Background:

Glottic view differed when assistants provide external laryngeal manipulation (ELM) from right or left side. Objectives were to compare glottic view during direct laryngoscopy with ELM applied by assistant stationed on right side of scopist versus left. Primary outcome was best percentage of glottic opening (POGO) score. Secondary outcome was proportion of patients requiring switch back to initial intervention for best glottic view and intubation.

Methods:

With Institutional Review Board and Ethics Committee approval and written informed consent, this randomised cross over trial enrolled participants of American Society of Anesthesiologists (ASA) grade I–II aged 20–70 years for elective surgery under General Anaesthesia (GA). Study interventions were application of ELM during modified bimanual laryngoscopy by trained assistant on right (ELM-R) and left (ELM-L) sides in each participant as per random sequence.

Results:

Of the 150 participants, 68 were analysed for study interventions using Wilcoxon matched pairs test. Thirty three participants received interventions first from ELM-R and subsequently from ELM-L, while 35 had interventions vice versa. Median POGO score with ELM-R was 40 (IQR: 32.5, 50) and with ELM-L 30 (IQR: 20, 40). There was 10% difference in POGO score between interventions found to be significant (P < .05). Fifty six out of 68 (82.35%) participants had better POGO score when intervention was from right side. Proportion requiring switch back to initially applied intervention was 66.7% (22 out of 33) with ELM-R and 2.9% (one out of 35) with ELM-L.

Conclusion:

For best glottic view, ELM applied by an assistant by right hand standing on right side of scopist is more effective.

Keywords: External laryngeal manipulation, modified bimanual laryngoscopy, difficult airway, POGO score, personal protective equipment, Macintosh laryngoscope, glottic view