[Clinical experience of laryngeal mask airway in lateral position during anesthesia]

Abstract

Background: The laryngeal mask airway (LMA), inserted blindly into hypopharynx in patients in supine position, has been reported to be successful in the management of the airway and can provide adequate ventilation during anesthesia. In our study, we used LMA to maintain airway during anesthesia in patients in lateral position.

Methods: Eighty surgical patients, ASA class I-II, undergoing hemorrhoidectomy, were placed in lateral surgical position before induction. The induction agents were propofol (2 mg/kg), fentanyl (2 micrograms/kg) and atracurium (0.5 mg/kg, i.v.). When mouth opening can be done passively, a LMA was inserted into the mouth and advanced blindly over the tongue into the pharynx until resistance was felt. The rim was immediately inflated with air and several manual positive pressure ventilatory breaths were given to the patient to check for leaks in the LMA system. Chest movement was observed and bilateral lung ausculation was performed to confirm the adequacy of ventilation. Once the LMA was in place, enflurane with oxygen was administered until operation was completed. During the anesthetic course, EKG, blood pressure, pulse oximeter, end-tidal CO2 and inspiratory pressure were monitored.

Results: Blind insertion of LMA in lateral position was successful in the first attempt in 70% (56/80) of patients. Twenty (18/80) patients required a second or third trial making the total successful rate of LMA insertion as high as 90% (74/80). In four patients, airway control through LMA was unsatisfactory due to large air leakage during manual ventilation. In two patients the LMA could not be inserted in proper position for maintaining airway. In six cases, the LMA was immediately removed and was substituted by face-mask for anesthesia. Two patients complained of postoperative sore throat. No other specific complications such as cough, laryngospasm and aspiration was noted.

Conclusion: We demonstrated that LMA can be easily inserted and can provide effective patency of airway during anesthesia even in lateral position. It can be used as a substitute for face-mask in anesthesia in this position to prevent complications such as pressure injury that a face-mask may cause.