51
|
Mijacika T, Frestad D, Kyhl K, Barak O, Drvis I, Secher NH, Buca A, Obad A, Dujic Z, Madsen PL. Blood pooling in extrathoracic veins after glossopharyngeal insufflation. Eur J Appl Physiol 2017; 117:641-649. [PMID: 28243777 DOI: 10.1007/s00421-017-3545-9] [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: 09/12/2016] [Accepted: 01/10/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE Trained breath-hold divers hyperinflate their lungs by glossopharyngeal insufflation (GPI) to prolong submersion time and withstand lung collapse at depths. Pulmonary hyperinflation leads to profound hemodynamic changes. METHODS Thirteen divers performed preparatory breath-holds followed by apnea with GPI. Filling of extrathoracic veins was determined by ultrasound and magnetic resonance imaging and peripheral extravasation of fluid was assessed by electrical impedance. Femoral vein diameter was measured by ultrasound throughout the easy-going and struggle phase of apnea with GPI in eight divers in a sub-study. RESULTS After GPI, pulmonary volume increased by 0.8 ± 0.6 L above total lung capacity. The diameter of the superior caval (by 36 ± 17%) and intrathoracic part of the inferior caval vein decreased (by 21 ± 16%), while the diameters of the internal jugular (by 53 ± 34%), hepatic (by 28 ± 40%), abdominal part of the inferior caval (by 28 ± 28%), and femoral veins (by 65 ± 50%) all increased (P < 0.05). Blood volume of the internal jugular, the hepatic, the abdominal part of the inferior caval vein, and the combined common iliac and femoral veins increased by 145 ± 115, 80 ± 88, 61 ± 60, and 183 ± 197%, respectively. In the sub-study, femoral vein diameter increased by 44 ± 33% in the easy-going phase of apnea with GPI, subsequently decreasing by 20 ± 16% during the struggle phase. Electrical impedance remained unchanged over the thigh and forearm, thus excluding peripheral fluid extravasation. CONCLUSIONS GPI leads to heart and pulmonary vessel compression, resulting in redistribution of blood to extrathoracic capacitance veins proximal to venous valves. This is partially reversed by the onset of involuntary breathing movements.
Collapse
Affiliation(s)
- Tanja Mijacika
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia
| | - Daria Frestad
- Department of Cardiology, Copenhagen University Hospital, Hvidovre, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Kyhl
- The Cardiac MRI Group, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Otto Barak
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia.,Department of Physiology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Ivan Drvis
- University of Zagreb School of Kinesiology, Zagreb, Croatia
| | - Niels H Secher
- Department of Anesthesiology, The Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ante Buca
- Department of Radiology, University Hospital Center, Split, Croatia
| | - Ante Obad
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia.
| | - Per Lav Madsen
- Department of Cardiology, Copenhagen University Hospital, Herlev, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
52
|
Eichhorn L, Kessler F, Böhnert V, Erdfelder F, Reckendorf A, Meyer R, Ellerkmann RK. A Model to Simulate Clinically Relevant Hypoxia in Humans. J Vis Exp 2016. [PMID: 28060323 DOI: 10.3791/54933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to hypoxia sensitive organs such as the brain, compensatory circulatory mechanisms help to maintain an adequate oxygen supply. This is mainly achieved by increased cerebral blood flow. Intermittent hypoxia is a commonly seen phenomenon in patients with obstructive sleep apnea. Acute airway obstruction can also result in hypoxia and hypercapnia. Until now, no adequate model has been established to simulate these dynamics in humans. Previous investigations focusing on human hypoxia used inhaled hypoxic gas mixtures. However, the resulting hypoxia was combined with hyperventilation and is therefore more representative of high altitude environments than of apnea. Furthermore, the transferability of previously performed animal experiments to humans is limited and the pathophysiological background of apnea induced physiological changes is poorly understood. In this study, healthy human apneic divers were utilized to mimic clinically relevant hypoxia and hypercapnia during apnea. Additionally, pulse-oximetry and Near Infrared Spectroscopy (NIRS) were used to evaluate changes in cerebral and peripheral oxygen saturation before, during, and after apnea.
Collapse
Affiliation(s)
- Lars Eichhorn
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Bonn;
| | - Florian Kessler
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Bonn
| | - Volker Böhnert
- Institute of Clinical Chemistry and Clinical Pharmacology, University of Bonn
| | - Felix Erdfelder
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Bonn
| | - Anja Reckendorf
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover
| | | | - Richard K Ellerkmann
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital of Bonn
| |
Collapse
|
53
|
Eckberg DL, Cooke WH, Diedrich A, Biaggioni I, Buckey JC, Pawelczyk JA, Ertl AC, Cox JF, Kuusela TA, Tahvanainen KUO, Mano T, Iwase S, Baisch FJ, Levine BD, Adams-Huet B, Robertson D, Blomqvist CG. Respiratory modulation of human autonomic function on Earth. J Physiol 2016; 594:5611-27. [PMID: 27028958 PMCID: PMC5043049 DOI: 10.1113/jp271654] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/14/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We studied healthy supine astronauts on Earth with electrocardiogram, non-invasive arterial pressure, respiratory carbon dioxide concentrations, breathing depth and sympathetic nerve recordings. The null hypotheses were that heart beat interval fluctuations at usual breathing frequencies are baroreflex mediated, that they persist during apnoea, and that autonomic responses to apnoea result from changes of chemoreceptor, baroreceptor or lung stretch receptor inputs. R-R interval fluctuations at usual breathing frequencies are unlikely to be baroreflex mediated, and disappear during apnoea. The subjects' responses to apnoea could not be attributed to changes of central chemoreceptor activity (hypocapnia prevailed); altered arterial baroreceptor input (vagal baroreflex gain declined and muscle sympathetic nerve burst areas, frequencies and probabilities increased, even as arterial pressure climbed to new levels); or altered pulmonary stretch receptor activity (major breathing frequency and tidal volume changes did not alter vagal tone or sympathetic activity). Apnoea responses of healthy subjects may result from changes of central respiratory motoneurone activity. ABSTRACT We studied eight healthy, supine astronauts on Earth, who followed a simple protocol: they breathed at fixed or random frequencies, hyperventilated and then stopped breathing, as a means to modulate and expose to view important, but obscure central neurophysiological mechanisms. Our recordings included the electrocardiogram, finger photoplethysmographic arterial pressure, tidal volume, respiratory carbon dioxide concentrations and peroneal nerve muscle sympathetic activity. Arterial pressure, vagal tone and muscle sympathetic outflow were comparable during spontaneous and controlled-frequency breathing. Compared with spontaneous, 0.1 and 0.05 Hz breathing, however, breathing at usual frequencies (∼0.25 Hz) lowered arterial baroreflex gain, and provoked smaller arterial pressure and R-R interval fluctuations, which were separated by intervals that were likely to be too short and variable to be attributed to baroreflex physiology. R-R interval fluctuations at usual breathing frequencies disappear during apnoea, and thus cannot provide evidence for the existence of a central respiratory oscillation. Apnoea sets in motion a continuous and ever changing reorganization of the relations among stimulatory and inhibitory inputs and autonomic outputs, which, in our study, could not be attributed to altered chemoreceptor, baroreceptor, or pulmonary stretch receptor activity. We suggest that responses of healthy subjects to apnoea are driven importantly, and possibly prepotently, by changes of central respiratory motoneurone activity. The companion article extends these observations and asks the question, Might terrestrial responses to our 20 min breathing protocol find expression as long-term neuroplasticity in serial measurements made over 20 days during and following space travel?
Collapse
Affiliation(s)
- Dwain L Eckberg
- Departments of Medicine and Physiology, Hunter Holmes McGuire Department of Veterans Affairs, Medical Center and Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
| | - William H Cooke
- Department of Kinesiology, Health, and Nutrition, University of Texas at San Antonio, San Antonio, TX, USA
| | - André Diedrich
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Italo Biaggioni
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Jay C Buckey
- Dartmouth Hitchcock Medical Center, Lebanon, NH, USA
| | - James A Pawelczyk
- Department of Physiology, Pennsylvania State University, University Park and Hershey, PA, USA
| | - Andrew C Ertl
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - James F Cox
- Departments of Medicine and Physiology, Hunter Holmes McGuire Department of Veterans Affairs, Medical Center and Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Tom A Kuusela
- Department of Physics, University of Turku, Turku, Finland
| | - Kari U O Tahvanainen
- Department of Clinical Physiology and Nuclear Medicine, South Karelia Central Hospital, Lappeenranta, Finland
| | - Tadaaki Mano
- Gifu University of Medical Science, 795-1 Nagamine Ichihiraga, Seki, Gifu, 501-3892, Japan
| | - Satoshi Iwase
- Department of Physiology, Aichi Medical University, Aichi, Japan
| | | | - Benjamin D Levine
- Department of Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA
| | | | - David Robertson
- Department of Medicine, Division of Clinical Pharmacology, Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - C Gunnar Blomqvist
- Department of Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| |
Collapse
|
54
|
Costalat G, Coquart J, Castres I, Joulia F, Sirost O, Clua E, Lemaître F. The oxygen-conserving potential of the diving response: A kinetic-based analysis. J Sports Sci 2016; 35:678-687. [PMID: 27167834 DOI: 10.1080/02640414.2016.1183809] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO2]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO2) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (-0.86 bpm.%-1) while HR kinetics in NDs steadily decreased throughout BH (-0.47 bpm.%-1). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (-7.3 ± 3.2 vs. -3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an "oxygen-conserving breaking point" in the human diving response.
