Nelesen R A, Yu H, Ziegler M G, Mills P J, Clausen J L, Dimsdale J E
Departments of Psychiatry, University of California San Diego, La Jolla, CA 92093-0804, USA.
Chest. 2001 Apr;119(4):1092-101. doi: 10.1378/chest.119.4.1092.
We examined the effect of continuous positive airway pressure (CPAP) treatment for sleep apnea on cardiac contractility, heart rate variability, and hemodynamics at rest and in response to a laboratory stressor. SUBJECTS AND INSTRUMENTATION: Forty-one apneic patients were studied on three occasions: before treatment, after 1 full night of CPAP treatment, and after 1 week of CPAP treatment. The subjects were randomly assigned to receive effective treatment or placebo. Contractility and hemodynamics were determined with impedance cardiography, and parasympathetic activity was assessed by analysis of heart rate variability. Measures were determined at rest and in response to a stressor.
For the cardiac sympathetic (contractility) measures (preejection period, cardiac acceleration index [CAI], and low-frequency/high-frequency ratio) significant interactions were found in the combination treatment (CPAP vs placebo) by study day (day 1, day 3, day 11) by test period (baseline, preparation, talking) [p < 0.01]. For these measures, there were no differences between the treatment groups or responses to the stressor on day 1. Levels in placebo-treated subjects did not change or respond on the subsequent study days. In the CPAP-treated subjects, there was a decrease in these indexes at baseline, which became significantly lower by day 11 (ie, CAI levels were 24 Omega/s(2), 22 Omega/s(2), and 14 Omega/s(2) on day 1, day 3, and day 11, respectively). These measures also became responsive to the stressor by showing increased sympathetic activity (CAI levels on day 11 were 14 Omega/s(2) at baseline, 32 Omega/s(2) during speech preparation, and 36 Omega/s(2) while speaking). The parasympathetic indexes, such as high-frequency power or band of heart rate variability as determined by spectral analysis, showed a significant day-by-treatment interaction (p < 0.005), whereas the CPAP- treated group had significantly more parasympathetic activity after 1 week of treatment. For the hemodynamic measures (stroke volume [SV], cardiac output, and systemic vascular resistance [SVR]), there were significant treatment-by-study day-by-test-period interactions (p < 0.01). SV and cardiac output increased across days, and SVR decreased in the CPAP-treated patients.
These results indicate that CPAP normalizes contractility, increases cardiac vagal tone, and changes hemodynamic regulation from being resistance dominated to being cardiac dominated. Thus, after 1 week of treatment with CPAP, many of the indicators of poor cardiac functioning in apnea patients are improved.
我们研究了持续气道正压通气（CPAP）治疗睡眠呼吸暂停对静息状态以及应对实验室应激源时心脏收缩力、心率变异性和血流动力学的影响。
41名呼吸暂停患者接受了三次研究：治疗前、CPAP治疗1整夜后以及CPAP治疗1周后。受试者被随机分配接受有效治疗或安慰剂。通过阻抗心动图测定收缩力和血流动力学，通过分析心率变异性评估副交感神经活动。在静息状态和应对应激源时进行测量。
对于心脏交感神经（收缩力）指标（射血前期、心脏加速指数[CAI]和低频/高频比值），在联合治疗（CPAP与安慰剂）、研究日（第1天、第3天、第11天）和测试期（基线、准备期、交谈期）之间发现了显著的交互作用[p < 0.01]。对于这些指标，第1天治疗组之间或对应激源的反应没有差异。安慰剂治疗的受试者在随后的研究日水平没有变化或反应。在CPAP治疗的受试者中，这些指标在基线时有所下降，到第11天显著降低（即第1天、第3天和第11天的CAI水平分别为24Ω/s²、22Ω/s²和14Ω/s²）。这些指标对应激源也有反应，表现为交感神经活动增加（第11天基线时CAI水平为14Ω/s²，言语准备期间为32Ω/s²，说话时为36Ω/s²）。副交感神经指标，如通过频谱分析确定的高频功率或心率变异性频段，显示出显著的日与治疗交互作用（p < 0.005），而CPAP治疗组在治疗1周后副交感神经活动明显更多。对于血流动力学指标（每搏输出量[SV]、心输出量和全身血管阻力[SVR]），存在显著的治疗×研究日×测试期交互作用（p < 0.01）。CPAP治疗的患者中，SV和心输出量随时间增加，SVR降低。
这些结果表明，CPAP使收缩力正常化，增加心脏迷走神经张力，并将血流动力学调节从以阻力为主转变为以心脏为主。因此，CPAP治疗1周后，呼吸暂停患者心脏功能不良的许多指标得到改善。
