Determination of difficult intubation in the ED

The aim of this study is to determine the predictors of difficult intubation in the emergency setting.

This prospective observational clinical study was conducted in the emergency department (ED) of a University Hospital with an annually census of 50 000 visits from May 2005 to May 2007. All patients requiring intubation in the ED were included into the study. During the study period, same airway management protocol was used all intubations. The study form included patient's demographic and variables according to intubation such as the Cormack-Lehane grade, modified LEMON score, Glasgow Coma Scale score, success rate, and associated complications.

A total of 366 patients were included in the study. The mean age of the study patients was 46.8 +/- 22.8, and 68.6% (n = 251) of them were male. A total of 86 (23.5%) patients were classified in the difficult intubation group and 280 (76.5%) patients in easy intubation group. Logistic regression analysis performed by the variables found to be significant in the univariate analysis revealed thyroid-to-hyoid distance less than 2 fingers (odds ratio, 3.34; 95% confidence interval, 1.35-8.27; P = .009) as an independent factor complicating the intubation. Cormack and Lehane classification was strongly related to difficult intubation. Intubation was more difficult from grade 1 to 4 (11% vs 25.2% vs 34% vs 81.8%, respectively; P = .000).

The thyroid-to-hyoid distance less than 2 fingers is the only independent variable in predicting difficult intubation. Mallampati classification is not a useful tool in classifying the difficult intubation in the ED that the "LEMON" acrostic can be modified to "LEON".