Noninvasive mechanical ventilation in acute hypoxaemic respiratory failure.

In acute hypoxaemic respiratory failure (HRF), oxygenation, reduction in the work of breathing and in dyspnoea may be achieved by delivering noninvasive mechanical ventilation (NIMV). Several uncontrolled and 13 randomized controlled studies (RCS) were reviewed. Uncontrolled studies confirmed the feasibility and the possibility to improve arterial blood oxygenation with NIMV. The 13 RCS compared NIMV versus a conventional approach in a total of 720 patients with HRF. Endotracheal intubation was required in 186 of the 358 patients (median (95% confidence interval (CI)) 51%, (40-63%)) assigned to a conventional approach and in 107 of the 362 patients (29% (20-39%)) assigned to NIMV. Eleven of the 13 RCS found a reduction in the rate of endotracheal intubation with NIMV with an absolute risk reduction of 31% (30-33%). Ten of the 13 RCS found a reduction in the mortality rate which was 30% (19-40%) in the control group and 19% (13-26%) in the NIMV group. The mean absolute risk reduction was 15% (10-20%). In conclusion, noninvasive ventilation appears to be a useful method in avoiding endotracheal intubation and probably in reducing the morbidity of patients with hypoxaemic respiratory failure.