Effect of Dynamic Versus Stylet-Guided Intubation on First-Attempt Success in Difficult Airways Undergoing Glidescope Laryngoscopy: A Randomized Controlled Trial

Anesth Analg. 2019 Jun;128(6):1264-1271. doi: 10.1213/ANE.0000000000004102.


Background: Tracheal intubation failure in patients with difficult airway is still not uncommon. While videolaryngoscopes such as the Glidescope offer better glottic vision due to an acute-angled blade, this advantage does not always lead to an increased success rate because successful insertion of the tube through the vocal cords may be the limiting factor. We hypothesize that combined use of Glidescope and fiberscope used only as a dynamic guide facilitates tracheal intubation compared to a conventional Glidescope technique with a preshaped nondynamic stylet.

Methods: One hundred sixty adult patients with predicted difficult airway were randomly assigned to a conventional Glidescope (standard Glidescope group) or a combined Glidescope + fiberscope group intubation. In the Glidescope + fiberscope group under direct vision from the Glidescope, tracheal intubation was performed using the fiberscope as a guide without using fiberoptic vision, while in the standard Glidescope group, a conventional stylet-guided intubation technique was performed. We evaluated the rate of tracheal intubation success at first attempt as the primary end point (Fisher exact test). The difference between groups in airway injury, time to successful intubation, and the need for an alternative technique was also evaluated.

Results: First-attempt intubation success was higher in the Glidescope + fiberscope group than in the standard Glidescope group (91% vs 67%; P = .0012; fragility index, 8; absolute risk reduction, 24% [95% CI, 12%-36%]). Median time to successful tracheal intubation was shorter in the Glidescope + fiberscope group (50 vs 64 seconds; P = .035). Airway injury rate was lower in the Glidescope + fiberscope group than in the standard Glidescope group (1% vs 11%; P = .035; fragility index, 1; absolute risk reduction, 10% [95% CI, 3%-18%]). Alternative rescue technique requirements to achieve tracheal intubation were higher in the standard Glidescope group (24% vs 4%; P < .001; fragility index, 7).

Conclusions: The use of a dynamic, flexible guide during a Glidescope laryngoscopy in patients with a predicted difficult airway compared to a standard intubation technique improves first-attempt intubation success, decreases the incidence of airway injury and time to successful intubation, as well as the need of an alternative technique to succeed.

Trial registration: ClinicalTrials.gov NCT02627755.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Equipment Design
  • Female
  • Fiber Optic Technology
  • Glottis
  • Humans
  • Intubation, Intratracheal / adverse effects*
  • Intubation, Intratracheal / instrumentation
  • Intubation, Intratracheal / methods*
  • Laryngoscopes*
  • Laryngoscopy / adverse effects*
  • Laryngoscopy / instrumentation
  • Laryngoscopy / methods*
  • Male
  • Middle Aged
  • Oximetry
  • Surgical Instruments
  • Video Recording

Associated data

  • ClinicalTrials.gov/NCT02627755