A survey of tracheal intubation difficulty in the operating room: a prospective observational study

Background: The purpose of this study is to describe all degrees of endotra cheal intubation difficulty among patients attended by eight anesthesiologi sts during routine surgery over a six-month period. Airway characteristics were routinely assessed preoperatively, according to the anesthesiologists' usual practice. Methods: Difficult tracheal intubation was evaluated by the Intubation Diff iculty Scale (IDS), a quantitative score based on seven variables. An IDS v alue of 0 is consistent with a procedure without difficulty, and an IDS > 5 with a procedure involving moderate to major difficulty. Results: For 1171 patients undergoing tracheal intubation, IDS was 0 in 55% , and greater than 5 in 8% of cases. External laryngeal pressure, repositio ning the patient and added use of a stylet were the most frequent methods c hosen to facilitate tracheal intubation. Conclusion: There was a high incidence (37%) of minor difficulties encounte red during routine surgery.