USE OF ULTRASOUND PARAMETERS FOR PREDICTION OF DIFFICULT INTUBATION AND ITS RELATION WITH THE CORMACK AND LEHANE GRADE OF LARYNGOSCOPY

Background and AIMS: Airway ultrasound is novel,safe and noninvasive modality that help in predicting difficult airway.This study aimed todetermine the usefulness of airway ultrasound in order to predict difficult intubation.

Method:- This was a hospital based prospective observational study on 100 patients aged 18-60 years of either sex undergoing elective surgery under general anaesthesia with endotracheal intubation.Preoperatively physical airway evaluation was performed byusing six parameters including Modified Mallampati class(MMC), thyromental distance(TMD), sternomental distance(SMD) , inter-incisor (IID)distance , hyomental distance(HMD)and neck circumference(NC). In preoperatively, Airway Ultrasoundwas performed andnoted the ratio of the depth of the pre‑epiglottic space (PES) to the distance from the epiglottis to the mid‑point of the distance between the vocal cords (E‑VC). CL grade was also noted during laryngoscopy. Compared ultrasound parameters with Cormack–Lehane grade. Specificity,Sensitivity, positive predictive value (PPV), negative predictive value (NPV) and accuracywere calculated.Airway ultrasound measurements were compared with physical parametersin predicting Cormack –Lehane grade.

Results: The incidence of difficult intubation was 7%. Sensitivity of PES/E-VC ratio was higher than NC, TMD, HMD, IID and SMD but less than Mallampati class. Specificity, PPV was lower than physical parameters.NPV was comparable.

Conclusion: Percutaneous airway ultrasound is useful and promising technique for predicting Cormack and Lehane grading but a combination of all these is definitely helpful for better prediction.