Prediction of difficult tracheal intubation in thyroid surgery

The incidence of difficult endotracheal intubation (DEI) for patients undergoing thyroidectomy has rarely been studied, and evaluation of factors linked to DEI is limited to a few studies. We undertook this prospective study to investigate the incidence of DEI in the presence of goiter (an enlargement of the thyroid gland) and to evaluate factors linked to DEI. We studied 320 consecutive patients scheduled for thyroidectomy. DEI was evaluated by an intubation difficulty scale. The trachea was intubated by an unassisted anesthesiologist, and the intubation difficulty scale was calculated. A univariate analysis was performed to identify potential factors predicting DEI, followed by a multivariate analysis. DEI was reported in 17 patients. The rate of easy tracheal intubation was 36.9%; the rate for patients who had minor difficulty of intubation was 57.8%. Sex (male), body mass index, Mallampati class, thyromental distance, neck mobility, Cormack grade, cancerous goiter, and tracheal deviation or compression were identified in the univariate analysis as potential DEI risk factors. With multivariate analysis, two criteria were recognized as independent for DEI (Cormack Grade III or IV and cancerous goiter). We conclude that the large goiter is not associated with a more frequent DEI. However, the presence of a cancerous goiter is a major factor for predicting DEI.