Hypoxemia during apnea in normal subjects: mechanisms and impact of lung volume

Findley, Larry J.; Ries, Andrew L.; Tisi, Gennaro M.; Wagner, Peter D.

doi:10.1152/jappl.1983.55.6.1777

Cited by 110 publications

(59 citation statements)

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“…The subjects in this study had moderate degrees of desaturation, as assessed by nadir SaO 2 . If hypoxia is critical to changes in either CECs or circulating EPCs, then it is possible that subjects with more profound nocturnal desaturation, such as those with lower resting lung volumes [26,27] or longer apnea duration [28], might demonstrate altered numbers of CECs and circulating EPCs. In addition, we chose to express the degree of hypoxemia as nadir SaO 2 , which may not be as sensitive as other noninvasive markers such as percentage of time during sleep spent with an SaO 2 < 90%.…”

Section: Discussionmentioning

confidence: 99%

Circulating Endothelial Cells and Endothelial Progenitor Cells in Obstructive Sleep Apnea

Martin

Stanchina

Kouttab

et al. 2008

Lung

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Increased circulating endothelial cells (CECs) have been observed in patients with vascular injury associated with acute myocardial infarction, pulmonary hypertension, and congestive heart failure. Decreased circulating endothelial progenitor cells (EPCs) have been observed in patients with risk factors for cardiovascular disease. Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular disease and endothelial dysfunction. Subjects were recruited from patients referred for overnight polysomnograms; 17 subjects had OSA and 10 control subjects did not have OSA. All subjects lacked vascular disease and risk factors for vascular disease. Peripheral blood was obtained from fasting subjects in the morning, following sleep studies. CECs and EPCs were quantified using magnetic bead separation with UV epifluorescence microscopy and flow

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Section: Discussionmentioning

confidence: 99%

Circulating Endothelial Cells and Endothelial Progenitor Cells in Obstructive Sleep Apnea

Martin

Stanchina

Kouttab

et al. 2008

Lung

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“…The reservoir of oxygen in the lung is proportional to the alveolar volume, as shown in healthy individuals who experience significantly greater DSa O 2 after voluntary apnea at residual volume compared with voluntary apnea at total lung capacity (24). The effect of excess body weight on lung volume is the principal mechanism by which BMI influences DSa O 2 (23), an effect likely accentuated in the presence of greater whole-body oxygen demand (25).…”

Section: Mechanisms By Which Obesity Increases Dsa O 2 During Apnea Amentioning

confidence: 96%

The Impact of Obesity on Oxygen Desaturation during Sleep-disordered Breathing

Peppard

Ward²,

Morrell³

2009

Am J Respir Crit Care Med

169

110

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Rationale: Obesity increases the risk and severity of sleep-disordered breathing. The degree to which excess body weight contributes to blood oxygen desaturation during hypopneic and apneic events has not been comprehensively characterized. Objectives: To quantify the association between excess body weight and oxygen desaturation during sleep-disordered breathing. Methods: A total of 750 adult participants in the Wisconsin Sleep Cohort Study were assessed for body mass index (BMI) (kg/m 2 ) and sleep-disordered breathing. The amount of Sa O 2 , duration, and other characteristics of 37,473 observed breathing events were measured during polysomnography studies. A mixed-effects linear regression model estimated the association of blood oxygen desaturation with participant-level characteristics, including BMI, gender, and age, and event-level characteristics, including baseline Sa O 2 , change in VT, event duration, sleep state, and body position. Measurements and Main Results: BMI was positively associated with oxygen desaturation severity independent of age, gender, sleeping position, baseline Sa O 2 , and event duration. BMI interacted with sleep state such that BMI predicted greater desaturation in rapid eye movement (REM) sleep than in non-REM sleep. Each increment of 10 kg/m 2 BMI predicted a 1.0% (SE, 0.2%) greater mean blood oxygen desaturation for persons in REM sleep experiencing hypopnea events associated with 80% VT reductions. Conclusions: Excess body weight is an important predictor of the severity of blood oxygen desaturation during apnea and hypopnea events, potentially exacerbating the impact of sleep-disordered breathing in obese patients.Keywords: sleep apnea; overweight; hypoxia Obesity is one of the most important risk factors for sleepdisordered breathing (SDB) (1). Epidemiological studies have shown that the prevalence of SDB is strongly associated with excess body weight (2) and that weight gain independently predicts the development of SDB (3). Moreover, most (4), but not all (5), interventional studies have shown that weight loss is effective in reducing apneas and hypopneas. As the prevalence of obesity increases across industrialized nations, it is predicted that obesity will cause a corresponding increase in the prevalence of SDB (1, 6).The frequency of apneas and hypopneas increases with obesity (3, 7). The frequency of breathing events is an important predictor of the consequences of SDB, with a longitudinal doseresponse relationship between the apnea-hypopnea index (AHI) and the prevalence of cardiovascular morbidity (8). The severity of oxygen desaturation during obstructive breathing events and the cumulative burden of nocturnal hypoxia are important factors in this relationship; they also predict cardiovascular morbidity in patients with SDB, independent of the frequency of breathing events (9, 10). Because excess body weight is known to predispose to more severe oxygen desaturation during voluntary apneas (11), obese patients with SDB may be disadvantaged by greater oxygen desatu...

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“…Obstructive apnoea provokes excessive intrathoracic pressure swings that greatly influence central haemodynamics, creating a right-to-left shunt through the PFO, which may cause significant desaturation [8][9][10][11][12][13]. This may explain why more severe desaturation than predicted from alveolar hypoventilation has been demonstrated in OSA patients [14][15][16]. The present study hypothesised that desaturation will occur more often proportionally to the frequency of respiratory disturbances in OSA subjects with PFO than in those without.…”

mentioning

confidence: 92%

The influence of patent foramen ovale on oxygen desaturation in obstructive sleep apnoea

Johansson¹,

Eriksson²,

Peker³

et al. 2006

Eur Respir J

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Obstructive sleep apnoea (OSA) is associated with oxygen desaturation to a varying degree. A patent foramen ovale (PFO) may allow interatrial right-to-left shunting. The hypothesis of the current study was that oxygen desaturation will occur more often, in proportion to the frequency of respiratory disturbances, in OSA subjects with PFO than in those without.In a group of 209 subjects diagnosed with OSA, the proportion of desaturation to respiratory events was calculated as the ratio of oxygen desaturation index (ODI)/apnoea-hypopnoea index (AHI). A total of 15 cases with high proportional desaturation (ODI/AHI o0.66) were individually matched with 15 controls with low proportional desaturation (ODI/AHI f0.33), all without pulmonary disease. PFO was assessed with contrast transoesophageal echocardiography and considered large when o20 bubbles passed over from the right to the left atrium after a single injection.The prevalence of large PFO was nine out of 15 (60%) in the high proportional desaturation group versus two out of 15 (13%) in the low proportional desaturation group. The median number of passing bubbles was positively correlated to minimum oxygen saturation among those with PFO.In conclusion, oxygen desaturation occurs more often, in proportion to the frequency of respiratory disturbances, in obstructive sleep apnoea subjects with a patent foramen ovale than in those without.

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Hypoxemia during apnea in normal subjects: mechanisms and impact of lung volume

Cited by 110 publications

References 0 publications

Circulating Endothelial Cells and Endothelial Progenitor Cells in Obstructive Sleep Apnea

Circulating Endothelial Cells and Endothelial Progenitor Cells in Obstructive Sleep Apnea

The Impact of Obesity on Oxygen Desaturation during Sleep-disordered Breathing

The influence of patent foramen ovale on oxygen desaturation in obstructive sleep apnoea

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