Collapse
Affiliation(s)
| | - Jeremy Coquart
- a CETAPS Laboratory , Normandie University , Mont Saint-Aignan , France
| | - Ingrid Castres
- a CETAPS Laboratory , Normandie University , Mont Saint-Aignan , France
| | - Fabrice Joulia
- b UMR MD2, Aix Marseille University and IRBA , Marseille , France
| | - Olivier Sirost
- a CETAPS Laboratory , Normandie University , Mont Saint-Aignan , France
| | - Eric Clua
- c NRS-EPHE , USR3278 , Papetoai , French Polynesia
| | - Frédéric Lemaître
- a CETAPS Laboratory , Normandie University , Mont Saint-Aignan , France
| |
Collapse
|
55
|
Hoiland RL, Ainslie PN, Bain AR, MacLeod DB, Stembridge M, Drvis I, Madden D, Barak O, MacLeod DM, Dujic Z. β 1-Blockade increases maximal apnea duration in elite breath-hold divers. J Appl Physiol (1985) 2016; 122:899-906. [PMID: 27125844 DOI: 10.1152/japplphysiol.00127.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/04/2016] [Accepted: 04/26/2016] [Indexed: 11/22/2022] Open
Abstract
We hypothesized that the cardioselective β1-adrenoreceptor antagonist esmolol would improve maximal apnea duration in elite breath-hold divers. In elite national-level divers (n = 9), maximal apneas were performed in a randomized and counterbalanced order while receiving either iv esmolol (150 μg·kg-1·min-1) or volume-matched saline (placebo). During apnea, heart rate (ECG), beat-by-beat blood pressure, stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were measured (finger photoplethysmography). Myocardial oxygen consumption (MV̇o2) was estimated from rate pressure product. Cerebral blood flow through the internal carotid (ICA) and vertebral arteries (VA) was assessed using Duplex ultrasound. Apnea duration improved in the esmolol trial when compared with placebo (356 ± 57 vs. 323 ± 61 s, P < 0.01) despite similar end-apnea peripheral oxyhemoglobin saturation (71.8 ± 10.3 vs. 74.9 ± 9.5%, P = 0.10). The HR response to apnea was reduced by esmolol at 10-30% of apnea duration, whereas MAP was unaffected. Esmolol reduced SV (main effect, P < 0.05) and CO (main effect; P < 0.05) and increased TPR (main effect, P < 0.05) throughout apnea. Esmolol also reduced MV̇o2 throughout apnea (main effect, P < 0.05). Cerebral blood flow through the ICA and VA was unchanged by esmolol at baseline and the last 30 s of apnea; however, global cerebral blood flow was reduced in the esmolol trial at end-apnea (P < 0.05). Our findings demonstrate that, in elite breath-hold divers, apnea breakpoint is improved by β1-blockade, likely owing to an improved total body oxygen sparring through increased centralization of blood volume (↑TPR) and reduced MV̇o2NEW & NOTEWORTHY The governing bodies for international apnea competition, the Association Internationale pour le Développment de l'Apnée and La Confédération Mondaile des Activités Subaquatiques, have banned the use of β-blockers based on anecdotal reports that they improve apnea duration. Using a randomized placebo-controlled trial, we are the first to empirically confirm that β-blockade improves apnea duration. This improvement in apnea duration coincided with a reduced myocardial oxygen consumption.
Collapse
Affiliation(s)
- Ryan L Hoiland
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada;
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Anthony R Bain
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - David B MacLeod
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Mike Stembridge
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Ivan Drvis
- University of Zagreb School of Kinesiology, Zagreb, Croatia
| | - Dennis Madden
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Otto Barak
- Department of Physiology, University of Novi Sad School of Medicine, Novi Sad, Serbia; and
| | | | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| |
Collapse
|
56
|
Abstract
BACKGROUND Little is known about intracranial pressure (ICP)-cerebral haemodynamic interplay during repetitive apnoea. A recently developed method based on near-infrared transillumination/backscattering sounding (NIR-T/BSS) noninvasively measures changes in pial artery pulsation (cc-TQ) as well as subarachnoid width (sas-TQ) in humans. METHOD We tested the complex response of the pial artery and subarachnoid width to apnoea using this method. The pial artery and subarachnoid width response to consecutive apnoeas lasting 30, 60 s and maximal breath-hold (91.1 ± 23.1 s) were studied in 20 healthy volunteers. The cc-TQ and sas-TQ were measured using NIR-T/BSS; cerebral blood flow velocity (CBFV), pulsatility index and resistive index were measured using Doppler ultrasound of the left internal carotid artery; heart rate (HR) and beat-to-beat SBP and DBP blood pressure were recorded using a Finometer; end-tidal CO2 (EtCO2) was measured using a medical gas analyser. RESULTS Apnoea evoked a multiphasic response in blood pressure, pial artery compliance and ICP. First, SBP declined, which was accompanied by an increase in cc-TQ and sas-TQ. Directly after these changes, SBP exceeded baseline values, which was followed by a decline in cc-TQ and the return of sas-TQ to baseline. During these initial changes, CBFV remained stable. Towards the end of the apnoea, BP, cc-TQ and CBFV increased, whereas pulsatility index, resistive index and sas-TQ declined. Changes in sas-TQ were linked to changes in EtCO2, HR and SBP. CONCLUSION Apnoea is associated with ICP swings, closely reflecting changes in EtCO2, HR and peripheral BP. The baroreflex influences the pial artery response.
Collapse
|
57
|
Kyhl K, Drvis I, Barak O, Mijacika T, Engstrøm T, Secher NH, Dujic Z, Buca A, Madsen PL. Organ perfusion during voluntary pulmonary hyperinflation; a magnetic resonance imaging study. Am J Physiol Heart Circ Physiol 2015; 310:H444-51. [PMID: 26589331 DOI: 10.1152/ajpheart.00739.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/16/2015] [Indexed: 11/22/2022]
Abstract
Pulmonary hyperinflation is used by competitive breath-hold divers and is accomplished by glossopharyngeal insufflation (GPI), which is known to compress the heart and pulmonary vessels, increasing sympathetic activity and lowering cardiac output (CO) without known consequence for organ perfusion. Myocardial, pulmonary, skeletal muscle, kidney, and liver perfusion were evaluated by magnetic resonance imaging in 10 elite breath-hold divers at rest and during moderate GPI. Cardiac chamber volumes, stroke volume, and thus CO were determined from cardiac short-axis cine images. Organ volumes were assessed from gradient echo sequences, and organ perfusion was evaluated from first-pass images after gadolinium injection. During GPI, lung volume increased by 5.2 ± 1.5 liters (mean ± SD; P < 0.001), while spleen and liver volume decreased by 46 ± 39 and 210 ± 160 ml, respectively (P < 0.05), and inferior caval vein diameter by 4 ± 3 mm (P < 0.05). Heart rate tended to increase (67 ± 10 to 86 ± 20 beats/min; P = 0.052) as right and left ventricular volumes were reduced (P < 0.05). Stroke volume (107 ± 21 to 53 ± 15 ml) and CO (7.2 ± 1.6 to 4.2 ± 0.8 l/min) decreased as assessed after 1 min of GPI (P < 0.01). Left ventricular myocardial perfusion maximum upslope and its perfusion index decreased by 1.52 ± 0.15 s(-1) (P < 0.001) and 0.02 ± 0.01 s(-1) (P < 0.05), respectively, without transmural differences. Pulmonary tissue, spleen, kidney, and pectoral-muscle perfusion also decreased (P < 0.05), and yet liver perfusion was maintained. Thus, during pulmonary hyperinflation by GPI, CO and organ perfusion, including the myocardium, as well as perfusion of skeletal muscles, are reduced, and yet perfusion of the liver is maintained. Liver perfusion seems to be prioritized when CO decreases during GPI.
