The use of modified VBM laryngeal tube compared to Laryngeal Mask Airway during spontaneous ventilation

We have compared the use of the laryngeal mask airway with the new modified laryngeal tube in a prospective randomized controlled study. Sixty ASA 1 or 2 patients, aged 18 to 65 years, scheduled for elective surgery and breathing spontaneously under general anaesthesia, were studied. After preoxygenation, anaesthesia was induced with fentanyl and propofol. The patients were randomized to receive either a laryngeal mask airway or a laryngeal tube. Anaesthesia was maintained with nitrous oxide, oxygen and isoflurane. We recorded the speed and the ease of insertion, the number of attempts needed to successfully secure the airway and intraoperative complications, such as partial airway obstruction needing airway manipulation. The airway devices were removed with the patients fully awake at the end of surgery. Systolic arterial blood pressure, heart rate and end-tidal CO2 were recorded at various time intervals. Postoperative complications were recorded. We found that the incidence of partial airway obstruction needing intraoperative airway manipulation was higher with the laryngeal tube than with the laryngeal mask airway. We conclude that during spontaneous ventilation the modified laryngeal tube is not as reliable in providing a satisfactory airway and we consider it is not a suitable alternative to the laryngeal mask airway.