BACKGROUND The recognition of difficult intubation during pre-operative check-up is very important for the anaesthesiologist. Various anatomical parameters assist in predicting difficult intubation. Till date, there are no predictors available to precisely assess the risk of difficult intubation, pre-operatively.Therefore, we aim to identify the adequacy of predictors for preoperative assessment of difficult intubation.
MATERIALS AND METHODSAfter ethical approval of Institutional Ethics Committee, a total of 200 non-obese patients (Body mass index less than or equal to 30) were recruited in this prospective observational study after obtaining informed consent. Mouth Opening (MO), Modified Mallampati Grading (MMG), neck circumference (cm), Thyromental Distance (TM), Sternomental Distance (SM), Neck Movement (NM), Neck Circumference (NC) and Ratio of Height to Thyromental Distance (RHTMD) were measured pre-operatively. In each patient, validated Intubation Difficulty Score (IDS score) was assessed intraoperatively by the anaesthetist. All patients were divided into two groups on the basis of easy (IDS score < 5) and difficult intubation (IDS score ≥ 5). Multivariate logistic regression analysis including all variables was used to create a predictive model.
RESULTSLaryngoscopy was difficult in 12.0% of the patients. The MO, MMG, NM, NC, TM, SM, NC/TM were significantly different in between easy and difficult intubation. The Area Under Curve (AUC) in ROC for the TM, SM, NC/TM, RHTMD and MPC were 0, 270, 0.138, 0.848, 0.807 and 0.699, respectively. Among all indices, NC/TM and RHTMD were found to have high sensitivity and specificity. NC/TM was showing maximum area under the curve on ROC curve (AUC) followed by RHTMD.
CONCLUSIONAmong non-obese patients, NC/TMD ratio and RHTMD can be used for better predictor of difficult intubation, pre-operatively.
