Prehospital continuous positive airway pressure (CPAP) for acute respiratory distress: a randomised controlled trial.

Objective: To compare the efficacy of continuous positive airway pressure (CPAP) versus usual care for prehospital patients with severe respiratory distress.
Methods: We conducted a parallel group, individual patient, non-blinded randomised controlled trial in Western Australia between March 2016 and December 2018. Eligible patients were aged ≥40 years with acute severe respiratory distress of non-traumatic origin and unresponsive to initial treatments by emergency medical service (EMS) paramedics. Patients were randomised (1:1) to usual care or usual care plus CPAP. The primary outcomes were change in dyspnoea score and change in RR at ED arrival, and hospital length of stay.
Results: 708 patients were randomly assigned (opaque sealed envelope) to usual care (n=346) or CPAP (n=362). Compared with usual care, patients randomised to CPAP had a greater reduction in dyspnoea scores (usual care -1.0, IQR -3.0 to 0.0 vs CPAP -3.5, IQR -5.2 to -2.0), median difference -2.0 (95% CI -2.5 to -1.6); and RR (usual care -4.0, IQR -9.0 to 0.0 min ^-1 vs CPAP -8.0, IQR -14.0 to -4.0 min ^-1 ), median difference -4.0 (95% CI -5.0 to -4.0) min ^-1 . There was no difference in hospital length of stay (usual care 4.2, IQR 2.1 to 7.8 days vs CPAP 4.8, IQR 2.5 to 7.9 days) for the n=624 cases admitted to hospital, median difference 0.36 (95% CI -0.17 to 0.90).
Conclusions: The use of prehospital CPAP by EMS paramedics reduced dyspnoea and tachypnoea in patients with acute respiratory distress but did not impact hospital length of stay.
Trial Registration Number: ACTRN12615001180505.
Competing Interests: Competing interests: Several of the authors are affiliated with St John Western Australia, as follows: DB, AG, PB (employees); JF, SB (adjunct research positions); JF (research funding).
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