Noninvasive ventilation acutely modifies heart rate variability in chronic obstructive pulmonary disease patients.

Summary Objective The purpose of present study was to evaluate the acute effects of bi-level positive airway pressure (BiPAP) on heart rate variability (HRV) of stable chronic obstructive pulmonary disease patients (COPD). Methods Nineteen males with COPD (69±8 years and with forced expiratory volume in 1s 2 O and 4–6cmH 2 O, respectively). Peripheral oxygen saturation (SpO 2 ), end-tidal of carbon dioxide (ETCO 2 ), systolic blood pressure (SBP) and R–R interval were obtained. HRV was analyzed by time (RMSSD and SDNN index) and frequency domains (high frequency – HF, low frequency – LF and HF/LF ratio). Results Significant reduction of ETCO 2 and SBP in both groups and increase of SpO 2 in COPD group was observed during BiPAP ventilation ( p p 2 and ΔHF were found ( r =0.89). Conclusions Sympathetic and parasympathetic neural control of heart rate is altered in COPD patients and that BiPAP acutely improves ventilation, enhances sympathetic response and decreases vagal tonus. The improvement of ventilation caused by BiPAP was associated with reduced cardiac vagal activity in stable moderate-to-severe COPD patients.