Flevari Aikaterini, Vagiakis Emmanouil, Zakynthinos Spyridon
First University Department of Critical Care and Pulmonary Services, Center of Sleep Disorders, Medical School of Athens University, Evangelismos General Hospital, 45-47 Ipsilantou str., 10676, Athens, Greece,
Sleep Breath. 2015 Mar;19(1):359-67. doi: 10.1007/s11325-014-1029-2. Epub 2014 Jul 11.
Data on cardiac autonomic functioning, as expressed by heart rate variability (HRV), in patients with positional obstructive sleep apnea (p-OSA) disorder are lacking. The purpose of the study was to compare HRV indices between sleep segments derived from supine body position and another body position with and without apneic events, respectively. Our intention was to find some correlation between HRV indices and the pathophysiological characteristics of the corresponding temporal period.
Nocturnal polysomnograms derived from twenty-seven patients (22 men) with documented positional apnea were retrospectively reviewed. Patients never treated for OSA and free from diseases/drugs altering HRV were examined. Data from total sleep studies were collected. Two N2 sleep segments, from supine body position with sleep-disordered breathing (SDB) and another body position without SDB were analyzed. Apneic events (namely, apneas, hypopneas, and respiratory effort-related arousals (RERAs)), arousals, number of desaturations, minimum pulse oximetry (SaO2min), time domain variables (average RR, SDNN, SDSD, RMSSD, pNN50, and HRV triangular index) and frequency domain variables (VLF, LF, HF, TP, LF/HF) were recorded for both temporal periods.
With the exception of average RR and HF, all other variables were significantly higher in segments with SDB. Only LF/HF_supine ratio was positively correlated with the apneic_supine_index (t = 3.13, p < 0.01) and negatively correlated with SaO2min (t = -2.9, p < 0.01) and the desaturation_supine_index (t = -2.5, p = 0.02). Arousals were negatively correlated with SaO2min (t = -2.8, p < 0.01).
SDB augments autonomic tone in patients with p-OSA, but only LF/HF correlates with its severity and might be used as a screening tool in the future. On the contrary, parasympathetic tone, as reflected by HF, remains constant in both periods.
关于体位性阻塞性睡眠呼吸暂停（p-OSA）患者心脏自主功能（通过心率变异性（HRV）表示）的数据尚缺。本研究的目的是比较分别来自仰卧位和另一个体位且有或无呼吸暂停事件的睡眠时段的HRV指标。我们旨在找出HRV指标与相应时间段病理生理特征之间的某些相关性。
回顾性分析了27例（22例男性）有记录的体位性呼吸暂停患者的夜间多导睡眠图。检查了从未接受过阻塞性睡眠呼吸暂停治疗且无改变HRV的疾病/药物的患者。收集了整个睡眠研究的数据。分析了两个N2睡眠时段，一个来自仰卧位伴有睡眠呼吸障碍（SDB），另一个来自无SDB的另一个体位。记录了两个时间段的呼吸暂停事件（即呼吸暂停、低通气和呼吸努力相关觉醒（RERA））、觉醒、血氧饱和度下降次数、最低脉搏血氧饱和度（SaO2min）、时域变量（平均RR、SDNN、SDSD、RMSSD、pNN50和HRV三角指数）和频域变量（VLF、LF、HF、TP、LF/HF）。
除平均RR和HF外，所有其他变量在有SDB的时段均显著更高。仅仰卧位LF/HF比值与仰卧位呼吸暂停指数呈正相关（t = 3.13，p < 0.01），与SaO2min呈负相关（t = -2.9，p < 0.01）以及与仰卧位血氧饱和度下降指数呈负相关（t = -2.5，p = 0.02）。觉醒与SaO2min呈负相关（t = -2.8，p < 0.01）。
SDB增强了p-OSA患者的自主神经张力，但只有LF/HF与其严重程度相关，未来可能用作筛查工具。相反，由HF反映的副交感神经张力在两个时段均保持恒定。
