Written by Sam Parnell
There was no significant difference in first-attempt success rate for ramped and upright position intubations in the ED when comparing hyperangulated and standard geometry video laryngoscopes.
Why does this matter?
Emergency intubation is a relatively common procedure but can be associated with significant risk, especially for patients with anatomically or physiologically difficult airways. Ramped and upright intubation positions can assist with preoxygenation and have been associated with reduced risk of hypoxemia and peri-intubation adverse events1-5. Furthermore, video laryngoscopy (VL) can improve glottic view6 and is associated with increased first-attempt intubation success and lower risk of adverse events7-9 compared to direct laryngoscopy (DL).
There are two main types of VL blades, hyperangulated and standard geometry, and each blade type has specific advantages and disadvantages. However, for non-supine patients, the standard geometry VL may be superior due to differences in patient positioning and endotracheal tube delivery10-12. Does the available evidence show any difference in first-pass intubation success for hyperangulated vs. standard geometry blades for patients in ramped and upright positions?
Ramped and upright first-pass intubation success…what’s your angle?
This was a secondary analysis of the National Emergency Airway Registry (NEAR) for adult patients undergoing emergent intubation with VL in ramped or upright positions from January 1, 2016 to December 31, 2018. Nasal intubations, intubations performed without rapid sequence intubation, intubations due to trauma indications, and intubations during cardiopulmonary resuscitation were excluded. The primary outcome was first-attempt success, which was defined as successful intubation with a single VL blade insertion. Secondary outcomes included first-attempt success without adverse events, Cormack-Lehane view, esophageal intubation, post-induction hypoxemia, and any adverse events.
There were 636 first attempts in the ramped position (266 hyperangulated and 370 standard geometry) and 171 first attempts in the upright position (116 hyperangulated and 55 standard geometry). Age, sex, obesity, and operator-perceived difficult airways were similar between the blade types and upright/ramped cohorts. Overall, first-attempt success rate was similar between blade types for both upright and ramped positions. For the ramped position, 244 (91.7%) of hyperangulated first attempts were successful, and 341 (92.2%) of standard geometry first attempts were successful (% Difference − 0.4% [95% CI -5.1, 4.2]). For the upright position, 107 (92.2%) of hyperangulated first attempts were successful, and 50 (90.9%) of standard geometry first attempts were successful. There were no significant differences in secondary outcomes. Additionally, there was no significant difference in first-attempt success when comparing the upright position to the ramped position in the secondary analyses.
This study had several limitations and used registry data at risk for confounding by indication and unmeasured confounders. Further studies are needed to investigate subgroups that may benefit from specific positions and blade types. However, based on this study, hyperangulated and standard geometry video laryngoscopes appear to have similar outcomes and can both be used with high probability of success when intubating patients in ramped and upright positions.
Impact of video laryngoscope shape on first-attempt success during non-supine emergency department intubations. Am J Emerg Med. 2022 Apr 27;57:47-53. doi: 10.1016/j.ajem.2022.04.024. Online ahead of print.
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