[Design and clinical application of an auxiliary tool for airway assessment and laryngoscope blade selection]

Tracheal intubation is a key technology for establishing an artificial airway during the resuscitation of critically ill patients. Its success directly impacts patient life safety and prognosis. Identification of difficult airway and improper selection of laryngoscope blades are important factors leading to intubation failure and complications. To optimize this process, medical staff at Guangdong Provincial Hospital of Chinese Medicine have designed an auxiliary tool for airway assessment and laryngoscope blade selection, and have obtained a National Utility Model Patent of China (patent number: ZL 2021 2 1187307.9). The device is mainly composed of two right-angled handles and a ruler. The width of the handle is based on the "3-3-2" airway assessment rule (LEMON rule), corresponding to the patient's three-finger and two-finger widths, respectively, and is used to measure mouth opening (three-finger handle), chin-hyoid distance (three-finger handle), hyoid-thyroid notch distance (two-finger handle) to preliminarily identify difficult airways. The ruler is used to accurately measure the distance from the earlobe to the corner of the mouth, providing an objective basis for selecting the appropriate laryngoscope blade length. This tool is designed to be simple and is intended to shorten intubation time and indirectly improve first-time intubation success rate. To verify the clinical application effect of the auxiliary tool for airway assessment and laryngoscope blade selection, 80 patients who required emergency endotracheal intubation admitted to the department of emergency and intensive care unit of Guangdong Provincial Hospital of Chinese Medicine from January to December 2023 were enrolled, and the tool was used for pre-intubation assessment (observation group); and 80 patients who received routine emergency tracheal intubation in 2022 were used as the control (control group). The results showed that 6 cases (7.5%) in observation group had difficulty in identifying difficult airways before intubation using the tool, and all were successfully intubated using fiberoptic bronchoscopes. The success rate of one-time intubation for the remaining 74 patients was 98.6% (73/74). The success rate of one-time intubation in the observation group was significantly higher than that in the control group [91.3% (73/80) vs. 73.8% (59/80), χ² = 8.485, P = 0.004]. Although the incidence of complications such as tooth loss and oral bleeding in the observation group was lower than that in the control group, the differences were not statistically significant (tooth loss: 2.5% vs. 5.0%, χ ² = 0.692, P = 0.405; oral bleeding: 6.3% vs. 15.0%, χ ² = 3.224, P = 0.073). The results showed that the auxiliary tool can effectively identify difficult airways, guide the accurate selection of laryngoscope blades, and significantly improve the one-time endotracheal intubation success rate of critically ill patients.