Author(s): Vaishali Chandrashekhar Shelgaonkar1, Jaideep Sonowal2, Medha K. Badwaik3, Sandhya P. Manjrekar4, Manish Pawar5
BACKGROUND: This study was carried out to evaluate usefulness of preoperative Mallampati & Wilson’s score grading as a predictor for difficult laryngoscopy & intubation.
AIMS: To determine the accuracy of the modified Mallampati test and Wilson score for predicting difficult tracheal intubation and correlation with Cormack Lehane grading.
METHODS: This prospective randomized cross sectional Study carried out in 200 patients, posted for surgical procedure under GA with ETT intubation. Preoperative airway assessment using Mallampati grading (MPG) & Wilson score done. Conventional anesthesia technique followed. Cormack Lehane grading done at laryngoscopy & correlated with previous scores for each patient.
RESULTS: A MPG of I/II was found in 140 patients (70%), while 60 patients (30%) were class III/IV. 138 patients (69%) had a Wilson score of 0/1, while 60(30%) had a score of 2/3 and 2 patients (1%) scored ≥4. One hundred & eighty patients (90%) were classified as Cormack-Lehane grade I/II, while 20 patients (10%) were considered grade III/IV. Of the 60 patients with a Wilson score of 2/3, 6 cases (10%) two attempts were required and in 2 cases (3.3%) in spite of more than two attempts intubation proved impossible with the conventional laryngoscope, articulated McCoy blade was used. Two patients with a Wilson score ≥4 were intubated with gum elastic bougie, using articulated McCoy blade. Overall, out of 200, in 6 patients (3%) two attempts of intubation was required and 4 patients (2%) intubation required the use of some kind of gadget other than conventional laryngoscope and more than 2 attempts. The correlation between the Cormack-Lehane classification and the number of endotracheal intubation attempts showed that of the 180 patients with I / II grade, 4 patients (1.3%) two attempts were required. Of the 20 patients classified as Cormack-Lehane III/IV, 4 cases (20%) intubation proved impossible with conventional technique. This correlation was statistically significant.
DISCUSSION: The Wilson score can successfully predict the patients in whom laryngoscopy may prove difficult (Wilson 2/3) (p=0.01). This reflects the good sensitivity.
CONCLUSIONS: Wilson score, despite being seldom used in clinical practice, is a highly sensitive predictor of a difficult airway, although its specificity is low.