Ramped versus sniffing position for videolaryngoscopy-guided tracheal intubation in adult patients: A systematic review and meta-analysis with trial sequential analysis.

Abstract

<h4>Background and aims</h4>The sniffing position is required for direct laryngoscopy to align the oropharyngeal-laryngeal axis in the line of sight. However, videolaryngoscope (VL)-guided intubation may not need a sniffing position. This meta-analysis compared intubation using VL in the sniffing position versus ramped or head-elevated positions.<h4>Methods</h4>This prospective systematic review and meta-analysis included randomised controlled trials comparing VL in a ramped or head-elevated position with the sniffing position in adult patients undergoing endotracheal intubation. The primary outcome was time for intubation. The secondary outcomes included the first attempt success and the glottic view during intubation. Trial sequential analysis (TSA) was conducted for the primary outcome.<h4>Results</h4>This review adhered to the PRISMA 2020 guidelines. Four studies were included, with 341 patients (173 in the ramped and 168 in the sniffing position). The pooled data showed that intubation time was comparable in the ramped as well as in the sniffing position [standard mean difference: -0.74; 95% confidence interval (CI): -1.59, 0.11; <i>P</i> = 0.089; <i>I</i> ² <i>=</i> 92.4%; prediction interval = -3.59, 2.11]. Similarly, no significant difference in first attempt success rate between the two groups [risk ratio (RR): 1.03; 95% CI: 0.95, 1.12; <i>P</i> = 0.368; <i>I</i> ² <i>=</i> 33.1%]. The comparison of the good glottic view showed a pooled RR of 1.14; 95% CI: 0.61, 2.12; and <i>P</i> = 0.461. TSA showed an adequate sample for the primary outcome.<h4>Conclusion</h4>The current meta-analysis suggests that during VL, the intubation time, first-attempt success, and glottic view were comparable in both ramped and sniffing positions. However, high heterogeneity makes the results less robust.