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 endotracheal intubation difficulty among patients attended by eight anesthesiologists 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 Difficulty Scale (IDS), a quantitative score based on seven variables. An IDS value 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, repositioning the patient and added use of a stylet were the most frequent methods chosen to facilitate tracheal intubation. CONCLUSION: There was a high incidence (37%) of minor difficulties encountered during routine surgery.