In a recent issue of the Archives, Batra et al presented a systematic review and meta-analysis comparing two strategies for weaning neonates from positive pressure mechanical ventilation: synchronised intermittent mandatory ventilation (SIMV) and pressure support ventilation (PSV).1 With the former, some breaths are assisted and others are not, but with the latter, all breaths are synchronised with some positive pressure assistance. Analyses like this are valuable, as choices of ventilation strategies in our nurseries are typically based on personal preferences rather than carefully developed evidence. The small sizes of the trials identified for this meta-analysis demonstrate the difficulty of enrolling sufficient numbers of subjects to produce useful information. When such evidence is available, it must be assessed with careful attention to detail, particularly when it suggests that one approach or another may lead to superior outcomes. The analysis by Batra et al exemplifies some of the pitfalls in grappling with these challenges. We are indebted to them for taking on this important task.

The only identified significant difference between effects of the two weaning strategies was shorter duration of weaning from assisted ventilation in the PSV arms of these trials. Because some may rely on it to guide practice, this conclusion requires close scrutiny. There are several reasons to view it with scepticism. First, the patient populations from which subjects were drawn and eligibility criteria for trial enrolment were quite diverse (table 1). The study of term infants with …