Authors : Dr. Champa. B.V., Dr. Gurudatta. K.N., Dr. Yashoda.

Volume/Issue :-
 Volume 4 Issue 1

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Background Difficult airway remains a potential problem for practicing anaesthesiologists. Various studies have been conducted to assess the airway and hence predict the difficulty in intubation. However, modified mallampatti test is one of the important tests to predict a difficult airway. Modified mallampatti test alone has low sensitivity and specificity. Preoperative assessment of the airway using a combination of simple tests will increase the sensitivity and specificity of prediction of difficult airway than using a single parameter alone. Hence this study was undertaken to assess the validity of combination of parameters in preoperative prediction of difficult endotracheal intubation in adults posted for elective surgeries under GA.
 Objectives  To compare the sensitivity, specificity and accuracy for preoperative prediction of difficult endotracheal intubation in adults undergoing elective surgeries using combination of Modified Mallampati test, Sternomental distance, Thyromental distance and Neck mobility over Modified Mallampati test alone.  To assess whether MMT alone or in combination with TMD, SMD and NM is a better predictor of difficult laryngoscopy.
 Material and Methods This is a prospective study conducted at the Shivamogga Institute of Medical Sciences between June 2017 to June 2018. 100 patients in the age group of 1870 years undergoing elective surgeries under general anaesthesia were selected. Alternate patients were enrolled into two groups. Group 1 was the MMT group and Group 2 was the MMT,TMD,SMD& NM Group. An investigator visited the selected patients on the day prior to surgery, performed a standard preoperative airway and clinical assessment and documented the
findings using pretested data collection form and obtained the informed and written consent. On the day of surgery, another investigator with atleast 5 years of experience in anaesthesiology, not involved in preoperative assessment of airway performed laryngoscopy, attempted intubation with appropriate sized endotracheal tube. He/She documented the level of difficulty by grading the patient using Cormack and Lehane grading. The preoperative assessment data and the intubation findings were used to determine the accuracy of the above mentioned tests in predicting difficult intubation. Results were analysed using SPSS software Version 12 and STATA used for analysing the sensitivity, specificity, PPV, NPV and accuracy in each group. P value calculated using Chi Square test.
 Results The present study comprised of 50 patients in each group. Group 1 had lower sensitivity, specificity, PPV, NPV as well as Accuracy when compared with that of Group 2. The combination of the parameters yielded a greater accuracy in predicting the difficult intubation stressing the importance of assessing the evaluation of other parameters like TMD, SMD & NM along with MMD for successful prediction of a difficult endotracheal intubation. The p value was not significant between the two groups.
 Conclusion The MMT alone in preoperative assessment of difficult laryngoscopy is less sensitive. The combination of MMT, TMD, SMD & NM is more sensitive as well as specific to predict a difficult intubation than using MMT alone in the pre operative period. The accuracy too is increased with combination of above mentioned parameters. Though not statistically significant, we conclude to practice a routine assessment of airway using modified mallampatti score, Thyromental distance, sternomental distance and neck mobility in the preoperative period for the proper assessment of airway thereby avoiding unanticipated difficult airway.
Keywords:- Difficult Intubation, Modified Mallampatti Test(MMT), Thyromental Distance(TMD), Sternomental Distance(SMD), Neck Mobility(NM), Cormack Lehane(CL) Grading.