Sympathetic activation and parasympathetic withdrawal are commonly observed during acute exacerbations of chronic obstructive pulmonary disease (COPD). We have demonstrated previously that noninvasive positive-pressure ventilation (NPPV) improves parasympathetic neural control of heart rate in patients with obstructive sleep apnea. We hypothesized that NPPV may exert such beneficial effects in COPD as well. Therefore, we assessed the acute effects of NPPV on systemic blood pressure and indexes of heart rate variability (HRV) in 23 patients with acute exacerbations of COPD. The measurements of HRV in the frequency domain were computed by an autoregressive spectral technique. The use of NPPV resulted in significant increases of oxygen saturation (from 89.2+/-1.0 to 92.4+/-0.9 %, p<0.001) in association with reductions in systolic and diastolic blood pressures and heart rate (from 147+/-3 to 138+/-3 mm Hg, from 86+/-2 to 81+/-2 mm Hg, from 85+/-3 to 75+/-2 bpm, p<0.001 for all variables), and increases in ln-transformed high frequency band of HRV (from 6.4+/-0.5 to 7.4+/-0.6 ms(2)/Hz, p<0.01). Reductions in heart rate and increases in ln-transformed HF band persisted after NPPV withdrawal. In conclusion, these findings suggest that NPPV may cause improvements in the neural control of heart rate in patients with acute exacerbations of COPD.
Low-Level Lead Exposure and Elevations in Blood Pressure during Pregnancy
