Written by Aaron Lacy
This systematic review and meta-analysis does not show any statistical difference in first-pass success rate or adverse intubation-related events between patients intubated in an inclined versus supine position.
Why does this matter?
First-pass success for intubation is commonly used as a research endpoint, because we know any subsequent intubation attempt after the first is associated with worse outcomes. Optimizing all aspects of an RSI attempt are crucial, including the positioning. If inclining your patient leads to increased first pass success, it is an easy step to optimize your procedure.
Reverse Trendelenburg – helpful or just fancy sounding?
The authors searched for studies looking at outcomes related to endotracheal intubation with patients in either the supine or inclined position. Ten studies, representing 18,371 intubations, were included in this meta-analysis. The authors’ definition of an ‘inclined patient’ was if any portion of their thorax was at least 10 degrees higher than the pelvis. Pre-defined subgroup analyses were performed with patients inclined < 45 degrees and > 45 degrees. If a patient was placed in the sniffing position, but the bed angle was not changed, they would qualify for the supine group.
There was no statistically significant difference in first-pass success rate (RR 1.02, 95%CI 0.98 to 1.05), which was the primary outcome. There was also no significant difference in intubation adverse events, including esophageal intubation, glottic view, hypotension, hypoxemia, mortality, or peri-intubation arrest.
We have covered this topic before on JF with varying conclusions (see here, here, and here). The conclusion I take from this meta-analysis is not that incline versus no incline doesn’t matter, but we just don’t have enough good information to provide a definitive answer. Most included studies were rated low or very low quality of evidence, and there was inability to control for variables such as obesity and VL vs DL intubation technique. There also seemed to be differing definitions of what a ramped position was in many of the articles. This is a messy topic with a messy conclusion. For the time being, we should continue to modify things we know have a positive effect on patient outcomes during RSI, such as hemodynamic optimization and video laryngoscopy.
Effect of inclined positioning on first-pass success during endotracheal intubation: a systematic review and meta-analysis. Emerg Med J. 2022;0:1-7. Doi:10.1136/emermed-2021-212968