Comparison of oropharyngeal leak pressure of LMA Protector and LMA-ProSeal in different head and neck positions in anaesthetized and paralyzed patients; A prospective randomized study.

Background and Aims: Oropharyngeal leak pressure (OLP) of LMA Protector is reported to be higher compared to other second generation supraglottic devices (SGDs) indicating better seal with patient's airway and hence enhanced safety. To ascertain its benefit in patients undergoing surgeries where head and neck position other than neutral is required, we conducted a prospective randomized study to compare OLP of LMA Protector with LMA-ProSeal (PLMA) with head and neck in neutral, extension, flexion, and rotation position. Methods: 80 American Society of Anesthesiologists (ASA) I-II patients aged more than 18 years undergoing elective surgery under general anaesthesia were recruited. Patients were randomized in the LMA Protector or PLMA group. After induction of anaesthesia, OLP was measured in both the groups in different head and neck position. The insertion characteristics of both SGDs were also recorded and compared. Results: The OLP of LMA Protector and PLMA was found to be comparable in neutral head position (p = 0.08). There was no significant difference in OLP of both devices in extension, flexion, or head rotation. In both the study groups, head extension position led to significant decrease in OLP compared to supine position. With the flexion and rotation positioning of head and neck, significant increase in OLP in each group was noted. Conclusion: The OLP of LMA Protector and PLMA are comparable in different head and neck position. With both the devices, there was significant decrease in OLP with extension whereas significant increase was noted in flexion and rotation of head and neck.