Collapse
Affiliation(s)
- Kasper Kyhl
- Cardiac MRI Group, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark;
| | - Ivan Drvis
- School of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Otto Barak
- Department of Integrative Physiology, School of Medicine, University of Split, Split, Croatia; Department of Physiology, School of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Tanja Mijacika
- Department of Integrative Physiology, School of Medicine, University of Split, Split, Croatia
| | - Thomas Engstrøm
- Cardiac MRI Group, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Niels H Secher
- Department of Anesthesiology, The Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Zeljko Dujic
- Department of Integrative Physiology, School of Medicine, University of Split, Split, Croatia
| | - Ante Buca
- Department of Radiology, Clinical Hospital Center, Split, Croatia; and
| | - Per Lav Madsen
- Cardiac MRI Group, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
58
|
Bain AR, Dujic Z, Hoiland RL, Barak OF, Madden D, Drvis I, Stembridge M, MacLeod DB, MacLeod DM, Ainslie PN. Peripheral chemoreflex inhibition with low-dose dopamine: new insight into mechanisms of extreme apnea. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1162-71. [PMID: 26290106 DOI: 10.1152/ajpregu.00271.2015] [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] [Received: 06/16/2015] [Accepted: 08/11/2015] [Indexed: 01/02/2023]
Abstract
The purpose of this study was to determine the impact of peripheral chemoreflex inhibition with low-dose dopamine on maximal apnea time, and the related hemodynamic and cerebrovascular responses in elite apnea divers. In a randomized order, participants performed a maximal apnea while receiving either intravenous 2 μg·kg(-1)·min(-1) dopamine or volume-matched saline (placebo). The chemoreflex and hemodynamic response to dopamine was also assessed during hypoxia [arterial O2 tension, (PaO2 ) ∼35 mmHg] and mild hypercapnia [arterial CO2 tension (PaCO2 ) ∼46 mmHg] that mimicked the latter parts of apnea. Outcome measures included apnea duration, arterial blood gases (radial), heart rate (HR, ECG), mean arterial pressure (MAP, intra-arterial), middle (MCAv) and posterior (PCAv) cerebral artery blood velocity (transcranial ultrasound), internal carotid (ICA) and vertebral (VA) artery blood flow (ultrasound), and the chemoreflex responses. Although dopamine depressed the ventilatory response by 27 ± 41% (vs. placebo; P = 0.01), the maximal apnea duration was increased by only 5 ± 8% (P = 0.02). The PaCO2 and PaO2 at apnea breakpoint were similar (P > 0.05). When compared with placebo, dopamine increased HR and decreased MAP during both apnea and chemoreflex test (P all <0.05). At rest, dopamine compared with placebo dilated the ICA (3.0 ± 4.1%, P = 0.05) and VA (6.6 ± 5.0%, P < 0.01). During apnea and chemoreflex test, conductance of the cerebral vessels (ICA, VA, MCAv, PCAv) was increased with dopamine; however, flow (ICA and VA) was similar. At least in elite apnea divers, the small increase in apnea time and similar PaO2 at breakpoint (∼31 mmHg) suggest the apnea breakpoint is more related to PaO2 , rather than peripheral chemoreflex drive to breathe.
Collapse
Affiliation(s)
- Anthony R Bain
- Center for Heart Lung and Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada;
| | - Zeljko Dujic
- School of Medicine, University of Split, Split, Croatia
| | - Ryan L Hoiland
- Center for Heart Lung and Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - Otto F Barak
- School of Medicine, University of Split, Split, Croatia
| | - Dennis Madden
- School of Medicine, University of Split, Split, Croatia
| | - Ivan Drvis
- School of Kinesiology, University of Zagreb, Zagreb, Croatia
| | | | - David B MacLeod
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina; and
| | | | - Philip N Ainslie
- Center for Heart Lung and Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| |
Collapse
|
59
|
Winklewski PJ, Barak O, Madden D, Gruszecka A, Gruszecki M, Guminski W, Kot J, Frydrychowski AF, Drvis I, Dujic Z. Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers. PLoS One 2015; 10:e0135429. [PMID: 26285143 PMCID: PMC4540420 DOI: 10.1371/journal.pone.0135429] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 07/21/2015] [Indexed: 11/30/2022] Open
Abstract
Purpose The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). Methods The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Results Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Conclusions Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not change throughout the apnoea.
Collapse
Affiliation(s)
- Pawel J. Winklewski
- Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland
- * E-mail:
| | - Otto Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Dennis Madden
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Agnieszka Gruszecka
- Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland
| | - Marcin Gruszecki
- Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Guminski
- Department of Computer Communications, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Jacek Kot
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | | | - Ivan Drvis
- University of Zagreb School of Kinesiology, Zagreb, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| |
Collapse
|
60
|
Winklewski PJ, Tkachenko Y, Mazur K, Kot J, Gruszecki M, Guminski W, Czuszynski K, Wtorek J, Frydrychowski AF. Sympathetic Activation Does Not Affect the Cardiac and Respiratory Contribution to the Relationship between Blood Pressure and Pial Artery Pulsation Oscillations in Healthy Subjects. PLoS One 2015; 10:e0135751. [PMID: 26284650 PMCID: PMC4540578 DOI: 10.1371/journal.pone.0135751] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/25/2015] [Indexed: 12/12/2022] Open
Abstract
Introduction Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects. Methods The pial artery and subarachnoid width response to handgrip (HGT) and cold test (CT) were studied in 20 healthy subjects. The cc-TQ and sas-TQ were measured using NIR-T/BSS; cerebral blood flow velocity (CBFV) was measured using Doppler ultrasound of the left internal carotid artery; heart rate (HR) and beat-to-beat mean BP were recorded using a continuous finger-pulse photoplethysmography; respiratory rate (RR), minute ventilation (MV), end-tidal CO2 (EtCO2) and end-tidal O2 (EtO2) were measured using a metabolic and spirometry module of the medical monitoring system. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. Results HGT evoked an increase in BP (+15.9%; P<0.001), HR (14.7; P<0.001), SaO2 (+0.5; P<0.001) EtO2 (+2.1; P<0.05) RR (+9.2%; P = 0.05) and MV (+15.5%; P<0.001), while sas-TQ was diminished (-8.12%; P<0.001), and a clear trend toward cc-TQ decline was observed (-11.0%; NS). CBFV (+2.9%; NS) and EtCO2 (-0.7; NS) did not change during HGT. CT evoked an increase in BP (+7.4%; P<0.001), sas-TQ (+3.5%; P<0.05) and SaO2(+0.3%; P<0.05). HR (+2.3%; NS), CBFV (+2.0%; NS), EtO2 (-0.7%; NS) and EtCO2 (+0.9%; NS) remained unchanged. A trend toward decreased cc-TQ was observed (-5.1%; NS). The sas-TQ response was biphasic with elevation during the first 40 seconds (+8.8% vs. baseline; P<0.001) and subsequent decline (+4.1% vs. baseline; P<0.05). No change with respect to wavelet coherence and wavelet phase coherence was found between the BP and cc-TQ oscillations. Conclusions Short sympathetic activation does not affect the cardiac and respiratory contribution to the relationship between BP—cc-TQ oscillations. HGT and CT display divergent effects on the width of the subarachnoid space, an indirect marker of changes in intracranial pressure.
Collapse
Affiliation(s)
- Pawel J. Winklewski
- Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland
- * E-mail:
| | - Yurii Tkachenko
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | - Kamila Mazur
- Department of Biomedical Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Jacek Kot
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | - Marcin Gruszecki
- Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Guminski
- Department of Computer Communications, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Krzysztof Czuszynski
- Department of Biomedical Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Jerzy Wtorek
- Department of Biomedical Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | | |
Collapse
|
61
|
Mansukhani MP, Kara T, Caples SM, Somers VK. Chemoreflexes, sleep apnea, and sympathetic dysregulation. Curr Hypertens Rep 2015; 16:476. [PMID: 25097113 DOI: 10.1007/s11906-014-0476-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Obstructive sleep apnea (OSA) and hypertension are closely linked conditions. Disordered breathing events in OSA are characterized by increasing efforts against an occluded airway while asleep, resulting in a marked sympathetic response. This is predominantly due to hypoxemia activating the chemoreflexes, resulting in reflex increases in sympathetic neural outflow. In addition, apnea - and the consequent lack of inhibition of the sympathetic system that occurs with lung inflation during normal breathing - potentiates central sympathetic outflow. Sympathetic activation persists into the daytime, and is thought to contribute to hypertension and other adverse cardiovascular outcomes. This review discusses chemoreflex physiology and sympathetic modulation during normal sleep, as well as the sympathetic dysregulation seen in OSA, its extension into wakefulness, and changes after treatment. Evidence supporting the role of the peripheral chemoreflex in the sympathetic dysregulation seen in OSA, including in the context of comorbid obesity, metabolic syndrome, and systemic hypertension, is reviewed. Finally, alterations in cardiovascular variability and other potential mechanisms that may play a role in the autonomic imbalance in OSA are also discussed.
Collapse
Affiliation(s)
- Meghna P Mansukhani
- Sleep Medicine, Affiliated Communities Medical Center, 101 Willmar Avenue SW, Willmar, MN, USA,
| | | | | | | |
Collapse
|
62
|
Lemaitre F, Chowdhury T, Schaller B. The trigeminocardiac reflex - a comparison with the diving reflex in humans. Arch Med Sci 2015; 11:419-26. [PMID: 25995761 PMCID: PMC4424259 DOI: 10.5114/aoms.2015.50974] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/03/2013] [Accepted: 06/30/2013] [Indexed: 12/21/2022] Open
Abstract
The trigeminocardiac reflex (TCR) has previously been described in the literature as a reflexive response of bradycardia, hypotension, and gastric hypermotility seen upon mechanical stimulation in the distribution of the trigeminal nerve. The diving reflex (DR) in humans is characterized by breath-holding, slowing of the heart rate, reduction of limb blood flow and a gradual rise in the mean arterial blood pressure. Although the two reflexes share many similarities, their relationship and especially their functional purpose in humans have yet to be fully elucidated. In the present review, we have tried to integrate and elaborate these two phenomena into a unified physiological concept. Assuming that the TCR and the DR are closely linked functionally and phylogenetically, we have also highlighted the significance of these reflexes in humans.
