The LMA Supreme TM – a pilot study

The LMA Supreme™ (Fig. 1; Laryngeal Mask Company, Singapore), is a new extraglottic airway device which brings together features of both the LMA ProSeal™ (high seal cuff, gastric access and bite block – to facilitate ventilation, airway protection and airway obstruction, respectively) (Laryngeal Mask Company), the LMA Fastrach™ (fixed curve tube and guiding handle – to facilitate insertion and fixation) (Laryngeal Mask Company) and the LMA Unique™ (single use – prevention of disease transmission) (Laryngeal Mask Company) [1]. The new features are that the airway tube incorporates a drain tube within its lumen to shorten and straighten its path, it is oval-shaped to match the shape of the mouth and to reduce rotation in the pharynx, the inner cuff has been strengthened to prevent airway obstruction from infolding and epiglottic fins have been added to prevent airway obstruction from epiglottic downfolding. LMA-Supreme™ (Laryngeal Mask Company). With Ethical Committee approval and informed consent, one of us (AZ) conducted a pilot study to determine ease of insertion (number of insertion attempts and time taken from picking up the device to the first breath), the oropharyngeal leak pressure, the fiberoptically determined anatomic position, the intracuff pressure changes and the frequency of airway trauma and morbidity. Twenty-two patients (ASA I/II, aged 18–60) were studied. Induction of anaesthesia was with fentanyl 0.5–1 μg.kg−1 and propofol 2–3 mg.kg−1. The lungs were manually inflated via a facemask using 2–3% sevoflurane in oxygen. Additional boluses of propofol were given as required until the jaw thrust test was negative. The LMA Supreme was inserted using a single-handed rotational technique like the LMA Fastrach and the cuff inflated to 60 cmH2O. A size 4 mask was used in all patients as the size 5 was unavailable for male patients. A gastric tube was inserted through the drain tube and its position confirmed by epigastric auscultation. Maintenance of anaesthesia was with 1.5–2% sevoflurane in nitrous oxide and oxygen using a circle system with fresh gas flow of 3 l.min−1. Patients were initially ventilated and then allowed to breath spontaneously. The results are presented in Table 3. Insertion was easy at the first attempt in all patients and an effective airway time of 28 s. Oropharyngeal leak pressure averaged 37 cmH2O and increased during anaesthesia. This was probably related to an increase in intracuff pressure. The vocal cords were visible within the view of an endoscope from the distal end of the airway tube in all patients. Gastric tube insertion was successful at the first attempt in all patients. There was no blood on the device at removal and no lip, tongue or mouth trauma. No patient had a sore throat, dysphagia or dysphonia 2 h postoperatively. We conclude that the LMA Supreme appears to bring together in a single device many of the best features of the ProSeal, Fastrach and Unique laryngeal mask airway devices. Comparative studies with these and other devices are currently underway to better determine the safety and efficacy of the LMA Supreme and to help define its role in anaesthesia and emergency medicine.