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Angus SA, Taylor JL, Mann LM, Williams AM, Stöhr EJ, Au JS, Sheel AW, Dominelli PB. Mechanical ventilation in a conscious male during exercise: a case report. Appl Physiol Nutr Metab 2024. [PMID: 38885533 DOI: 10.1139/apnm-2024-0100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
We recently explored the cardiopulmonary interactions during partial unloading of the respiratory muscles during exercise. Expanding upon this work, we present a noteworthy case study whereby we eliminated the influence of respiration on cardiac function in a conscious but mechanically ventilated human during exercise. This human was a young healthy endurance-trained male who was mechanically ventilated during semi-recumbent cycle exercise at 75 Watts (W) (∼30% Wmax). During mechanically ventilated exercise, esophageal pressure was reduced to levels indistinguishable from the cardiac artefact which led to a 94% reduction in the power of breathing. The reduction in respiratory pressures and respiratory muscle work led to a decrease in cardiac output (-6%), which was due to a reduction in stroke volume (-13%), left ventricular end-diastolic volume (-15%), and left-ventricular end-systolic volume (-17%) that was not compensated for by heart rate. Our case highlights the influence of extreme mechanical ventilation on cardiac function while noting the possible presence of a maximal physiological limit to which respiration (and its associated pressures) impacts cardiac function when the power of breathing is maximally reduced.
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Affiliation(s)
- Sarah A Angus
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Joshua L Taylor
- School of Kinesiology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Leah M Mann
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Alexandra M Williams
- International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC Y6T 1Z4,Canada
| | - Eric J Stöhr
- Institute of Sports Science, COR-HELIX, Leibniz University Hannover, Hannover 30167, Germany
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York City, NY 10032, USA
| | - Jason S Au
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - A William Sheel
- School of Kinesiology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Paolo B Dominelli
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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Baur DA, Baur KG, Buchanan BK, Ortiz MJ, Doody AG. Load carriage physiology in normoxia and hypoxia. Eur J Appl Physiol 2024; 124:925-943. [PMID: 37740748 PMCID: PMC10879375 DOI: 10.1007/s00421-023-05320-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/08/2023] [Indexed: 09/25/2023]
Abstract
PURPOSE To determine the effects of load carriage in normoxia and normobaric hypoxia on ventilatory responses, hemodynamics, tissue oxygenation, and metabolism. METHODS Healthy males (n = 12) completed 3 randomly ordered baseline graded exercise tests in the following conditions: (1) unloaded normoxic (U: FIO2 = 20.93%), (2) loaded (~ 30 kg) normoxic (LN), and (3) loaded hypoxic simulating ~ 3650 m (LH: FIO2 = ~ 13%). Thereafter, experimental exercise trials were completed in quasi-randomized order (i.e., U completed first) consisting of 3 × 10 min of walking (separated by 5 min seated rest) with stages matched with the U condition (in ascending order) for relative intensity, absolute oxygen consumption ([VO2]; 1.7 L min-1), and walking speed (1.45 ± 0.15 m s-1). RESULTS Load carriage increased perceived exertion and reduced VO2max (LN: - 7%; LH: - 32%; p < 0.05). At matched VO2, stroke volume and tidal volume were reduced and maintained with LN and LH vs. U, respectively (p < 0.05). Increases in cardiac output and minute ventilation at matched VO2 (with LH) and speed (with LN and LH), were primarily accomplished via increases in heart rate and breathing frequency (p < 0.05). Cerebral oxygenated hemoglobin (O2HHb) was increased at all intensities with LN, but deoxygenated hemoglobin and total hemoglobin were increased with LH (p < 0.05). Muscle oxygen kinetics and substrate utilization were similar between LN and U, but LH increased CHO dependence and reduced muscle O2HHb at matched speed (p < 0.05). CONCLUSION Load carriage reduces cardiorespiratory efficiency and increases physiological strain, particularly in hypoxic environments. Potential load carriage-induced alterations in cerebral blood flow may increase the risk for altitude illnesses and requires further study.
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Affiliation(s)
- Daniel A Baur
- Department of Human Performance and Wellness, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA.
| | - Katherine G Baur
- Department of Human Performance and Wellness, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA
| | - Beverley K Buchanan
- Department of Human Performance and Wellness, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA
| | - Miles J Ortiz
- Department of Human Performance and Wellness, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA
| | - Abaigeal G Doody
- Department of Human Performance and Wellness, Virginia Military Institute, 208 Cormack Hall, Lexington, VA, 24450, USA
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Furst B, González-Alonso J. The heart, a secondary organ in the control of blood circulation. Exp Physiol 2023. [PMID: 38126953 DOI: 10.1113/ep091387] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
Circulation of the blood is a fundamental physiological function traditionally ascribed to the pressure-generating function of the heart. However, over the past century the 'cardiocentric' view has been challenged by August Krogh, Ernst Starling, Arthur Guyton and others, based on haemodynamic data obtained from isolated heart preparations and organ perfusion. Their research brought forth experimental evidence and phenomenological observations supporting the concept that cardiac output occurs primarily in response to the metabolic demands of the tissues. The basic tenets of Guyton's venous return model are presented and juxtaposed with their critiques. Developmental biology of the cardiovascular system shows that the blood circulates before the heart has achieved functional integrity and that its movement is intricately connected with the metabolic demands of the tissues. Long discovered, but as yet overlooked, negative interstitial pressure may play a role in assisting the flow returning to the heart. Based on these phenomena, an alternative circulation model has been proposed in which the heart functions like a hydraulic ram and maintains a dynamic equilibrium between the arterial (centrifugal) and venous (centripetal) forces which define the blood's circular movement. In this focused review we introduce some of the salient arguments in support of the proposed circulation model. Finally, we present evidence that exercising muscle blood flow is subject to local metabolic control which upholds optimal perfusion in the face of a substantive rise in muscle vascular conductance, thus lending further support to the permissive role of the heart in the overall control of blood circulation.
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Affiliation(s)
- Branko Furst
- Department of Anesthesiology, Albany Medical Center, Albany, New York, USA
| | - José González-Alonso
- Sport, Health and Exercise Sciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
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Flodin J, Wallenius P, Guo L, Persson NK, Ackermann P. Wearable Neuromuscular Electrical Stimulation on Quadriceps Muscle Can Increase Venous Flow. Ann Biomed Eng 2023; 51:2873-2882. [PMID: 37598135 PMCID: PMC10632221 DOI: 10.1007/s10439-023-03349-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 08/09/2023] [Indexed: 08/21/2023]
Abstract
Neuromuscular electrical stimulation (NMES) of the quadriceps (Q) may increase venous blood flow to reduce the risk of venous thromboembolism. This study assessed whether Q-NMES pants could increase peak venous velocity (PVV) in the femoral vein using Doppler ultrasound and minimize discomfort. On 15 healthy subjects, Q-NMES using textile electrodes integrated in pants was applied with increasing intensity (mA) until the first visible muscle contraction [measurement level (ML)-I] and with an additional increase of six NMES levels (ML II). Discomfort using a numeric rating scale (NRS, 0-10) and PVV were used to assess different NMES parameters: frequency (1, 36, 66 Hz), ramp-up/-down time (RUD) (0, 1 s), plateau time (1.5, 4, and 6 s), and on:off duty cycle (1:1, 1:2, 1:3, 1:4). Q-NMES pants significantly increased PVV from baseline with 93% at ML I and 173% at ML II. Frequencies 36 Hz and 66 Hz and no RUD resulted in significantly higher PVV at both MLs compared to 1 Hz and 1 s RUD, respectively. Plateau time, and duty cycle did not significantly change PVV. Discomfort was only significantly higher with increasing intensity and frequency. Q-NMES pants produces intensity-dependent 2-3-fold increases of venous blood flow with minimal discomfort. The superior NMES parameters were a frequency of 36 Hz, 0 s RUD, and intensity at ML II. Textile-based NMES wearables are promising for non-episodic venous thromboembolism prevention.
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Affiliation(s)
- Johanna Flodin
- Integrative Orthopedic Laboratory, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
- Department of Trauma, Acute Surgery and Orthopaedics, Karolinska University Hospital, 171 76, Stockholm, Sweden.
| | - Philip Wallenius
- Integrative Orthopedic Laboratory, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Trauma, Acute Surgery and Orthopaedics, Karolinska University Hospital, 171 76, Stockholm, Sweden
| | - Li Guo
- Polymeric E-textiles Research Group, Swedish School of Textiles, Smart Textiles, University of Borås, Borås, Sweden
| | - Nils-Krister Persson
- Polymeric E-textiles Research Group, Swedish School of Textiles, Smart Textiles, University of Borås, Borås, Sweden
| | - Paul Ackermann
- Integrative Orthopedic Laboratory, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Trauma, Acute Surgery and Orthopaedics, Karolinska University Hospital, 171 76, Stockholm, Sweden
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Angus SA, Taylor JL, Mann LM, Williams AM, Stöhr EJ, Au JS, Sheel AW, Dominelli PB. Attenuating intrathoracic pressure swings decreases cardiac output at different intensities of exercise. J Physiol 2023; 601:4807-4821. [PMID: 37772933 DOI: 10.1113/jp285101] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/05/2023] [Indexed: 09/30/2023] Open
Abstract
Intrathoracic pressure (ITP) swings that permit spontaneous ventilation have physiological implications for the heart. We sought to determine the effect of respiration on cardiac output (Q ̇ $\dot Q$ ) during semi-supine cycle exercise using a proportional assist ventilator to minimize ITP changes and lower the work of breathing (Wb ). Twenty-four participants (12 females) completed three exercise trials at 30%, 60% and 80% peak power (Wmax ) with unloaded (using a proportional assist ventilator, PAV) and spontaneous breathing. Intrathoracic and intraabdominal pressures were measured with balloon catheters placed in the oesophagus and stomach. Left ventricular (LV) volumes andQ ̇ $\dot Q$ were determined via echocardiography. Heart rate (HR) was measured with electrocardiogram and a customized metabolic cart measured oxygen uptake (V ̇ O 2 ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}}}$ ). Oesophageal pressure swings decreased from spontaneous to PAV breathing by -2.8 ± 3.1, -4.9 ± 5.7 and -8.1 ± 7.7 cmH2 O at 30%, 60% and 80% Wmax , respectively (P = 0.01). However, the decreases in Wb were similar across exercise intensities (27 ± 42 vs. 35 ± 24 vs. 41 ± 22%, respectively, P = 0.156). During PAV breathing compared to spontaneous breathing,Q ̇ $\dot Q$ decreased by -1.0 ± 1.3 vs. -1.4 ± 1.4 vs. -1.5 ± 1.9 l min-1 (all P < 0.05) and stroke volume decreased during PAV breathing by -11 ± 12 vs. -9 ± 10 vs. -7 ± 11 ml from spontaneous breathing at 30%, 60% and 80% Wmax , respectively (all P < 0.05). HR was lower during PAV breathing by -5 ± 4 beats min-1 at 80% Wmax (P < 0.0001). Oxygen uptake decreased by 100 ml min-1 during PAV breathing compared to spontaneous breathing at 80% Wmax (P < 0.0001). Overall, attenuating ITPs mitigated LV preload and ejection, thereby suggesting that the ITPs associated with spontaneous respiration impact cardiac function during exercise. KEY POINTS: Pulmonary ventilation is accomplished by alterations in intrathoracic pressure (ITP), which have physiological implications on the heart and dynamically influence the loading parameters of the heart. Proportional assist ventilation was used to attenuate ITP changes and decrease the work of breathing during exercise to examine its effects on left ventricular (LV) function. Proportional assist ventilation with progressive exercise intensities (30%, 60% and 80% Wmax ) led to reductions in cardiac output at all intensities, primarily through reductions in stroke volume. Decreases in LV end-diastolic volume (30% and 60% Wmax ) and increases in LV end-systolic volume (80% Wmax ) were responsible for the reduction in stroke volume. The relationship between cardiac output and oxygen uptake is disrupted during respiratory muscle unloading.
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Affiliation(s)
- Sarah A Angus
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Joshua L Taylor
- School of Kinesiology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Leah M Mann
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Alexandra M Williams
- International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Science, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric J Stöhr
- Institute of Sports Science, COR-HELIX, Leibniz University Hannover, Hannover, Germany
- Department of Medicine, Division of Cardiology, Columbia University Irving Medical Center, New York, NY, USA
| | - Jason S Au
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew William Sheel
- School of Kinesiology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Paolo B Dominelli
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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Cohen JN, Samra RA, Au JS. Supporting evidence for an "arterial pump" venous return mechanism in humans. J Appl Physiol (1985) 2023; 135:1120-1125. [PMID: 37823204 DOI: 10.1152/japplphysiol.00480.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/27/2023] [Accepted: 10/05/2023] [Indexed: 10/13/2023] Open
Abstract
Blood flow in large veins is dependent on arterial-atrial pressure gradients and pumping mechanisms in concert with valve recruitment. Classic descriptions of muscle and respiratory pumps describe venous transmural pressure changes that cause flow. Not often considered is the transmission of pulsatile energy from arteries to veins directly adjacent to each other. Recently, an ex vivo study demonstrated a novel arterial pump effect in venoarterial bundles when valves were active in managing venous flow. We sought to show in vivo evidence of this arterial pump mechanism in 16 healthy young adults. Venous blood flow was measured in the venoarterial bundled deep femoral vein (DFV) and the greater saphenous vein (GSV), which is not bundled with an artery. Veins were studied through randomized body positions of -6° head-down tilt (HDT), supine, 20° head-up tilt (HUT), and 40° HUT, with the assumption that greater HUT postures increased valve dependence to observe the arterial pump effect. Between 20° and 40° HUT conditions, bundled DFV blood flow did not change (68 ± 36 vs. 71 ± 56 mL·min-1; Padj > 0.99), whereas nonbundled GSV blood flow decreased (6.1 ± 4.8 vs. 3.5 ± 3.9 mL·min-1; P = 0.01). Diameters between 20° and 40° HUT conditions increased in DFV (0.90 ± 0.16 vs. 1.04 ± 0.19 cm; P < 0.01), but not in GSV (0.33 ± 0.10 vs. 0.32 ± 0.08 cm; P = 0.60). These data support previous ex vivo observations that when venous pressure gradients rely on valve recruitment, presence of an adjacent artery may protect against further decreases in blood flow. The arterial pump mechanism is an underappreciated contributor to venous return and warrants further investigation.NEW & NOTEWORTHY Venous return mechanisms have classically considered muscle and respiratory pumps; however, recent ex vivo evidence suggests that pulsatile energy imparted from arteries to adjacent bundled veins can increase venous flow under certain driving pressures. We tested this concept in humans by manipulating hydrostatic pressures and measuring flow in bundled and nonbundled veins. The bundled vein exhibited flow preservation at the highest hydrostatic pressure. We suggest a novel conservation of energy mechanism within the circulatory system.
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Affiliation(s)
- Jeremy N Cohen
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Rose A Samra
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Jason S Au
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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Sikora M, Jastrzębski D, Pilzak K, Ziora D, Hall B, Żebrowska A. Impact of physical functional capacity on quality of life in patients with interstitial lung diseases. Respir Physiol Neurobiol 2023; 313:104064. [PMID: 37076026 DOI: 10.1016/j.resp.2023.104064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/05/2023] [Accepted: 04/16/2023] [Indexed: 04/21/2023]
Abstract
This study aimed to investigate the physical functioning predictors for health-related quality of life (HRQL) decline in patients with idiopathic interstitial fibrosis (IPF), sarcoidosis and other interstitial lung disease (ILD). The study enrolled 52 patients with ILD and 16 healthy individuals. Participants' HRQL was assessed using the 36-item Short-Form Health Survey questionnaire. Spirometry, physical performance, and daily physical activity (PA) were monitored. Patients with IPF showed significantly lower PA compared to patients with other ILD (p =0.002)and sarcoidosis (p =0.01). The type of disease aetiology had no significant effect on aerobic capacity, HRQL and fatigue. Patients with ILD showed significant greater fatigue, lower physical functioning and greater physical aspects scores compared to the control group (F=6.0; p=0.018; F=12.64; p=0.001, respectively). A significant positive correlation was observed between 6-minute walking distance (6MWD) and the physical domain of HRQL (r=0.35, p=0.012) and PA and the physical aspects of HRQL (r=0.37, p=0.007). This study revealed that the key predictors for HRQL decline were lower lung function, lower PA and physical performance.
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Affiliation(s)
- Marcin Sikora
- Institute of Sport Science The Jerzy Kukuczka Academy of Physical Education, 72A Mikolowska Street, 40-065 Katowice, Poland.
| | - Dariusz Jastrzębski
- Department of Lung Diseases and Tuberculosis, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 41-800 Zabrze, Poland
| | - Katarzyna Pilzak
- Department of Physiological and Medical Sciences, The Jerzy Kukuczka Academy of Physical Education, 72A Mikolowska Street, 40-065 Katowice, Poland
| | - Dariusz Ziora
- Department of Lung Diseases and Tuberculosis, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 41-800 Zabrze, Poland
| | - Barbara Hall
- School of Biological Sciences, Division of Infection, Immunity and Respiratory Medicine University of Manchester, United Kondon
| | - Aleksandra Żebrowska
- Institute of Sport Science The Jerzy Kukuczka Academy of Physical Education, 72A Mikolowska Street, 40-065 Katowice, Poland
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Do Sports Compression Garments Alter Measures of Peripheral Blood Flow? A Systematic Review with Meta-Analysis. Sports Med 2023; 53:481-501. [PMID: 36622554 DOI: 10.1007/s40279-022-01774-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2022] [Indexed: 01/10/2023]
Abstract
BACKGROUND One of the proposed mechanisms underlying the benefits of sports compression garments may be alterations in peripheral blood flow. OBJECTIVE We aimed to determine if sports compression garments alter measures of peripheral blood flow at rest, as well as during, immediately after and in recovery from a physiological challenge (i.e. exercise or an orthostatic challenge). METHODS We conducted a systematic literature search of databases including Scopus, SPORTDiscus and PubMed/MEDLINE. The criteria for inclusion of studies were: (1) original papers in English and a peer-reviewed journal; (2) assessed effect of compression garments on a measure of peripheral blood flow at rest and/or before, during or after a physiological challenge; (3) participants were healthy and without cardiovascular or metabolic disorders; and (4) a study population including athletes and physically active or healthy participants. The PEDro scale was used to assess the methodological quality of the included studies. A random-effects meta-analysis model was used. Changes in blood flow were quantified by standardised mean difference (SMD) [± 95% confidence interval (CI)]. RESULTS Of the 899 articles identified, 22 studies were included for the meta-analysis. The results indicated sports compression garments improve overall peripheral blood flow (SMD = 0.32, 95% CI 0.13, 0.51, p = 0.001), venous blood flow (SMD = 0.37, 95% CI 0.14, 0.60, p = 0.002) and arterial blood flow (SMD = 0.30, 95% CI 0.01, 0.59, p = 0.04). At rest, sports compression garments did not improve peripheral blood flow (SMD = 0.18, 95% CI - 0.02, 0.39, p = 0.08). However, subgroup analyses revealed sports compression garments enhance venous (SMD = 0.31 95% CI 0.02, 0.60, p = 0.03), but not arterial (SMD = 0.12, 95% CI - 0.16, 0.40, p = 0.16), blood flow. During a physiological challenge, peripheral blood flow was improved (SMD = 0.44, 95% CI 0.19, 0.69, p = 0.0007), with subgroup analyses revealing sports compression garments enhance venous (SMD = 0.48, 95% CI 0.11, 0.85, p = 0.01) and arterial blood flow (SMD = 0.44, 95% CI 0.03, 0.86, p = 0.04). At immediately after a physiological challenge, there were no changes in peripheral blood flow (SMD = - 0.04, 95% CI - 0.43, 0.34, p = 0.82) or subgroup analyses of venous (SMD = - 0.41, 95% CI - 1.32, 0.47, p = 0.35) and arterial (SMD = 0.12, 95% CI - 0.26, 0.51, p = 0.53) blood flow. In recovery, sports compression garments did not improve peripheral blood flow (SMD = 0.25, 95% CI - 0.45, 0.95, p = 0.49). The subgroup analyses showed enhanced venous (SMD = 0.67, 95% CI 0.17, 1.17, p = 0.009), but not arterial blood flow (SMD = 0.02, 95% CI - 1.06, 1.09, p = 0.98). CONCLUSIONS Use of sports compression garments enhances venous blood flow at rest, during and in recovery from, but not immediately after, a physiological challenge. Compression-induced changes in arterial blood flow were only evident during a physiological challenge.
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Stucky F, Uva B, Kayser B, Aliverti A. Blood shifts between body compartments during submaximal exercise with induced expiratory flow limitation in healthy humans. J Physiol 2023; 601:227-244. [PMID: 36367253 DOI: 10.1113/jp283176] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 11/03/2022] [Indexed: 11/13/2022] Open
Abstract
External expiratory flow limitation (EFLe) can be applied in healthy subjects to mimic the effects of chronic obstructive pulmonary disease during exercise. At maximal exercise intensity, EFLe leads to exercise intolerance owing to respiratory pump dysfunction limiting venous return. We quantified blood shifts between body compartments to determine whether such effects can be observed during submaximal exercise, when the load on the respiratory system is milder. Ten healthy men (25.2 ± 3.2 years of age, 177.3 ± 5.4 cm in height and weighing 67.4 ± 5.8 kg) exercised at 100 W (∼40% of maximal oxygen uptake) while breathing spontaneously (CTRL) or with EFLe. We measured respiratory dynamics with optoelectronic plethysmography, oesophageal (Pes ) and gastric (Pga ) pressures with balloon catheters, and blood shifting between body compartments with double body plethysmography. During exercise, EFLe resulted in the following changes: (i) greater intrabreath blood shifts between the trunk and the extremities [518 ± 221 (EFLe) vs. 224 ± 60 ml (CTRL); P < 0.001] associated with lower Pes during inspiration (r = 0.53, P < 0.001) and higher Pga during expiration (r = 0.29, P < 0.024); and (ii) a progressive pooling of blood in the trunk over time (∼700 ml after 3 min of exercise; P < 0.05), explained by a predominant effect of lower inspiratory Pes (r = 0.54, P < 0.001) over that of increased Pga . It follows that during submaximal exercise, EFLe amplifies the respiratory pump mechanism, with a prevailing contribution from lower inspiratory Pes over increased expiratory Pga , drawing blood into the trunk. Whether these results can be replicated in chronic obstructive pulmonary disease patients remains to be determined. KEY POINTS: External expiratory flow limitation (EFLe) can be applied in healthy subjects to mimic the effects of chronic obstructive pulmonary disease and safely study the mechanisms of exercise intolerance associated with the disease. At maximal exercise intensity with EFLe, exercise intolerance results from high expiratory pressures altering the respiratory pump mechanism and limiting venous return. We used double body plethysmography to quantify blood shifting between the trunk and the extremities and to examine whether the same effects occur with EFLe at submaximal exercise intensity, where the increase in expiratory pressures is milder. Our data show that during submaximal exercise, EFLe amplifies the respiratory pump mechanism, each breath producing greater blood displacements between the trunk and the extremities, with a prevailing effect from lower inspiratory intrathoracic pressure progressively drawing blood into the trunk. These results help us to understand the haemodynamic effects of respiratory pressures during submaximal exercise with expiratory flow restriction.
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Affiliation(s)
- Frédéric Stucky
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Barbara Uva
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
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LeFevre NM, Sarvazyan N. The essential role of arterial pulse in venous return. Am J Physiol Regul Integr Comp Physiol 2022; 323:R962-R967. [PMID: 36279504 PMCID: PMC9722249 DOI: 10.1152/ajpregu.00204.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/13/2022] [Accepted: 10/21/2022] [Indexed: 11/22/2022]
Abstract
The close proximity of arteries and veins is a well-known anatomical finding documented in the extremities of all vertebrates. However, the physiological consequences of this arrangement are rarely given proper consideration nor are they covered in the textbook list of mechanisms that aid blood flow. We hypothesized that arterial pressure pulsations can significantly increase blood flow in the adjacent valve-containing vein segments. To demonstrate the existence of this mechanism, 10- to 15-cm sections of the bovine forelimb neurovascular bundle were isolated. The proximal and distal ends of the median artery and adjacent veins were cannulated, their tributaries were tied off, and the dissected bundle was then inserted into an airtight enclosure to mimic in vivo encasement by surrounding muscle. Pulsatile pressure was subsequently applied to the arterial segment while recording venous flow. At pressure settings mimicking physiological scenarios, arterial pulsations caused a highly significant increase in venous return. The amplitude of this effect was dependent on the arterial pulsation rate, stroke volume, and pressure gradient across the vein segment.
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Affiliation(s)
- Narine M LeFevre
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia
| | - Narine Sarvazyan
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, District of Columbia
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Sanchez MM, Bagdasarian IA, Darch W, Morgan JT. Organotypic cultures as aging associated disease models. Aging (Albany NY) 2022; 14:9338-9383. [PMID: 36435511 PMCID: PMC9740367 DOI: 10.18632/aging.204361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/21/2022] [Indexed: 11/24/2022]
Abstract
Aging remains a primary risk factor for a host of diseases, including leading causes of death. Aging and associated diseases are inherently multifactorial, with numerous contributing factors and phenotypes at the molecular, cellular, tissue, and organismal scales. Despite the complexity of aging phenomena, models currently used in aging research possess limitations. Frequently used in vivo models often have important physiological differences, age at different rates, or are genetically engineered to match late disease phenotypes rather than early causes. Conversely, routinely used in vitro models lack the complex tissue-scale and systemic cues that are disrupted in aging. To fill in gaps between in vivo and traditional in vitro models, researchers have increasingly been turning to organotypic models, which provide increased physiological relevance with the accessibility and control of in vitro context. While powerful tools, the development of these models is a field of its own, and many aging researchers may be unaware of recent progress in organotypic models, or hesitant to include these models in their own work. In this review, we describe recent progress in tissue engineering applied to organotypic models, highlighting examples explicitly linked to aging and associated disease, as well as examples of models that are relevant to aging. We specifically highlight progress made in skin, gut, and skeletal muscle, and describe how recently demonstrated models have been used for aging studies or similar phenotypes. Throughout, this review emphasizes the accessibility of these models and aims to provide a resource for researchers seeking to leverage these powerful tools.
