2022 Volume 13 Issue 2 Pages 77-86
Background: Video laryngoscopy (VL) is an attractive airway management device; however, its user's motion during tracheal intubation (TI) has not been evaluated. Therefore, this study aimed to investigate the differences in head and eye movement during TI using VL, McGRATH®, between experts and novices.
Methods: Time for TI, head movements, and gaze distribution during TI in a mannequin with McGRATH® were recorded using motion capture and eye-tracking systems. TI was divided into three phases: A) from mouth opening to laryngoscope insertion, B) from the insertion into the mouth to enable visualization of the vocal cords, and C) from holding a constant vocal cord view to the finish of intubation. Data were compared between the experts and novices according to the phases.
Results: In the experts, total TI time was significantly shorter (17.5 vs. 20.5 sec, p＜0.001), and the duration of Phases A and C were significantly shorter (A: 5.0 vs. 6.4 sec, p＜0.001; C: 8.1 vs. 9.2 sec, p=0.031). The intra-group comparison showed the head height in both groups significantly decreased until the Phase B and significantly increased in Phase C. Inter-group comparison showed the head heights in the Phases B and C were significantly lower in the novices (B: 152.2 vs. 142.6 cm, p＜0.001; C: 157.4 vs. 145.9 cm, p＜0.001). The height differences between the occipital and temporal regions indicated both groups turned their faces down from Phase A to B and upward in Phase C. The extent of head tilting in each phase was significantly larger in the novices. Gaze analysis indicated that while the experts continued looking down and further throughout TI, the novices looked up during Phases B and C.
Conclusion: Posture and gaze distribution during TI using McGRATH® were different between the novices and experts. These results should be considered in instructing and learning TI.
