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Airway Scope®: initial clinical experience with novice personnel

Jichi Medical University, Tochigi, Japan, E-mail: yhira{at}jichi.ac.jp

To the Editor:

The Airway Scope® (AWS; Pentax Corporation, Tokyo, Japan) (Figure 1A–B) is a novel system for tracheal intubation that provides a view of the glottis without requiring alignment of oral, pharyngeal, and laryngeal axes.¹ The AWS has a charge-coupled device image sensor and light-emitting diode attached to its tip. The image is transmitted to a 2.4-inch built-in liquid crystal device (LCD) colour monitor at the top of the grip. The curve-shaped blade has a side channel that acts as the housing for placement and insertion of the endotracheal tube. Once the target signal shown on the monitor has been aligned with the glottic opening (Figure 1C), the endotracheal tube is advanced through the vocal cords (Figure 1D), held in place, and the device is removed. The views of the glottis and endotracheal tube are maintained throughout the intubation process, and the endotracheal tube does not obstruct the view of the vocal cords (Figure 1C). The target signal on the monitor may be of particular benefit to novice laryngoscopists. This new intubating device recently received regulatory approval in Japan.

View larger version (98K): [in this window] [in a new window]   FIGURE 1 Photograph of the Air way Scope® with a tracheal tube in place in the side channel. A) Front view. B) Lateral view. The device is held in the left hand and passed into the mouth over the tongue, and the tip is placed under the epiglottis. C) View of the glottis of a 33-yr-old female, which was obtained during tracheal intubation using the Air way Scope®. The target signal shown on the monitor is aligned with the glottic opening. D) A cuffed tube is passed from its position in the channel through the vocal cords. E) The position of the tracheal tube is confirmed at the level of the cords.

Patients were comparable with respect to age [AWS group: 48 ± 19 (mean ± SD) vs DL group: 54 ± 17 yr], weight (55 ± 11 vs 56 ± 11 kg) and height (157 ± 8 vs 161 ± 9 cm). After obtaining glottic visualization, the airway operators secured and verified the endotracheal tube position within the trachea. A staff anesthesiologist supervised each laryngoscopy and an independent observer recorded the duration of tracheal intubation attempts. If the first intubation attempt failed, the patient’s lungs were ventilated again with 100% oxygen via bag-mask ventilation, and the duration of the second attempt was added to the time of the first attempt to secure the airway. Endotracheal intubation was achieved in 33 ± 12 (range: 19–68) sec with the AWS, while requiring 59 ± 29 (27–148) sec with DL (P < 0.001, Student’s t test). Endotracheal intubation was successful on the first attempt in all patients using the AWS, while first attempt intubation was unsuccessful in four of 20 patients in the DL group (P < 0.05, Chi-square test). In the remaining four patients, the second attempt resulted in successful endotracheal intubation. No patient experienced esophageal intubation in the AWS group, while one trainee performed an esophageal intubation at the first attempt of the DL group. The incorrect tube placement was identified immediately and endotracheal intubation was successfully established. No patient experienced oxygen desaturation during laryngoscopy.

This preliminary study suggests that, in comparison with DL, the AWS provides personnel training in airway management superior intubation conditions, resulting in less time to secure the airway, and a higher success rate of first-attempt correct endotracheal tube placement. There are several potential advantages of the AWS for novice laryngoscopists. First, an unobstructed view of the glottis is easily secured without alignment of oral, pharyngeal, and laryngeal axes, requiring minimal airway manipulation during the management of routine and difficult airways. Second, everyone can view the intubation. The built-in LCD monitor screen has a wide viewing angle and is readily visible from behind and from the side of the scope, allowing the supervisor and other individuals, apart from the laryngoscopist, to verify the tracheal intubation status. The target signal shown on the monitor is also helpful for teaching. Third, the AWS appears to require less operator skill. Our observations are not directly applicable to experienced operators, because it is rare to require more than 30 sec to secure the airway with experienced anesthesiologists even with the Macintosh laryngoscope.² However, none of the participants in this study had prior experience in using the AWS in patients. A short demonstration of the device and a brief practice with a manikin were the only requirements to perfect tracheal intubations. The AWS may be advantageous for individuals who are required to perform tracheal intubation only infrequently, such as emergency room staff. Fourth, the AWS does not require manipulations of a stylet to facilitate intubation. Stylet-related complications are avoidable.³ Finally, the blade of the AWS is for a single-use device. This removes the potential risk of contamination and infection. Since our observations were drawn from a small number of examinations, further clinical studies are warranted to confirm these initial positive findings.

The author declares no conflict of interest with the manufacturers and distributors of the devices named in this communication.

Footnotes

Accepted for publication November 9, 2006.

References

1 Koyama J, Aoyama T, Kusano Y, et al. Description and first clinical application of AirWay Scope for tracheal intubation. J Neurosurg Anesthesiol 2006; 18: 247– 50.[Medline]

2 Hung OR, Pytka S, Morris I, et al. Clinical trial of a new lightwand device (Trachlight) to intubate the trachea. Anesthesiology 1995; 83: 509–14.[Medline]

3 Fan CM, Ko PC, Tsai KC, et al. Tracheal rupture complicating emergent endotracheal intubation. Am J Emerg Med 2004; 22: 289–93.[Medline]

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				N. Sasano, H. Yamauchi, and Y. Fujita Failure of the Airway Scope to reach the larynx Can J Anesth, September 1, 2007; 54(9): 774 - 775. [Full Text] [PDF]

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