A comparison between the PLA Cobra and the Laryngeal Mask Airway Unique during spontaneous ventilation: a randomized prospective study.

The Laryngeal Mask (LMA) Unique and the Cobra Perilaryngeal Airway (PLA) are single-use supraglottic devices. There are no published studies comparing these devices during spontaneous ventilation. We compared the LMA Unique and the Cobra PLA with respect to 1) ventilatory variables during spontaneous ventilation, 2) time to achieve an effective airway, 3) airway intervention requirements, 4) cuff seal pressures, 5) fiberoptic score, and 6) perioperative adverse events. Eighty adult ASA physical status I-II patients undergoing general anesthesia for minor routine surgery were randomly allocated to LMA Unique or PLA Cobra for airway management. No statistically significant differences were found between the devices with respect to inspiratory tidal volume, expiratory tidal volume, end-tidal CO2 concentration, respiratory rate, number and type of airway interventions required with placement, the fiberoptic score, and the incidence of perioperative adverse events. The oropharyngeal leak (seal) pressure was higher for the CobraPLA (27 +/- 7 versus 21 +/- 4 cm H2O; P < 0.001). The oxygen saturation was higher (98.1% +/- 1% versus 97.3% +/- 2%; P = 0.02) in the LMA group. Time of insertion was shorter for LMA (23.7 +/- 2 s versus 26.6 +/- 7 s; P = 0.02) and insertion difficulty was less for LMA (P = 0.03). As these differences were not judged to be clinically important, both devices appear to be effective in establishing an adequate airway in patients who are spontaneously breathing under general anesthesia.