The Application Of Ultrasound In The Assessment Of Difficult Laryngoscope Exposed

Objective Ultrasound can provide reliable upper airway anatomical images,but it is unclear whether it is more advantageous for airway assessment.Through the application of ultrasound to measure the thickness of skin and soft tissue at different levels in front of the neck,the volume of the tongue and other indicators,and compare them with traditional airway assessment indicators,the value of ultrasound in evaluating difficult laryngoscope exposure is evaluated,and a new method for clinical difficult airway assessment is provided.Methods Select patients who underwent elective general anesthesia for tracheal intubation in our hospital from July 2020 to December 2020.Over 18 years of age,regardless of gender,American society of anesthesiologists(ASA)classification I-III;the day before surgery,an anesthesiologist would conduct pre-anaesthesia assessment and collect general patient information,including surgery information,gender,age,height,weight,body mass index(BMI),ASA classification.After induction of conventional anesthesia on the day of surgery,record the corresponding laryngoscopy exposure(Cormack-Lehane,C-L)grade,C-L grade 1 to II are non-difficult laryngoscopy exposure group(group N),and C-L grade III to IV are difficult larynx Endoscope exposure(group D).After the operation,patients would enter the postanesthesia care unit to remove the tracheal intubation,perform traditional airway examination first,measure and record the patient’s Modified Mallampati Test(MMT),mouth opening,neck circumference,thyromental distance(TMD),and sternomental distance(SMD).Then perform an airway ultrasound examination to measure and record the distance from skin to hyoid bone(DSH),the distance from skin to epiglottis(DSE),and the distance from the front of the vocal cords to the skin(DSV),distance from skin to thyroid isthmus(DST),tongue cross-sectional width,tongue longitudinal cross-sectional area,tongue volume.Results Among the 86 patients included in the statistical analysis,48 were males and 38 were females,aged 22～78 years.Among them,43 people were in group D and 43 people were in group N.There were no statistical differences in gender,height,and weight between the two groups(P>0.05),and there were statistical differences in age and BMI(P<0.05).There was no statistical difference in DSV between the two groups in ultrasound indicators(P>0.05),there were statistical differences in tongue cross-sectional width,tongue longitudinal cross-sectional area,tongue body volume,DSE,DSH,DST(P<0.05).In the measurement of different levels of anterior cervical soft tissue thickness in this experiment,the AUC of DSH,DSE,DSV,and DST for predicting difficult laryngoscope exposure were 0.639(0.527,0.741),0.890(0.803,0.948),0.603(0.491,0.708),0.724(0.616,0.816),and compared with the AUC of traditional indicators,DSE has the best correlation.When the Youden index is the highest,the distance from the epiglottis to the skin is 2.10 cm,that is,the DSE value is greater than 2.10 cm.When the laryngoscope is exposed,the sensitivity,specificity,and accuracy are 81.40%,83.72%,and 82.56%,respectively.The cross-sectional width of the tongue and the longitudinal cross-sectional area of the tongue separately predict difficult laryngoscope exposure with AUC values of0.685 and 0.668.AUC value for predicting difficult laryngoscope exposure increased to0.705 by taking the product of the two indicators.The DSE,DST,tongue volume,and SMD were tested in series and in parallel,and the paired-corrected chi-square test was performed.The P value was all less than 0.1,and the consistency test was performed.The Kappa value was all less than 0.6,and the consistency was poor.Therefore,the clinical application effect is limited.Conclusion Ultrasonic measurement of epiglottis-skin distance has better predictive ability than traditional airway assessment and other ultrasound measurements in predicting difficult laryngoscopy exposure.However,the diagnostic efficiency and consistency of the combined diagnostic test have not been significantly improved,and the clinical application is limited.