A study of effect of lateral position on oropharyngeal seal pressure of i-gel(®) and ProSeal(™) LMA in children

BACKGROUND AND AIMS: Supraglottic airways (SGAs) should have good oropharyngeal seal pressures (OSP) for adequate ventilation and prevention of aspiration. Our aim was to study the effect of lateral position on OSP and thereby on ventilatory parameters for i-gel(®) and ProSeal™ laryngeal mask airway (PLMA) in children. METHODS: In this prospective observational study, 86 children of ASA I-II, aged 1 month to 12 years, scheduled for elective surgery under general anaesthesia using i-gel(®) or PLMA and requiring lateral position either for surgery or regional blocks were included. In both supine and lateral position OSP (constant flow method), expired tidal volume, fractional volume loss (%), and end-tidal carbon dioxide (ETCO(2)) were noted. Intragroup and intergroup difference in OSP from supine to lateral position was analyzed using paired and unpaired t-test respectively. RESULTS: In lateral position, there was a significant decrease in the OSP (cm H(2)O) in both i-gel(®) (supine: 21.94 ± 5.82, lateral: 15.54 ± 5.37) and PLMA (supine: 17.53 ± 5.05, lateral: 12.76 ± 3.37) groups (P = 0.000). Percentage reduction in OSP from supine to lateral with i-gel(®) (28.14 ± 18.86) and PLMA (24.06 ± 19.75) were comparable (P = 0.339). With both i-gel(®) and PLMA significant increase in fractional volume loss and ETCO(2) were noted in lateral position. I-gel(®) group had higher OSP compared to PLMA in supine (P = 0.001) and lateral position (P = 0.009). CONCLUSION: In lateral position there was significant reduction in OSP compared to supine position with both i-gel(®) and PLMA.