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Affiliation(s)
- Martina M. Sanchez
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | | | - William Darch
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Joshua T. Morgan
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
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12
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Faghy MA, Shei R, Armstrong NCD, White M, Lomax M. Physiological impact of load carriage exercise: Current understanding and future research directions. Physiol Rep 2022; 10:e15502. [PMID: 36324291 PMCID: PMC9630762 DOI: 10.14814/phy2.15502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 09/18/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Load carriage (LC) refers to the use of personal protective equipment (PPE) and/or load-bearing apparatus that is mostly worn over the thoracic cavity. A commonplace task across various physically demanding occupational groups, the mass being carried during LC duties can approach the wearer's body mass. When compared to unloaded exercise, LC imposes additional physiological stress that negatively impacts the respiratory system by restricting chest wall movement and altering ventilatory mechanics as well as circulatory responses. Consequently, LC activities accelerate the development of fatigue in the respiratory muscles and reduce exercise performance in occupational tasks. Therefore, understanding the implications of LC and the effects specific factors have on physiological capacities during LC activity are important to the implementation of effective mitigation strategies to ameliorate the detrimental effects of thoracic LC. Accordingly, this review highlights the current physiological understanding of LC activities and outlines the knowledge and efficacy of current interventions and research that have attempted to improve LC performance, whilst also highlighting pertinent knowledge gaps that must be explored via future research activities.
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Affiliation(s)
- Mark A. Faghy
- Biomedical Research Theme, School of Human SciencesUniversity of DerbyDerbyUK
| | - Ren‐Jay Shei
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Nicola C. D. Armstrong
- Defence Science and Technology LaboratorySalisburyUK
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
| | - Mark White
- Rocky Mountain University of Health ProfessionsProvoUtahUSA
| | - Mitch Lomax
- Extreme Environments Laboratory, School of Sport, Health and Exercise ScienceUniversity of PortsmouthPortsmouthUK
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13
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Léger MC, Cardoso MR, Dion C, Albert WJ. Does active sitting provide more physiological changes than traditional sitting and standing workstations? APPLIED ERGONOMICS 2022; 102:103741. [PMID: 35287085 DOI: 10.1016/j.apergo.2022.103741] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 02/25/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
This cross-sectional study examined the physiological effects of two active chairs (AC1: had the feature to pedal and slide forward; AC2: was a multiaxial chair) compared to a traditional office chair and standing workstation. Twenty-four healthy participants computed at each of the workstations for 60 min. The active protocol was to alternate between a pedalling/side-to-side motion and sliding forward/front-to-back motion to the sound of a metronome operating at 40 bpm. The participants' physiological effects were recorded using near-infrared spectroscopy (NIRS); electrodermal activity (EDA) and a heart rate (HR) monitor for each collection period. Statistical analysis was conducted using a repeated measures analysis of variance for within-task and between-workstation comparisons. A Tukey's post hoc analysis was calculated for significant findings. Both active chairs significantly increased oxygenated blood in the gastrocnemius and participants' heart rate and EDA (stress) levels were affected slightly by task and time. However, participants felt more "productive" sitting in the control chair than in either of the active chairs.
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Affiliation(s)
| | | | - Cynthia Dion
- École de kinésiologie et de loisir, Université de Moncton, NB, Canada
| | - Wayne J Albert
- Faculty of Kinesiology, University of New Brunswick, NB, Canada
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14
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THE EFFECTS OF INSPIRATORY MUSCLE TRAINING VERSUS CALF MUSCLE TRAINING ON QUALITY OF LIFE, PAIN, VENOUS FUNCTION AND ACTIVITY IN PATIENTS WITH CHRONIC VENOUS INSUFFICIENCY. J Vasc Surg Venous Lymphat Disord 2022; 10:1137-1146. [PMID: 35710091 DOI: 10.1016/j.jvsv.2022.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/01/2022] [Accepted: 04/14/2022] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the effect of inspiratory muscle training(IMT) and calf muscle exercise training(ETC) in addition to compression therapy(CT) on quality of life, venous refilling time, disease severity, pain, edema, range of motion, muscle strength and functionality in patients with chronic venous insufficiency (CVI) compared to compression treatment alone. METHODS Thirty-two participants diagnosed with CVI were randomly divided into three groups. IMT in addition to compression therapy, Group 1, exercise training for the calf muscle in addition to compression therapy, Group 2, and compression therapy alone, Group 3. All the patients were assessed with the Chronic Venous Insufficiency Quality of Life Questionnaire-20, Nottingham Health Profile, photoplethysmography, venous clinical severity score, visual analog scale, intraoral pressure measurements, dynamometer, digital goniometer, 6-minute walk test and lower extremity functional scale. RESULTS After treatment, Group 2 improved more than groups 1 and 3 in terms of quality of life, venous refilling time, pain, edema, range of motion, muscle strength and functionality scores; Group 1 improved more than groups 2 and 3 in terms of disease severity, inspiratory and expiratory muscle strength values(p<0.05). Only physical mobility and right leg venous refilling time increased in group 3(p<0.05). CONCLUSIONS IMT and ETC improve venous function in both legs in patients with CVI while CT alone improves venous function only in the right leg of patients with CVI.
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15
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Stucky F, Churchill TW, Churchill JL, Petek BJ, Guseh JS, Wasfy MM, Kayser B, Baggish AL. Priming Cardiac Function with Voluntary Respiratory Maneuvers and Effect on Early Exercise Oxygen Uptake. J Appl Physiol (1985) 2022; 132:1179-1189. [PMID: 35271410 DOI: 10.1152/japplphysiol.00750.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Oxygen uptake (V'O2) at exercise onset is determined in part by acceleration of pulmonary blood flow (Q'p). Impairments in the Q'p response can decrease exercise tolerance. Prior research has shown that voluntary respiratory maneuvers can augment venous return, but the corollary impacts on cardiac function, Q'p and early-exercise V'O2 remain uncertain. We examined a) the cardiovascular effects of 3 distinct respiratory maneuvers (abdominal, AB; rib cage, RC and deep breathing, DB) under resting conditions in healthy subjects (Protocol 1, n=13) and b) the impact of pre-exercise DB on pulmonary O2 transfer during initiation of moderate intensity exercise (Protocol 2, n=8). In Protocol 1, echocardiographic analysis showed increased RV and LV cardiac output (RVCO and LVCO, respectively) following AB (by +23±13 and +18±15%, respectively, P<0.05), RC (+23±16; +14±15%, P<0.05) and DB (+27±21; +23±14%, P<0.05). In Protocol 2, DB performed for 12 breaths produced a pre-exercise increase in V'O2 (+801±254 ml·min-1 over ~ 6 s), presumably from increased Q'p followed by a reduction in pulmonary O2 transfer during early phase exercise (first 20 s) compared to the control condition (149±51 vs 233±65 ml, P<0.05). We conclude that (1) respiratory maneuvers enhance RVCO and LVCO in healthy subjects under resting conditions, (2) AB, RC and DB have similar effects on RVCO and LVCO, and (3) DB can increase Q'p prior to exercise onset. These findings suggest that pre-exercise respiratory maneuvers may represent a promising strategy to prime V'O2 kinetics and thereby to potentially improve exercise tolerance in patients with impaired cardiac function.
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Affiliation(s)
- Frédéric Stucky
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Timothy W Churchill
- Cardiovascular Performance Program, Massachusetts General Hospital, Boston, MA, United States.,Echocardiography Laboratory, Division of Cardiology, Massachusetts General Hospital, Boston, MA, United States
| | - Jessica L Churchill
- Echocardiography Laboratory, Division of Cardiology, Massachusetts General Hospital, Boston, MA, United States
| | - Bradley J Petek
- Cardiovascular Performance Program, Massachusetts General Hospital, Boston, MA, United States
| | - James Sawalla Guseh
- Cardiovascular Performance Program, Massachusetts General Hospital, Boston, MA, United States
| | - Meagan M Wasfy
- Cardiovascular Performance Program, Massachusetts General Hospital, Boston, MA, United States.,Echocardiography Laboratory, Division of Cardiology, Massachusetts General Hospital, Boston, MA, United States
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Aaron L Baggish
- Cardiovascular Performance Program, Massachusetts General Hospital, Boston, MA, United States.,Echocardiography Laboratory, Division of Cardiology, Massachusetts General Hospital, Boston, MA, United States
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16
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Dempsey JA, Neder JA, Phillips DB, O'Donnell DE. The physiology and pathophysiology of exercise hyperpnea. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:201-232. [PMID: 35965027 DOI: 10.1016/b978-0-323-91534-2.00001-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In health, the near-eucapnic, highly efficient hyperpnea during mild-to-moderate intensity exercise is driven by three obligatory contributions, namely, feedforward central command from supra-medullary locomotor centers, feedback from limb muscle afferents, and respiratory CO2 exchange (V̇CO2). Inhibiting each of these stimuli during exercise elicits a reduction in hyperpnea even in the continuing presence of the other major stimuli. However, the relative contribution of each stimulus to the hyperpnea remains unknown as does the means by which V̇CO2 is sensed. Mediation of the hyperventilatory response to exercise in health is attributed to the multiple feedback and feedforward stimuli resulting from muscle fatigue. In patients with COPD, diaphragm EMG amplitude and its relation to ventilatory output are used to decipher mechanisms underlying the patients' abnormal ventilatory responses, dynamic lung hyperinflation and dyspnea during exercise. Key contributions to these exercise-limiting responses across the spectrum of COPD severity include high dead space ventilation, an excessive neural drive to breathe and highly fatigable limb muscles, together with mechanical constraints on ventilation. Major controversies concerning control of exercise hyperpnea are discussed along with the need for innovative research to uncover the link of metabolism to breathing in health and disease.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, University of Wisconsin-Madison, Madison, WI, United States.
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
| | - Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
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17
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Katayama K, Dominelli PB, Foster GE, Kipp S, Leahy MG, Ishida K, Sheel AW. Respiratory modulation of sympathetic vasomotor outflow during graded leg cycling. J Appl Physiol (1985) 2021; 131:858-867. [PMID: 34197231 DOI: 10.1152/japplphysiol.00118.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Respiratory modulation of sympathetic vasomotor outflow to skeletal muscles (muscle sympathetic nerve activity; MSNA) occurs in resting humans. Specifically, MSNA is highest at end-expiration and lowest at end-inspiration during quiet, resting breathing. We tested the hypothesis that within-breath modulation of MSNA would be amplified during graded leg cycling. Thirteen (n = 3 females) healthy young (age: 25.2 ± 4.7 yr) individuals completed all testing. MSNA (right median nerve) was measured at rest (baseline) and during semirecumbent cycle exercise at 40%, 60%, and 80% of maximal workload (Wmax). MSNA burst frequency (BF) was 20.0 ± 4.0 bursts/min at baseline and was not different during exercise at 40%Wmax (21.3 ± 3.7 bursts/min; P = 0.292). Thereafter, MSNA BF increased significantly compared with baseline (60%Wmax: 31.6 ± 5.8 bursts/min; P < 0.001, 80%Wmax: 44.7 ± 5.3 bursts/min; P < 0.001). At baseline and all exercise intensities, MSNA BF was lowest at end-inspiration and greatest at mid-to-end expiration. The within-breath change in MSNA BF (ΔMSNA BF; end-expiration minus end-inspiration) gradually increased from baseline to 60%Wmax leg cycling, but no further increase appeared at 80%Wmax exercise. Our results indicate that within-breath modulation of MSNA is amplified from baseline to moderate intensity during dynamic exercise in young healthy individuals, and that no further potentiation occurs at higher exercise intensities. Our findings provide an important extension of our understanding of respiratory influences on sympathetic vasomotor control.NEW & NOTEWORTHY Within-breath modulation of sympathetic vasomotor outflow to skeletal muscle (muscle sympathetic nerve activity; MSNA) occurs in spontaneously breathing humans at rest. It is unknown if respiratory modulation persists during dynamic whole body exercise. We found that MSNA burst frequency was lowest at end-inspiration and highest at mid-to-end expiration during rest and graded leg cycling. Respiratory modulation of sympathetic vasomotor outflow remains intact and is amplified during dynamic whole body exercise.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Paolo B Dominelli
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Shalaya Kipp
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael G Leahy
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Andrew William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
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18
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Fetter C, Souza LAD, Dartora DR, Schein A, Eibel B, Casali K, Irigoyen MC. Increased Maximal Expiratory Pressure, Abdominal and Thoracic Respiratory Expansibility in Healthy Yoga Practitioners Compared to Healthy Sedentary Individuals. INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2021. [DOI: 10.36660/ijcs.20200030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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19
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Reduced calf muscle pump function is a risk factor for venous thromboembolism: a population-based cohort study. Blood 2021; 137:3284-3290. [PMID: 33657212 DOI: 10.1182/blood.2020010231] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/29/2021] [Indexed: 12/14/2022] Open
Abstract
The calf muscle pump is a major determinate of venous return in the legs but has not been studied as a risk factor for venous thromboembolism (VTE). A population-based cohort study of Olmsted County, Minnesota residents was performed using calf pump function (CPF) measurements from venous plethysmography studies from 1998 to 2015. Patients with a history of VTE were excluded. Nursing validated VTE outcomes from the Rochester Epidemiology Project were identified after the index study date, and patients with reduced CPF (rCPF) were compared with patients with normal CPF. A total of 1532 patients with recorded CPF (28% air and 72% strain gauge plethysmography) were included; 591 (38.5%) had normal CPF, 353 (23.0%) had unilateral rCPF, and 588 (38.3%) had bilateral rCPF. Any VTE occurred in 87 patients (5.7%) after a median follow-up of 11.7 years (range, 0-22.0 years). Comparing patients with bilateral reduced to bilateral normal CPF, the unadjusted hazard ratio (HR) for incident VTE was 2.0 (95% confidence interval [CI], 1.2-3.4) and after adjusting for age, BMI, and Charlson Comorbidity Index, the HR was 1.68 (95% CI, 0.98-2.89). The adjusted HR for ipsilateral deep vein thrombosis was evaluated in 3064 legs comparing legs with reduced to normal CPF and was 1.71 (95% CI, 1.03-2.84). Mortality was significantly higher in both the bilateral (P < .001) and unilateral (P < .001) rCPF groups compared with normal CPF. Our results demonstrate that CPF is a risk factor for VTE in an otherwise low-risk ambulatory population and might be a useful component in risk stratification models.
