Abstract: Objective: To observe the clinical application of flexible endoscope assisted by general versus pillow-under-shoulder supine position in nasotracheal intubation of the patients with difficult airway, and to explore the influence of intubation position in the intubation effect.Methods: A total of 168 patients with difficult airway who underwent nasotracheal intubation and oromaxillofacial surgery under general anesthesia were randomly divided into general supine position (control group) and pillow-under-shoulder supine position (experimental group) with 84 cases in each group. The first-time and the total success rate of intubation, the intubation time, and the rate of direct glottis exposure of the patients in two groups were recorded. The mean arterial pressure(MAP), heart rate (HR), and complications of intubation of the patients in two groups before induction, before tracheal intubation, during intubation, 1 and 5 min after intubation, were also recorded.Results: The first-time success rate of intubation in experimental group (94.0%, 79/84) was significantly higher than that in control group (71.4%, 60/84) (P<0.01); the total success rate of intubation (98.8%, 83/84) had no difference compared with control group (97.6%, 82/84) (P>0.05); the intubation time (57 s±12 s) was significantly shorter than that in control group (146 s±29 s) (P<0.01); the rate of direct glottis exposure (47.6%, 40/84) when the flexible endoscope passed through the posterior nasal apertures was obviously higher than that in control group (15.5%, 13/84) (P<0.01).The values of MAP and HR of the patients in two groups before and during intubation were decreased significantly compared with the baselines (P<0.01), and came back to the baselines 1 and 5 min after intubation (P>0.05). There were no significant differences in the MAP and HR between different time points (P>0.05). The incidence rates of complications including pharyngalgia, hoarseness and epistaxis had no differences between two groups (P>0.05).Conclusion: Flexible endoscope assisted by pillow-under-shoulder in nasotracheal intubation has a higher intubation success rate, shorter intubation time and it is a superior procedure for the patients with difficult airway.

Key words: flexible endoscope, pillow-under-shoulder, difficult airway, nasotracheal intubation