Influence of head rotation on oropharyngeal leak pressure of LMA-ProtectorTM and i-gel® in paralysed, anaesthetised patients: A randomised comparative study.

Background and aims: The most important parameter to provide adequate and safe ventilation for the supralaryngeal airway device (SAD) is its sealing effectivity measured as oropharyngeal leak pressure (OPLP). Various studies have been conducted to elucidate the effects of head extension and flexion on the OPLP of SAD devices; however, the literature regarding the influence of head rotation on OPLP is limited. The primary objective of the study was to evaluate and compare the influence of head rotation on the OPLP of LMA-Protector^TM with i-gel® in paralysed, anaesthetised patients.

Methods: Sixty patients of either gender scheduled for elective laparoscopic cholecystectomy were randomly allocated into two Group, namely group L and Group I. Ten min following the induction of pneumoperitoneum, OPLP was recorded at 0°, 30°, and 60° left head rotation. The insertion characteristics of both SADs were also recorded and compared. Normally distributed continuous variables were compared using the unpaired t-test. Categorical variables were analysed using either the Chi-square test or Fisher's exact test. A paired t-test was used for the group analysis.

Results: OPLP of Group L and Group I was comparable in neutral and 30° head rotation. OPLP was significantly higher in the LMA-Protector compared to the i-gel® at 60° head rotation (P = 0.041). In both the study groups, there was a significant decrease in OPLP when the head was turned from neutral to 60°.

Conclusion: OPLP of Group L and Group I was comparable in neutral and 30° head rotation. LMA-Protector^TM offered better OPLP as compared to i-gel® at 60° head rotation.