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20
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Hopkins SR, Dominelli PB, Davis CK, Guenette JA, Luks AM, Molgat-Seon Y, Sá RC, Sheel AW, Swenson ER, Stickland MK. Face Masks and the Cardiorespiratory Response to Physical Activity in Health and Disease. Ann Am Thorac Soc 2021; 18:399-407. [PMID: 33196294 PMCID: PMC7919154 DOI: 10.1513/annalsats.202008-990cme] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 11/16/2020] [Indexed: 11/21/2022] Open
Abstract
To minimize transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus responsible for coronavirus disease (COVID-19), the U.S. Centers for Disease Control and Prevention and the World Health Organization recommend wearing face masks in public. Some have expressed concern that these may affect the cardiopulmonary system by increasing the work of breathing, altering pulmonary gas exchange and increasing dyspnea, especially during physical activity. These concerns have been derived largely from studies evaluating devices intentionally designed to severely affect respiratory mechanics and gas exchange. We review the literature on the effects of various face masks and respirators on the respiratory system during physical activity using data from several models: cloth face coverings and surgical masks, N95 respirators, industrial respirators, and applied highly resistive or high-dead space respiratory loads. Overall, the available data suggest that although dyspnea may be increased and alter perceived effort with activity, the effects on work of breathing, blood gases, and other physiological parameters imposed by face masks during physical activity are small, often too small to be detected, even during very heavy exercise. There is no current evidence to support sex-based or age-based differences in the physiological responses to exercise while wearing a face mask. Although the available data suggest that negative effects of using cloth or surgical face masks during physical activity in healthy individuals are negligible and unlikely to impact exercise tolerance significantly, for some individuals with severe cardiopulmonary disease, any added resistance and/or minor changes in blood gases may evoke considerably more dyspnea and, thus, affect exercise capacity.
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Affiliation(s)
| | - Paolo B. Dominelli
- Department of Pediatrics, University of California, San Diego, California
| | | | - Jordan A. Guenette
- Centre for Heart Lung Innovation
- Department of Physical Therapy, Faculty of Medicine, and
- School of Kinesiology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrew M. Luks
- St. Paul’s Hospital, Vancouver, British Columbia, Canada
| | - Yannick Molgat-Seon
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington
| | | | - A. William Sheel
- Department of Kinesiology and Applied Health, University of Winnipeg, Winnipeg, Manitoba, Canada
| | - Erik R. Swenson
- St. Paul’s Hospital, Vancouver, British Columbia, Canada
- Medical Service, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
| | - Michael K. Stickland
- Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada; and
- G. F. MacDonald Centre for Lung Health (Covenant Health) and
- Medicine Strategic Clinical Network, Alberta Health Services, Edmonton, Alberta, Canada
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21
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Hardy TA, Paula-Ribeiro M, Silva BM, Lyall GK, Birch KM, Ferguson C, Taylor BJ. The cardiovascular consequences of fatiguing expiratory muscle work in otherwise resting healthy humans. J Appl Physiol (1985) 2021; 130:421-434. [PMID: 33356985 DOI: 10.1152/japplphysiol.00116.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In 11 healthy adults (25 ± 4 yr; 2 female, 9 male subjects), we investigated the effect of expiratory resistive loaded breathing [65% maximal expiratory mouth pressure (MEP), 15 breaths·min-1, duty cycle 0.5; ERLPm] on mean arterial pressure (MAP), leg vascular resistance (LVR), and leg blood flow ([Formula: see text]). On a separate day, a subset of five male subjects performed ERL targeting 65% of maximal expiratory gastric pressure (ERLPga). ERL-induced expiratory muscle fatigue was confirmed by a 17 ± 5% reduction in MEP (P < 0.05) and a 16 ± 12% reduction in the gastric twitch pressure response to magnetic nerve stimulation (P = 0.09) from before to after ERLPm and ERLPga, respectively. From rest to task failure in ERLPm and ERLPga, MAP increased (ERLPm = 31 ± 10 mmHg, ERLPga = 18 ± 9 mmHg, both P < 0.05), but group mean LVR and [Formula: see text] were unchanged (ERLPm: LVR = 0.78 ± 0.21 vs. 0.97 ± 0.36 mmHg·mL-1·min, [Formula: see text] = 133 ± 34 vs. 152 ± 74 mL·min-1; ERLPga: LVR = 0.70 ± 0.21 vs. 0.84 ± 0.33 mmHg·mL-1·min, [Formula: see text] = 160 ± 48 vs. 179 ± 110 mL·min-1) (all P ≥ 0.05). Interestingly, [Formula: see text] during ERLPga oscillated within each breath, increasing (∼66%) and decreasing (∼50%) relative to resting values during resisted expirations and unresisted inspirations, respectively. In conclusion, fatiguing expiratory muscle work did not affect group mean LVR or [Formula: see text] in otherwise resting humans. We speculate that any sympathetically mediated peripheral vasoconstriction was counteracted by transient mechanical effects of high intra-abdominal pressures during ERL.NEW & NOTEWORTHY Fatiguing expiratory muscle work in otherwise resting humans elicits an increase in sympathetic motor outflow; whether limb blood flow ([Formula: see text]) and leg vascular resistance (LVR) are affected remains unknown. We found that fatiguing expiratory resistive loaded breathing (ERL) did not affect group mean [Formula: see text] or LVR. However, within-breath oscillations in [Formula: see text] may reflect a sympathetically mediated vasoconstriction that was counteracted by transient increases in [Formula: see text] due to the mechanical effects of high intra-abdominal pressure during ERL.
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Affiliation(s)
- Tim A Hardy
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Marcelle Paula-Ribeiro
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Department of Physiology, Federal University of São Paulo, São Paulo, Brazil
| | - Bruno M Silva
- Department of Physiology, Federal University of São Paulo, São Paulo, Brazil
| | - Gemma K Lyall
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Karen M Birch
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Carrie Ferguson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Bryan J Taylor
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Department of Cardiovascular Diseases, Mayo Clinic, Jacksonville, Florida
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22
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Stucky F, Aliverti A, Kayser B, Uva B. Priming the cardiodynamic phase of pulmonary oxygen uptake through voluntary modulations of the respiratory pump at the onset of exercise. Exp Physiol 2020; 106:555-566. [PMID: 33369778 DOI: 10.1113/ep089180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/11/2020] [Indexed: 01/15/2023]
Abstract
NEW FINDINGS What is the central question of this study? The initial increase in oxygen uptake ( V ̇ O 2 ) at exercise onset results from pulmonary perfusion changes secondary to an increased venous return. Breathing mechanics contribute to venous return through abdominal and intrathoracic pressures variation. Can voluntary breathing techniques (abdominal or rib cage breathing) increase venous return and improve V ̇ O 2 at exercise onset? What is the main finding and its importance? Abdominal and rib cage breathing increase venous return and V ̇ O 2 at exercise onset. This mechanism could be clinically relevant in patients with impaired cardiac function limiting oxygen transport. ABSTRACT We examined how different breathing patterns can modulate venous return and alveolar gas transfer during exercise transients in humans. Ten healthy men transitioned from rest to moderate cycling while breathing spontaneously (SP) or with voluntary increases in abdominal (AB) or intrathoracic (RC) pressure swings. We used double body plethysmography to determine blood displacements between the trunk and the extremities (Vbs ). From continuous signals of airflow and O2 fraction, we calculated breath-by-breath oxygen uptake at the mouth and used optoelectronic plethysmography to correct for lung O2 store changes and calculate alveolar O2 transfer ( V ̇ O 2 A ). Oesophageal (Poes ) and gastric (Pga ) pressures were monitored using balloon-tipped catheters. Cardiac stroke volume was measured using impedance cardiography. During the cardiodynamic phase (Φ1) of V ̇ O 2 A -on kinetics (20 s following exercise onset), AB and RC increased total alveolar oxygen transfer compared to SP (227 ± 32, P = 0.019 vs. 235 ± 27, P = 0.001 vs. 206 ± 20 ml, mean ± SD). Pga and Poes swings increased with AB (by 24.4 ± 9.6 cmH2 O, P < 0.001) and RC (by 14.5 ± 5.7 cmH2 O, P < 0.001), respectively. AB yielded a greater increase in intra-breath Vbs swings compared with RC and SP (+0.30 ± 0.14 vs. +0.16 ± 0.11, P < 0.001 vs. +0.10 ± 0.05 ml, P = 0.006) and increased the sum of stroke volumes compared to SP (4.47 ± 1.28 vs. 3.89 ± 0.96 litres, P = 0.053), while RC produced significant central blood translocation from the extremities compared with SP (by 493 ± 311 ml, P < 0.001). Our findings indicate that combining exercise onset with AB or RC increases venous return, thus increasing mass oxygen transport above metabolic consumption during Φ1 and limiting the oxygen deficit incurred.
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Affiliation(s)
- Frédéric Stucky
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Barbara Uva
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Attenuated spontaneous postural sway enhances diastolic blood pressure during quiet standing. Eur J Appl Physiol 2020; 121:251-264. [PMID: 33040216 DOI: 10.1007/s00421-020-04519-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/26/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE Spontaneous postural sway during quiet standing has been considered a simple output error of postural control. However, as postural sway and inherent body orientation evoke compensatory activity of the plantar flexors, they might contribute to blood circulation under gravitational stress via the muscle pump. Hence, the present study employed an external support device to attenuate the plantar flexor activity in supported standing (SS), to experimentally identify its physiological impact on blood circulation. METHODS Eight healthy young subjects performed two 5-min quiet standing trials (i.e., normal standing (NS) and SS), and the beat-to-beat interval (RRI) and blood pressure (BP) were compared between trials. We confirmed that postural sway and corresponding plantar flexor activity, quantified by the anteroposterior displacement of the foot center of pressure and lower back position with respect to the wall, and by the amplitude of electromyography and mechanomyography, respectively, were attenuated in SS, while mean body orientation angle and relative position of the BP sensor were comparable to NS. RESULTS The 5-min averages of diastolic BP and mean arterial pressure during SS were significantly higher than during NS, while RRI and systolic BP did not change. These could be interpreted as an increase in peripheral vascular resistance; meanwhile, in NS, this effect was replaced by the muscle pump of the plantar flexors. CONCLUSION The muscle contractions related to spontaneous postural sway and body orientation produce substantial physiological impact on blood circulation during quiet standing.
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Niccolini G, Manuello A, Capone A, Marongiu G, Dell'Osa AH, Fois A, Velluzzi F, Concu A. Possible Assessment of Calf Venous Pump Efficiency by Computational Fluid Dynamics Approach. Front Physiol 2020; 11:1003. [PMID: 33013438 PMCID: PMC7510250 DOI: 10.3389/fphys.2020.01003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 07/23/2020] [Indexed: 11/24/2022] Open
Abstract
Three-dimensional simulations of peripheral, deep venous flow during muscular exercise in limbs of healthy subjects and in those with venous dysfunction were carried out by a computational fluid-dynamics (CFD) approach using the STAR CCM + platform. The aim was to assess the effects of valvular incompetence on the venous calf pump efficiency. The model idealizes the lower limb circulation by a single artery, a capillary bed represented by a porous region and a single vein. The focus is on a segment of the circuit which mimics a typical deep vein at the level of the calf muscle, such as the right posterior tibial vein. Valves are idealized as ball valves, and periodic muscle contractions are given by imposing time-dependent boundary conditions to the calf segment wall. Flow measurements were performed in two cross-sections downstream and upstream of the calf pump. Model results demonstrate a reduced venous return for incompetent valves during calf exercise. Two different degrees of valvular incompetence are considered, by restricting the motion of one or both valves. Model results showed that only the proximal valve is critical, with a 30% reduction of venous return during calf exercise in case of valvular incompetence: the net flow volume ejected by the calf in central direction was 0.14 mL per working cycle, against 0.2 mL for simulated healthy limbs. This finding appeared to be consistent with a 25% reduction of the calf ejection fraction, experimentally observed in chronic venous disease limbs compared with healthy limbs.
