Studies on inspiratory and expiratory glossopharyngeal breathing in breath-hold divers employing magnetic resonance imaging and spirometry

Lindholm, Peter; Nyrén, Sven

doi:10.1007/s00421-005-1358-8

Cited by 66 publications

(71 citation statements)

References 10 publications

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“…In these forms tracheae differ noticeably through the irregular shape of the cartilaginous rings, which are sometimes complete (O-shaped); they also have reduced amounts of connective tissue and lack muscle tissue (Tarasoff and Kooyman, 1973;Davenport et al, 2009b;Bagnoli et al, 2011). Studies examining reductions in human tracheal volume have shown that decreases are achieved through inward movement of the smooth muscle connecting the two tracheal tips (Griscom and Wohl, 1983;Lindholm and Nyrén, 2005;Fitz-Clarke, 2007). In a similar manner, increases in volume are managed through outward protruding of the smooth muscle.…”

Section: Discussionmentioning

confidence: 99%

Shape and material characteristics of the trachea in the leatherback sea turtle promote progressive collapse and reinflation during dives

Murphy

Kelliher

Davenport

2012

Journal of Experimental Biology

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SUMMARYThe leatherback turtle regularly undertakes deep dives and has been recorded attaining depths in excess of 1200m. Its trachea is an almost solid, elliptical-section tube of uncalcified hyaline cartilage with minimal connective tissue between successive rings. The structure appears to be advantageous for diving and perfectly designed for withstanding repeated collapse and reinflation. This study applies Boyleʼs law to the respiratory system (lungs, trachea and larynx) and estimates the changes in tracheal volume during a dive. These changes are subsequently compared with the results predicted by a corresponding finite element (FE) structural model, itself based on laboratory studies of the trachea of an adult turtle. Boyleʼs law predicts that the lungs will collapse first during the initial stages of a dive with tracheal compression beginning at much deeper depths after complete air mass expulsion from the lungs. The FE model reproduces the changes extremely well (agreeing closely with Boyleʼs law estimations) and provides visual representation of the deformed tracheal luminal area. Initially, the trachea compresses both ventrally and dorsally before levelling ventrally. Bulges are subsequently formed laterally and become more pronounced at deeper depths. The geometric configuration of the tracheal structure confers both homogeneity and strength upon it, which makes it extremely well suited for enduring repeated collapse and re-expansion. The structure actually promotes collapse and is an adaptation to the turtleʼs natural environment in which large numbers of deep dives are performed annually.

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Section: Discussionmentioning

confidence: 99%

Shape and material characteristics of the trachea in the leatherback sea turtle promote progressive collapse and reinflation during dives

Murphy

Kelliher

Davenport

2012

Journal of Experimental Biology

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“…The divers all reported to us that they hyperventilate for at least two minutes; PET CO 2 of 15 Torr has been observed in these divers (Ferrigno et al, personal communication). The divers also reported they distend their lungs beyond TLC through glossopharyngeal inspirations (Lindholm and Nyren 2005;Seccombe et al 2006;Loring et al 2007); this provides some additional O 2 reserve, and presumably stimulates pulmonary stretch receptors. Lung volume was controlled throughout our present study, so divers were unable to take large breaths and achieve relief from air hunger.…”

Section: Comparison Of Laboratory Air Hunger Test With Competitive Brmentioning

confidence: 98%

The air hunger response of four elite breath-hold divers

Binks

Vovk²,

Ferrigno

et al. 2007

Respiratory Physiology & Neurobiology

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Normal subjects terminate breath-holds due to intolerable 'air hunger'. We hypothesize that competitive breath-hold divers might have increased tolerance of air hunger. We tested the air hunger (AH) response of 4 divers who could hold their breath for 6 -9 min. Tidal volume and respiratory rate were controlled by mechanical ventilation (ventilation ≈ 0.16 L·min −1 ·kg −1 ). AH was induced by raising P CO 2 and rated using a visual analog scale whose maximum was defined as intolerable. SpO 2 was maintained at >97%. Three divers reported the same uncomfortable urge to breathe as normal subjects; the slopes of their responses were within normal range. Both resting CO 2 and AH threshold were shifted to higher CO 2 in some divers. Diver 3 was unique amongst neurologically intact subjects we have studied: he denied feeling an urge to breathe, and denied discomfort. We conclude that elite divers' strategies to tolerate intense air hunger are a minor factor in their ability to tolerate long breath holds.