Collapse
Affiliation(s)
- Frederic Lemaitre
- Faculty of Sports Sciences, University of Rouen, Mont-Saint-Aignan, France
| | - Tumul Chowdhury
- Department of Anesthesia and Perioperative Medicine, University of Manitoba, Winnipeg, Canada
| | - Bernhard Schaller
- Department of Neurosurgery, University Hospital Paris, Paris, France
| |
Collapse
|
63
|
Costalat G, Pichon A, Joulia F, Lemaître F. Modeling the diving bradycardia: Toward an "oxygen-conserving breaking point"? Eur J Appl Physiol 2015; 115:1475-84. [PMID: 25691132 DOI: 10.1007/s00421-015-3129-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/09/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE Although it has been demonstrated that the exponential decay model fits the heart rate (HR) kinetics in short static breath holding (BH), this model might be inaccurate when BH is maintained for several minutes. The aim of this study was to build a new meaningful model to quantify HR kinetics during prolonged static BH. METHODS Nonlinear regression analysis was used to build a model able to quantify the beat-to-beat HR reduction kinetics observed in prolonged static BH performed both in air and in immersed condition by 11 trained breath-hold divers. Dynamic changes in cardiac autonomic regulation through heart rate variability indices [root mean square of successive difference of R-R intervals (RMSSD); short-term fractal scaling exponent: (DFAα1)] and peripheral oxygen saturation (SpO2) were also analyzed to strengthen the model. RESULTS The tri-phasic model showed a sharp exponential drop in HR immediately followed by a slight linear rise up until a breaking point preceding a linear drop in HR. The breaking points had similar level of SpO2 whether in air or in immersed condition (95.1 ± 2.1 vs. 95.2 ± 3.0 %, respectively; P = 0.49), and the subsequent linear drop in HR was concomitant with a shift in cardiac autonomic regulation in air (RMSSD: +109.0 ± 47.8 %; P < 0.001; DFAα1: -18.0 ± 17.4 %; P < 0.05) and in immersion (RMSSD: +112.6 ± 55.8 %; P < 0.001; DFAα1: -26.0 ± 12 %; P < 0.001). CONCLUSION In addition to accurately fitting the HR kinetics, the most striking finding is an "oxygen-conserving breaking point" highlighted by the model, which might be interpreted as unique adaptive feature against hypoxic damages in the human diving bradycardia.
Collapse
Affiliation(s)
- Guillaume Costalat
- CETAPS Laboratory, EA no 3832, Faculté des Sciences du Sport, Boulevard Siegfried, Normandie University, Mont Saint-Aignan, France,
| | | | | | | |
Collapse
|
64
|
Eichhorn L, Erdfelder F, Kessler F, Doerner J, Thudium MO, Meyer R, Ellerkmann RK. Evaluation of near-infrared spectroscopy under apnea-dependent hypoxia in humans. J Clin Monit Comput 2015; 29:749-57. [PMID: 25649718 DOI: 10.1007/s10877-015-9662-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 01/27/2015] [Indexed: 11/25/2022]
Abstract
In this study we investigated the responsiveness of near-infrared spectroscopy (NIRS) recordings measuring regional cerebral tissue oxygenation (rSO2) during hypoxia in apneic divers. The goal was to mimic dynamic hypoxia as present during cardiopulmonary resuscitation, laryngospasm, airway obstruction, or the "cannot ventilate cannot intubate" situation. Ten experienced apneic divers performed maximal breath hold maneuvers under dry conditions. SpO2 was measured by Masimo™ pulse oximetry on the forefinger of the left hand. NIRS was measured by NONIN Medical's EQUANOX™ on the forehead or above the musculus quadriceps femoris. Following apnea median cerebral rSO2 and SpO2 values decreased significantly from 71 to 54 and from 100 to 65%, respectively. As soon as cerebral rSO2 and SpO2 values decreased monotonically the correlation between normalized cerebral rSO2 and SpO2 values was highly significant (Pearson correlation coefficient = 0.893). Prior to correlation analyses, the values were normalized by dividing them by the individual means of stable pre-apneic measurements. Cerebral rSO2 measured re-saturation after termination of apnea significantly earlier (10 s, SD = 3.6 s) compared to SpO2 monitoring (21 s, SD = 4.4 s) [t(9) = 7.703, p < 0.001, r(2) = 0.868]. Our data demonstrate that NIRS monitoring reliably measures dynamic changes in cerebral tissue oxygen saturation, and identifies successful re-saturation faster than SpO2. Measuring cerebral rSO2 may prove beneficial in case of respiratory emergencies and during pulseless situations where SpO2 monitoring is impossible.
Collapse
Affiliation(s)
- Lars Eichhorn
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
| | - Felix Erdfelder
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Florian Kessler
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Jonas Doerner
- Department of Radiology, University Hospital Bonn, Bonn, Germany
| | - Marcus O Thudium
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - Rainer Meyer
- Institute of Physiology 2, University of Bonn, Bonn, Germany
| | - Richard K Ellerkmann
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| |
Collapse
|
65
|
Regulation of brain blood flow and oxygen delivery in elite breath-hold divers. J Cereb Blood Flow Metab 2015; 35:66-73. [PMID: 25370857 PMCID: PMC4294396 DOI: 10.1038/jcbfm.2014.170] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 01/07/2023]
Abstract
The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n=17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) while breathing. End-apnea PaO2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF.
Collapse
|
66
|
Parkes MJ, Green S, Stevens AM, Clutton-Brock TH. Assessing and ensuring patient safety during breath-holding for radiotherapy. Br J Radiol 2014; 87:20140454. [PMID: 25189121 PMCID: PMC4207152 DOI: 10.1259/bjr.20140454] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective: While there is recent interest in using repeated deep inspiratory breath-holds, or prolonged single breath-holds, to improve radiotherapy delivery, breath-holding has risks. There are no published guidelines for monitoring patient safety, and there is little clinical awareness of the pronounced blood pressure rise and the potential for gradual asphyxia that occur during breath-holding. We describe the blood pressure rise during deep inspiratory breath-holding with air and test whether it can be abolished simply by pre-oxygenation and hypocapnia. Methods: We measured blood pressure, oxygen saturation (SpO2) and heart rate in 12 healthy, untrained subjects performing breath-holds. Results: Even for deep inspiratory breath-holds with air, the blood pressure rose progressively (e.g. mean systolic pressure rose from 133 ± 5 to 175 ± 8 mmHg at breakpoint, p < 0.005, and in two subjects, it reached 200 mmHg). Pre-oxygenation and hypocapnia prolonged breath-hold duration and prevented the development of asphyxia but failed to abolish the pressure rise. The pressure rise was not a function of breath-hold duration and was not signalled by any fall in heart rate (remaining at resting levels of 72 ± 2 beats per minute). Conclusion: Colleagues should be aware of the progressive blood pressure rise during deep inspiratory breath-holding that so far is not easily prevented. In breast cancer patients scheduled for breath-holds, we recommend routine screening for heart, cardiovascular, renal and cerebrovascular disease, routine monitoring of patient blood pressure and SpO2 during breath-holding and requesting patients to stop if systolic pressure rises consistently >180 mmHg and or SpO2 falls <94%. Advances in knowledge: There is recent interest in using deep inspiratory breath-holds, or prolonged single breath-holding techniques, to improve radiotherapy delivery. But there appears to be no clinical awareness of the risks to patients from breath-holding. We demonstrate the progressive blood pressure rise during deep inspiratory breath-holds with air, which we show cannot be prevented by the simple expedient of pre-oxygenation and hypocapnia. We propose patient screening and safety guidelines for monitoring both blood pressure and SpO2 during breath-holds and discuss their clinical implications.
Collapse
Affiliation(s)
- M J Parkes
- 1 National Institute for Health Research (NIHR)/Wellcome Trust Birmingham Clinical Research Facility, University of Birmingham and University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | | | | | | |
Collapse
|
67
|
Cross TJ, Kavanagh JJ, Breskovic T, Johnson BD, Dujic Z. Dynamic cerebral autoregulation is acutely impaired during maximal apnoea in trained divers. PLoS One 2014; 9:e87598. [PMID: 24498340 PMCID: PMC3911978 DOI: 10.1371/journal.pone.0087598] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 12/21/2013] [Indexed: 11/22/2022] Open
Abstract
Aims To examine whether dynamic cerebral autoregulation is acutely impaired during maximal voluntary apnoea in trained divers. Methods Mean arterial pressure (MAP), cerebral blood flow-velocity (CBFV) and end-tidal partial pressures of O2 and CO2 (PETO2 and PETCO2) were measured in eleven trained, male apnoea divers (28±2 yr; 182±2 cm, 76±7 kg) during maximal “dry” breath holding. Dynamic cerebral autoregulation was assessed by determining the strength of phase synchronisation between MAP and CBFV during maximal apnoea. Results The strength of phase synchronisation between MAP and CBFV increased from rest until the end of maximal voluntary apnoea (P<0.05), suggesting that dynamic cerebral autoregulation had weakened by the apnoea breakpoint. The magnitude of impairment in dynamic cerebral autoregulation was strongly, and positively related to the rise in PETCO2 observed during maximal breath holding (R2 = 0.67, P<0.05). Interestingly, the impairment in dynamic cerebral autoregulation was not related to the fall in PETO2 induced by apnoea (R2 = 0.01, P = 0.75). Conclusions This study is the first to report that dynamic cerebral autoregulation is acutely impaired in trained divers performing maximal voluntary apnoea. Furthermore, our data suggest that the impaired autoregulatory response is related to the change in PETCO2, but not PETO2, during maximal apnoea in trained divers.
