Clinical Application of Laryngeal Mask Airway in Cesarean Section / 대한마취과학회지

ABSTRACT

BACKGROUND: Laryngeal mask airway (LMA) is a useful instrument for routine anesthesia. It permits spontaneous or positive pressure ventilation but its use in obstetric anesthesia has not been described. In this study, we evaluated the effectiveness and the side effects of the LMA during elective cesarean sections. METHODS: Institutional approval and patients' permission were obtained. One thousand sixty-seven patients scheduled for elective an cesarean section, that have been NPO for more than 6 (6-48) hours were evaluated. They were premedicated with an H2 receptor blocker (ranitidine 50 mg i.m.) 1 hour before the operation. They were anesthetized with penthotal sodium (3-4 mg/kg), vecuronium (1 mg/10 kg i.m.) and then a 3 or 4 LMA was inserted after the mask ventilation with 100% oxygen for 1 min. The cuff was inflated with air 15.3 +/- 2.6 ml. On auscultation, air entry was good in both lungs. Anesthesia was maintained by 50% oxygen in N2O with 0.7 - 1.0% enflurane. Analgesics (tramadol 30 mg i.v.) was given incrementally after delivery of the baby. Manual assisted ventilation was used throughout the procedure. The number of insertion attempts, cuff volume and the incidences of complications were evaluated. RESULTS: In 1051 patients, the LMA was inserted on the first attempt. In 16 patients more than 2 attempts were needed and change to endotracheal intubation were needed in 7 cases. The mean cuff volume was 15 +/- 2.6 ml at insertion and increased to 18.5 +/- 3.2 ml after removal. The average airway pressure was 20 cmH2O during positive pressure ventilation, above that pressure air leakage was detected in 16 cases. Complications noted were mild sore throat in 5 cases, and blood tinged after removal of LMA in 3 cases but gastric distention was not detected. No incidence of aspiration was noted. CONCLUSIONS: In this study, the LMA proved to be a useful tool for the management of patients presenting for elective an cesarian section. There is the remote possibility of aspiration which did not happen in our study.