Effect of Acetazolamide on Hypoxemia during Sleep at High Altitude

Sutton,; Cs, Houston; Al, Mansell; McFadden,; Pm, Hackett; Rigg,; Ac, Powles

doi:10.1056/nejm197912133012406

Cited by 183 publications

(95 citation statements)

References 9 publications

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“…The more pronounced nocturnal hypoxemia found in subjects developing AMS in comparison with controls matched in regard to anthropometric characteristics and prior acclimatisation is consistent with earlier studies indicating a central role of hypoxemia in causing AMS [6,7,11]. In contrast, median nocturnal oxygen saturation by pulse oximetry did not differ among five subjects with AMS and eight controls (i.e.…”

Section: Discussionsupporting

confidence: 89%

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Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation

Pa¹,

Anastasi²,

Senn³

et al. 2004

Eur Respir J

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Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation. P. Erba, S. Anastasi, O. Senn, M. Maggiorini, K.E. Bloch. #ERS Journals Ltd 2004. ABSTRACT: The purpose of the study was to investigate determinants of acute mountain sickness after rapid ascent to high altitude.A total of 21 climbers were studied ascending from v1,200 m to Capanna Regina Margherita, a hut in the Alps at 4,559 m, within v24 h. During their overnight stay at 4,559 m, breathing patterns and ventilation were recorded by calibrated respiratory inductive plethysmography along with pulse oximetry. In the following morning, acute mountain sickness was assessed.Altogether, 11 mountaineers developed pronounced symptoms of acute mountain sickness (Lake Louise score o5) and 10 did not (controls). Compared to controls, subjects with acute mountain sickness had lower nocturnal oxygen saturation (mean¡SD 59¡13% versus 73¡6%), higher minute ventilation (7.94¡2.35 versus 6.06¡ 1.34 L?min -1 ), and greater mean inspiratory flow, a measure of respiratory centre drive (0.29¡0.09 versus 0.22¡0.05 L?s -1 ). Periodic respiration was prevalent but not significantly different among the two groups (apnoea/hypopnea index 60.1¡34.6 versus 47.1¡42.6 events per h).The data suggest that pronounced nocturnal hypoxemia, which was not related to hypoventilation, may have promoted acute mountain sickness. Periodic breathing seems not to play a predominant role in the pathogenesis of acute mountain sickness. Otherwise healthy subjects ascending rapidly to altitudes w2,500 m often develop acute mountain sickness (AMS), a condition characterised by insomnia, headache, dizziness, loss of appetite, nausea and vomiting [1]. In the Alps, symptoms and signs of AMS sufficiently severe to force a reduction in activity were found in 6-8% of climbers examined at altitudes between 2,850 and 3,650 m, and in 30% of climbers at 4,559 m [2]. AMS is promoted by a rapid ascent rate, depends on the altitude reached, and on acclimatisation [3]. It occurs in both sexes, at all ages, and athletic fitness does not protect against it [1,4,5].Despite its high prevalence, the pathophysiology of AMS is incompletely understood. Hypoxia seems to play an important role [3,6,7]. A reduced ventilatory response to hypoxia, and impaired pulmonary gas exchange related to pulmonary fluid accumulation, and water and salt retention have been implicated in development of exaggerated hypoxemia in subjects with AMS [8][9][10]. As AMS often develops or worsens over the night, when periodic breathing and repetitive oxygen desaturation are also prevalent, a causal relationship or a common pathophysiological pathway have been evaluated [11,12]. However, the results of these earlier studies were inconclusive due to the small number of subjects with AMS enrolled, and the lack of quantitative estimation of ventilation during sleep.Therefore, the purpose of the current study was to further explore the potential role of periodic respiration, and other characteristics of breathing patterns, in p...

