Laryngeal mask in prone position: pure exhibitionism or a valid technique

The laryngeal mask airway (LMA) is used worldwide during general anesthesia with controlled or spontaneous breathing. Normally its use is limited to patients undergoing surgery in the supine but not the prone position.

A prospective study of 50 consecutive ASA 1 and 2 patients who underwent ambulatory surgery in the prone position. In the first 25 patients anesthesia was induced in the supine position on a transport trolley after which the patients were turned face down following tracheal intubation. The next 25 patients were asked to lie comfortably in the prone position before receiving anesthesia. Induction and insertion of LMA were performed when they were already prone.

There were neither complications nor airway loss when LMA was used in the prone position. The induction-incision time was 23.6+/-3.6 min (range 21-37) in Group 1 and 7+/-2.44 min (range 5-15) in Group 2 (P<0.0001) and the manpower required for positioning (the number of medical and paramedical personnel required to place the patient prone) was considerable reduced in Group 2 (LMA) compared to Group 1 (1.0 versus 3.12+/-0.6 (range 2-4; P<0.0001). Group 2 showed also, significantly more favorable hemodynamic parameters.

To start anesthesia with patients already prone shortens the induction-incision time, reduces the manpower involved in the positioning process and causes fewer hemodynamic changes than the standard technique of induction and intubation in the supine position followed by turning the patient facedown.