BREATHING EFFORT DURING NONINVASIVE PROPO RTIONAL ASSIST VENTILATION IN PATIENTS WITH ACUTE EXACERBATIONS OF CHRONIC RESPIRATORY-FAILURE

Background: The aim of the present study was to evaluate if Proportion al Assist Ventilation (PAV), when applied noninvasively via face mask, can reduce ventilatory effort in patients with respiratory failure. W e present preliminary results of an ongoing study. Patients ann Method s: In 5 patients with respiratory failure due to different underlying disorders (pulmonary fibrosis, bilateral diaphragm paralysis, COPD) we compared the transdiaphragmal pressure-time integral, PTdi (integral Pdi dt) after 15 minutes of noninvasive PAV to the baseline values wit hout ventilatory support. Results and Conclusion: Four patients showed reduction of PTdi to various extend. One patient who presented low di aphragmal activity at baseline due to diaphragmal paralysis showed a s light increase in PTdi during ventilation. Mean PTdi decreased by 26.7 %. PaCO2 in the 5 patients showed no significant change after 15 minut es of ventilation, thus indicating that with noninvasive PAV patients can maintain constant ventilation with reduced effort.