation. Blood flow through intrapulmonary arteriovenous anastomoses is a normal occurrence during exercise or inhalation of reduced oxygen gas mixtures in most healthy humans. However, the importance of blood flow through these anastomoses to the efficiency of pulmonary gas exchange in normal and pathological states remains controversial. Newly reported three-dimensional dissections of human lung samples provide direct anatomic evidence of intrapulmonary arteriovenous anastomoses in the lungs of prematurely born infants, and suggest that these vessels contribute consequentially to the severe arterial hypoxemia experienced by infants who die of bronchopulmonary dysplasia. Surgical construction of a cavopulmonary anastomosis can also induce pathological arteriovenous shunting suggestive of a regression to the fetal state, possibly implicating an enigmatic hepatic factor in arteriovenous shunt regulation. These two observations support an important contribution of blood flow through intrapulmonary arteriovenous anastomoses to arterial hypoxemia under at least some pathological conditions. The degree to which these vessels contribute to arterial hypoxemia in other disease states where intrapulmonary shunting is present, such as hepatopulmonary syndrome, remains unknown.
Collapse
|
50
|
Cameron Norris H, Mangum TS, Duke JW, Straley TB, Hawn JA, Goodman RD, Lovering AT. Exercise- and hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses is reduced in older adults. J Appl Physiol (1985) 2014; 116:1324-33. [DOI: 10.1152/japplphysiol.01125.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mean pulmonary arterial pressure (Ppa) during exercise is significantly higher in individuals aged ≥50 yr compared with their younger counterparts, but the reasons for this are unknown. Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) can be detected during exercise or while breathing hypoxic gas mixtures using saline contrast echocardiography in almost all healthy young individuals. It has been previously hypothesized that a lower degree of exercise-induced blood flow through IPAVA is associated with high Ppa during exercise. This association may suggest that individuals who are known to have high Ppa during exercise, such as those ≥50 yr of age, may have lower blood flow through IPAVA, but the presence and degree of exercise-induced blood flow through IPAVA has not been specifically studied in older populations. Using transthoracic saline contrast echocardiography, we investigated the potential effects of age on exercise-induced blood flow through IPAVA in a cross-section of subjects aged 19–72 yr. To verify our findings, we assessed the effects of age on hypoxia-induced blood flow through IPAVA. Age groups were ≤41 yr (younger, n = 16) and ≥50 yr (older, n = 14). Qualitatively measured exercise- and hypoxia-induced blood flow through IPAVA was significantly lower in older individuals compared with younger controls. Older individuals also had significantly higher pulmonary arterial systolic pressure and total pulmonary resistance (TPR) during exercise. Low blood flow through IPAVA was independently associated with high TPR. The reasons for the age-related decrease in blood flow through IPAVA are unknown.
Collapse
Affiliation(s)
- H. Cameron Norris
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Tyler S. Mangum
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Joseph W. Duke
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Taylor B. Straley
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| | - Jerold A. Hawn
- Oregon Heart and Vascular Institute, RiverBend, Springfield, Oregon
| | - Randy D. Goodman
- Oregon Heart and Vascular Institute, RiverBend, Springfield, Oregon
| | - Andrew T. Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon; and
| |
Collapse
|