Collapse
Affiliation(s)
- Troy J. Cross
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| | - Justin J. Kavanagh
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Bruce D. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| |
Collapse
|
68
|
Costalat G, Coquart J, Castres I, Tourny C, Lemaitre F. Hemodynamic adjustments during breath-holding in trained divers. Eur J Appl Physiol 2013; 113:2523-9. [PMID: 23821240 DOI: 10.1007/s00421-013-2690-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 06/25/2013] [Indexed: 11/29/2022]
Abstract
PURPOSE Voluntary breath-holding (BH) elicits several hemodynamic changes, but little is known about maximal static immersed-body BH. We hypothesized that the diving reflex would be strengthened with body immersion and would spare more oxygen than maximal dry static BH, resulting in a longer BH duration. METHODS Eleven trained breath-hold divers (BHDs) performed a maximal dry-body BH and a maximal immersed-body BH. Cardiac output (CO), stroke volume (SV), heart rate (HR), left ventricular end-diastolic volume (LVEDV), contractility index (CTI), and ventricular ejection time (VET) were continuously recorded by bio-impedancemetry (PhysioFlow PF-05). Arterial oxygen saturation (SaO2) was assessed with a finger probe oximeter. RESULTS In both conditions, BHDs presented a bi-phasic kinetic for CO and a tri-phasic kinetic for SV and HR. In the first phase of immersed-body BH and dry-body BH, results (mean ± SD) expressed as percentage changes from starting values showed decreased CO (55.9 ± 10.4 vs. 39.3 ± 16.8 %, respectively; p < 0.01 between conditions), due to drops in both SV (24.9 ± 16.2 vs. 9.0 ± 8.5 %, respectively; p < 0.05 between conditions) and HR (39.7 ± 16.7 vs. 33.6 ± 17.0 %, respectively; p < 0.01 between conditions). The second phase was marked by an overall stabilization of hemodynamic variables. In the third one, CO kept stabilizing due to increased SV (17.0 ± 20.2 vs. 10.9 ± 13.8 %, respectively; p < 0.05 between conditions) associated with a second HR drop (14.0 ± 10.0 vs. 12.7 ± 8.9 %, respectively; p < 0.01 between conditions). CONCLUSION This study highlights similar time-course patterns for cardiodynamic variables during dry-body and immersed-body BH, although the phenomenon was more pronounced in the latter condition.
Collapse
Affiliation(s)
- Guillaume Costalat
- CETAPS, EA No. 3832, Faculté des Sciences du Sport, Boulevard Siegfried, Université de Rouen, 76130, Mont-Saint-Aignan, France,
| | | | | | | | | |
Collapse
|
69
|
Cross TJ, Kavanagh JJ, Breskovic T, Zubin Maslov P, Lojpur M, Johnson BD, Dujic Z. The Effects of Involuntary Respiratory Contractions on Cerebral Blood Flow during Maximal Apnoea in Trained Divers. PLoS One 2013; 8:e66950. [PMID: 23840561 PMCID: PMC3694127 DOI: 10.1371/journal.pone.0066950] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/14/2013] [Indexed: 11/26/2022] Open
Abstract
The effects of involuntary respiratory contractions on the cerebral blood flow response to maximal apnoea is presently unclear. We hypothesised that while respiratory contractions may augment left ventricular stroke volume, cardiac output and ultimately cerebral blood flow during the struggle phase, these contractions would simultaneously cause marked ‘respiratory’ variability in blood flow to the brain. Respiratory, cardiovascular and cerebrovascular parameters were measured in ten trained, male apnoea divers during maximal ‘dry’ breath holding. Intrathoracic pressure was estimated via oesophageal pressure. Left ventricular stroke volume, cardiac output and mean arterial pressure were monitored using finger photoplethysmography, and cerebral blood flow velocity was obtained using transcranial ultrasound. The increasingly negative inspiratory intrathoracic pressure swings of the struggle phase significantly influenced the rise in left ventricular stroke volume (R2 = 0.63, P<0.05), thereby contributing to the increase in cerebral blood flow velocity throughout this phase of apnoea. However, these contractions also caused marked respiratory variability in left ventricular stroke volume, cardiac output, mean arterial pressure and cerebral blood flow velocity during the struggle phase (R2 = 0.99, P<0.05). Interestingly, the magnitude of respiratory variability in cerebral blood flow velocity was inversely correlated with struggle phase duration (R2 = 0.71, P<0.05). This study confirms the hypothesis that, on the one hand, involuntary respiratory contractions facilitate cerebral haemodynamics during the struggle phase while, on the other, these contractions produce marked respiratory variability in blood flow to the brain. In addition, our findings indicate that such variability in cerebral blood flow negatively impacts on struggle phase duration, and thus impairs breath holding performance.
Collapse
Affiliation(s)
- Troy J. Cross
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| | - Justin J. Kavanagh
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Petra Zubin Maslov
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Mihajlo Lojpur
- Department of Anaesthesiology, Clinical Hospital Center Split, Split, Croatia
| | - Bruce D. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| |
Collapse
|
70
|
Sharpe AL, Andrade MA, Herrera-Rosales M, Britton SL, Koch LG, Toney GM. Rats selectively bred for differences in aerobic capacity have similar hypertensive responses to chronic intermittent hypoxia. Am J Physiol Heart Circ Physiol 2013; 305:H403-9. [PMID: 23709603 DOI: 10.1152/ajpheart.00317.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Exposure to chronic intermittent hypoxia (CIH) is an animal model that mimics the repetitive bouts of hypoxemia experienced by humans with sleep apnea. Rats exposed to CIH develop hypertension that depends on the activation of sympathetic nerve activity (SNA). Since obesity and metabolic syndrome have been linked to neurogenic hypertension and sleep apnea, and because sleep apnea can adversely affect aerobic exercise capacity, we tested the hypothesis that rats bred for selection of low aerobic capacity running (LCR) would have a greater hypertensive response to CIH than rats bred for high aerobic capacity running (HCR). Blockade of ganglionic transmission was performed to compare the contribution of SNA to the maintenance of resting mean arterial pressure (MAP). Next, hypertensive responses to 7 days of CIH were compared across LCR and HCR rats (14-16 mo old). Finally, the contribution of the hypothalamic paraventricular nucleus (PVN) to the maintenance of SNA and hypertension after CIH was determined and compared across groups. Although LCR rats were less active and had greater body weights than HCR rats, resting MAP, the contribution of ongoing SNA to the maintenance of MAP, and hypertensive responses to CIH were similar between groups. Contrary to our hypothesis, chemical inhibition of the PVN with muscimol (1 mmol/100 nl) caused a larger fall of MAP in HCR rats than in LCR rats. We conclude that LCR rats do not have resting hypertension or an exaggerated hypertensive response to CIH. Interestingly, the maintenance of CIH hypertension in LCR rats compared with HCR rats appears less reliant on ongoing PVN neuronal activity.
Collapse
Affiliation(s)
- Amanda L Sharpe
- Department of Pharmaceutical Sciences, Feik School of Pharmacy, University of the Incarnate Word, San Antonio, TX 78209, USA.
| | | | | | | | | | | |
Collapse
|
71
|
Abstract
AbstractElite breath-hold divers are unique athletes challenged with compression induced by hydrostatic pressure and extreme hypoxia/hypercapnia during maximal field dives. The current world records for men are 214 meters for depth (Herbert Nitsch, No-Limits Apnea discipline), 11:35 minutes for duration (Stephane Mifsud, Static Apnea discipline), and 281 meters for distance (Goran Čolak, Dynamic Apnea with Fins discipline). The major physiological adaptations that allow breath-hold divers to achieve such depths and duration are called the “diving response” that is comprised of peripheral vasoconstriction and increased blood pressure, bradycardia, decreased cardiac output, increased cerebral and myocardial blood flow, splenic contraction, and preserved O2 delivery to the brain and heart. This complex of physiological adaptations is not unique to humans, but can be found in all diving mammals. Despite these profound physiological adaptations, divers may frequently show hypoxic loss of consciousness. The breath-hold starts with an easy-going phase in which respiratory muscles are inactive, whereas during the second so-called “struggle” phase, involuntary breathing movements start. These contractions increase cerebral blood flow by facilitating left stroke volume, cardiac output, and arterial pressure. The analysis of the compensatory mechanisms involved in maximal breath-holds can improve brain survival during conditions involving profound brain hypoperfusion and deoxygenation.
Collapse
|
72
|
Seitz MJ, Brown R, Macefield VG. Inhibition of augmented muscle vasoconstrictor drive following asphyxic apnoea in awake human subjects is not affected by relief of chemical drive. Exp Physiol 2012; 98:405-14. [DOI: 10.1113/expphysiol.2012.067421] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
73
|
Kiviniemi AM, Breskovic T, Uglesic L, Kuch B, Maslov PZ, Sieber A, Seppänen T, Tulppo MP, Dujic Z. Heart rate variability during static and dynamic breath-hold dives in elite divers. Auton Neurosci 2012; 169:95-101. [DOI: 10.1016/j.autneu.2012.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 03/28/2012] [Accepted: 05/17/2012] [Indexed: 10/28/2022]
|
74
|
Abstract
Freediving is a sport in which athletes aim to achieve the longest or the deepest breath-hold dive. Divers are at risk of gradually increasing hypoxia and hypercapnia due to a long time spent underwater and additionally of increasing hyperoxia while depth diving. Exceeding the limits of hypoxia endurance leads to loss of consciousness or even to death whithout immediate first aid. Often enhanced world records indicate the ability to shape specific to the discipline adaptive mechanisms of cardio-pulmonary system which are individually conditioned. During stay underwater heartbeats decelerating called bradycardia, increase in blood pressure, peripheral blood vessels narrowing and blood centralization in freediver’s organism. These mechanisms enhance blood oxygen management as well as transporting it first of all to essential for survival organs, i.e. brain and heart. These mechanisms are supported by spleen and adrenal glands hormonal reactions.
