PHONATION-ENHANCED MODIFIED MALLAMPATI TESTING FOR DIFFICULT AIRWAY PREDICTION IN ADULTS AT SIUT: A PROSPECTIVE OBSERVATIONAL STUDY

Abstract

Objective: To compare the Modified Mallampati Test (MMT) with and without phonation and the Upper Lip Bite Test (ULBT) against Cormack-Lehane laryngoscopic grading and intubation difficulty and to determine their diagnostic performance.

Study design: Prospective observational cross-sectional study.

Place and duration of the study: Department of Anesthesiology, Sindh Institute of Urology and Transplantation, over at least six months.

Methodology: Adults aged 18-65 years undergoing elective surgery under general anesthesia with endotracheal intubation were enrolled by non-probability consecutive sampling. Preoperative MMT without phonation, MMT with phonation and ULBT were recorded in 309 participants. Difficult laryngoscopy was Cormack-Lehane Grade III-IV. Difficult intubation was more than one attempt and/or use of a bougie, stylet or video aid. Diagnostic indices, receiver operating characteristic curves, correlations and paired McNemar comparisons were analyzed in SPSS version 26.

Results: Difficult laryngoscopy occurred in 31 (10.0%) participants and protocol-defined difficult intubation in 16 (5.2%). For difficult laryngoscopy, MMT without versus with phonation had sensitivity 90.3% versus 61.3%, specificity 72.7% versus 100.0%, accuracy 74.4% versus 96.1% and AUC 0.815 versus 0.806. For difficult intubation, corresponding values were sensitivity 93.8% versus 81.3%, specificity 69.6% versus 98.0%, accuracy 70.9% versus 97.1% and AUC 0.817 versus 0.896. The paired sensitivity difference was significant for difficult laryngoscopy (p=0.004) but not difficult intubation (p=0.500); specificity differences favored phonation for both outcomes (p<0.001). No ULBT Class III or IDS >5 case occurred.

Conclusion: MMT without phonation provided greater sensitivity, whereas phonation-enhanced MMT provided markedly greater specificity and overall accuracy.