Hemodynamic adjustments during breath-holding in trained divers

Costalat, Guillaume; Coquart, Jérémy; Castres, Ingrid; Tourny, Claire; Lemaître, F.

doi:10.1007/s00421-013-2690-z

Cited by 24 publications

(17 citation statements)

References 35 publications

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“…That both vessels also had similar profiles during apnea shows their additive response to altered perfusion pressure. The IBM of prolonged apnea is associated with oscillations in intrathoracic pressure that augment left ventricular stroke volume, 13,19,29 suggesting that CBF (as indexed by MCAv) is augmented by IBM during the latter half of a prolonged apnea. The present study does not support this conclusion.…”

Section: Regulation Of Cerebral Blood Flow During Apneamentioning

confidence: 99%

Regulation of Brain Blood Flow and Oxygen Delivery in Elite Breath-Hold Divers

Willie

Ainslie

Drviš

et al. 2014

J Cereb Blood Flow Metab

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The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n = 17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO 2 (PaO 2 ) and increasing arterial PCO 2 (PaCO 2 ) while breathing. End-apnea PaO 2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF.

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Section: Regulation Of Cerebral Blood Flow During Apneamentioning

confidence: 99%

Regulation of Brain Blood Flow and Oxygen Delivery in Elite Breath-Hold Divers

Willie

Ainslie

Drviš

et al. 2014

J Cereb Blood Flow Metab

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“…A considerable number of studies have explored the diving response induced by breath-holding dives in humans, with its consequent bradycardia, redistribution of blood flow and effects of increased pressure (e.g. Dujic and Breskovic, 2012;Costalat et al, 2013). Human record breath-holding divers have reached a maximum submerged time of over 11 min during pool competitions (static apnea in the swimming pool involves no elevation of external pressure), and an open-water depth limit of −214 msw (source for both: https://www.aidainternational.org/#recordsMan), obtained with a mechanical device to speed up descent and help in ascent to the surface.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of blood circulation during diving in the bottlenose dolphin (Tursiops truncatus). The role of the retia mirabilia

Bonato

Bagnoli

Centelleghe

et al. 2019

Journal of Experimental Biology

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The retia mirabilia are vascular nets composed of small vessels dispersed among numerous veins, allowing blood storage, regulation of flow and pressure damping effects. Here, we investigated their potential role during the diving phase of the bottlenose dolphin (Tursiops truncatus). To this effect, the whole vertebral retia mirabilia of a series of dolphins were removed during post-mortem analysis and examined to assess vessel diameters, and estimate vascular volume and flow rate. We formulated a new hemodynamic model to help clarify vascular dynamics throughout the diving phase, based on the total blood volume of a bottlenose dolphin, and using data available about the perfusion of the main organs and body systems. We computed the minimum blood perfusion necessary to the internal organs, and the stroke volume and cardiac output during the surface state. We then simulated breath-holding conditions and perfusion of the internal organs under the diving-induced bradycardia and reduction of stroke volume and cardiac output, using 10 beats min −1 as the limit for the heart rate for an extended dive of over 3 min. Within these simulated conditions, the retia mirabilia play a vital role as reservoirs of oxygenated blood that permit functional performances and survival of the heart and brain. Our theoretical model, based on the actual blood capacity of the retia mirabilia and available data on organ perfusion, considers the dynamic trend of vasoconstriction during the diving phase and may represent a baseline for future studies on the diving physiology of dolphins and especially for the blood supply to their brain.

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“…In recent years, changes in blood pressure, heart rate (f H ), stroke volume (SV), cardiac output (Q ) and total peripheral resistance (TPR) in response to apnoea (cardiovascular response to apnoea) were determined beat-by-beat on elite divers during apnoeas prolonged to the volitional breaking point (Costalat et al, 2013;Lemaître et al, 2008;Perini et al, 2008Perini et al, , 2010Sivieri et al, 2015). These studies described the cardiovascular response to apnoea as consisting of three distinct phases: (i) a short dynamic phase ( 1), that lasts less than 30 s, characterised by rapid changes in blood Abbreviation: DBP, diastolic blood pressure; fH, heart rate; FIO2, inspired oxygen fraction; MBP, mean blood pressure;Q , cardiac output; SaO2, arterial oxygen saturation; SBP, systolic blood pressure; SV, stroke volume; TPR, total peripheral resistance;V O2, oxygen uptake; 1, first, dynamic phase of the cardiovascular response to apnoea; 2, second, steady-state phase of the cardiovascular response to apnoea; 3, third, dynamic phase of the cardiovascular response to apnoea.pressure and f H ; (ii) a steady state phase ( 2), of about 2 min, in which the values attained by each variable at the end of 1 are maintained invariant; and (iii) a further subsequent dynamic phase ( 3), lasting about 1.5 min, characterised by a continuous decrease in f H and increase in blood pressure, until the volitional breaking point was reached.…”

Section: Introductionmentioning

confidence: 99%

Cardiovascular responses to dry resting apnoeas in elite divers while breathing pure oxygen

Fagoni

Sivieri

Antonutto

et al. 2015

Respiratory Physiology & Neurobiology

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a b s t r a c tPurpose: We hypothesized that the third dynamic phase ( 3) of the cardiovascular response to apnoea requires attainment of the physiological breaking point, so that the duration of the second steady phase ( 2) of the classical cardiovascular response to apnoea, though appearing in both air and oxygen, is longer in oxygen. Methods: Nineteen divers performed maximal apnoeas in air and oxygen. We measured beat-by-beat arterial pressure, heart rate (f H ), stroke volume (SV), cardiac output (Q ). Results: The f H , SV andQ changes during apnoea followed the same patterns in oxygen as in air. Duration of steady 2 was 105 ± 37 and 185 ± 36 s, in air and oxygen (p < 0.05), respectively. At end of apnoea, arterial oxygen saturation was 1.00 ± 0.00 in oxygen and 0.75 ± 0.10 in air. Conclusions:The results support the tested hypothesis. Lack of hypoxaemia during oxygen apnoeas suggests that, if chemoreflexes determine 3, the increase in CO 2 stores might play a central role in eliciting their activation.

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Hemodynamic adjustments during breath-holding in trained divers

Abstract: This study highlights similar time-course patterns for cardiodynamic variables during dry-body and immersed-body BH, although the phenomenon was more pronounced in the latter condition.

Cited by 24 publications

References 35 publications

Regulation of Brain Blood Flow and Oxygen Delivery in Elite Breath-Hold Divers

Regulation of Brain Blood Flow and Oxygen Delivery in Elite Breath-Hold Divers

Dynamics of blood circulation during diving in the bottlenose dolphin (Tursiops truncatus). The role of the retia mirabilia

Cardiovascular responses to dry resting apnoeas in elite divers while breathing pure oxygen

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