Effects of bi-level positive airway pressure ventilation on muscular fatigue of diaphragm and respiratory failure in acute exacerbation of chronic obstructive pulmonary disease

Objective To evaluate the effects of bi-level positive airway pressure(BiPAP) ventilation on muscular fatigue of diaphragm and respiratory failure in acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Methods Sixtyfive inpatients with AECOPD from Sep 2003 to Aug 2005 were enrolled in the study.The subjects were randomly divided into control group(23 cases) and ventialtion group(42 cases) in 1∶2 proportion.Both groups were given the routine therapy and the ventilation group was given BiPAP ventilation.Diaphragm electromyogram was conducted in all cases to measure the phrenic nerve conduction time(PNCT) and the swing of action potential(AP) before and 7 days after treatment.Results The PNCTs in control group had no significant differences before and after treatment [(8.130±0.710)ms vs(8.270±0.410)ms on the left and(8.072±0.690)ms vs(8.350±0.390)ms on the right,both P0.05].The APs in control group had significant differences before and after treatment[(0.414±0.141)mV vs(0.590±0.140)mV on the left and(0.414±0.135)mV vs(0.550±0.170)mV on the right,both P0.01].The PNCTs in the ventialtion group had significant differences before and after BiPAP treatment(7.991±0.560)ms vs(7.664±0.509)ms on the left and(8.041±0.590)ms vs(7.719±0.520)ms on the right,both P0.01].The APs in the ventilation group had significant differences before and after treatment [(0.405±(0.165)mV) vs(0.613±0.164)mV on the left and(0.388±0.170)mV vs(0.599±0.171)mV on the right,both P0.01].There were no significant differences in the PNCTs and APs between both groups at baseline(both P0.05).After the treatment PNCTs were different significantly(P0.01) and APs were not different significantly between two groups(P0.05).(Conclusion) BiPAP ventilation can improve conductive speed of phrenic nerve in patients with AECOPD while the routine treatment only increases the swing of action potential.