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Affiliation(s)
- Gianni Niccolini
- Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Turin, Italy
| | - Andrea Manuello
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
| | - Antonio Capone
- Orthopedic Clinic, Department of Surgical Sciences, University of Cagliari, Cagliari, Italy
| | - Giuseppe Marongiu
- Orthopedic Clinic, Department of Surgical Sciences, University of Cagliari, Cagliari, Italy
| | - Antonio Hector Dell'Osa
- Instituto de Desarrollo Economico e Innovación, Universidad Nacional de Tierra del Fuego, Antartida e Islas del Atlantico Sur, Ushuaia, Argentina
| | - Andrea Fois
- Biosignal Acquisition System, Nomadyca Ltd., Kampala, Uganda
| | - Fernanda Velluzzi
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Alberto Concu
- 2C Technologies Ltd., Academic Spin-Off, University of Cagliari, Cagliari, Italy
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25
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Fetter C, Marques JR, de Souza LA, Dartora DR, Eibel B, Boll LFC, Goldmeier SN, Dias D, De Angelis K, Irigoyen MC. Additional Improvement of Respiratory Technique on Vascular Function in Hypertensive Postmenopausal Women Following Yoga or Stretching Video Classes: The YOGINI Study. Front Physiol 2020; 11:898. [PMID: 32982766 PMCID: PMC7485134 DOI: 10.3389/fphys.2020.00898] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/06/2020] [Indexed: 12/21/2022] Open
Abstract
Background: Hypertension remains highly prevalent in postmenopausal women, along with vascular dysfunction and increased oxidative stress. In such context, regular exercises, yoga practice, and slow breathing have been recommended to treat hypertension. However, the effects of the multiple components of yoga, including the respiratory techniques involved in the practice, on hypertension and on vascular and endothelial function have never been evaluated. Objective: This study aimed to investigate the additional effects of respiratory technique on vascular function and oxidative stress profile in hypertensive postmenopausal women (HPMWs) following yoga or stretching video classes. Study Design: Hypertensive postmenopausal women were recruited and randomized for 12 weeks, twice a week, of supervised yoga or stretching video classes of 75 min for 12 weeks associated or not with respiratory technique. Baseline and post-intervention measurements included pulse wave velocity (PWV), flow-mediated dilation (FMD), and oxidative stress parameters. Hypertensive postmenopausal women (59 ± 0.7 years) who ended the protocol were distributed into three groups: (1) control group (yoga or stretching, C, n = 14); (2) yoga + respiratory technique (Y+, n = 10); (3) stretching + respiratory technique (S+, n = 9). Results: Diastolic blood pressure and FMD [baseline: C: 6.94 ± 1.97%, Y+: 7.05 ± 1.65%, and S+: 3.54 ± 2.01% vs. post: C: 16.59 ± 3.46% (p = 0.006), Y+: 13.72 ± 2.81% (p = 0.005), and S+: 11.79 ± 0.99% (p = 0.0001)] have significantly increased in all groups when baseline and post-practice values were compared. However, resting heart rate and PWV [baseline: Y+: 10.44 ± 3.69 and S+: 9.50 ± 0.53 m/s vs. post: Y+: 9.45 ± 0.39 (p = 0.003) and S+: 8.02 ± 0.47 m/s (p = 0.003)] decreased significantly only in the Y+ and S+ groups (baseline vs. post). Systemic antioxidant enzyme activities (superoxide dismutase and catalase) increased in all groups, and hydrogen peroxide and lipoperoxidation reduced in Y+ and S+ (baseline vs. post). Conclusions: Twelve weeks of yoga or stretching video classes promoted positive changes in several outcomes generally regarded as cardiovascular risk factors in HPMWs, and these changes were even more pronounced by the association with respiratory technique.
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Affiliation(s)
- Cláudia Fetter
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil
| | - Juliana Romeu Marques
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil
| | - Liliane Appratto de Souza
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil
| | - Daniela Ravizzoni Dartora
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil.,Sainte Justine Hospital and Research Center, Montreal, QC, Canada
| | - Bruna Eibel
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil
| | - Liliana Fortini Cavalheiro Boll
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil
| | - Sílvia Noll Goldmeier
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil
| | - Danielle Dias
- Department of Physiology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.,Laboratory of Translational Physiology, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil
| | - Katia De Angelis
- Department of Physiology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.,Laboratory of Translational Physiology, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil
| | - Maria Cláudia Irigoyen
- Clinical Investigation Laboratory (LIC), Cardiology Institute of Rio Grande do Sul/Cardiology University Foundation (IC-FUC), Porto Alegre, Brazil.,Experimental Laboratory of Hypertension, Heart Institute (InCor), University of São Paulo (USP), São Paulo, Brazil
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26
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Hu X, Li Y, Li J, Chen H. Effects of altered blood flow induced by the muscle pump on thrombosis in a microfluidic venous valve model. LAB ON A CHIP 2020; 20:2473-2481. [PMID: 32543635 DOI: 10.1039/d0lc00287a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Deep vein thrombosis (DVT) often occurs in the lower limb veins of bedridden patients and greatly reduces the quality of life. The altered blood flow in venous valves induced by the insufficient efficacy of the muscle pump is commonly considered as a main factor. However, it is still a great challenge to observe the altered blood flow in real time, and its role in the formation of thrombi is poorly understood. Here we make a microfluidic venous valve model with flexible leaflets in a deformable channel that can mimic the motion of valves and the compression of vessels by muscle contraction, and identify the stasis and intermittent reflux in the valve pocket generated by the muscle pump. A thrombus forms in the stasis flow, while the intermittent reflux removes the fibrin and inhibits the growth of the thrombus. A flexible microfluidic device that can mimic the motion of valves and the contraction of vessels would have wide applications in the research on cardiovascular diseases.
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Affiliation(s)
- Xiangyu Hu
- State Key Laboratory of Tribology, Mechanical Engineering Department, Tsinghua University, Beijing, 100084, China.
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27
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Relationship between the fall in blood pressure in the standing position and diaphragmatic muscle thickness: proof of concept study. Blood Press Monit 2020; 24:284-288. [PMID: 31567294 DOI: 10.1097/mbp.0000000000000403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND The diaphragm is an important muscle of respiration, and regulates the intrathoracic pressure. Blood pressure is regulated by the baroreceptor reflex system, and is also affected by intrathoracic pressure. We examined the relationship between the diaphragmatic muscle thickness and the degree of drop in blood pressure in the standing position. METHODS We prospectively studied 15 healthy subjects. The diaphragmatic muscle thickness was measured using a B-mode ultrasonic imaging device. The blood pressure before and after standing was measured by a head-up tilt test. RESULTS The diastolic blood pressure difference during expiration and inspiration showed a significant correlation with the diaphragmatic muscle thickness (r = 0.578, P = 0.024 and r = 0.518, P = 0.048, respectively). CONCLUSION The diaphragmatic muscle thickness was related to the fall in diastolic blood pressure in the standing position. This indicates that adequate diaphragmatic muscle thickness helps to maintain intrathoracic pressure and prevents excessive drop in blood pressure in the standing position.
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Hayashi H, Abe M. Grip Exercise of Non-Paretic Hand Can Improve Venous Return in the Paretic Arm in Stroke Patients: An Experimental Study in the Supine and Sitting Positions. Ann Vasc Dis 2020; 13:170-175. [PMID: 32595794 PMCID: PMC7315231 DOI: 10.3400/avd.oa.20-00024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objective: This study aims to determine the effect of grip exercise by the non-paretic hand on venous return in the paretic arm in stroke in sitting and supine positions. Methods: The study population included 21 stroke patients (mean age, 59.5 years). The diameter (mm) and time-averaged mean velocity (TAMV) (cm/s) of the axillary vein on the paretic side were measured by ultrasound during three distinct conditions: resting, rhythmic non-resistive grip exercise, and resistive exercise (30% of maximum grip strength) in supine and sitting positions. The venous flow volume (ml/min) was calculated using the obtained data. Results: In the supine and sitting positions, the venous flow volume during rhythmic non-resistive and resistive exercises was increased in comparison to resting, which resulted in more increased venous flow volume by rhythmic resistive grip exercise than by non-resistive grip exercise (both, p=0.01). Conclusion: Grip exercise by the non-paretic hand was found to be effective for increasing the venous flow volume in the paretic hand, and resistive grip exercise caused the greatest increase. Our results suggest that rhythmic handgrip exercise may be clinically useful for reducing the incidence of hand edema in stroke patients.
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Affiliation(s)
- Hiroyuki Hayashi
- Faculty of Care and Rehabilitation, Division of Occupational Therapy, Seijoh University, Tokai, Aichi, Japan
| | - Motoyuki Abe
- Faculty of Care and Rehabilitation, Division of Physical Therapy, Seijoh University, Tokai, Aichi, Japan
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Abstract
Lymphology is evolving in search of a better management of lymphedema patients, both as to the diagnostic pathway and as to the therapeutic options. Similarly, lymphatic system is involved in a wide spectrum of pathophysiologic processes of most chronic degenerative diseases. Translational medicine integrates the interdisciplinary scientific knowledge to improve diagnostic and therapeutic options in the biomedical field. Inflammation and lymphatic function are regarded as the connecting biochemical factors in most diseases. This review focuses on the scientific publications regarding lymphatic system in connection to psycho-neuroendocrine immunology, hormesis, epigenetics and more generally nutrition and lifestyle. The interaction between lymphology and translational medicine may play a relevant role to improve management of lymphedema on the one hand, and of chronic degenerative diseases on the other.
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Affiliation(s)
- Attilio Cavezzi
- Eurocenter Venalinfa, San Benedetto del Tronto, Ascoli Piceno, Italy -
| | - Roberto Colucci
- Eurocenter Venalinfa, San Benedetto del Tronto, Ascoli Piceno, Italy
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30
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Xu H, Medina-Sánchez M, Maitz MF, Werner C, Schmidt OG. Sperm Micromotors for Cargo Delivery through Flowing Blood. ACS NANO 2020; 14:2982-2993. [PMID: 32096976 DOI: 10.1021/acsnano.9b07851] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Micromotors are recognized as promising candidates for untethered micromanipulation and targeted cargo delivery in complex biological environments. However, their feasibility in the circulatory system has been limited due to the low thrust force exhibited by many of the reported synthetic micromotors, which is not sufficient to overcome the high flow and complex composition of blood. Here we present a hybrid sperm micromotor that can actively swim against flowing blood (continuous and pulsatile) and perform the function of heparin cargo delivery. In this biohybrid system, the sperm flagellum provides a high propulsion force while the synthetic microstructure serves for magnetic guidance and cargo transport. Moreover, single sperm micromotors can assemble into a train-like carrier after magnetization, allowing the transport of multiple sperm or medical cargoes to the area of interest, serving as potential anticoagulant agents to treat blood clots or other diseases in the circulatory system.
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Affiliation(s)
- Haifeng Xu
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), TU Chemnitz, Rosenbergstraße 6, 09126 Chemnitz, Germany
| | - Mariana Medina-Sánchez
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Manfred F Maitz
- Max Bergmann Center of Biomaterials, Leibniz Institute of Polymer Research Dresden, 01069 Dresden, Germany
| | - Carsten Werner
- Max Bergmann Center of Biomaterials, Leibniz Institute of Polymer Research Dresden, 01069 Dresden, Germany
| | - Oliver G Schmidt
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), TU Chemnitz, Rosenbergstraße 6, 09126 Chemnitz, Germany
- School of Science, TU Dresden, 01062 Dresden, Germany
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31
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Cheyne WS, Harper MI, Gelinas JC, Sasso JP, Eves ND. Mechanical cardiopulmonary interactions during exercise in health and disease. J Appl Physiol (1985) 2020; 128:1271-1279. [PMID: 32163324 DOI: 10.1152/japplphysiol.00339.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The heart and lungs are anatomically coupled through the pulmonary circulation and coexist within the sealed thoracic cavity, making the function of these systems highly interdependent. Understanding of the complex mechanical interactions between cardiac and pulmonary systems has evolved over the last century to appreciate that changes in respiratory mechanics significantly impact pulmonary hemodynamics and ventricular filling and ejection. Furthermore, given that the left and right heart share a common septum and are surrounded by the nondistensible pericardium, direct ventricular interaction is an important mediator of both diastolic and systolic performance. Although it is generally considered that cardiopulmonary interaction in healthy individuals at rest minimally affects hemodynamics, the significance during exercise is less clear. Adverse heart-lung interaction in respiratory disease is of growing interest as it may contribute to the pathogenesis of comorbid cardiovascular dysfunction and exercise intolerance in these patients. Similarly, heart failure represents a pathological uncoupling of the cardiovascular and pulmonary systems, whereby cardiac function may be impaired by the normal ventilatory response to exercise. Despite significant research contributions to this complex area, the mechanisms of cardiopulmonary interaction in the intact human and the clinical consequences of adverse interactions in common respiratory and cardiovascular diseases, particularly during exercise, remain incompletely understood. The purpose of this review is to present the key physiological principles of cardiopulmonary interaction as they pertain to resting and exercising hemodynamics in healthy humans and the clinical implications of adverse cardiopulmonary interaction during exercise in chronic obstructive pulmonary disease (COPD), pulmonary hypertension, and heart failure.