Collapse
|
75
|
Laurino M, Menicucci D, Mastorci F, Allegrini P, Piarulli A, Scilingo EP, Bedini R, Pingitore A, Passera M, L'Abbate A, Gemignani A. Mind-body relationships in elite apnea divers during breath holding: a study of autonomic responses to acute hypoxemia. FRONTIERS IN NEUROENGINEERING 2012; 5:4. [PMID: 22461774 PMCID: PMC3309925 DOI: 10.3389/fneng.2012.00004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 03/05/2012] [Indexed: 11/13/2022]
Abstract
The mental control of ventilation with all associated phenomena, from relaxation to modulation of emotions, from cardiovascular to metabolic adaptations, constitutes a psychophysiological condition characterizing voluntary breath-holding (BH). BH induces several autonomic responses, involving both autonomic cardiovascular and cutaneous pathways, whose characterization is the main aim of this study. Electrocardiogram and skin conductance (SC) recordings were collected from 14 elite divers during three conditions: free breathing (FB), normoxic phase of BH (NPBH) and hypoxic phase of BH (HPBH). Thus, we compared a set of features describing signal dynamics between the three experimental conditions: from heart rate variability (HRV) features (in time and frequency-domains and by using nonlinear methods) to rate and shape of spontaneous SC responses (SCRs). The main result of the study rises by applying a Factor Analysis to the subset of features significantly changed in the two BH phases. Indeed, the Factor Analysis allowed to uncover the structure of latent factors which modeled the autonomic response: a factor describing the autonomic balance (AB), one the information increase rate (IIR), and a latter the central nervous system driver (CNSD). The BH did not disrupt the FB factorial structure, and only few features moved among factors. Factor Analysis indicates that during BH (1) only the SC described the emotional output, (2) the sympathetic tone on heart did not change, (3) the dynamics of interbeats intervals showed an increase of long-range correlation that anticipates the HPBH, followed by a drop to a random behavior. In conclusion, data show that the autonomic control on heart rate and SC are differentially modulated during BH, which could be related to a more pronounced effect on emotional control induced by the mental training to BH.
Collapse
Affiliation(s)
- Marco Laurino
- Department of Physiological Sciences, University of PisaPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Danilo Menicucci
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | | | - Paolo Allegrini
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Andrea Piarulli
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Enzo P. Scilingo
- Interdepartment Research Center “E. Piaggio”, University of PisaPisa, Italy
| | - Remo Bedini
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Alessandro Pingitore
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Mirko Passera
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Antonio L'Abbate
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| | - Angelo Gemignani
- Department of Physiological Sciences, University of PisaPisa, Italy
- Institute of Clinical Physiology, National Research CouncilPisa, Italy
- EXTREME Centre, Scuola Superiore Sant'AnnaPisa, Italy
| |
Collapse
|
76
|
Batinic T, Utz W, Breskovic T, Jordan J, Schulz-Menger J, Jankovic S, Dujic Z, Tank J. Cardiac magnetic resonance imaging during pulmonary hyperinflation in apnea divers. Med Sci Sports Exerc 2012; 43:2095-101. [PMID: 21552160 DOI: 10.1249/mss.0b013e31821ff294] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Apnea divers hyperinflate the lung by taking a deep breath followed by glossopharyngeal insufflation. The maneuver can lead to symptomatic arterial hypotension. We tested the hypotheses that glossopharyngeal insufflation interferes with cardiac function further reducing cardiac output (CO) using cardiac magnetic resonance imaging (MRI) to fully sample both cardiac chambers. METHODS Eleven dive athletes (10 men, 1 woman; age = 26 ± 5 yr, body mass index = 23.5 ± 1.7 kg·m(-2)) underwent cardiac MRI during breath holding at functional residual capacity (baseline), at total lung capacity (apnea), and with submaximal glossopharyngeal insufflation. Lung volumes were estimated from anatomic images. Short-axis cine MR images were acquired to study biventricular function. Dynamic changes were followed by long-axis cine MRI. RESULTS Left and right ventricular end-diastolic volumes (LVEDV, RVEDV) decreased during apnea with and without glossopharyngeal insufflation (baseline: LVEDV = 198 ± 19 mL, RVEDV = 225 ± 30 mL; apnea: LVEDV = 125 ± 38 mL, RVEDV = 148 ± 37 mL, P < 0.001; glossopharyngeal insufflation: LVEDV = 108 ± 26 mL, RVEDV = 136 ± 29 mL, P < 0.001 vs baseline). CO decreased during apnea (left = -29 ± 4 %, right = -29 ± 4 %) decreasing further with glossopharyngeal insufflation (left = -38% ± 4%, right = -39% ± 4%, P < 0.05). HR increased 16 ± 4 bpm with apnea and 17 ± 5 bpm with glossopharyngeal insufflation (P < 0.01). Ejection fraction moderately decreased (apnea: left = -5% ± 2%, right = -7% ± 2%, glossopharyngeal insufflation: left = -6% ± 2%, right = -10% ± 2%, P < 0.01). With continued apnea with and without glossopharyngeal insufflation, LVEDV and CO increased over time by a similar but small amount (P < 0.01). CONCLUSIONS The major finding of our study was that submaximal glossopharyngeal insufflation decreased CO further albeit by a small amount compared to maximal inspiratory apnea. The response was not associated with severe biventricular dysfunction.
Collapse
Affiliation(s)
- Tonci Batinic
- Department of Radiology, University Hospital Split, Croatia
| | | | | | | | | | | | | | | |
Collapse
|
77
|
Alboni P, Alboni M, Gianfranchi L. Diving bradycardia: a mechanism of defence against hypoxic damage. J Cardiovasc Med (Hagerstown) 2011; 12:422-7. [PMID: 21330930 DOI: 10.2459/jcm.0b013e328344bcdc] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A feature of all air-breathing vertebrates, diving bradycardia is triggered by apnoea and accentuated by immersion of the face or whole body in cold water. Very little is known about the afferents of diving bradycardia, whereas the efferent part of the reflex circuit is constituted by the cardiac vagal fibres. Diving bradycardia is associated with vasoconstriction of selected vascular beds and a reduction in cardiac output. The diving response appears to be more pronounced in mammals than in birds. In humans, the bradycardic response to diving varies greatly from person to person; the reduction in heart rate generally ranges from 15 to 40%, but a small proportion of healthy individuals can develop bradycardia below 20 beats/min. During prolonged dives, bradycardia becomes more pronounced because of activation of the peripheral chemoreceptors by a reduction in the arterial partial pressure of oxygen (O2), responsible for slowing of heart rate. The vasoconstriction is associated with a redistribution of the blood flow, which saves O2 for the O2-sensitive organs, such as the heart and brain. The results of several investigations carried out both in animals and in humans show that the diving response has an O2-conserving effect, both during exercise and at rest, thus lengthening the time to the onset of serious hypoxic damage. The diving response can therefore be regarded as an important defence mechanism for the organism.
Collapse
Affiliation(s)
- Paolo Alboni
- Division of Cardiology and Arrhythmologic Center, Ospedale Civile, Cento, FE, Italy.
| | | | | |
Collapse
|
78
|
Breskovic T, Uglesic L, Zubin P, Kuch B, Kraljevic J, Zanchi J, Ljubkovic M, Sieber A, Dujic Z. Cardiovascular changes during underwater static and dynamic breath-hold dives in trained divers. J Appl Physiol (1985) 2011; 111:673-8. [PMID: 21719730 DOI: 10.1152/japplphysiol.00209.2011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Limited information exists concerning arterial blood pressure (BP) changes in underwater breath-hold diving. Simulated chamber dives to 50 m of freshwater (mfw) reported very high levels of invasive BP in two divers during static apnea (SA), whereas a recent study using a noninvasive subaquatic sphygmomanometer reported unchanged or mildly increased values at 10 m SA dive. In this study we investigated underwater BP changes during not only SA but, for the first time, dynamic apnea (DA) and shortened (SHT) DA in 16 trained breath-hold divers. Measurements included BP (subaquatic sphygmomanometer), ECG, and pulse oxymetry (arterial oxygen saturation, SpO2, and heart rate). BP was measured during dry conditions, at surface fully immersed (SA), and at 2 mfw (DA and SHT DA), whereas ECG and pulse oxymetry were measured continuously. We have found significantly higher mean arterial pressure (MAP) values in SA (∼40%) vs. SHT DA (∼30%). Postapneic recovery of BP was slightly slower after SHT DA. Significantly higher BP gain (mmHg/duration of apnea in s) was found in SHT DA vs. SA. Furthermore, DA attempts resulted in faster desaturation vs. SA. In conclusion, we have found moderate increases in BP during SA, DA, and SHT DA. These cardiovascular changes during immersed SA and DA are in agreement with those reported for dry SA and DA.
