Predictive Value Of Ultrasonic Localization In Measuring The Hyomental Distance Ratio In Different Head Positions For Difficult Airway In Zhuang Population

Objective Evaluation of the predictive value of ultrasonic measurement of hyomental distance ratio in different head positions for difficult airway in Zhuang population.Methods 171 zhuang patients(Over 18 years of age,regardless of sex,ASA I~III).Before anesthesia,the general data of the patients and some commonly used clinical evaluation indexes,such as modified Mallampati test,upper lip bite test,thyromental distance and so on,were recorded.Measurement and recording of the distance between the hyoid bone and the tip of the chin at the extreme of head extension(HMDe)and the one in the neutral position(HMDn)by ultrasonic,and calculate its ratio(HMDR= HMDe/HMDn).After anesthesia induction,Cormaek-Lehane grade 3 or 4 under direct laryngoscopy was defined as difficult airway.Results The measurement indexes of 171 Zhuang patients were analyzed,There was no significant difference in sex,age,BMI and other general data between the two groups.The sensitivity and specificity of the modified Mallampati test and upper lip bite test were 68.2% and 50%,85.2%and 90.6%,respectively.The sensitivity of HMDR was 81.8%,the specificity was 70.5%,and the optimum critical value was 1.19.The sensitivity of HMDe was 63.6%,the specificity was 65.1%,and the optimum critical value was5.25 cm.The sensitivity,specificity and optimum critical value of HMDn were31.8%,79.9% and 4.95 cm,respectively.Combined with modified Mallampati test 、 upper lip bite test and hyomental distance ratio,the sensitivity and specificity for predicting difficult airway were relatively high,which were86.4% and 87.2%,respectively.The area under ROC curve was 0.928,95% CI(0.875-0.981).Conclusion 1.The hyomental distance ratio obtained by ultrasound has a high predictive value in evaluating the difficult airway of Zhuang population,and hyomental distance ratio of < 1.19 can be used as the best cut-off point to indicate the possibility of difficult tracheal intubation.2.The modified Mallampati test and upper lip bite test have certain value in predicting difficult intubation in Zhuang population.3.Combined with modified Mallampati test、upper lip bite test and hyomental distance ratio obtained under ultrasound,the accuracy of predicting difficult airway can be improved.