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Affiliation(s)
- William S Cheyne
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Megan I Harper
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Jinelle C Gelinas
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - John P Sasso
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Neil D Eves
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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32
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Hockin BCD, Claydon VE. Intermittent Calf Compression Delays the Onset of Presyncope in Young Healthy Individuals. Front Physiol 2020; 10:1598. [PMID: 32038283 PMCID: PMC6993600 DOI: 10.3389/fphys.2019.01598] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 12/19/2019] [Indexed: 12/26/2022] Open
Abstract
Orthostatic fluid shifts reduce the effective circulating volume and thus contribute to syncope susceptibility. Recurrent syncope has a devastating impact on quality of life and is challenging to manage effectively. To blunt orthostatic fluid shifts, static calf compression garments are often prescribed to patients with syncope, but have questionable efficacy. Intermittent calf compression, which mimics the skeletal muscle pump to minimize pooling and filtration, holds promise for the management of syncope. We aimed to evaluate the effectiveness of intermittent calf compression for increasing orthostatic tolerance (OT; time to presyncope). We conducted a randomized single-blind crossover study, in which participants (n = 21) underwent three graded 60° head-up-tilt tests to presyncope with combined lower body negative pressure on separate days. Low frequency intermittent calf compression (ICLF; 4 s on and 11 s off) at 0-30 and 0-60 mmHg was applied during two tests and compared to a placebo condition where the garment was fitted, but no compression applied. We measured continuous leg circumference changes (strain gauge plethysmography), cardiovascular responses (finger plethysmography; Finometer Pro), end tidal gases (nasal cannula), and cerebral blood flow velocity (CBFv, transcranial Doppler). The 0-60 mmHg ICLF increased OT (33 ± 2.2 min) compared to both placebo (26 ± 2.4 min; p < 0.001) and 0-30 mmHg ICLF (25 ± 2.7 min; p < 0.001). Throughout testing 0-60 mmHg ICLF reduced orthostatic fluid shifts compared to both placebo and 0-30 mmHg ICLF (p < 0.001), with an associated improvement in stroke volume (p < 0.001), allowing blood pressure to be maintained at a reduced heart rate (p < 0.001). In addition, CBFv was higher with 0-60 mmHg ICLF than 0-30 mmHg ICLF and placebo (p < 0.001). Intermittent calf compression is a promising novel intervention for the management of orthostatic intolerance, which may provide affected individuals renewed independence and improved quality of life.
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Affiliation(s)
- Brooke C D Hockin
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.,International Collaboration On Repair Discoveries, The University of British Columbia, Vancouver, BC, Canada
| | - Victoria E Claydon
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada.,International Collaboration On Repair Discoveries, The University of British Columbia, Vancouver, BC, Canada
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33
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Magder S, Famulari G, Gariepy B. Periodicity, time constants of drainage, and the mechanical determinants of peak cardiac output during exercise. J Appl Physiol (1985) 2019; 127:1611-1619. [PMID: 31414960 DOI: 10.1152/japplphysiol.00688.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To analyze mechanical adaptations that must occur in the cardiovascular system to reach the high cardiac outputs known to occur at peak aerobic performance, we adapted a computational model of the circulation by adding a second parallel venous compartment as proposed by August Krogh in 1912. One venous compartment has a large compliance and slow time constant of emptying; it is representative of the splanchnic circulation. The other has a low compliance and fast time constant of emptying and is representative of muscle beds. Fractional distribution between the two compartments is an important determinant of cardiac output. Parameters in the model were based on values from animal and human studies normalized to a 70 kg male. The baseline cardiac output was set at 5 L/min, and we aimed for 25 L/min at peak exercise with a fractional flow to the peripheral-muscle region of 90%. Finally, we added the equivalent of a muscle pump. Adjustments in circuit and cardiac parameters alone increased cardiac output to only 15.6 L/min because volume accumulated in the muscle compartment and limited a higher cardiac output. Addition of muscle contractions decompressed the muscle region and allowed cardiac output to increase to 23.4 L/min. The pulsatility of blood flow imposes important constraints on the adaptations of cardiac and circulatory functions because it fixes the times for filling and emptying. Flow is further limited by the limits of cardiac filling on each beat. Muscle contractions play a key role by decompressing volume that would otherwise accumulate in the muscle vasculature and by decreasing the time for stroke return to the right ventricle.NEW & NOTEWORTHY We used a computational model of the circulation and previous human and animal data to model mechanical changes in the heart and circulation that are needed to reach the known high cardiac output at peak aerobic exercise. Key points are that time constants of drainage of circulatory compartments put limits on peak flow in a pulsatile system. Muscle contractions increase the rate of return to the heart and by doing so prevent accumulation of volume in the muscle compartment and greatly increase circulatory capacity.
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Affiliation(s)
- Sheldon Magder
- McGill University Health Centre, Department of Critical Care and Department of Physiology, Montreal, Quebec, Canada
| | - Gabriel Famulari
- McGill University Health Centre, Department of Critical Care and Department of Physiology, Montreal, Quebec, Canada
| | - Brian Gariepy
- McGill University Health Centre, Department of Critical Care and Department of Physiology, Montreal, Quebec, Canada
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34
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Horwood A. The biomechanical function of the foot pump in venous return from the lower extremity during the human gait cycle: An expansion of the gait model of the foot pump. Med Hypotheses 2019; 129:109220. [DOI: 10.1016/j.mehy.2019.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/08/2019] [Accepted: 05/12/2019] [Indexed: 11/27/2022]
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35
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Wu X, Liu R, Lao TT. Therapeutic compression materials and wound dressings for chronic venous insufficiency: A comprehensive review. J Biomed Mater Res B Appl Biomater 2019; 108:892-909. [PMID: 31339655 DOI: 10.1002/jbm.b.34443] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/06/2019] [Accepted: 06/28/2019] [Indexed: 01/15/2023]
Abstract
Chronic venous insufficiency (CVI) is a common disorder worldwide. Related pathophysiological mechanisms reportedly involve venous pooling and reduced venous return, leading to heaviness, aching, itchiness, tiredness, varicosities, pigmentation, and even lower limb ulceration. Approaches adopted to manage CVI at various stages of clinical-etiology-anatomy-pathophysiology include compression therapy, pharmacological treatment, ultrasound treatment, surgery, electrical or wireless microcurrent stimulation, and pulsed electromagnetic treatment. Among these, polymer-based therapeutic compression materials and wound dressings play increasingly key roles in treating all stages of CVI because of their unique physical, mechanical, chemical, and biological functions. However, the characteristics, working mechanisms, and effectiveness of these CVI treatment materials are not comprehensively understood. The present systematic review examines the structures, properties, types, and applications of various polymer-based compression materials and wound dressings used in prophylaxis and treatment of CVI. Existing problems, limitations, and future trends of CVI treatment materials are also discussed. This review could contribute to the design and application of new functional polymer materials and dressings to enhance the efficiency of CVI treatments, thereby facilitating patients' self-care ability and long-term health improvement.
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Affiliation(s)
- Xinbo Wu
- Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Rong Liu
- Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Terence T Lao
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong SAR, China
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36
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Stewart JM, Pianosi P, Shaban MA, Terilli C, Svistunova M, Visintainer P, Medow MS. Hemodynamic characteristics of postural hyperventilation: POTS with hyperventilation versus panic versus voluntary hyperventilation. J Appl Physiol (1985) 2018; 125:1396-1403. [PMID: 30138078 DOI: 10.1152/japplphysiol.00377.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Upright hyperventilation occurs in ~25% of our patients with postural tachycardia syndrome (POTS). Poikilocapnic hyperventilation alone causes tachycardia. Here, we examined changes in respiration and hemodynamics comprising cardiac output (CO), systemic vascular resistance (SVR), and blood pressure (BP) measured during head-up tilt (HUT) in three groups: patients with POTS and hyperventilation (POTS-HV), patients with panic disorder who hyperventilate (Panic), and healthy controls performing voluntary upright hyperpnea (Voluntary-HV). Though all were comparably tachycardic during hyperventilation, POTS-HV manifested hyperpnea, decreased CO, increased SVR, and increased BP during HUT; Panic patients showed both hyperpnea and tachypnea, increased CO, and increased SVR as BP increased during HUT; and Voluntary-HV were hyperpneic by design and had increased CO, decreased SVR, and decreased BP during upright hyperventilation. Mechanisms of hyperventilation and hemodynamic changes differed among POTS-HV, Panic, and Voluntary-HV subjects. We hypothesize that the hyperventilation in POTS is caused by a mechanism involving peripheral chemoreflex sensitization by intermittent ischemic hypoxia. NEW & NOTEWORTHY Hyperventilation is common in postural tachycardia syndrome (POTS) and has distinctive cardiovascular characteristics when compared with hyperventilation in panic disorder or with voluntary hyperventilation. Hyperventilation in POTS is hyperpnea only, distinct from panic in which tachypnea also occurs. Cardiac output is decreased in POTS, whereas peripheral resistance and blood pressure (BP) are increased. This is distinct from voluntary hyperventilation where cardiac output is increased and resistance and BP are decreased and from panic where they are all increased.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York.,Department of Physiology, New York Medical College, Valhalla, New York
| | - Paul Pianosi
- Paediatric Respiratory Medicine, King's College Hospital National Health Surface Foundation Trust , London , United Kingdom
| | - Mohamed A Shaban
- Department of Pediatrics, New York Medical College, Valhalla, New York
| | - Courtney Terilli
- Department of Pediatrics, New York Medical College, Valhalla, New York
| | - Maria Svistunova
- Department of Pediatrics, New York Medical College, Valhalla, New York
| | - Paul Visintainer
- Epidemiology and Biostatistics, Baystate Medical Center, University of Massachusetts School of Medicine , Worcester, Massachusetts
| | - Marvin S Medow
- Department of Pediatrics, New York Medical College, Valhalla, New York.,Department of Physiology, New York Medical College, Valhalla, New York
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Joyce W, Elsey RM, Wang T, Crossley DA. Maximum heart rate does not limit cardiac output at rest or during exercise in the American alligator (Alligator mississippiensis). Am J Physiol Regul Integr Comp Physiol 2018; 315:R296-R302. [DOI: 10.1152/ajpregu.00027.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In most vertebrates, increases in cardiac output result from increases in heart rate (fH) with little or no change in stroke volume (Vs), and maximum cardiac output (Q̇) is typically attained at or close to maximum fH. We therefore tested the hypothesis that increasing maximum fH may increase maximum Q̇. To this end, we investigated the effects of elevating fH with right atrial pacing on Q̇ in the American alligator ( Alligator mississippiensis) at rest and while swimming. During normal swimming, Q̇ increased entirely by virtue of a tachycardia (29 ± 1 to 40 ± 3 beats/min), whereas Vs remained stable. In both resting and swimming alligators, increasing fH with right atrial pacing resulted in a parallel decline in Vs that resulted in an unchanged cardiac output. In swimming animals, this reciprocal relationship extended to supraphysiological fH (up to ~72 beats/min), which suggests that maximum fH does not limit maximum cardiac output and that fH changes are secondary to the peripheral factors (for example vascular capacitance) that determine venous return at rest and during exercise.
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Affiliation(s)
- William Joyce
- Department of Zoophysiology, Aarhus University, Aarhus, Denmark
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana
| | - Tobias Wang
- Department of Zoophysiology, Aarhus University, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
| | - Dane A. Crossley
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, Texas
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Verma AK, Xu D, Bruner M, Garg A, Goswami N, Blaber AP, Tavakolian K. Comparison of Autonomic Control of Blood Pressure During Standing and Artificial Gravity Induced via Short-Arm Human Centrifuge. Front Physiol 2018; 9:712. [PMID: 29988521 PMCID: PMC6026653 DOI: 10.3389/fphys.2018.00712] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 05/23/2018] [Indexed: 12/11/2022] Open
Abstract
Autonomic control of blood pressure is essential toward maintenance of cerebral perfusion during standing, failure of which could lead to fainting. Long-term exposure to microgravity deteriorates autonomic control of blood pressure. Consequently, astronauts experience orthostatic intolerance on their return to gravitational environment. Ground-based studies suggest sporadic training in artificial hypergravity can mitigate spaceflight deconditioning. In this regard, short-arm human centrifuge (SAHC), capable of creating artificial hypergravity of different g-loads, provides an auspicious training tool. Here, we compare autonomic control of blood pressure during centrifugation creating 1-g and 2-g at feet with standing in natural gravity. Continuous blood pressure was acquired simultaneously from 13 healthy participants during supine baseline, standing, supine recovery, centrifugation of 1-g, and 2-g, from which heart rate (RR) and systolic blood pressure (SBP) were derived. The autonomic blood pressure regulation was assessed via spectral analysis of RR and SBP, spontaneous baroreflex sensitivity, and non-linear heart rate and blood pressure causality (RR↔SBP). While majority of these blood pressure regulatory indices were significantly different (p < 0.05) during standing and 2-g centrifugation compared to baseline, no change (p > 0.05) was observed in the same indices during 2-g centrifugation compared to standing. The findings of the study highlight the capability of artificial gravity (2-g at feet) created via SAHC toward evoking blood pressure regulatory controls analogous to standing, therefore, a potential utility toward mitigating deleterious effects of microgravity on cardiovascular performance and minimizing post-flight orthostatic intolerance in astronauts.
