Bonsignore M R, Parati G, Insalaco G, Castiglioni P, Marrone O, Romano S, Salvaggio A, Mancia G, Bonsignore G, Di Rienzo M
Institute of Medicine and Pneumology, University of Palermo, Via Trabucco, 180, Palermo, Italy.
Eur Respir J. 2006 Jan;27(1):128-35. doi: 10.1183/09031936.06.00042904.
Baroreflex control of heart rate during sleep (baroreflex sensitivity; BRS) has been shown to be depressed in obstructive sleep apnoea (OSA), and improved after treatment with continuous positive airway pressure (CPAP). Whether CPAP also acutely affects BRS during sleep in uncomplicated severe OSA is still debatable. Blood pressure was monitored during nocturnal polysomnography in 18 patients at baseline and during first-time CPAP application. Spontaneous BRS was analysed by the sequence method, and estimated as the mean sequence slope. CPAP did not acutely affect mean blood pressure or heart rate but decreased cardiovascular variability during sleep. Mean BRS increased slightly during CPAP application (from 6.5+/-2.4 to 7.5+/-2.9 ms x mmHg(-1)), mostly in response to decreasing blood pressure. The change in BRS did not correlate with changes in arterial oxygen saturation or apnoea/hypopnoea index. The small change in baroreflex control of heart rate during sleep at first application of continuous positive airway pressure in severe obstructive sleep apnoea was unrelated to the acute resolution of nocturnal hypoxaemia, and might reflect autonomic adjustments to positive intrathoracic pressure, and/or improved sleep architecture. The small increase in baroreflex control of heart rate during sleep may be of clinical relevance as it was accompanied by reduced cardiovascular variability, which is acknowledged as an independent cardiovascular risk factor.
睡眠期间压力反射对心率的控制（压力反射敏感性；BRS）在阻塞性睡眠呼吸暂停（OSA）中已被证明受到抑制，而在持续气道正压通气（CPAP）治疗后有所改善。在无并发症的重度OSA患者中，CPAP是否也会在睡眠期间急性影响BRS仍存在争议。对18例患者在基线时和首次应用CPAP期间进行夜间多导睡眠监测时监测血压。通过序列法分析自发BRS，并将其估计为平均序列斜率。CPAP并未急性影响平均血压或心率，但降低了睡眠期间的心血管变异性。在应用CPAP期间，平均BRS略有增加（从6.5±2.4增至7.5±2.9 ms·mmHg-1），主要是对血压下降的反应。BRS的变化与动脉血氧饱和度或呼吸暂停/低通气指数的变化无关。在重度阻塞性睡眠呼吸暂停患者首次应用持续气道正压通气时，睡眠期间压力反射对心率控制的微小变化与夜间低氧血症的急性缓解无关，可能反映了自主神经对胸腔内正压的调整和/或睡眠结构的改善。睡眠期间压力反射对心率控制的微小增加可能具有临床意义，因为它伴随着心血管变异性的降低，而心血管变异性被认为是一个独立的心血管危险因素。
