Rotational vs. standard smooth laryngeal mask airway insertion in adults

To compare the ease of insertion between rotational laryngeal mask airway (LMA) insertion and Brain's LMA insertion technique in terms of number of LMA insertion attempts, time duration of LMA insertion and complications: trauma, laryngospasm, and hypoxaemia.

Randomized control study.

The Aga Khan University Hospital, Karachi, from September 2006 to May 2007.

One hundred ASA I and II adults undergoing short elective surgical procedures requiring general anaesthesia with spontaneous breathing were enrolled. Following pre-oxygenation, anaesthesia was induced with propofol 2 mg/kg and fentanyl 2 μg/kg. Patients were randomly assigned into one of the study groups: rotational-(R) and standard-(S). LMA insertion was performed when patients became apnoeic and adequate LMA insertion depth achieved. Successful placement was confirmed by chest expansion, reservoir bag movement and appearance of capnographic tracing in both spontaneously breathing patients and in apnoeic patients with assisted ventilation.

Significant differences were not seen in patient's demographics, Mallampati score, ASA status and pre-operative vital signs. Statistically insignificant difference was found for the time duration and number of LMA insertion attempts. The incidence of trauma was significantly noted in standard insertion technique (28%) compared to (6%) in rotational insertion technique (p = 0.003). The hypoxaemia and laryngospasm was not reported among the groups.

The rotational technique was practically easy while negotiating the back of mouth and it requires little efforts with lowest complication rate. This technique can be considered in adults when encountering difficulty and repetitive failures with standard LMA insertion technique.