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Affiliation(s)
- Ajay K. Verma
- Department of Electrical Engineering, University of North Dakota, Grand Forks, ND, United States
| | - Da Xu
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Michelle Bruner
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Amanmeet Garg
- Department of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Nandu Goswami
- Physiology Division, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz, Graz, Austria
| | - Andrew P. Blaber
- Department of Electrical Engineering, University of North Dakota, Grand Forks, ND, United States
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Kouhyar Tavakolian
- Department of Electrical Engineering, University of North Dakota, Grand Forks, ND, United States
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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Moses KL, Seymour M, Beshish A, Baker KR, Pegelow DF, Lamers LJ, Eldridge MW, Bates ML. Inspiratory and expiratory resistance cause right-to-left bubble passage through the foramen ovale. Physiol Rep 2018; 6:e13719. [PMID: 29952137 PMCID: PMC6021277 DOI: 10.14814/phy2.13719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 11/29/2022] Open
Abstract
A patent foramen ovale (PFO) is linked to increased risk of decompression illness in divers. One theory is that venous gas emboli crossing the PFO can be minimized by avoiding lifting, straining and Valsalva maneuvers. Alternatively, we hypothesized that mild increases in external inspiratory and expiratory resistance, similar to that provided by a SCUBA regulator, recruit the PFO. Nine healthy adults with a Valsalva-proven PFO completed three randomized trials (inspiratory, expiratory, and combined external loading) with six levels of increasing external resistance (2-20 cmH2 O/L/sec). An agitated saline contrast echocardiogram was performed at each level to determine foramen ovale patency. Contrary to our hypothesis, there was no relationship between the number of subjects recruiting their PFO and the level of external resistance. In fact, at least 50% of participants recruited their PFO during 14 of 18 trials and there was no difference between the combined inspiratory, expiratory, or combined external resistance trials (P > 0.05). We further examined the relationship between PFO recruitment and intrathoracic pressure, estimated from esophageal pressure. Esophageal pressure was not different between participants with and without a recruited PFO. Intrasubject variability was the most important predictor of PFO patency, suggesting that some individuals are more likely to recruit their PFO in the face of even mild external resistance. Right-to-left bubble passage through the PFO occurs in conditions that are physiologically relevant to divers. Transthoracic echocardiography with mild external breathing resistance may be a tool to identify divers that are at risk of PFO-related decompression illness.
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Affiliation(s)
- Kayla L. Moses
- John Rankin Laboratory of Pulmonary MedicineDepartment of PediatricsCritical Care DivisionUniversity of Wisconsin School of Medicine and Public HealthMadisonWisconsin
- Department of KinesiologyUniversity of Wisconsin‐MadisonMadisonWisconsin
| | - McKayla Seymour
- Department of Health and Human PhysiologyUniversity of IowaIowa CityIowa
| | - Arij Beshish
- John Rankin Laboratory of Pulmonary MedicineDepartment of PediatricsCritical Care DivisionUniversity of Wisconsin School of Medicine and Public HealthMadisonWisconsin
| | - Kim R. Baker
- Adult Echocardiography LaboratoryUniversity of Wisconsin Hospitals and ClinicsMadisonWisconsin
| | - David F. Pegelow
- John Rankin Laboratory of Pulmonary MedicineDepartment of PediatricsCritical Care DivisionUniversity of Wisconsin School of Medicine and Public HealthMadisonWisconsin
| | - Luke J. Lamers
- Division of Pediatric CardiologyUniversity of Wisconsin School of Medicine and Public HealthMadisonWisconsin
| | - Marlowe W. Eldridge
- John Rankin Laboratory of Pulmonary MedicineDepartment of PediatricsCritical Care DivisionUniversity of Wisconsin School of Medicine and Public HealthMadisonWisconsin
- Department of KinesiologyUniversity of Wisconsin‐MadisonMadisonWisconsin
- Department of Biomedical EngineeringUniversity of Wisconsin‐MadisonIowa CityIowa
| | - Melissa L. Bates
- Department of Health and Human PhysiologyUniversity of IowaIowa CityIowa
- Stead Family Department of PediatricsUniversity of IowaIowa CityIowa
- Holden Comprehensive Cancer CenterUniversity of IowaIowa CityIowa
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LoMauro A, Aliverti A. Blood Shift During Cough: Negligible or Significant? Front Physiol 2018; 9:501. [PMID: 29892226 PMCID: PMC5985436 DOI: 10.3389/fphys.2018.00501] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/18/2018] [Indexed: 11/13/2022] Open
Abstract
Rationale: It was reported how forceful rhythmic coughing can provide effective blood flow during ventricular fibrillation without direct chest compression. This mechanism of cough-assisted cardiopulmonary resuscitation constitutes a form of "cardiac massage" secondary to the intrathoracic and intra-abdominal pressure changes during cough. We have previously shown that significant blood shifts (BSs) occurs from the thorax to the extremities during expulsive maneuvers and that abdominal pressure controls the outflow of blood from the splanchnic vasculature. This mechanism was called abdominal circulatory pump. BS was quantified by using double body plethysmography (DBP), which combines total body plethysmography and opto-electronic plethysmography. Aim: We hypothesized that coughing activates also the abdominal circulatory pump, being an additional mechanism that displaces a circulatory output sufficient to maintain consciousness in a patient with a non-beating heart. Methods and Results: We studied seven healthy subjects (age: 28.6 ± 2.5 years) during series of voluntary coughs at three different operating volumes: after a spontaneous tidal volume, at total lung capacity (TLC) and at an intermediate volume. BS from the thorax to the extremities were measured by DBP during quiet breathing and during cough at each operating lung volume. BS during cough resulted significantly higher than during quiet breathing (p < 0.05). During the compressive phase, the blood outflow is around 200 ml, whereas during the expulsive phase BS increased (p < 0.05) with increasing operating volume, being almost 700 ml at TLC. At lower operating volume it is almost 400 ml. Conclusion: Deep, vigorous coughing and the consequent fluctuations in intra-thoracic and intra-abdominal pressure activate both the thoracic and the abdominal pump mechanism. The former leads the low-resistance pulmonary veins to empty into the left heart. The latter can generate a circulatory output from the splanchnic region, which acts as a blood reservoir, to other body tissues. These findings might help to better understand the cardiopulmonary interactions during cough, particularly in patients with unstable cardiac function, and the mechanism by which coughing during unstable cardiac rhythms can maintain consciousness in human subjects.
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Affiliation(s)
- Antonella LoMauro
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Andrea Aliverti
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
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Aslan SC, Legg Ditterline BE, Park MC, Angeli CA, Rejc E, Chen Y, Ovechkin AV, Krassioukov A, Harkema SJ. Epidural Spinal Cord Stimulation of Lumbosacral Networks Modulates Arterial Blood Pressure in Individuals With Spinal Cord Injury-Induced Cardiovascular Deficits. Front Physiol 2018; 9:565. [PMID: 29867586 PMCID: PMC5968099 DOI: 10.3389/fphys.2018.00565] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 04/30/2018] [Indexed: 12/23/2022] Open
Abstract
Disruption of motor and autonomic pathways induced by spinal cord injury (SCI) often leads to persistent low arterial blood pressure and orthostatic intolerance. Spinal cord epidural stimulation (scES) has been shown to enable independent standing and voluntary movement in individuals with clinically motor complete SCI. In this study, we addressed whether scES configured to activate motor lumbosacral networks can also modulate arterial blood pressure by assessing continuous, beat-by-beat blood pressure and lower extremity electromyography during supine and standing in seven individuals with C5-T4 SCI. In three research participants with arterial hypotension, orthostatic intolerance, and low levels of circulating catecholamines (group 1), scES applied while supine and standing resulted in increased arterial blood pressure. In four research participants without evidence of arterial hypotension or orthostatic intolerance and normative circulating catecholamines (group 2), scES did not induce significant increases in arterial blood pressure. During scES, there were no significant differences in electromyographic (EMG) activity between group 1 and group 2. In group 1, during standing assisted by scES, blood pressure was maintained at 119/72 ± 7/14 mmHg (mean ± SD) compared with 70/45 ± 5/7 mmHg without scES. In group 2 there were no arterial blood pressure changes during standing with or without scES. These findings demonstrate that scES configured to facilitate motor function can acutely increase arterial blood pressure in individuals with SCI-induced cardiovascular deficits.
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Affiliation(s)
- Sevda C Aslan
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Bonnie E Legg Ditterline
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Michael C Park
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Department of Neurosurgery and Neurology, University of Minnesota School of Medicine, Minneapolis, MN, United States
| | - Claudia A Angeli
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Frazier Rehab Institute, Louisville, KY, United States
| | - Enrico Rejc
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Yangsheng Chen
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Alexander V Ovechkin
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States
| | - Andrei Krassioukov
- Experimental Medicine Program, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC, Canada.,GF Strong Rehabilitation Centre, Vancouver Coastal Health, Vancouver, BC, Canada
| | - Susan J Harkema
- Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Frazier Rehab Institute, Louisville, KY, United States
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Caggiati A, De Maeseneer M, Cavezzi A, Mosti G, Morrison N. Rehabilitation of patients with venous diseases of the lower limbs: State of the art. Phlebology 2018; 33:663-671. [PMID: 29361892 DOI: 10.1177/0268355518754463] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND To date, no document comprehensively focused on the complex issue of the rehabilitation of chronic venous diseases of the lower limbs. METHOD This article overviews and summarizes current strategies concerning venous rehabilitation of lower limbs. RESULTS Venous rehabilitation is based on four main strategies: (1) lifestyle adaptations and occupational therapies; (2) physical therapies; (3) adapted physical activities; (4) psychological and social support. Rehabilitative protocols must be tailored to the specific needs of each patient, depending on the severity of chronic venous disease and on the location and pattern of venous lesion(s), but also on age, motor deficits, co-morbidities and psychosocial conditions. CONCLUSIONS Venous rehabilitation consists of non-pharmacologic and non-surgical interventions aiming at prevention of venous disease progression and complications, reduction of symptoms and improvement of quality of life. Well-designed clinical trials are required to evaluate the efficacy of the described rehabilitative protocols in influencing the evolution of venous disorders.
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Nakanishi K, Takahira N, Sakamoto M, Yamaoka-Tojo M, Katagiri M, Kitagawa J. Effects of forced deep breathing on blood flow velocity in the femoral vein: Developing a new physical prophylaxis for deep vein thrombosis in patients with plaster cast immobilization of the lower limb. Thromb Res 2017; 162:53-59. [PMID: 29291451 DOI: 10.1016/j.thromres.2017.12.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 12/20/2017] [Accepted: 12/21/2017] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Patients with plaster cast immobilization of the lower limb have an estimated symptomatic venous thromboembolism rate of 5.5%. However, there is currently no practical physical prophylaxis for deep-vein thrombosis (DVT). The objective of this study was to examine the effects of forced deep breathing on peak blood velocity in the superficial femoral vein (PBVFV), which is a surrogate measure of the efficacy of thromboprophylaxis against DVT, in patients with plaster cast immobilization of the lower limb. MATERIALS AND METHODS Nine young males and 18 elderly males were recruited. We immobilized the right lower limb of each subject with a plaster splint and measured PBVFV during forced deep breathing in supine and sitting positions. RESULTS In all subjects, PBVFV during forced deep breathing in both positions was significantly higher than at rest. There was no significant difference in the PBVFV change ratio for three breathing rates in the sitting position for the young subjects (15breaths/min: 415%, 5breaths/min: 475%, 3breaths/min: 483%), whereas that for the elderly subjects at 3breaths/min (449%) was significantly higher than that at 15breaths/min (284%). CONCLUSIONS Forced deep breathing significantly increased PBVFV in patients with plaster cast immobilization of the lower limb in both supine and sitting positions. Testing the efficacy and adherence in clinical contexts, and following up with the incidence rate of DVT in future studies, is necessary for the development of a new physical prophylaxis for DVT.
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Affiliation(s)
- Keisuke Nakanishi
- Sensory and Motor Control, Functional Restoration Sciences, Kitasato University Graduate School of Medical Sciences, 1-15-1, Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan
| | - Naonobu Takahira
- Sensory and Motor Control, Functional Restoration Sciences, Kitasato University Graduate School of Medical Sciences, 1-15-1, Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan; Department of Orthopaedic Surgery, Kitasato University Graduate School of Medical Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan; Physical Therapy Course, Department of Rehabilitation, Kitasato University School of Allied Health Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan.
| | - Miki Sakamoto
- Physical Therapy Course, Department of Rehabilitation, Kitasato University School of Allied Health Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan.
| | - Minako Yamaoka-Tojo
- Physical Therapy Course, Department of Rehabilitation, Kitasato University School of Allied Health Sciences, 1-15-1 Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan.
| | - Masato Katagiri
- Department of Medical Laboratory, Kitasato University School of Allied Health Sciences, 1-15-1, Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan.
| | - Jun Kitagawa
- Sensory and Motor Control, Functional Restoration Sciences, Kitasato University Graduate School of Medical Sciences, 1-15-1, Kitasato, Minami-ku, Sagamihara-shi, Kanagawa 252-0373, Japan.
