[Light-guided tracheal intubation using a Trachlight: causes of difficulty and skill acquisition]

We studied the reasons why tracheal intubation using a lighted stylet (Trachlight) was sometimes difficult for unexperienced intubators. We also examined light-guided intubation skill acquisition in inexperienced anesthesiologists. Two anesthesiologists, with no prior experience in using a Trachlight, performed orotracheal intubation using a Trachlight in 60 anesthetized patients (30 patients each). During intubation, an assistant observed the advancement of the tracheal tube using a fiberscope passed nasally and recorded the reason for difficulty in intubation. The time to successful intubation was also measured. Data were divided into epochs of 10 cases, and the intubation time and the incidence of difficult cases were compared between the groups. Tracheal intubation was successful using the Trachlight in 59 of 60 patients. The incidence of difficult cases, defined as cases requiring two or more attempts, was 31.7%. Fiberscopy showed that when the tube tip was located in the vallecula or in the esophagus, it was sometimes difficult to determine the position of the tube tip by transillumination of the soft tissues of the neck, and this results in the need for multiple attempts. Both the intubation time and the incidence of difficult cases decreased significantly between the first and last epoch. The present study confirms that light-guided intubation is sometimes difficult when the tube tip is advanced to the vallecula or to the esophagus. An acceptable level of skill in light-guided intubation is achieved within 30 uses.