The effect of nitrous oxide on intracuff pressure of the size 2 ProSeal Laryngeal Mask Airway.

Study Objective: To investigate intracuff pressure changes in the ProSeal Laryngeal Mask Airway (PLMA) during 50% nitrous oxide (N₂O) anesthesia.

Design: Prospective, randomized study.

Setting: Operating room of a university-affiliated hospital.

Patients: 40 ASA 1 and 2 children, aged 2 to 6 years, weighing 10-20 kg, undergoing elective inguinal herniorrhaphy with general anesthesia.

Interventions And Measurements: Patients were assigned to two groups (n = 20). Patients in Group A were anesthetized with 50% N(2)O in oxygen and sevoflurane, while patients in Group B were anesthetized with 50% air in oxygen and sevoflurane. PLMA cuffs were inflated with air. PLMA intracuff pressures starting from a baseline pressure of 30 mmHg were recorded using a pressure transducer for 30 minutes. The occurrence of postoperative throat discomfort was recorded.

Main Results: In Group A, who inhaled 50% N₂O for 30 minutes, intracuff pressures reached 86.7 ± 10.4 mmHg, while in Group B, who inhaled 50% air for 30 minutes, intracuff pressures were 29.7 ± 1.0 mmHg. The postoperative throat complication rate in Group A was 45%, which was significantly higher than in Group B (5%).

Conclusion: PLMA intracuff pressure increased significantly during 50% N₂O anesthesia. The children's postoperative throat complication rate also was increased.