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Verma AK, Xu D, Garg A, Cote AT, Goswami N, Blaber AP, Tavakolian K. Non-linear Heart Rate and Blood Pressure Interaction in Response to Lower-Body Negative Pressure. Front Physiol 2017; 8:767. [PMID: 29114227 PMCID: PMC5660688 DOI: 10.3389/fphys.2017.00767] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/20/2017] [Indexed: 12/14/2022] Open
Abstract
Early detection of hemorrhage remains an open problem. In this regard, blood pressure has been an ineffective measure of blood loss due to numerous compensatory mechanisms sustaining arterial blood pressure homeostasis. Here, we investigate the feasibility of causality detection in the heart rate and blood pressure interaction, a closed-loop control system, for early detection of hemorrhage. The hemorrhage was simulated via graded lower-body negative pressure (LBNP) from 0 to -40 mmHg. The research hypothesis was that a significant elevation of causal control in the direction of blood pressure to heart rate (i.e., baroreflex response) is an early indicator of central hypovolemia. Five minutes of continuous blood pressure and electrocardiogram (ECG) signals were acquired simultaneously from young, healthy participants (27 ± 1 years, N = 27) during each LBNP stage, from which heart rate (represented by RR interval), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were derived. The heart rate and blood pressure causal interaction (RR↔SBP and RR↔MAP) was studied during the last 3 min of each LBNP stage. At supine rest, the non-baroreflex arm (RR→SBP and RR→MAP) showed a significantly (p < 0.001) higher causal drive toward blood pressure regulation compared to the baroreflex arm (SBP→RR and MAP→RR). In response to moderate category hemorrhage (-30 mmHg LBNP), no change was observed in the traditional marker of blood loss i.e., pulse pressure (p = 0.10) along with the RR→SBP (p = 0.76), RR→MAP (p = 0.60), and SBP→RR (p = 0.07) causality compared to the resting stage. Contrarily, a significant elevation in the MAP→RR (p = 0.004) causality was observed. In accordance with our hypothesis, the outcomes of the research underscored the potential of compensatory baroreflex arm (MAP→RR) of the heart rate and blood pressure interaction toward differentiating a simulated moderate category hemorrhage from the resting stage. Therefore, monitoring baroreflex causality can have a clinical utility in making triage decisions to impede hemorrhage progression.
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Affiliation(s)
- Ajay K Verma
- Department of Electrical Engineering, University of North Dakota, Grand Forks, ND, United States
| | - Da Xu
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Amanmeet Garg
- Department of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Anita T Cote
- School of Human Kinetics, Trinity Western University, Langley, BC, Canada
| | - Nandu Goswami
- Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Andrew P Blaber
- Department of Electrical Engineering, University of North Dakota, Grand Forks, ND, United States.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Kouhyar Tavakolian
- Department of Electrical Engineering, University of North Dakota, Grand Forks, ND, United States.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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Folino A, Benzo M, Pasquero P, Laguzzi A, Mesin L, Messere A, Porta M, Roatta S. Vena Cava Responsiveness to Controlled Isovolumetric Respiratory Efforts. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2017; 36:2113-2123. [PMID: 28543857 DOI: 10.1002/jum.14235] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/23/2017] [Indexed: 06/07/2023]
Abstract
OBJECTIVES Respirophasic variation of inferior vena cava (IVC) size is affected by large variability with spontaneous breathing. This study aims at characterizing the dependence of IVC size on controlled changes in intrathoracic pressure. METHODS Ten healthy subjects, in supine position, performed controlled isovolumetric respiratory efforts at functional residual capacity, attaining positive (5, 10, and 15 mmHg) and negative (-5, -10, and -15 mmHg) alveolar pressure levels. The isovolumetric constraint implies that equivalent changes are exhibited by alveolar and intrathoracic pressures during respiratory tasks. RESULTS The IVC cross-sectional area equal to 2.88 ± 0.43 cm2 at baseline (alveolar pressure = 0 mmHg) was progressively decreased by both expiratory and inspiratory efforts of increasing strength, with diaphragmatic efforts producing larger effects than thoracic ones: -55 ± 15% decrease, at +15 mmHg of alveolar pressure (P < .01), -80 ± 33 ± 12% at -15 mmHg diaphragmatic (P < .01), -33 ± 12% at -15 mmHg thoracic. Significant IVC changes in size (P < .01) and pulsatility (P < .05), along with non significant reduction in the response to respiratory efforts, were also observed during the first 30 minutes of supine rest, detecting an increase in vascular filling, and taking place after switching from the standing to the supine position. CONCLUSIONS This study quantified the dependence of the IVC cross-sectional area on controlled intrathoracic pressure changes and evidenced the stronger influence of diaphragmatic over thoracic activity. Individual variability in thoracic/diaphragmatic respiratory pattern should be considered in the interpretation of the respirophasic modulations of IVC size.
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Affiliation(s)
- Anna Folino
- Integrative Physiology Laboratory, Department of Neuroscience, Torino, Italy
| | - Marco Benzo
- Department of Electronics and Telecommunications, Mathematical Biology and Physiology, Politecnico di Torino, Torino, Italy
| | - Paolo Pasquero
- Department of Medical Sciences, AOU San Giovanni Battista, University of Torino, Torino, Italy
| | - Andrea Laguzzi
- Department of Medical Sciences, AOU San Giovanni Battista, University of Torino, Torino, Italy
| | - Luca Mesin
- Department of Electronics and Telecommunications, Mathematical Biology and Physiology, Politecnico di Torino, Torino, Italy
| | - Alessandro Messere
- Integrative Physiology Laboratory, Department of Neuroscience, Torino, Italy
| | - Massimo Porta
- Department of Medical Sciences, AOU San Giovanni Battista, University of Torino, Torino, Italy
| | - Silvestro Roatta
- Integrative Physiology Laboratory, Department of Neuroscience, Torino, Italy
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Laganà MM, Di Rienzo M, Rizzo F, Ricci C, D'Onofrio S, Forzoni L, Cecconi P. Cardiac, Respiratory and Postural Influences on Venous Return of Internal Jugular and Vertebral Veins. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:1195-1204. [PMID: 28385470 DOI: 10.1016/j.ultrasmedbio.2017.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 01/17/2017] [Accepted: 02/12/2017] [Indexed: 06/07/2023]
Abstract
It is known from physiology that heartbeat and respiration influence venous return, but little is known regarding the extent to which these two factors affect flow. In this study, we estimated the prevalence of cardiac- and breathing-induced venous flow modulations in the internal jugular vein (IJV) and vertebral vein (VV) and the effects of posture. In 19 healthy patients, neck vein flow was examined with pulsed wave Doppler. Electrocardiogram and respiratory signals were simultaneously acquired. In supine position, heart contraction always influenced venous flow, whereas breathing influenced 68% of IJV and 34% of VV flow. In sitting position, heart contraction influenced 74% of IJV and 42% of VV flow; breathing influenced 68% of IJV and 61% of VV measures. Thus, cardiac influence is greatly present in supine position, whereas breathing influence prevails in the VV while sitting. This setup allowed us to observe that in some patients, expiration may cause an unexpected increase in venous flow.
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Affiliation(s)
- Maria M Laganà
- Fondazione Don Carlo Gnocchi ONLUS, IRCCS S. Maria Nascente, Milan, Italy.
| | - Marco Di Rienzo
- Fondazione Don Carlo Gnocchi ONLUS, IRCCS S. Maria Nascente, Milan, Italy
| | - Francesco Rizzo
- Fondazione Don Carlo Gnocchi ONLUS, IRCCS S. Maria Nascente, Milan, Italy
| | - Cristian Ricci
- Fondazione Don Carlo Gnocchi ONLUS, IRCCS S. Maria Nascente, Milan, Italy; Centre of Excellence for Nutrition (CEN), North-West University, Potchefstroom, South Africa
| | | | | | - Pietro Cecconi
- Fondazione Don Carlo Gnocchi ONLUS, IRCCS S. Maria Nascente, Milan, Italy
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Abstract
Postural tachycardia syndrome (POTS) represents a common form of orthostatic intolerance that disproportionately affects young women from puberty through adulthood. Patients with POTS have day-to-day orthostatic symptoms with the hallmark feature of an excessive, sustained, and symptomatic rise in heart rate during orthostatic testing. Although considerable overlap exists, three subtypes of POTS have been described: neuropathic, hyperadrenergic, and hypovolemic forms. The wide spectrum of symptoms and comorbidities can make treatment particularly challenging. Volume expansion with fluid and salt, exercise, and education constitute a reasonable initial therapy for most patients. Several medicines are also available to treat orthostatic intolerance and the associated comorbidities. Defining the POTS subtypes clinically in each patient may help to guide medicine choices. A multidisciplinary approach to overall management of the patient with POTS is advised. This review highlights several aspects of POTS with a specific focus on adolescent and young adult patients. [Pediatr Ann. 2017;46(4):e145-e154.].
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Joseph AA, Merboldt KD, Voit D, Dahm J, Frahm J. Real-time magnetic resonance imaging of deep venous flow during muscular exercise-preliminary experience. Cardiovasc Diagn Ther 2016; 6:473-481. [PMID: 28123969 DOI: 10.21037/cdt.2016.11.02] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The accurate assessment of peripheral venous flow is important for the early diagnosis and treatment of disorders such as deep-vein thrombosis (DVT) which is a major cause of post-thrombotic syndrome or even death due to pulmonary embolism. The aim of this work is to quantitatively determine blood flow in deep veins during rest and muscular exercise using a novel real-time magnetic resonance imaging (MRI) method for velocity-encoded phase-contrast (PC) MRI at high spatiotemporal resolution. METHODS Real-time PC MRI of eight healthy volunteers and one patient was performed at 3 Tesla (Prisma fit, Siemens, Erlangen, Germany) using a flexible 16-channel receive coil (Variety, NORAS, Hoechberg, Germany). Acquisitions were based on a highly undersampled radial FLASH sequence with image reconstruction by regularized nonlinear inversion at 0.5×0.5×6 mm3 spatial resolution and 100 ms temporal resolution. Flow was assessed in two cross-sections of the lower leg at the level of the calf muscle and knee using a protocol of 10 s rest, 20 s flexion and extension of the foot, and 10 s rest. Quantitative analyses included through-plane flow in the right posterior tibial, right peroneal and popliteal vein (PC maps) as well as signal intensity changes due to flow and muscle movements (corresponding magnitude images). RESULTS Real-time PC MRI successfully monitored the dynamics of venous flow at high spatiotemporal resolution and clearly demonstrated increased flow in deep veins in response to flexion and extension of the foot. In normal subjects, the maximum velocity (averaged across vessel lumen) during exercise was 9.4±5.7 cm·s-1 for the right peroneal vein, 8.5±4.6 cm·s-1 for the right posterior tibial vein and 17.8±5.8 cm·s-1 for the popliteal vein. The integrated flow volume per exercise (20 s) was 1.9, 1.6 and 50 mL (mean across subjects) for right peroneal, right posterior tibial and popliteal vein, respectively. A patient with DVT presented with peak flow velocities of only about 2 cm·s-1 during exercise and less than 1 cm·s-1 during rest. CONCLUSIONS Real-time PC MRI emerges as a new tool for quantifying the dynamics of muscle-induced flow in deep veins. The method provides both signal intensity changes and velocity information for the assessment of blood flow and muscle movements. It now warrants extended clinical trials to patients with suspected thrombosis.
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Affiliation(s)
- Arun Antony Joseph
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany;; DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
| | - Klaus-Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Johannes Dahm
- Herz & Gefäßzentrum Göttingen am Krankenhaus Neu-Bethlehem, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany;; DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
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Resistance exercise in chronic heart failure: hemodynamic and metabolic adjustments. SPORT SCIENCES FOR HEALTH 2016. [DOI: 10.1007/s11332-016-0307-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gutkin M, Stewart JM. Orthostatic Circulatory Disorders: From Nosology to Nuts and Bolts. Am J Hypertens 2016; 29:1009-19. [PMID: 27037712 PMCID: PMC4978226 DOI: 10.1093/ajh/hpw023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 11/27/2015] [Accepted: 02/12/2016] [Indexed: 12/17/2022] Open
Abstract
When patients complain of altered consciousness or discomfort in the upright posture, either relieved by recumbency or culminating in syncope, physicians may find themselves baffled. There is a wide variety of disorders that cause abnormal regulation of blood pressure and pulse rate in the upright posture. The aim of this focused review is 3-fold. First, to offer a classification (nosology) of these disorders; second, to illuminate the mechanisms that underlie them; and third, to assist the physician in the practical aspects of diagnosis of adult orthostatic hypotension, by extending clinical skills with readily available office technology.
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Affiliation(s)
- Michael Gutkin
- Hypertension Section, Saint Barnabas Medical Center, Livingston, New Jersey, USA;
| | - Julian M Stewart
- Center for Hypotension, New York Medical College, Valhalla, New Jersey, USA
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