DIAGNOSTIC ACCURACY OF MODIFIED MALLAMPATI CLASSIFICATION IN PREDICTING DIFFICULT INTUBATION

Abstract

Accurate prediction of a difficult airway is critical for avoiding complications during anesthesia. In this cross sectional study of 218 adult patients undergoing elective cholecystectomy, we compared the Modified Mallampati Classification (MMC) to the Cormack-Lehane grade (CLG) (grades III-IV defined as difficult) as the gold standard. Using WHO-recommended sample size calculations (anticipated prevalence 22.2%, sensitivity 53.8%, specificity 91.4%), all patients underwent a preoperative MMC assessment and direct laryngoscopy performed by experienced anesthesiologists. The percentage of difficult intubations was 20.2% (44/218). MMC predicted a difficult airway in 48 patients. True positives (MMC+, CL+) totaled 25, false positives 23, false negatives 19, and true negatives 151. MMC had 56.8% sensitivity, 86.8% specificity, 52.1% positive predictive value (PPV), and 88.8% negative predictive value (NPV). The results are summarized in Table 1. Our sensitivity is comparable to previous reports (e.g., ~53.8% [3]), and specificity remains high. The low sensitivity highlights that MMC alone misses nearly half of difficult intubations; however, the high NPV indicates that a negative MMC is reassuring. Recent literature shows that pooled analyses have a sensitivity of approximately 39% [10]. Combining MMC with other assessments can improve prediction. For example, the Mallampati + Wilson score had 75% sensitivity and 98.8% specificity [4]. Our clinical data are consistent with studies from similar settings. An Ethiopian series found MMC sensitivity to be 53.8% and specificity to be 91.4% [3], while an Indian cohort reported high sensitivity (~95%) but low specificity [5], indicating methodological variability. This demonstrates that relying solely on MMC is insufficient, and additional tests or preparation for difficult airways (per current guidelines [1]) are recommended. In conclusion, MMC has limited diagnostic accuracy and should be used alongside other screening methods.