For nasotracheal intubation, which nostril results in less epistaxis: right or left?

BACKGROUND: Nasotracheal intubation is usually required in patients undergoing oromaxillofacial, otolaryngological or plastic surgery to prevent the airway encroaching into the operating field. Epistaxis is the most common complication, but which nostril is associated with a lower incidence and severity of epistaxis is still unclear. OBJECTIVE: When both nostrils are patent, to determine the preferred nostril for nasotracheal intubation under general anaesthesia. DESIGN: A systematic review and meta-analysis of randomised controlled trials (RCTs). The primary outcome was the incidence of epistaxis and the secondary outcomes included the incidence of severe epistaxis, the time required to pass the tube through the nasal passage and total intubation time. DATA SOURCES: PubMed, Embase and the Cochrane Register of Controlled Trials were searched from database inception to 1 March 2020. ELIGIBILITY CRITERIA: The only studies included were RCTs comparing epistaxis related to nasotracheal intubation via right or left nostril, in adult surgery patients undergoing general anaesthesia. RESULTS: Ten RCTs with 1658 patients were included. Compared with the left nostril, intubation via the right nostril was associated with a significantly lower incidence of epistaxis: risk ratio (RR) and 95% confidence intervals (CI) were 0.78 (0.62 to 0.99), P = 0.04: a lower incidence of severe epistaxis (five studies, n=923), RR 0.40 (0.22 to 0.75), P = 0.004: and a shorter intubation time (three studies, n=345), mean difference -7.28 (-14.40 to -0.16) seconds, P = 0.05. In two studies (n=310), no significant difference between the right and left nostril was observed in the time to pass the tube through the nasal passages, mean difference -0.59 (-1.95 to 0.77) s, P = 0.40. CONCLUSION: On the basis of the current available evidence, when both nostrils are patent, the right nostril is more appropriate for nasotracheal intubation, with a lower incidence and severity of epistaxis and faster intubation time. TRIAL REGISTRATION: The study protocol has been registered in PROSPERO (CRD42020169949).