Advancing Airway Management: Channeled Laryngoscopes

In a previous article we explored the different tools utilized for endotracheal intubation. This article focuses on channeled laryngoscopes, both optical and video, that assist with achieving safe and rapid intubation of the trachea. The two systems discussed are the Airtraq optical device and King Systems’ King Vision video laryngoscope.

The Airtraq received FDA approval in November 2006 and was initially marketed as an MRI-compatible intubating device. It utilizes a set of reflective prisms with a distal light source to enable the airway manager to view around the tongue without requiring its displacement. A channel on the right side of the device holds an endotracheal tube (ETT) at the ready. Once an appropriate view of the glottis is obtained, the ETT is gently slid forward through the channel into the trachea. Once in position, it is gently disconnected laterally from the Airtraq, and the device is removed from the patient’s mouth.

A PubMed literature review for the Airtraq reveals numerous articles describing its utilization in normal and predicted difficult airway cases. In 2006 a team led by Chrisen Maharaj, MD, BSc, described a comparison of the Airtraq versus the Macintosh laryngoscope (direct laryngoscopy) in routine airway management of 60 patients. All patients were intubated successfully, and only one patient in the Macintosh control group required additional attempts. Modest improvements in ease of use and less hemodynamic variation during the intubation occurred with the Airtraq. This article supported the Airtraq in routine airway management with similar success to DL.

Several studies also evaluated the Airtraq in predicted or known difficult airways. In 2008 Dr. Serge Ndoko, et al, presented a comparison between the Macintosh and the Airtraq in 106 morbidly obese patients. Patients were randomly assigned to either a Macintosh #3 or the Airtraq. In addition, if intubation could not be performed with the randomized device within 120 seconds, then the alternative device was attempted. Results showed that intubation via the Macintosh #3 blade occurred on the first attempt 49 of 53 times (92%), required some alternative technique 17/53 times (32%) and needed external manipulation of the larynx 31/53 times (58%). Alternatively the Airtraq was successful on the first attempt 53 out of 53 times, required some alternative technique zero times, and needed external manipulation of the larynx 4/53 times (8%). This particular study showed a clear benefit to using the Airtraq in the predicted difficult airway of the morbidly obese patient.

A similar study was published in 2012 by Dr. Dante Ranieri, Jr., et al, in which intubating conditions and success of intubation were evaluated in 128 obese patients undergoing bariatric surgery. This study found that, using the Cormack-Lehane (CL) scoring for glottic visualization, the Macintosh produced a grade 3 or 4 view (no direct view of the glottic opening) in 7/64 patients (11%). One patient in this group could not be intubated successfully with the Macintosh and was subsequently intubated with the Airtraq. The Airtraq was evaluated utilizing the same CL scoring system and produced a grade 3 or 4 view in 0/64 patients. Additionally it was noted that the Airtraq scored significantly better in CL grade 2 views (in which only part of the glottic structure is visualized) compared to the Macintosh (Airtraq 3 vs. Macintosh 20). This article further supports use of the Airtraq in the morbidly obese patient population. Exercise caution, though, as factors beyond morbid obesity affect intubation difficulty.

The King Vision channeled video laryngoscope is similar to the Airtraq but uses video technology to see around the tongue and display the glottic structures on the attached video screen. A review in PubMed did not reveal any studies published on the King Vision thus far, though it is being widely adopted.

Challenges