da L Goulart C, San Martin E A, Mansour K M K, Schneiders P B, da Silva A L G
Iniciação Científica, Curso de Fisioterapia, Universidade de Santa Cruz do Sul, Santa Cruz do Sul, RS, Brasil.
Curso de Fisioterapia, Departamento de Educação Física e Saúde, Universidade de Santa Cruz do Sul, Santa Cruz do Sul, RS, Brasil.
Braz J Med Biol Res. 2018;51(6):e7180. doi: 10.1590/1414-431x20187180. Epub 2018 Apr 19.
The aim of this study was to evaluate the effect of expiratory positive airway pressure (EPAP) on heart rate variability (HRV) indices at rest and during 6-min walk test (6MWT) in chronic obstructive pulmonary disease (COPD) patients. Fifteen moderate to severe COPD patients were randomized and evaluated with and without (Non-EPAP) a 5 cmH2O EPAP device. Respiratory rate (RR) was collected at rest (5 min), during the 6MWT (5 min), and at recovery (5 min). Indices of HRV were computed in the time domain, in the frequency domain, and nonlinear analysis. For EPAP and Non-EPAP during the 6MWT, we found an increased mean heart rate (HR) (P=0.001; P=0.001) while mean RR (P=0.001; P=0.015) and RR tri index decreased (P=0.006; P=0.028). Peripheral oxygen saturation (P=0.019) increased at rest only in the EPAP group. In EPAP, correlations were found between forced expiratory volume in 1 s (FEV1) and low frequency (LF) sympathetic tonus (P=0.05; r=-0.49), FEV1 and high frequency (HF) parasympathetic tonus at rest (P=0.05; r=0.49), lactate at rest and LF during the 6MWT (P=0.02; r=-0.57), and lactate at rest and HF during 6MWT (P=0.02; r=0.56). Through a linear regression model, we found that lactate at rest explained 27% of the alterations of LF during 6MWT. The use of 5 cmH2O EPAP improved autonomic cardiac modulation and its complexity at rest in COPD patients. Although it did not influence the performance of the 6MWT, the EPAP device caused alterations in resting lactate concentration with an effect on sympatho-vagal control during the test.
本研究旨在评估呼气末正压通气（EPAP）对慢性阻塞性肺疾病（COPD）患者静息状态及6分钟步行试验（6MWT）期间心率变异性（HRV）指标的影响。15例中重度COPD患者被随机分组，分别在使用和不使用（非EPAP组）5 cmH₂O的EPAP装置的情况下进行评估。在静息状态（5分钟）、6MWT期间（5分钟）和恢复阶段（5分钟）收集呼吸频率（RR）。在时域、频域和非线性分析中计算HRV指标。对于6MWT期间的EPAP组和非EPAP组，我们发现平均心率（HR）升高（P = 0.001；P = 0.001），而平均RR（P = 0.001；P = 0.015）和RR三角指数降低（P = 0.006；P = 0.028）。仅在EPAP组中，静息状态下外周血氧饱和度（P = 0.019）升高。在EPAP组中，发现1秒用力呼气量（FEV₁）与低频（LF）交感神经张力之间存在相关性（P = 0.05；r = -0.49），静息状态下FEV₁与高频（HF）副交感神经张力之间存在相关性（P = 0.05；r = 0.49），静息状态下乳酸水平与6MWT期间的LF之间存在相关性（P = 0.02；r = -0.57），以及静息状态下乳酸水平与6MWT期间的HF之间存在相关性（P = 0.02；r = 0.56）。通过线性回归模型，我们发现静息状态下的乳酸水平可解释6MWT期间LF变化的27%。使用5 cmH₂O的EPAP可改善COPD患者静息状态下的自主心脏调节及其复杂性。尽管它不影响6MWT的表现，但EPAP装置会导致静息乳酸浓度改变，并在试验期间对交感-迷走神经控制产生影响。
