Ramped versus sniffing position for tracheal intubation: A systematic review and meta-analysis

Background Whether the ramped or sniffing laryngoscopy position is better for tracheal intubation is unclear. This study aimed to determine the efficacy and safety of tracheal intubation in the ramped versus sniffing position. Methods We conducted a systematic review and meta-analysis of randomized clinical trials to compare the ramped position with the sniffing position for tracheal intubation. We searched the databases of Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Excerpta Medica Database (Embase), ClinicalTrials.gov , and World Health Organization Clinical Trials Registry Platform up to December 2018. We included randomized-controlled trials, trials of participants who required tracheal intubation in any setting, and that compared tracheal intubation in the ramped and the sniffing positions. Two authors independently screened the trials, extracted the data, and assessed the risk of bias. We conducted the meta-analysis using the random-effects model to calculate the pooled risk ratio with 95% confidence interval. Results Of the 2631 titles/abstracts screened, three studies (representing 513 patients) were included in the meta-analysis. The pooled risk ratio with 95% confidence interval (CI) of the sniffing versus the ramped position was as follows: a first successful attempt, 0.97 (95% CI, 0.86–1.09; I2 = 55%); laryngoscopy attempts ≤2, 1.08 (95% CI, 0.88–1.31; I2 = 93%); and good glottic view with Cormack–Lehane grade ≤ 2, 0.86 (95% CI, 0.69–1.07; I2 = 86%). Conclusions This systematic review and meta-analysis indicated no favorable aspects of the ramped position as compared to the sniffing position. Thus, further research is warranted to identify which is better in tracheal intubation. Trial registration: PROSPERO identifier, CRD42019116819.