Use of the laryngeal mask in oral and dental surgery: Objective

Objective: The suitability of the laryngeal mask (LM) for anesthesia in oral and dental surgery of the face was investigated considering in particular the risks of aspiration and dislocation. We also examined acceptability to the surgeon. Methods: In a prospective study, a total of 105 patients (ASA I - III) was included. Provided with flexible LMs, patients were operated upon the third molars (n = 64), around the dentoalveolar area (n = 32) and extraorally (n = 9). The number of placing efforts, preoperative leakage pressure, cuff pressure and complications occurring during the course of anesthesia were recorded. After the operation, the procedure was compared to endotracheal anesthesia (ETA) by the surgeon. A retrospective study comparing LM with ETA was performed on 1395 patients examining the time in between two operations, the period from the end of operation to the beginning of control of vital signs in the recovery room, and the time spent in the recovery room. The number of patients necessitating a change of anesthesia from LM to ETA was recorded. Results: In 33 patients (31%), introperative leakage due to dislocation was observed. 33 patients (31 %) had obstruction of the airway. Only when leakage occurred together with obstruction of the airway, SaO(2) fell below 94% (n = 11). This was seen in particular during exposure of the wisdom teeth. In 2 of theses cases, SaO(2) decreased below 70 or 34% respectively. Aspiration of blood, gastric juice or dental and bone fragments was not observed. In one case, ETA became necessary. 19 patients complained of local pains (cough, sore throat, dvsphagia). Operative conditions for the surgeon were comparable to oral ETA in 79% of the cases. The time in between two operations decreased about 35%, the period from the end of operation until first control of vital signs in the recovery room was reduced of about 41%, and the time spent in the recovery room decreased by 37% when compared to ETA. Out of 1111 anesthesias performed with the LM, 17 had to be exchanged for ETA. Conclusion: Leakage due to dislocation of the LM and airway obstruction only leads to a relevant risk of SaO(2) to drop if both components occur simultaneously. With increasing experience and close cooperation between surgeon and anesthesiologist, they may be almost completely avoided so that even exposure of the lower. wisdom teeth will seldom iiecessiiate the LM to be replaced by ETA. In relation to the tongue depressor, cuff pressure should be kept at low levels in order to obtain better flexibility of the LM. The LM provides sufficient protection against aspiration of intraoperative fluid in the pharynx. Acceptability to the surgeon is high because of good operative conditions and shortened periods in between two operations when compared to ETA. Improved protective reflex responses after the operation and its advantages when used in patients with tightness of the jaw make the LM a suitable instrument for anesthesia in oral and dental surgery.