Backward, upward, rightward pressure (BURP) effect improves the glottic view in retrograde light-guided laryngoscopy for tracheal intubation.

text, there is no statement to discuss the possible reasons why RLGL got better glottic view than direct laryngoscopy. As we know, backward, upward, rightward pressure (BURP) maneuver is a useful skill to facilitate glottis visualization for tracheal intubation.3 In Yang’s study, there is no description of applying BURP during tracheal intubation in both study groups. If no BURP was applied in direct laryngoscopy group, the improved Cormack and Lehane grades in RLGL group could be due to the “BURP effect” induced by the light-emitting diode flashlight. The site where the flashlight placed in this study (the caudal edge of the thyroid cartilage) is just the same site for BURP maneuver. According to the statement in method section, the operator could adjust and optimize the location of the flashlight while performing the RLGL. Thus, the “BURP effect” should be considered to be the cause of improving glottis view in RLGL group.