Background and objective: The Supreme laryngeal mask airway (LMA) is a new single-use polyvinyl chloride supraglottic device that combines the functionality of the ProSeal and Fastrach airways. High oropharyngeal leak pressures are important as they indicate airway protection, feasibility of positive pressure ventilation and likelihood of successful LMA placement. The oropharyngeal leak pressure of the LMA Supreme is not well established versus the LMA ProSeal. This study was designed to compare the safety and efficacy of the LMA Supreme versus the LMA ProSeal in elective ambulatory procedures.
Method: Hospital ethics board approval was obtained. One hundred and five patients were consented and randomly allocated to LMA Supreme or ProSeal groups. Anaesthesia was induced with intravenous propofol 2-3 mg kg(-1) and fentanyl 1-2 microg kg(-1) and maintained with desflurane in an air-oxygen mixture. Anaesthesiologists with more than 5 years of experience performed all of the LMA insertions. Manometry was used to standardize intracuff pressure at 60 cmH2O. The primary outcome was the oropharyngeal leak pressure. Secondary outcomes were the time and number of attempts for insertion, ease of insertion and the anaesthesiologist's satisfaction score of the airway device. The success on first attempt insertion was measured. Patients were interviewed postoperatively for any pharyngolaryngeal adverse events.
Results: A total of 99 patients were analysed for the primary outcome. The baseline demographic data for both groups were comparable. The mean oropharyngeal leak pressure with the LMA Supreme was 21 +/- 5 cmH2O (95% confidence interval 20-22). This was significantly lower than that of the LMA ProSeal, 25 +/- 6 cmH2O (95% confidence interval 23-27; P<0.001). The success rate of the first attempt insertion was higher for the LMA Supreme than for the LMA ProSeal (98 and 88%, respectively; P=0.04). There was no difference in the median time taken for insertion with the LMA Supreme versus the LMA ProSeal: 26 s (interquartile range 23-45) versus 30 s (interquartile range 20-38), respectively (P=0.16). The ease of insertion, postoperative pharyngolaryngeal adverse events, patient satisfaction scores and anaesthesiologist's satisfaction scores were comparable in both groups. There were no complications of aspiration or nerve injuries.
Conclusion: The LMA Supreme has lower oropharyngeal leak pressures than the LMA ProSeal. The success of the first attempt insertion was higher for the LMA Supreme. The LMA Supreme is a safe, efficacious and easy-to-use disposable supraglottic airway device in elective ambulatory procedures. The higher rate of success on first attempt insertion may make it more suitable as an airway rescue device.