Collapse
Affiliation(s)
- Toni Breskovic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Lovro Uglesic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Petra Zubin
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Benjamin Kuch
- Real-Time Systems Laboratory, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Jasenka Kraljevic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Jaksa Zanchi
- Department of Internal Medicine, University Hospital Split, Split, Croatia; and
| | - Marko Ljubkovic
- 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
| |
Collapse
|
79
|
Breskovic T, Steinback CD, Salmanpour A, Shoemaker JK, Dujic Z. Recruitment pattern of sympathetic neurons during breath-holding at different lung volumes in apnea divers and controls. Auton Neurosci 2011; 164:74-81. [PMID: 21641877 DOI: 10.1016/j.autneu.2011.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 05/10/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
Abstract
We tested the hypothesis that breath-hold divers (BHD) attain higher level of sympathetic activation than controls due to the duration of breath-hold rather than a different recruitment strategy. In 6 control subjects and 8 BHD we measured muscle sympathetic neural activity (MSNA) prior to and during functional residual capacity (FRC) and total lung capacity (TLC) breath-holding. On a subset of subjects we applied a new technique for the detection of action potentials (APs) in multiunit MSNA. Compared with controls, BHD group had lower burst AP content (13±7 vs. 6±3AP/burst; P=0.05) and number of active clusters (5±1 vs. 3±1clusters/burst; P=0.05) at baseline. However, the overall sympathetic AP/unit-time was comparable between the groups (131±105 vs. 173±152AP/min; P=0.62) due to increased burst frequency in BHD group (20±4bursts/min) vs. controls (13±3bursts/min) (P=0.039). The achieved level in total MSNA during FRC breath-holds was higher in divers (2298±780 vs. 1484±575a.u./min; P=0.039). Total MSNA at the end of TLC breath-hold was comparable between the groups (157±50 (controls) vs. 214±41s (BHD); P=0.61). FRC and TLC breath-holds increased AP frequency, burst AP content and active clusters/bursts in both groups but the response magnitude was determined by the type of the breath-hold. The divers used fewer number of APs/burst and active clusters/burst. In both groups breath-holds resulted in similar increases in MSNA which were reached both by an increase in firing frequency and by recruitment of previously silent, larger (faster conducting) sympathetic neurons, and possibly by repeated firing within the same burst.
Collapse
Affiliation(s)
- Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia
| | | | | | | | | |
Collapse
|
80
|
Dujic Z, Breskovic T, Ljubkovic M. Breath hold diving: In vivo model of the brain survival response in man? Med Hypotheses 2011; 76:737-40. [DOI: 10.1016/j.mehy.2011.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 02/04/2011] [Indexed: 11/15/2022]
|
81
|
Tank J, Biller H, Heusser K, Holz O, Diedrich A, Framke T, Koch A, Grosshennig A, Koch W, Krug N, Jordan J, Hohlfeld JM. Effect of acute ozone induced airway inflammation on human sympathetic nerve traffic: a randomized, placebo controlled, crossover study. PLoS One 2011; 6:e18737. [PMID: 21494635 PMCID: PMC3073001 DOI: 10.1371/journal.pone.0018737] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 03/12/2011] [Indexed: 11/18/2022] Open
Abstract
Background Ozone concentrations in ambient air are related to cardiopulmonary
perturbations in the aging population. Increased central sympathetic nerve
activity induced by local airway inflammation may be one possible
mechanism. Methodology/Principal Findings To elucidate this issue further, we performed a randomized, double-blind,
cross-over study, including 14 healthy subjects (3 females, age 22–47
years), who underwent a 3 h exposure with intermittent exercise to either
ozone (250 ppb) or clean air. Induced sputum was collected 3 h after
exposure. Nineteen to 22 hours after exposure, we recorded ECG, finger blood
pressure, brachial blood pressure, respiration, cardiac output, and muscle
sympathetic nerve activity (MSNA) at rest, during deep breathing,
maximum-inspiratory breath hold, and a Valsalva maneuver. While the ozone
exposure induced the expected airway inflammation, as indicated by a
significant increase in sputum neutrophils, we did not detect a significant
estimated treatment effect adjusted for period on cardiovascular
measurements. Resting heart rate (clean air: 59±2, ozone 60±2
bpm), blood pressure (clean air: 121±3/71±2 mmHg; ozone:
121±2/71±2 mmHg), cardiac output (clean air: 7.42±0.29
mmHg; ozone: 7.98±0.60 l/min), and plasma norepinephrine levels
(clean air: 213±21 pg/ml; ozone: 202±16 pg/ml), were similar
on both study days. No difference of resting MSNA was observed between ozone
and air exposure (air: 23±2, ozone: 23±2 bursts/min). Maximum
MSNA obtained at the end of apnea (air: 44±4, ozone: 48±4
bursts/min) and during the phase II of the Valsalva maneuver (air:
64±5, ozone: 57±6 bursts/min) was similar. Conclusions/Significance Our study suggests that acute ozone-induced airway inflammation does not
increase resting sympathetic nerve traffic in healthy subjects, an
observation that is relevant for environmental health. However, we can not
exclude that chronic airway inflammation may contribute to sympathetic
activation.
Collapse
Affiliation(s)
- Jens Tank
- Institute of Clinical Pharmacology, Hannover Medical School, Hannover, Germany.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
82
|
Lambrechts K, Germonpré P, Charbel B, Cialoni D, Musimu P, Sponsiello N, Marroni A, Pastouret F, Balestra C. Ultrasound lung “comets” increase after breath-hold diving. Eur J Appl Physiol 2010; 111:707-13. [DOI: 10.1007/s00421-010-1697-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2010] [Indexed: 11/29/2022]
|
83
|
Heusser K, Dzamonja G, Breskovic T, Steinback CD, Diedrich A, Tank J, Jordan J, Dujic Z. Sympathetic and cardiovascular responses to glossopharyngeal insufflation in trained apnea divers. J Appl Physiol (1985) 2010; 109:1728-35. [PMID: 20864558 DOI: 10.1152/japplphysiol.00522.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glossopharyngeal insufflation (lung packing) is a common maneuver among experienced apnea divers by which additional air is pumped into the lungs. It has been shown that packing may compromise cardiovascular homeostasis. We tested the hypothesis that the packing-mediated increase in intrathoracic pressure enhances the baroreflex-mediated increase in muscle sympathetic nerve activity (MSNA) in response to an exaggerated drop in cardiac output (CO). We compared changes in hemodynamics and MSNA (peroneal microneurography) during maximal breath-holds without and with prior moderate packing (0.79 ± 0.40 liters) in 14 trained divers (12 men, 2 women, 26.7 ± 4.5 yr, body mass index 24.8 ± 2.4 kg/m(2)). Packing did not change apnea time (3.8 ± 1.0 vs. 3.8 ± 1.2 min), hemoglobin oxygen desaturation (-17.6 ± 12.3 vs. -18.7 ± 12.8%), or the reduction in CO (1 min: -3.65 ± 1.83 vs. -3.39 ± 1.96 l/min; end of apnea: -2.44 ± 1.33 vs. -2.16 ± 1.44 l/min). On the other hand, packing dampened the early, i.e., 1-min increase in mean arterial pressure (MAP, 1 min: 9.2 ± 8.3 vs. 2.4 ± 11.0 mmHg, P < 0.01) and in total peripheral resistance (relative TPR, 1 min: 2.1 ± 0.5 vs. 1.9 ± 0.5, P < 0.05) but it augmented the concomitant rise in MSNA (1 min: 28.0 ± 11.7 vs. 39.4 ± 12.7 bursts/min, P < 0.001; 32.8 ± 16.4 vs. 43.9 ± 14.8 bursts/100 heart beats, P < 0.01; 3.3 ± 2.1 vs. 4.8 ± 3.2 au/min, P < 0.05). We conclude that the early sympathoactivation 1 min into apnea after moderate packing is due to mechanisms other than excessive reduction in CO. We speculate that lower MAP despite increased MSNA after packing might be explained by vasodilator substances released by the lungs. This idea should be addressed in future studies.
Collapse
Affiliation(s)
- Karsten Heusser
- Institute of Clinical Pharmacology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
84
|
Gargne O, Joulia F, Golé Y, Coulange M, Bessereau J, Fontanari P, Desruelle AV, Gavarry O, Boussuges A. Cardiac alterations induced by a fish-catching diving competition. Scand J Med Sci Sports 2010; 22:335-40. [PMID: 20738824 DOI: 10.1111/j.1600-0838.2010.01169.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cardiac changes induced by repeated breath-hold diving were investigated after a fish-catching diving competition. Eleven healthy subjects carried out repeated breath-hold dives at a mean maximal depth of 20 ± 2.7 msw (66 ± 9 fsw) during 5 h. One hour after the competition, the body mass loss was -1.7 ± 0.5 kg. Most of the breath-hold divers suffered from cold and although the core temperature remained normal, a decrease in cutaneous temperature was recorded in the extremities. Systolic blood pressure was reduced in both upper and lower limbs. Heart rate was unchanged, but left ventricular (LV) stroke volume was reduced leading to a decrease in cardiac output (-20%). Left atrial and LV diameters were significantly decreased. LV filling was assessed on a trans-mitral profile. An increase in the contribution of the atrial contraction to LV filling was observed. Right cavity diameters were increased. The cardiac autonomic alterations were in favor of sympathetic hyperactivity. After a fish-catching diving competition in cold water, alterations suggesting dehydration, contraction in plasma volume and sympathetic hyperactivity were observed. Furthermore, enlargements of right cavities were in favor of right ventricular strains. Repeated apnea and swimming in cold water may account for these alterations.
