Objective To measure the pharyngeal and laryngeal anatomical diameters related to laryngeal mask placement in Chinese adults based on computed tomography (CT) images of throat and to explore the correlation between the diameters and clinical indicators.

Methods Totally, 121 patients (60 males and 61 females) who underwent elective surgery under laryngeal mask general anesthesia in Jinshan Hospital, Fudan University from May 2018 to January 2019 were included in the study. The length of the epiglottic tongue surface (line 1), the root width of the epiglottic tongue surface (line 2), the distance from the root of the epiglottic tongue surface to the entrance of the esophagus (line 3), and the distance between the lateral margin of piriform fossa on both sides (line 4) were measured. The differences between diameters of male and female patients were compared and Pearson correlation analysis was performed for the length of diameters with age, height, weight, and body mass index (BMI).

Results The lengths of each line were:line 1, (1.56±0.34) cm; line 2, (2.18±0.37) cm; line 3, (2.15±0.34) cm; and line 4, (3.79±0.43) cm, respectively. The difference of length of four lines between male and female groups was statistically significant (P < 0.01). The length of four lines was not significantly correlated with age, but was positively correlated with height (P < 0.001). The body weight was positively correlated with the length of line 1, line 3, and line 4 (P < 0.01), and BMI was only positively correlated with the length of line 3 (P < 0.01).

Conclusions Gender, height, and weight are found to be important factors influencing the size selection of laryngeal mask in Chinese adults, it is suggested that the above three factors should be taken into consideration in the design of laryngeal mask suitable for Chinese patients and the model selection.