Modified Mallampati test and thyromental distance as a predictor of difficult laryngoscopy in Thai patients

Wichai Ittichaikulthol, Suwanna Chanpradub, Sakda Amnoundetchakorn, Niramon Arayajarernwong, Wilailux Wongkum
Journal of the Medical Association of Thailand, Chotmaihet Thangphaet 2010, 93 (1): 84-9

BACKGROUND: Preoperative evaluation of anatomical landmarks and clinical factors are important in the detection of patients at risk for difficult laryngoscopy. The modified Mallampati test (MMT) and thyromental distance (TMD) are commonly used for this purpose but there are controversies regarding their accuracy.

OBJECTIVE: The objective of the present study was to evaluate the accuracy of MMT and TMD in the prediction of difficult laryngoscopy in Thai patients.

MATERIAL AND METHOD: 1888 consecutive patients undergoing general anesthesia requiring endotracheal intubation were evaluated preoperatively using the MMT and TMD. The cut-off points for the difficult airway predictors were: Mallampati 3, 4 and TMD less than 6 cm. During direct laryngoscopy, the laryngeal view was graded using the Cormack and Lehane (CL) classification. CL grades III and IV were considered difficult laryngoscopy. Sensitivity and specificity for each airway predictor in isolation and in combination were determined.

RESULTS: The present study found Mallampati grade I 1050 patients (55.6%), grade II 730 patients (38.7%), grade III 104 patients (5.5%), grade IV 4 pateints (0.2%) and TMD less than 6 cm 85 patients (4.5%), TMD more than 6 cm 1803 patients (95.5%). Difficult laryngoscopy occurred in 60 patients (3.2%). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the two airway predictors were: MMT 41.7%, 95.5%, 23.1% and 98.0% and TMD 23.3%, 96.1%, 16.5% and 97.4% respectively. The combination of two predictors with a sensitivity, specificity PPV and NPV were 55.0%, 92.3%, 19.1% and 98.4%.

CONCLUSION: MMT TMD and their combination are good predictors of difficult laryngoscopy in a Thai population.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"