COMPARISON OF BIPAP NASAL VENTILATION AND VENTILATION VIA IRON LUNG IN SEVERE STABLE COPD

The effects of noninvasive ventilators on COPD remain controversial be cause of their obscure mechanisms. A randomized crossover study, using iron lung and positive pressure nasal ventilation (BiPAP) each for 40 min, was performed in 11 stable patients with severe COPD. Throughout the study, we monitored surface EMGdi, EMGst, ECG, SaO2, ETCO2, and t he movements of RC and AB. Afterwards the data were replayed to calcul ate VT, RR, PR, VT/TI, iEMG, and phase angle. No statistically signifi cant improvement was found in view of the above parameters. However, t he percentage of iEMGst change after 40-min BiPAP ventilation, compare d with the baseline, was much more significant in patients with FEV1 b elow 0.55 L than those with FEV, above 0.55 L (n = 4:7, DELTAiEMGst - 62.93 percent +/- 23.27 percent vs 32.45 percent +/- 42.79 percent, p = 0.0056). DELTAiEMGst correlated significantly with FEV, during BiPAP ventilation (p<0.05, r = 0.59). We conclude that the iEMGst during sh ort-term BiPAP ventilation correlates with the severity of the disease .