Collapse
Affiliation(s)
- O Gargne
- UMR MD2, Faculté de Médecine Nord, Université de la Méditerranée et IRBA Antenne Toulon, IMNSSA, Physiologie et Physiopathologie en Conditions d'Oxygénation Extrême, Marseille, Cedex, France
| | | | | | | | | | | | | | | | | |
Collapse
|
85
|
Fagius J, Nygren I. Strong potential for baroreflex-governed sympathetic outflow revealed during nausea. Clin Auton Res 2010; 20:371-4. [PMID: 20680386 DOI: 10.1007/s10286-010-0076-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 06/25/2010] [Indexed: 12/14/2022]
Abstract
Muscle sympathetic nerve activity (MSNA) was recorded in two patients with amyotrophic lateral sclerosis. As expected, they exhibited a high level of MSNA at rest, with an inverse weak response to different maneuvers normally eliciting strong increase in MSNA. About 30 min after the intake of a glucose solution, they developed nausea with an extreme rise in MSNA and blood pressure. In one patient, a quantified analysis of this reaction could be done: the outflow was close to 200% above the already high resting level and >100% stronger than the response to any of the performed maneuvers. We regard this observation of importance, because it seems to unveil resources utilized only rarely, and strongly overcoming the "ceiling effect" that seemingly is a hindrance for sympathetic activation in subjects with high lever of MSNA at rest. An inhibitory "safety limit" might exist, the trespassing of which would damage the organism and thus occurs only during extraordinary circumstances.
Collapse
Affiliation(s)
- Jan Fagius
- Department of Neurology, Akademiska sjukhuset/University Hospital, 751 85 Uppsala, Sweden.
| | | |
Collapse
|
86
|
Steinback CD, Breskovic T, Banic I, Dujic Z, Shoemaker JK. Autonomic and cardiovascular responses to chemoreflex stress in apnoea divers. Auton Neurosci 2010; 156:138-43. [DOI: 10.1016/j.autneu.2010.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 04/05/2010] [Accepted: 05/13/2010] [Indexed: 10/19/2022]
|
87
|
Dzamonja G, Tank J, Heusser K, Palada I, Valic Z, Bakovic D, Obad A, Ivancev V, Breskovic T, Diedrich A, Luft FC, Dujic Z, Jordan J. Glossopharyngeal insufflation induces cardioinhibitory syncope in apnea divers. Clin Auton Res 2010; 20:381-4. [DOI: 10.1007/s10286-010-0075-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 06/10/2010] [Indexed: 10/19/2022]
|
88
|
Breskovic T, Ivancev V, Banic I, Jordan J, Dujic Z. Peripheral chemoreflex sensitivity and sympathetic nerve activity are normal in apnea divers during training season. Auton Neurosci 2010; 154:42-7. [PMID: 19926535 DOI: 10.1016/j.autneu.2009.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 10/26/2009] [Accepted: 11/02/2009] [Indexed: 11/28/2022]
Abstract
Apnea divers are exposed to repeated massive arterial oxygen desaturation, which could perturb chemoreflexes. An earlier study suggested that peripheral chemoreflex regulation of sympathetic vasomotor tone and ventilation may have recovered 4 or more weeks into the off season. Therefore, we tested the hypothesis that peripheral chemoreflex regulation of ventilation and sympathetic vasomotor tone is present during the training season. We determined ventilation, heart rate, blood pressure, cardiac stroke volume, and muscle sympathetic nerve activity (MSNA) during isocapnic hypoxia in 10 breath hold divers and 11 matched control subjects. The study was carried out at the end of the season of intense apnea trainings. Baseline MSNA frequency was 30+/-4bursts/min in control subjects and 25+/-4bursts/min in breath hold divers (P=0.053). During hypoxia burst frequency and total sympathetic activity increased similarly in both groups. Sympathetic activity normalized during the 30-minute recovery. Hypoxia-induced stimulation of minute ventilation was similar in both groups, although in divers it was maintained by higher tidal volumes and lower breathing frequency compared with control subjects. In both groups, hypoxia increased heart rate and cardiac output whereas total peripheral resistance decreased. Blood pressure remained unchanged. We conclude that peripheral chemoreflex regulation of ventilation and sympathetic vasomotor tone is paradoxically preserved in apnea divers, both, during the off and during the training season. The observation suggests that repeated arterial oxygen desaturation may not be sufficient explaining sympathetic reflex abnormalities similar to those in obstructive sleep apnea patients.
Collapse
Affiliation(s)
- Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | | | | | | | | |
Collapse
|
89
|
CIH: from sleep apnea to breath-hold diving. Is sympathetic activation inevitable? Clin Auton Res 2010; 20:53-5. [PMID: 20405161 DOI: 10.1007/s10286-010-0064-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
90
|
Taneja I, Medow MS, Clarke DA, Ocon AJ, Stewart JM. Postural change alters autonomic responses to breath-holding. Clin Auton Res 2009; 20:65-72. [PMID: 20012144 DOI: 10.1007/s10286-009-0046-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 11/17/2009] [Indexed: 01/10/2023]
Abstract
OBJECTIVE We used breath-holding during inspiration as a model to study the effect of pulmonary stretch on sympathetic nerve activity. METHODS Twelve healthy subjects (7 females, 5 males; 19-27 years) were tested while they performed an inspiratory breath-hold, both supine and during a 60 degrees head-up tilt (HUT 60). Heart rate (HR), mean arterial blood pressure (MAP), respiration, muscle sympathetic nerve activity (MSNA), oxygen saturation (SaO(2)) and end tidal carbon dioxide (ETCO(2)) were recorded. Cardiac output (CO) and total peripheral resistance (TPR) were calculated. RESULTS While breath-holding, ETCO(2) increased significantly from 41 +/- 2 to 60 +/- 2 Torr during supine (p < 0.05) and 38 +/- 2 Torr to 58 +/- 2 during HUT60 (p < 0.05); SaO(2) decreased from 98 +/- 1.5% to 95 +/- 1.4% supine, and from 97 +/- 1.5% to 94 +/- 1.7% during HUT60 (p = NS). MSNA showed three distinctive phases, a quiescent phase due to pulmonary stretch associated with decreased MAP, HR, CO, and TPR; a second phase of baroreflex-mediated elevated MSNA which was associated with recovery of MAP and HR only during HUT60; CO and peripheral resistance returned to baseline while supine and HUT60; a third phase of further increased MSNA activity related to hypercapnia and associated with increased TPR. INTERPRETATION Breath-holding results in initial reductions of MSNA, MAP, and HR by the pulmonary stretch reflex followed by increased sympathetic activity related to the arterial baroreflex and chemoreflex.
Collapse
Affiliation(s)
- Indu Taneja
- Department of Pediatrics, New York Medical College, Valhalla, NY, USA.
| | | | | | | | | |
Collapse
|
91
|
Dujic Z, Uglesic L, Breskovic T, Valic Z, Heusser K, Marinovic J, Ljubkovic M, Palada I. Involuntary breathing movements improve cerebral oxygenation during apnea struggle phase in elite divers. J Appl Physiol (1985) 2009; 107:1840-6. [PMID: 19850736 DOI: 10.1152/japplphysiol.00334.2009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated whether the involuntary breathing movements (IBM) during the struggle phase of breath holding, together with peripheral vasoconstriction and progressive hypercapnia, have a positive effect in maintaining cerebral blood volume. The central hemodynamics, arterial oxygen saturation, brain regional oxyhemoglobin (bHbO(2)), deoxyhemoglobin, and total hemoglobin changes and IBM were monitored during maximal dry breath holds in eight elite divers. The frequency of IBM increased (by approximately 100%), and their duration decreased ( approximately 30%), toward the end of the struggle phase, whereas the amplitude was unchanged (compared with the beginning of the struggle phase). In all subjects, a consistent increase in brain regional deoxyhemoglobin and total hemoglobin was also found during struggle phase, whereas bHbO(2) changed biphasically: it initially increased until the middle of the struggle phase, with the subsequent relative decline at the end of the breath hold. Mean arterial pressure was elevated during the struggle phase, although there was no further rise in the peripheral resistance, suggesting unchanged peripheral vasoconstriction and implying the beneficial influence of the IBM on the cardiac output recovery (primarily by restoration of the stroke volume). The IBM-induced short-lasting, sudden increases in mean arterial pressure were followed by similar oscillations in bHbO(2). These results suggest that an increase in the cerebral blood volume observed during the struggle phase of dry apnea is most likely caused by the IBM at the time of the hypercapnia-induced cerebral vasodilatation and peripheral vasoconstriction.
Collapse
Affiliation(s)
- Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia.
| | | | | | | | | | | | | | | |
Collapse
|
92
|
Peripheral chemoreflex regulation of sympathetic vasomotor tone in apnea divers. Clin Auton Res 2009; 20:57-63. [DOI: 10.1007/s10286-009-0034-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 09/14/2009] [Indexed: 10/20/2022]
|
93
|
Guaraldi P, Serra M, Barletta G, Pierangeli G, Terlizzi R, Calandra-Buonaura G, Cialoni D, Cortelli P. Cardiovascular changes during maximal breath-holding in elite divers. Clin Auton Res 2009; 19:363-6. [DOI: 10.1007/s10286-009-0025-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 06/28/2009] [Indexed: 11/30/2022]
|