While many intubations in critically ill patients go smoothly, they are a high risk procedure that EM and ICU physicians seek to continuously improve upon. Blade size is one aspect of the procedure that has received attention over the past several years. We don’t have prospective trials addressing this question, but there are several retrospective analyses that have investigated it.
- For Direct Laryngoscopy:
- The 2022 MacSize-ICU study and a 2023 study by Landefeld and colleagues with the Pragmatic Critical Care Research Group suggested that when using Macintosh geometry blades for direct laryngoscopy there was improved first pass success with size 3 blade. Secondary outcomes for these studies point to a worse glottic view with a size 4 blade.
- For Video Laryngoscopy:
- This finding did not hold up in video laryngoscopy. A 2023 study by Park et al. and now a 2026 retrospective study again by Landefeld et al. that looked at blade size for video laryngoscopy with Macintosh geometry blades found no difference in first pass success with size 3 vs size 4 blades.
Bottom Line: Continue to use your best clinical judgment when selecting a blade size, especially when performing video laryngoscopy. When performing direct laryngoscopy, if you are on the fence, consider using size 3 blade.
*These studies do not address intubation with hyperangulated designs
References
- Godet, Thomas, et al. "Impact of Macintosh blade size on endotracheal intubation success in intensive care units: a retrospective multicenter observational MacSize-ICU study." Intensive Care Medicine 48.9 (2022): 1176-1184.
- Landefeld, Kevin R., et al. "Effect of laryngoscope blade size on first pass success of tracheal intubation in critically ill adults." Critical Care Explorations 5.3 (2023): e0855.
- Park, Jeongyong, et al. "Effect of blade size on the first-pass success rate of endotracheal intubation using the C-MAC video laryngoscope." Journal of Clinical Medicine 12.22 (2023): 7055.
- Landefeld, Kevin R., et al. "Blade Size and Outcomes with Standard-Geometry Video Laryngoscopy in Emergency Tracheal Intubations: Secondary Analysis of Two Randomized Controlled Trials." CHEST Critical Care (2026): 100257.