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Is Video Laryngoscope-Assisted Flexible Tracheoscope Intubation Feasible for Patients with Predicted Difficult Airway? A Prospective, Randomized Clinical Trial

Lenhardt, Rainer MD*†; Burkhart, Mary Tyler MD*; Brock, Guy N. PhD; Kanchi-Kandadai, Sunitha MD*; Sharma, Rachana MD*; Akça, Ozan MD, FCCM*†

doi: 10.1213/ANE.0000000000000220
Patient Safety: Research Report

BACKGROUND: Failed intubation may result in both increased morbidity and mortality. The combination of a video laryngoscope and a flexible tracheoscope used as a flexible video stylet may improve the success rate of securing a difficult airway. We tested the hypothesis that this combination is a feasible way to facilitate intubation in patients with a predicted difficult airway in that it will shorten intubation times and reduce the number of intubation attempts.

METHODS: We conducted a randomized, prospective trial in 140 patients with anticipated difficult airways undergoing elective or urgent surgery. After insertion of video laryngoscope, patients were randomly assigned to either having their tube placed with the use of a preformed stylet (control group) or with a flexible tracheoscope (intervention group). The primary outcome measures were time to successful intubation and number of intubation attempts.

RESULTS: The number of intubations requiring 2 or more intubation attempts was similar in the 2 groups (14% control vs 13% intervention, P = 1.0); the number of patients requiring 3 or more intubation attempts was not significantly different (8.6% control vs 1.4% intervention, P = 0.12). Distribution for time to intubation also did not differ between the control (median of 66 seconds, interquartile range 47–89) and the intervention group (median of 71 seconds, interquartile range 52–100; P = 0.35). In the control group, 4 patients, all with cervical spine pathology, had the trachea intubated successfully with the video laryngoscope plus flexible tracheoscope after 3 failed attempts with video laryngoscope and rigid stylet. For these 4 patients, time from the decision to change the intubation method to successful intubation with a flexible tracheoscope was 36 ± 14 seconds. Overall success probability for cervical spine patients was 100% (20/20) in the intervention group and 80% (16/20) in the control group, with an exact 95% confidence interval for the difference of 1.4% to 44%, P = 0.04.

CONCLUSIONS: Flexible tracheoscope-assisted video laryngoscopic intubation is a feasible alternative to video laryngoscope only intubation in patients with predicted difficult airways. A flexible tracheoscope used in combination with video laryngoscope may also further increase the success rate of intubation in select patients with a proven difficult airway, particularly when in-line stabilization is required.

From the *Department of Anesthesiology and Perioperative Medicine, University of Louisville School of Medicine, Louisville, Kentucky; Outcomes Research Consortium, Cleveland, Ohio; and School of Public Health and Information Sciences, University of Louisville, Louisville, Kentucky.

Accepted for publication February 7, 2014.

Funding: This work was supported by institutional resources.

The authors declare no conflicts of interest.

This report was previously presented, in part, at the American Society of Anesthesiologists Annual meeting in Chicago, Illinois, October 2011.

Reprints will not be available from the authors.

Address correspondence to Rainer Lenhardt, MD, Department of Anesthesiology, University of Louisville, 530 S. Jackson St., Louisville, KY 40202. Address e-mail to

© 2014 International Anesthesia Research Society