Clinical Investigation of Laryngeal Mask Airway

Jeong, Jae Hun; Yang, Hong Seuk; Cho, Hyung Sang

Abstract

Laryngeal mask airway(LMA) is a new type of airway, which may be used as an alternative to either the endotracheal tube or the face-mask with either spontaneous or positive pressure ventilation without penetration of the larynx or esophagus. LMA have many advantages of easy intubation without laryngoscope and muscle relaxants, decreasing damages of larynx and pharynx., and also useful in difficult intubation or emergency airway care. Recently its interesting has been increased. Clinical studies of LMA was done in 242 patients, about hemodynamic changes, volume and pressure changes of cuff, problems and complications during insertion and maintaining of LMA. The results were as follows: 1) The average time taken to insert the laryngeal mask airway was 9.9sec(range:5~60sec), and 43 cases were correct placement at the second attempt. And the total insertion time was 103 min(range:15~355min). 2) Total ari volume of cuff was 20.5ml(range:15~35ml) in LMA No 3, 28.1 ml(range:25~60ml) in LMA No 4. The least volume of cuff without air leakage was 15ml in LMa No 3 and 25ml in LMA No 4. During positive pressure ventilation the peak airway pressure was 20 cmH2O(15mmHg). 3) In hemodynamic changes, blood pressure was increased about 27.5 mmHg in systolic, 21.2 mmHg in diastolic, and 22.4 mmHg in mean arterial pressure after LMA insertion. 4) Cuff pressure was increased from 70.5mmHg at insertion to 98.9mmHg after 1hours with use of N2O for anesthesia and more increased than without N2O. 5) LMA was used 229 patients in supine position and 5 patients in lateral position. In 8 cases was failed to insertion of LMA. 6) Compilcations were 3 cases of gastric distention, 1 case of difficult nasogastirc tube insertion, and 1 case of severe sore throat with mucosal bleeding on pharyax. Sor throat was complained 26.9% without regard to severity.