Impact of continuous positive airway pressure on the treatment of acute exacerbation of asthma: a randomised controlled trial

Introduction

Despite the extensive use of continuous positive airway pressure (CPAP) in various respiratory failure conditions, its role in acute asthmatic attack is uncertain [1–3]. This study aims at exploring the efficacy of CPAP when use in addition to the conventional treatment of acute asthma exacerbation in the emergency department (ED).

Methods

During May to December 2009, acute asthma patients attending ED were randomly assigned to CPAP and control groups. In addition to the conventional treatment, CPAP ventilation of 8 cmH₂O was applied to patients in the CPAP group. Data collections in both groups included peak expiratory flow rates (PEFR, %predicted) at each 15-minute interval (T0, T15, ...), the number of short-acting bronchodilators (SABA) used, ED length of stay, relapse rate and admission rate. The primary outcome is the improvement in peak expiratory flow rate during a short period stay in the ED.

Results

There were 86 patients enrolled, with 43 patients in each study group. PEFR in the CPAP group showed no difference from the control group at T0 (52.7 ± 20.33 vs. 47.2 ± 16.64, P = NS) but was significantly better at T15 (65.58 ± 21.64 vs. 56.49 ± 18.53%, P < 0.05). Such improvement was consistently observed for all subsequent PEFR measurement, along with the fewer SABA used and relapse rate, but the figures did not meet statistical difference.

Conclusion

The addition of CPAP to conventional acute asthma treatment in the ED could accelerate PEFR improvement with a trend showing fewer SABA needed, lower relapse rate and shorter ED length of stay.