Pressure stability of nasal CPAP and bilevel devices

被引：1

作者：

Schäfer T. ^{[1
]}

Vogelsang H. ^{[1
]}

机构：

[1] Department of Applied Physiology, Ruhr-University Bochum, D-44780 Bochum

来源：

Somnologie - Schlafforschung und Schlafmedizin | 2002年 / 6卷 / 2期

关键词：

Nasal continuous positive airway pressure; Obstructive sleep apnea; Treatment;

D O I：

10.1046/j.1439-054X.2002.02182.x

中图分类号：

学科分类号：

摘要：

Question of the study: Nasal continuous positive airway pressure (CPAP) prevents collapse of the upper airway during sleep in patients with obstructive sleep apnea provided that a positive transmural pressure can be maintained during inspiration. We examined pressure-flow characteristics in seven CPAP and bilevel devices during spontaneous breathing. Methods: The CPAP devices were set to a pressure level of 9.8 hPa (10 cm H2O) and adapted to a pneumotachograph using a standard CPAP hose and an outlet valve. We continuously measured flow, volume and pressure during resting ventilation and increasing voluntary hyperventilation and analysed the dependence of the variables on a breath-to-breath basis. Results: Mean CPAP pressures differed between the devices (9.9 - 10.6 hPa) despite the same settings. In all machines pressure fell during inspiration to 8.4 - 9.8 hPa and increased during expiration to 11.1 - 11.7 hPa. This effect increased with higher flow rates. Maximum expiratory pressures rose to 12 - 19 hPa at peak flow rates of 2 1/s, mean expiratory pressures to 9.5 - 16 hPa. Inspiratory pressures dropped to 8.5 - 4.5 hPa (minimum) and 10.5 - 6.0 (mean). Bilevel devices showed a higher stability than CPAP devices. Pressure swings during the respiratory cycle increased the additional work of breathing. Conclusions: Due to differences in mean and effective CPAP levels CPAP devices are not simply exchangeable but should be individually adapted. Patients with higher minute ventilation might benefit from more stable CPAP machines. The impact on patients' compliance remains to be evaluated.

引用

页码：79 / 84

页数：5

共 10 条

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