Edwards Bradley A, Sands Scott A, Feeney Clare, Skuza Elizabeth M, Brodecky Vojta, Wilkinson Malcolm H, Berger Philip J
Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton 3168, Australia.
Respir Physiol Neurobiol. 2009 Sep 30;168(3):239-49. doi: 10.1016/j.resp.2009.07.006. Epub 2009 Jul 16.
Continous positive airway pressure (CPAP) is used to treat infant respiratory distress syndrome and apnea of prematurity, but its mode of action is not fully understood. We hypothesised that CPAP increases lung volume and stabilises respiratory control by decreasing loop gain (LG). Experimentally induced periodic breathing (PB) in the lamb was terminated early by CPAP in a dose-dependent manner, with a control epoch of 45.4+/-5.1s at zero CPAP falling to 32.9+/-5.4, 13.2+/-4.2 and 9.8+/-3.1s at 2.5, 5 and 10 cmH(2)O, respectively (p<0.001); corresponding duty ratios (duration of the ventilatory phase of PB divided by its cycle duration) increased from 0.50+/-0.02 to 0.62+/-0.05, 0.76+/-0.06 and 0.68+/-0.08, respectively (p<0.001). Since epoch duration and duty ratio are surrogate measures of LG, we conclude that CPAP ameliorates the effects of recurrent central apneas, and perhaps mixed and obstructive apneas, by decreasing LG via increases in lung volume.
持续气道正压通气（CPAP）用于治疗婴儿呼吸窘迫综合征和早产儿呼吸暂停，但其作用机制尚未完全明确。我们推测CPAP通过降低环路增益（LG）来增加肺容量并稳定呼吸控制。在羔羊实验性诱导的周期性呼吸（PB）通过CPAP以剂量依赖性方式提前终止，在零CPAP时对照时段为45.4±5.1秒，在2.5、5和10 cmH₂O时分别降至32.9±5.4、13.2±4.2和9.8±3.1秒（p<0.001）；相应的占空比（PB通气相持续时间除以其周期持续时间）分别从0.50±0.02增加到0.62±0.05、0.76±0.06和0.68±0.08（p<0.001）。由于时段持续时间和占空比是LG的替代指标，我们得出结论，CPAP通过增加肺容量降低LG来改善复发性中枢性呼吸暂停的影响，也许还有混合性和阻塞性呼吸暂停的影响。
