Usefulness of video-laryngoscopy with the Airway Scope for intubation performance and learning: an experimental manikin controlled study

Abstract

Background: Different video-laryngoscopes (VDLs) for endotracheal intubation (ETI) have recently been developed. We compared the performance of the VDL Airway Scope (AWS) with the direct laryngoscopy by Macintosh (DLM) for ETI success, time and learning.

Methods: We performed an experimental manikin controlled study. Twenty experienced (experts) and 40 inexperienced operators (novices) for DLM-ETI were enrolled. None of them had experience with the use of AWS-VDL. Novices were assigned to start learning with DLM or AWS, and two sub-groups of 20 novices were formed. Experts group constituted the control group. Each participant performed 10 ETI attempts with each device on the same standard manikin. The primary endpoint was the ETI success probability. Secondary endpoints were ETI time, technical validity and qualitative evaluation for each technique. We also assessed the learning order and the successive attempts effects for these parameters.

Results: Overall, 1200 ETI attempts were performed. ETI success probability was higher with the AWS than with the DLM for all operators (98 vs. 81 %; p < 0.0001) and for experts compared to novices using devices in the same order (97 vs. 83 %; p = 0.0002). Overall ETI time was shorter with the AWS than with the DLM (13 vs. 20 s; p < 0.0001) and for experts compared to novices using devices in the same order (11 vs. 21 s; p < 0.0001). Among novices, those starting learning with AWS had higher ETI success probability (89 vs. 83 %; p = 0.03) and shorter ETI time (18 vs. 21 s; p = 0.02). Technical validity was found better with the AWS than DLM for all operators. Novices expressed global satisfaction and device preference for the AWS, whereas experts were indifferent.

Conclusions: AWS-VDL permits faster, easier and more reliable ETI compared to the DLM whatever the previous airway ETI experience and could be a useful device for DLM-ETI learning.

Keywords: Airway Scope; Intubation; Learning; Macintosh; Simulation; Video-laryngoscopy.

Fig. 1

Airway Scope® (AWS; Pentax Corp., Tokyo, Japan) device. a The AWS is a portable and battery-operated video-laryngoscope (VDL) with an integrated and wide-viewing-angle (180°) liquid crystal display (LCD) monitor (6.1 cm) providing an indirect laryngoscopy of the airway via a charged coupled device attached to the blade tip of the AWS. The single-use intlock blade has a specific tube guide to accept the ETT (internal diameter between 6.5 and 8 mm). AWS-ETI requires to load and lift the epiglottis with the AWS blade tip. b Once the target signal on the LCD monitor is aligned with the glottis opening, the ETT is passed through the vocal cords (a). Then, the AWS is removed laterally, leaving the ETT in place

Fig. 2

AWS-ETI learning curves according to ETI success rate by attempt and operator sub-group. ETI endotracheal intubation, DLM direct laryngoscopy with Macintosh, AWS video-laryngoscopy with Airway Scope^®. Success proportion is the observed number of successes among 100 attempts for the 3 study sub-groups (experts, novices 1 and novices 2) according to the attempt number in a series of ten attempts and the device used (DLM or AWS). p values refer to homogeneity tests for experience (experts compared to novices 1), device learning order (novices 1 compared to novices 2), and to the global test for any difference between attempts, which evaluate the learning effect of successive attempts

Fig. 3

AWS-ETI learning curves according to ETI time by attempt and operator sub-group. ETI endotracheal intubation, DLM direct laryngoscopy with Macintosh, AWS video-laryngoscopy with Airway Scope^®. Mean time to vocal cords corresponds to ETI time (time taken from the blade (DLM or AWS) first passing the incisors until ETT passage through the vocal cords) in seconds according to the attempt number in a series of ten attempts and the device used (DLM or AWS). p values refer to homogeneity tests for experience (experts compared to novices 1), device learning order (novices 1 compared to novices 2), and to the global test for any difference between attempts, which evaluate the learning effect of successive attempts

Fig. 4

DLM-ETI learning curves according to ETI success rate by attempt and operator sub-group. ETI endotracheal intubation, DLM direct laryngoscopy with Macintosh, AWS video-laryngoscopy with Airway Scope^®. Success proportion is the observed number of successes among 100 attempts for the 3 study sub-groups (experts, novices 1 and novices 2) according to the attempt number in a series of ten attempts and the device used (DLM or AWS). p values refer to homogeneity tests for experience (experts compared to novices 1), device learning order (novices 1 compared to novices 2), and to the global test for any difference between attempts, which evaluate the learning effect of successive attempts

Fig. 5

DLM-ETI learning curves according to ETI time by attempt and operator sub-group. ETI endotracheal intubation; DLM direct laryngoscopy with Macintosh, AWS video-laryngoscopy with Airway Scope®. Mean time to vocal cords corresponds to ETI time (time taken from the blade (DLM or AWS) first passing the incisors until ETT passage through the vocal cords) in seconds according to the attempt number in a series of ten attempts and the device used (DLM or AWS). p values refer to homogeneity tests for experience (experts compared to novices 1), device learning order (novices 1 compared to novices 2), and to the global test for any difference between attempts, which evaluate the learning effect of successive attempts