The effect of partial acclimatization to high altitude on loop gain and central sleep apnoea severity
The effect of partial acclimatization to high altitude on loop gain and central sleep apnoea severity
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DOI：
10.1111/j.1440-1843.2012.02170.x
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发表时间：
2012-07-01
期刊：
影响因子：
6.9
通讯作者：
Burgess, Keith R.
中科院分区：
文献类型：
--
作者：
Andrews, Gareth;Ainslie, Philip N.;Burgess, Keith R.
背景与目的：回路增益是一个工程术语，它预测反馈控制系统的稳定性，如呼吸控制。基于较低海拔的早期研究，假设适应高海拔将导致环路增益降低，从而降低中枢性睡眠呼吸暂停（CSA）的严重程度。研究方法：本研究采用极高海拔暴露诱发健康受试者CSA，探讨部分习服对回路增益和CSA严重程度的影响。对12名受试者（年龄30 +/- 10岁，体重指数22.8 +/- 1.9，8名男性，4名女性）在最初到达时（第24天）和部分适应后（第12 - 14天）在海拔5050 m的2周内进行测量。睡眠通过全多导睡眠描记法进行研究，并测量静息动脉血气。通过占空比方法（呼吸过度持续时间/周期长度）测量环路增益。结果如下：对高海拔暴露的部分适应与环路增益增加和环路增益增加有关。（占空比从0.60 +/- 0.05降至0.55 +/- 0.06（P = 0.03））和CSA的严重程度（呼吸暂停-低通气指数从76.8 +/- 48.8增加到115.9 +/- 20.2（P = 0.01）），而部分动脉二氧化碳浓度从29 +/- 3下降到26 +/- 2（P = 0.01）。结论：与低海拔地区的结果相反，在高海拔地区，环增益和CSA的严重程度增加。
Background and objective: Loop gain is an engineering term that predicts the stability of a feedback control system, such as the control of breathing. Based on earlier studies at lower altitudes, it was hypothesized that acclimatization to high altitude would lead to a reduction in loop gain and thus central sleep apnoea (CSA) severity. Methods: This study used exposure to very high altitude to induce CSA in healthy subjects to investigate the effect of partial acclimatization on loop gain and CSA severity. Measurements were made on 12 subjects (age 30 +/- 10 years, body mass index 22.8 +/- 1.9, eight males, four females) at an altitude of 5050 m over a 2-week period upon initial arrival (days 24) and following partial acclimatization (days 1214). Sleep was studied by full polysomnography, and resting arterial blood gases were measured. Loop gain was measured by the duty cycle method (duration of hyperpnoea/cycle length). Results: Partial acclimatization to high-altitude exposure was associated with both an increase in loop gain (duty cycle fell from 0.60 +/- 0.05 to 0.55 +/- 0.06 (P = 0.03)) and severity of CSA (apnoea-hypopnoea index increased from 76.8 +/- 48.8 to 115.9 +/- 20.2 (P = 0.01)), while partial arterial carbon dioxide concentration fell from 29 +/- 3 to 26 +/- 2 (P = 0.01). Conclusions: Contrary to the results at lower altitudes, at high-altitude loop gain and severity of CSA increased.