Comparison of modified Mallampati grading in sitting and supine position to predict difficult intubation in acromegaly patients

Abstract

BackgroundAcromegaly patients have a very high incidence of difficult endotracheal intubation. The Modified Mallampatti grading (MMPG) in the sitting position is a common test performed preoperatively to predict difficult intubation. It has been suggested that supine MMPG is possibly a better predictor of difficult tracheal intubation (DTI) rather than the sitting MMPG in normal individuals. ObjectiveWe wanted to determine if the supine MMPG had a better diagnostic accuracy than the sitting MMPG in predicting DTI in acromegaly patients. MethodsThis was a single-centre prospective observational study conducted in 70 adult acromegaly patients undergoing pituitary adenoma surgery requiring general anaesthesia and endotracheal intubation. MMPG in the sitting position was recorded during the pre-anaesthesia consultation. An independent observer recorded the MMPG in the supine position and the ease of intubation prior to surgery. The diagnostic performance of the MMPG for the prediction of DTI was evaluated in the sitting and supine positions through the area under the receiver operating characteristic (ROC) curve. The Naguib score was also calculated and its ability to predict DTI was tested. ResultsThirty-five patients (50%) out of a total of 70 patients had difficult tracheal intubation. The area under the ROC curve for MMPG in supine position 0.708 (0.587–0.810) was greater than that for the MMPG in the sitting position 0.616 (0.492–0.729) ; p = 0.0146∗). ConclusionMMPG performed in the supine position was possibly a superior predictor of difficult tracheal intubation in adult acromegaly patients compared with MMPG performed in the sitting position.