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Section: Discussionsupporting

confidence: 89%

“…Hypoxia seems to play an important role [3,6,7]. A reduced ventilatory response to hypoxia, and impaired pulmonary gas exchange related to pulmonary fluid accumulation, and water and salt retention have been implicated in development of exaggerated hypoxemia in subjects with AMS [8][9][10].…”

mentioning

confidence: 99%

Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation

Pa¹,

Anastasi²,

Senn³

et al. 2004

Eur Respir J

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show abstract

“…is lower than those reported previously in a hypoxic chamber (WAGGENER et al, 1984) and at altitudes higher than 5,300 m (LAHIRI et al, 1983;SUTTON et al, 1979;WEST et al, 1986) but is similar to that in the studies of WELL et al(1978) and HACKETT et al (1987). Figure 2 shows the relationship between ventilatory chemosensitivities and PB index.…”

Section: Disordered Breathing At Altitudesupporting

confidence: 85%

Periodic breathing at high altitude and ventilatory responses to O2 and CO2.

et al. 1989

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To determine the relationship between periodic breathing (PB) during sleep at high altitude and ventilatory chemosensitivities, we studied nine Japanese climbers who participated in the expedition to the Kunlun Mountains (7,167m) in China in 1986. At sea level, ventilatory response to hypoxia (HVR) by isocapnic progressive hypoxia test and to hypercapnia (HCVR) by Read's method were examined. At altitude 5,360 m, respiratory movements of the chest and abdominal wall, Saoz, ECG, and HR were monitored. Seven climbers manifested PB during sleep. There was a significant correlation between PB during sleep and HVR and HCVR (p <0.05). All the climbers showed severe desaturation during sleep. There was a significant negative correlation between degree of desaturation during sleep and HVR (p <0.05). A negative correlation was also detected between PB and the degree of desaturation during sleep. We concluded that ventilatory chemosensitivities play an important role in eliciting PB and that climbers with high HVR can maintain their arterial oxygenation during sleep, due to hyperventilation induced by PB, which is considered an advantageous adaptation for lowland sojourners.

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“…82 -83 Other sleep-improving drugs at high altitude, such as diphenhydramine, triazolam, or temazepam, can be used; however, they are potentially dangerous because they depress ventilation, relax the muscles of respiration, and further complicate conditions associated with hypoxemia at high altitude. 82 28 in 1989 examined the phenomena of nocturnal periodic breathing at high altitudes. Paradoxically, people with the greatest ventilatory drive in response to hypoxia in the daytime (an adaptive response) have the most pronounced periodic breathing at night.…”

Section: Sleepmentioning

confidence: 99%

Cognitive performance, mood, and neurological status at high terrestrial elevation

Banderet¹,

Shukitt-Hale²

2002

PsycEXTRA Dataset

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. ABSTRACT (Maximum 200 words)Cognitive and psychomotor performance and mood states, including many critical behavioral functions such as sleep, memory, ■ reasoning, and vigilance, are significantly impaired by ascent to HTE higher than 3,000 m. Impairments in behavior caused by HTE can degrade military operations because the judgment and rate and accuracy of performance of military personnel can be affected. Such adverse effects have distinct and measurable time courses; onset of some effects is immediate (cognitive performance), whereas the onset of others is delayed (symptoms of AMS or adverse moods). The behavioral consequences of HTE are primarily dependent on the level of altitude, the duration of exposure the rate of ascent, an individual's state of physiological acclimation or acclimatization, characteristics of the task performed, and characteristics of the individual such as hypoxic sensitivity. Military history documents that the adverse effects induced by HTE need to be considered when military operations at altitude are planned and undertaken. Current research indicates that some performance decrements induced by ascent to extremely high mountains (e.g., Mount Everest, 8,848 m) may persist for a year or longer after return to lower elevations. Psychological, operational, and medical strategies have been employed to minimize these adverse effects. Psychological strategies often involve training and familiarization with the adverse effects that will be experienced at high altitude. Operational strategies include staging at intermediate altitudes, acclimatizing, and using supplemental oxygen from tanks of oxygen generators. Medical strategies often involve the use of medications to improve functioning at altitude and techniques to avoid complications. In most situations, multiple strategies are employed. The strategies now available and new developments to come will ensure that high-altitude military operations in the future will be less affected by adverse changes in cognitive and psychomotor performance and mood.14. SUBJECT TERMS high altitude, hypoxia, cognitive performance, moods, symptoms, time course of altitude effects, behavior NUMBER OF PAGES 3516. PRICE CODE

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Effect of Acetazolamide on Hypoxemia during Sleep at High Altitude

Cited by 183 publications

References 9 publications

Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation

Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation

Periodic breathing at high altitude and ventilatory responses to O2 and CO2.

Cognitive performance, mood, and neurological status at high terrestrial elevation

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