The effect of cricoid pressure on tracheal intubation in adult patients: a systematic review and meta-analysis

Purpose: This meta-analysis aimed to assess the impact of cricoid pressure (CP) application on intubation outcomes. Source: Electronic databases (i.e., MEDLINE, PubMed, Embase, and Cochrane review) were searched from inception to 2 June 2020 for randomized-controlled trials that assessed the intubation outcomes in adult patients using laryngoscopic approaches with and without the application of CP (i.e., CP vs non-CP group). The primary outcome was the successful first-attempt intubation rate (SFAIR), and the secondary outcomes were intubation time, incidences of poor laryngoscopic views (i.e., Cormack and Lehane grade 3-4), airway complications, and pulmonary aspiration. Principal findings: A total of five trials (published from 2005 to 2018) were included, and all tracheal intubations were performed by anesthesiologists or nurse anesthetists with a video (n = 3) or Macintosh laryngoscope (n = 2) in the operating room. We found no significant difference in SFAIR (risk ratio [RR], 0.98; P = 0.37), incidence of poor laryngoscopic views (RR, 1.49; P = 0.21), and risk of sore throat (RR, 1.17; P = 0.73) between the two groups. Nevertheless, the intubation time on the first successful attempt was slightly longer (weighted mean difference = 4.40 sec, P = 0.002) and risk of hoarseness was higher (RR, 1.70; P = 0.03) in the CP group compared with in the non-CP group. The secondary outcome “pulmonary aspiration” was not analyzed because only one trial was available. Conclusion: The application of CP did not have a negative impact on the SFAIR or laryngoscopic view. Nevertheless, this maneuver may slightly prolong intubation time and increase the risk of postoperative hoarseness.