Results 

 

 

Participating Operators. Twelve staff anesthetists, 2 anesthesia residents, and 2 qualified anesthesia nurses volunteered and participated in this study. They performed laryngoscopy and tracheal intubation attempts with the Standard Adult GlideScope Video Laryngoscope (GVL) on from 18 to a maximum of 25 (median: 22) patients. The operators were novice users of the GVL. 

 

Patient Demographics. During May 2005 and April 2006, 334 patients requiring orotracheal intubation for elective thyroid surgery were enrolled into this study; none of these patients was excluded from the study because of difficult face-mask ventilation experienced during induction of general anesthesia. The demographic data of the patients according to conventional laryngoscopic view grading (CLV) are summarized in Table 1. Laryngeal views of grade 1 to 5 at conventional laryngoscopy (CL) were obtained in 112, 93, 53, 67, and 9 patients, respectively. There were no statistically significant differences in age, height, weight, male/female ratio, body mass index, and American Society of Anesthesiologists physical status classification between the groups of CLV. The majority of the study patients were female, usual in patients undergoing thyroid surgery.

 

Laryngeal Views in Patients with the First Attempt of Tracheal Intubation Successful. The success rate of GVL-assisted tracheal intubation at the first attempt of was 97 percent (324/334 patients). The laryngeal views obtained with the GVL compared with CLV are shown in Table 2. The GVL laryngeal views were always comparable or superior to those provided by CL. In summary, GVL laryngeal views of grade 1, 2, and 3 were found in 268, 54, and 2 patients, respectively.

 

Minor Problems and Difficulties in Patients with the First Attempt of Tracheal Intubation Successful. Impeded tracheal tube (TT) advancement was most frequently observed (see Table 3); minor problems and difficulties with TT advancement during oropharyngeal, laryngeal, and/or tracheal passage were encountered in altogether 32 percent. Impeded blade insertion due to limited mouth opening and/or restricted pharyngeal space and poor visibilty due to the presence of secretions were rarely a problem and poor visibility due to fogging of the camera system was never a problem.

 

Causes of Primary Failures of Laryngoscopy and Tracheal Intubation. In 8 of 10 patients, the primary failures of GVL-assisted tracheal intubation occured early in the series of performance; the causes of primary failures of tracheal intubation were failed identification of anatomical structures in one patient with CLV 4 and in one patient with CLV 5, failed TT advancement during oropharyngeal passage in 2 patients with CLV 4, laryngeal passage in one patient with CLV 2 and in 2 patients with CLV 4, and tracheal passage in one patient with CLV 4, and  malfunction of the Schroeder directional tracheal tube stylet in one patient with CLV 2 and in one patient with CVL 4.

 

Laryngeal Views and Minor Problems and Difficulties in Patients with the Second Attempt of Tracheal Intubation Successful. The remaining 10 patients required a second attempt for successful GVL-assisted tracheal intubation. The laryngeal views obtained with the GVL during the second attempt were grade 1, 2, and 3 in 5, 3, and 2 patients, respectively. Impeded TT advancement was encountered during laryngeal passage in one patient with CLV 5 and tracheal passage in one patient with CLV 4. 

 

Severe Complaints and Injuries Associated with Airway Management. Severe complaints and injuries to oropharyngeal, laryngeal, and/or tracheal structures associated with airway management were not observed at the postanesthesia care unit and during the postanesthesia visit on the first postoperative day at the normal ward.   

 

 

Discussion