Related Experiment Video
Updated: Mar 24, 2026
Minimally Invasive Murine Laryngoscopy for Close-Up Imaging of Laryngeal Motion During Breathing and Swallowing
Published on: December 1, 2023
Effect of head position on laryngeal visualisation with the McGrath MAC videolaryngoscope in paediatric patients: A
Eun-Hee Kim1, Ji-Hyun Lee, In-Kyung Song
1From the Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, South Korea.
Background:
The McGrath MAC video laryngoscope can improve visualisation of the glottis compared with the Macintosh direct laryngoscope. However, good visualisation of the glottis does not guarantee rapid or successful intubation because of difficulty in handling the McGrath device.
Objective:
We evaluated the effect of head elevation, aligning the positions of the external auditory meatus and sternal notch in the horizontal plane, on visualisation of the glottis and handling of the McGrath laryngoscope in paediatric patients.
Design:
A randomised controlled trial.
Setting:
The operating rooms of our tertiary care hospital.
Patients:
Forty-six children, American Society of Anaesthesiologists' physical status 1 or 2, aged 3 to 7 years.
Intervention:
Videolaryngoscopy using the McGrath device was performed with the head either flat or elevated.
Main Outcome Measures:
The percentage of glottis opening score, the use of optimisation manoeuvre and time to successful tracheal intubation were recorded.
Results:
The median (IQR) percentage of glottis opening score was higher after head elevation than when the head was flat in all patients [100 (100 to 100)% vs. 100 (90 to 100)%, P = 0.0001). The need for use of optimisation procedures (50 vs. 9%, P = 0.004) and mean (SD) time to intubation (17 ± 4 s vs. 15 ± 3 s, P = 0.008) were lower in the head-elevated group.
Conclusion:
Visualisation of the glottis and handling of the McGrath MAC video laryngoscope were significantly better when the external auditory meatus and sternal notch were aligned in the horizontal plane.
Trial Registration:
http://cris.nih.go.kridentifier:KCT0001443.
