Videolaryngoscopy versus direct laryngoscopy for nasotracheal intubation: A systematic review and meta-analysis of randomised controlled trials

Study objective: Nasotracheal intubation (NTI) is a common practice in the oral and maxillofacial surgeries. A systematic review and meta-analysis was performed to determine whether videolaryngoscopy (VL) compared with direct laryngoscopy (DL) can lead to better outcomes for NTI in adult surgical patients. Measurements: Only randomised controlled trials comparing VL and DL for NTI were included. The primary outcome was overall success rate and the second outcomes were first-attempt success rate, intubation time, rate of Cormack and Lehane classification 1, rate of Magill Forceps used, rate of postoperative sore throat, and ease of intubation. Main results: Fourteen studies with 20 comparisons (n = 1052) were included in quantitative synthesis. The overall success rate was similar between two groups (RR, 1.03; p = 0.14; moderate-quality evidence). VL was associated with a higher first-attempt success rate (RR 1.09; p = 0.04; low-quality evidence), a shorten intubation time (MD-6.72 s; p = 0.0001; low-quality evidence), a higher rate of Cormack and Lehane classification 1 (RR, 2.11; p < 0.01; high-quality evidence), a less use of the Magill forceps (RR, 0.11; p < 0.01; high-quality evidence) and a lower incidence of postoperative sore throat (RR, 0.50; p = 0.03; high-quality evidence). Subgroup analysis based on whether with a difficult airway showed higher overall success (p < 0.01) and first attempt success rates with VL (p = 0.04) in patients with difficult airways; however, these benefits was not shown in patients with a normal airway (p > 0.05); Subgroup analysis based on operators' experience showed that success rate did not differ between groups (p > 0.05), but intubation time was shortened by more than 50s by non-experienced operators (p < 0.05). Subgroup analysis based on different devices used showed that only non-integrated VL led to a shorter intubation time (p < 0.05). Conclusions: The use of VL does not increase the overall success rate of NTI in adult patients with general anesthesia, but it improves the first-attempt success rate and laryngeal visualization, and shortens the intubation time. VL is particularly beneficial for patients with difficult airways.