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“…A previous case report, based on dynamic magnetic resonance imaging, suggested that there was a symmetrical expansion in the thorax [10]. A second case report also demonstrated cardiac and vascular mediastinum configurational changes [9].…”

Section: Discussionmentioning

confidence: 95%

“…While some of this increase could be from displacement of structures within the thorax (heart, vessels or oesophagus) most of the increase may be related to the change in the configuration of the chest wall and diaphragm. Individual case reports on breath-hold divers have described pulmonary hyperinflation with cardiac compression, aortic stretch and reduction in blood flow using magnetic resonance imaging [9,10].…”

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confidence: 99%

Lung perfusion and chest wall configuration is altered by glossopharyngeal breathing

et al. 2009

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Glossopharyngeal insufflation is used by competitive breath-hold divers to increase lung gas content above baseline total lung capacity (TLC) in order improve performance. Whilst glossopharyngeal insufflation is known to induce hypotension and tachycardia, little is known about the effects on the pulmonary circulation and structural integrity of the thorax.Six male breath-hold divers were studied. Exhaled lung volumes were measured before and after glossopharyngeal insufflation. On two study days, subjects were studied in the supine position at baseline TLC and after maximal glossopharyngeal insufflation above TLC. Tc 99 m labelled macro-aggregated albumin was injected and a computed tomography (CT) scan of the thorax was performed during breath-hold. Single photon emission CT images determined flow and regional deposition. Registered CT images determined change in the volume of the thorax.CT and perfusion comparisons were possible in four subjects. Lung perfusion was markedly diminished in areas of expanded lung. 69% of the increase in expired lung volume was via thoracic expansion with a caudal displacement of the diaphragm. One subject who was not proficient at glossopharyngeal insufflation had no change in CT appearance or lung perfusion.We have demonstrated areas of hyperexpanded, under perfused lung created by glossopharyngeal insufflation above TLC.KEYWORDS: Breath-hold diving, glossopharyngeal insufflation, hyperinflation, perfusion imaging, pulmonary perfusion B reath-hold diving, or freediving, is a highly organised, increasingly popular extreme sport. Many competitive breathhold divers perform glossopharyngeal breathing both as a training exercise and just prior to a dive or submersed breath-hold. Glossopharyngeal breathing, a pump-like action involving the glossopharyngeal structures and larynx that forces air into the airways [1], was originally developed as a therapeutic technique for neuromuscular patients to help expand tidal volume and cough effectiveness [2,3]. The increase in expired lung volume above baseline total lung capacity (TLC) using glossopharyngeal breathing is achieved by a combination of an increase in the Euclidian size of the lung and gas compression [4,5]. Participants refer to this technique as lung packing; however this is described in the literature as glossopharyngeal insufflation (GI) [1,5,6].In theory, GI above TLC has the potential to assist breath-hold diving performance by increasing available oxygen stores and providing a volume buffer against the compressive effects of hyperbaria. Improvements in both static apnoea duration and breath-hold diving performance have been shown [7]. The potential for adverse cardiocirculatory effects is also clear. The extremely high transpulmonary pressures achieved, of up to 80 cmH 2 O [5], are associated with tachycardia, hypotension and biventricular systolic dysfunction [8]. In keeping with these observations, adverse neurological symptoms (e.g. presyncopal episodes and light-headedness) have been associated with this manoe...

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Studies on inspiratory and expiratory glossopharyngeal breathing in breath-hold divers employing magnetic resonance imaging and spirometry

Cited by 66 publications

References 10 publications

Shape and material characteristics of the trachea in the leatherback sea turtle promote progressive collapse and reinflation during dives

Shape and material characteristics of the trachea in the leatherback sea turtle promote progressive collapse and reinflation during dives

The air hunger response of four elite breath-hold divers

Lung perfusion and chest wall configuration is altered by glossopharyngeal breathing

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