HEMODYNAMIC-RESPONSE DURING INITIATION OF NONINVASIVE POSITIVE PRESSURE VENTILATION IN COPD PATIENTS WITH ACUTE VENTILATORY FAILURE

The aim of this study was to check non-invasively the acute haemodynam ic effects of non-invasive positive pressure ventilation (NPPV) initia tion in patients with chronic obstructive pulmonary disease (COPD) and acute ventilatory failure (AVF). Nineteen consecutive COPD patients w ith AVF were evaluated clinically and echocardiographically during spo ntaneous breathing with O-2 supplementation and during NPPV plus O-2. NPPV was administered with a scheduled inspiratory pressure of 15 cmH( 2)O and an expiratory pressure of 4 cmH(2)O, via facial mask. Arterial blood gas improved significantly (pH and PaCO2; P<0.001) during NPPV administration in all patients; none had hypotension or acute arrhythm ia. Doppler echocardiographic evaluation was feasible in most of the p atients (16/18). With reference to baseline values, no significant cha nges in pulmonary artery pressures and cardiac output (GO) were observ ed by Doppler echocardiography in most patients. Only four patients (2 1%) showed a significant reduction (>15%) of CO during NPPV. No correl ation was found between decreased CO and baseline data, but three pati ents showing CO reduction had poor tolerance to mask ventilation and d id not improve respiratory rate during NPPV. It was concluded that the initiation of NPPV by facial mask does not alter haemodynamics acutel y in most COPD patients with AVF, but individual patients may experien ce reduction in CO in spite of adequate oxygen saturation levels. This suggests that caution should be used when applying pre-determined and fixed pressures during NPPV. Monitoring haemodynamics by Doppler echo cardiography may be useful for early detection of haemodynamic alterat ions due to NPPV application in patients with AVF.