Results

 

 

Participating Operators. Four staff anesthetists, 3 anesthesia residents, and one qualified anesthesia nurse volunteered and participated in this study. They performed laryngoscopy and orotracheal intubation attempts with the McGrath Portable Video Laryngosope (MVL) on from 10 to a maximum of 20 (median: 14) patients. The operators were novice users of the MVL but experienced in the use of video laryngoscopes.

 

Patient Demographics. During August and October 2007, 120 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 view of grade 1 to 4 at conventional laryngoscopy were obtained in 40, 38, 26, and 16 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 MVL-assisted tracheal intubation at the first attempt was 97 percent (116/120 patients) with laryngeal views of grade 1 in all patients.

 

Minor Problems and Difficulties in Patients with the First Attempt of Tracheal Intubation Successful. Poor visibility due to fogging of the camera system and impeded tracheal tube (TT) advancement during laryngeal and/or tracheal passage were encountered in altogether 11 and 13 percent, respectively (see Table 2). There were no problems with impeded blade insertion due to limited mouth opening and/or restricted pharyngeal space, poor visibility due to the presence of secretions, and impeded TT advancement during oropharyngeal passage.

 

Causes of Primary Failures of Laryngoscopy and Tracheal Intubation. The causes of primary failures of MVL-assisted tracheal intubation were acute loss of battery power in one patient with CLV 1 and failed TT advancement during laryngeal passage in one patient with CVL 2 and in 2 patients with CVL 3.

 

Laryngeal Views and Minor Problems and Difficulties in Patients with the Second Attempt of Tracheal Intubation Successful. The remaining 4 patients required a second attempt for successful MVL-assisted tracheal intubation. The laryngeal views obtained with the MVL during the second attempt were grade 1 in all patients. Impeded TT advancement during laryngeal passage was observed in one patient with CVL 3.

 

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