But, as these authors state, the evidence for this practice is spotty – mostly observational evidence from controlled intubation settings. Our critically-ill patients hardly have the same physiology as those undergoing elective airway procedures, and are generally less responsive to oxygenation adjuncts. So, this is the FELLOW trial, a pragmatic, open-label randomized trial comparing apneic oxygenation vs. “usual care” – which was none.
With 150 patients in their intention-to-treat analysis, this cartoon sums up the results sufficiently:
Not much difference!
Their two groups were relatively well-balanced in terms of physiology and airway comorbidities. The intubating operators were reasonably experienced (median >50 intubations), and 2/3rds of the patients were intubated on the first attempt. There were probably no important differences in pre-oxygenation or procedural factors.
But, it is quite a small trial. There are small differences here favoring the apneic oxygenation arm that simply might not reach statistical significance. The exclusion criteria included “if the treating clinicians felt a specific approach to intra-procedural oxygenation or a specific laryngoscopy device was mandated for the safe performance of the procedure”, which could have introduced a selection bias. The open-label effects may or may not be confounding. The ICU environment and exclusion criteria also affect generalizability to the Emergency Department.
In the end, the answer is: apneic oxygenation still probably helps, particularly considering the pre-study evidence favored the intervention, and this one study does not move the needle much. However, the observation here of a clinically unimportant effect size is not unreasonable. If the effect size is small, the cost of an intervention becomes important. However, in this case, the cost is fairly minimal – a small addition to set-up time and procedural complexity. Considering the low cost and the post-test odds still favoring the intervention, it would be erroneous to stop providing apneic oxygenation based on this trial, and further study is indicated.
“Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill”