Liberation from mechanical ventilation

In the resources linked here the term “weaning” is often misused in reference to the process of liberating patients from ventilators. “Weaning” harks back to the days when we used sequential reductions of SIMV or pressure support levels to get patients off ventilators, methods which became obsolete more than a decade ago. Rather than weaning most patients need daily assessment for readiness for extubation. The patients who need weaning are the exceptions. If your patient truly needs weaning you might want to get help from a pulmonologist.

With that clarification out of the way it’s time for me to update an old post which summarized recommendations on this topic. That post presented an evidence based method for daily extubation assessment of mechanically ventilated patients, focusing on the spontaneous breathing trial (SBT). Although I stand by the premise of that post it needs updating in light of this study which looked at integrating the daily SBT with a daily spontaneous awakening trial (SAT) as a protocol. Given that daily SATs (sedation interruptions) and SBTs are commonplace (or should be) in mechanically ventilated patients what’s so new and different about this? I don’t know for sure, but when those two procedures were organized in the form of an explicit protocol they out performed usual care in several metrics including mortality (NNT=7!). So what was usual care? Surprisingly it looked pretty evidence based---it employed the daily spontaneous breathing trial. But, apparently, in the usual care group, given that the SATs were not coordinated with the SBTs as part of an explicit protocol patients tended to be over sedated at the time of their SBT. So more patients flunked their SBT or were judged too sleepy for extubation and thus experienced more days of mechanical ventilation.

In a subsequent review the authors explained their protocol and elaborated on issues surrounding it. For those without full text access here is a graphic of the protocol.