Continuous positive airway pressure vs. proportional assist ventilation for noninvasive ventilation in acute cardiogenic pulmonary edema.

OBJECTIVE: To compare continuous positive airway pressure (CPAP) and proportional assist ventilation (PAV) as modes of noninvasive ventilatory support in patients with severe cardiogenic pulmonary edema.

DESIGN AND SETTING: A prospective multicenter randomized study in the medical ICUs of three teaching hospitals.

PATIENTS: Thirty-six adult patients with cardiogenic pulmonary edema (CPA) with unresolving dyspnea, respiratory rate above 30/min and/or SpO2 above 90% with O2 higher than 10 l/min despite conventional therapy with furosemide and nitrates.

INTERVENTIONS: Patients were randomized to undergo either CPAP (with PEEP 10 cmH2O) or PAV (with PEEP 5-6 cmH2O) noninvasive ventilation through a full face mask and the same ventilator.

MEASUREMENTS AND RESULTS: The main outcome measure was the failure rate as defined by the onset of predefined intubation criteria, severe arrythmias or patient's refusal. On inclusion CPAP (n=19) and PAV (n=17) groups were similar with regard to age, sex ratio, type of heart disease, SAPS II, physiological parameters (mean arterial pressure, heart rate, blood gases), amount of infused nitrates and furosemide. Failure was observed in 7 (37%) CPAP and 7 (41%) PAV patients. Among these, 4 (21%) CPAP and 5 (29%) PAV patients required endotracheal intubation. Changes in physiological parameters were similar in the two groups. Myocardial infarction and ICU mortality rates were strictly similar in the two groups.

CONCLUSIONS: In the present study PAV was not superior to CPAP for noninvasive ventilation in severe cardiogenic pulmonary edema with regard to either efficacy and tolerance.