A randomized study of out-of-hospital continuous positive airway pressure for acute cardiogenic pulmonary oedema: physiological and clinical effects

Abstract

Aims: In acute cardiogenic pulmonary oedema (ACPE), continuous positive airway pressure (CPAP) added to medical treatment improves outcome. The present study was designed to assess the benefit of CPAP as a first line treatment of ACPE in the out-of-hospital environment.

Methods and results: The protocol lasted 45 min, divided into three periods of 15 min. Patients with ACPE were randomly assigned in two groups: 1/Early CPAP (n = 63): CPAP alone (T0-T15); CPAP + medical treatment (T15-T30); medical treatment alone (T30-T45) and 2/Late CPAP (n = 61): medical treatment alone (T0-T15); medical treatment + CPAP (T15-T30); medical treatment alone (T30-T45). Primary endpoint: effect of early CPAP on a dyspnoea clinical score and on arterial blood gases. Secondary endpoints: incidence of tracheal intubation, inotropic support, and in-hospital mortality. T0-T15: CPAP alone had a greater effect than medical treatment on the clinical score (P = 0.0003) and on PaO(2) (P = 0.0003). T15-T30: adding CPAP to medical treatment (late CPAP group) improved clinical score and blood gases and the two groups were no longer different at T30. T30-T45: in both groups, CPAP withdrawal worsened clinical score. Six patients in 'early CPAP' group vs. 16 in 'late CPAP' group were intubated [P = 0.01, odds-ratio: OR = 0.30 (0.09-0.89)]. Dobutamine was used only in the 'late CPAP' group (n = 5), (P = 0.02). Hospital death was higher in 'late CPAP' group (n = 8) than in 'early CPAP' group (n = 2) [P = 0.05, OR = 0.22 (0.04-1.0)].

Conclusion: When compared to usual medical care, immediate application of CPAP alone in out-of-hospital treatment of ACPO is significantly better improving physiological variables and symptoms and significantly reduces tracheal intubation incidence and in-hospital mortality.