Standard Laryngeal Mask Airway and LMA-ProSeal during laparoscopic surgery.

STUDY OBJECTIVE

To compare the frequency of airway seal and sore throat with the LMA-ProSeal (PLMA) and the standard Laryngeal Mask Airway (LMA) during laparoscopic surgery.

DESIGN

Prospective, controlled, randomized, nonblinded clinical study.

SETTING

University-affiliated hospital.

PATIENTS

60 adult, ASA physical status I, II, and III patients undergoing laparoscopic surgery with general anesthesia, without contraindication to the use of the laryngeal mask.

INTERVENTIONS

Patients were randomized to receive mechanical ventilation [tidal volume (V(T)) 7 mL/kg(-1); positive end-expiratory pressure (PEEP) 10 cmH(2)O] through the PLMA or the standard LMA, both equipped with a gastric tube.

MEASUREMENTS

Heart rate, arterial pressure, inspiratory and expiratory V(T), airway pressure, end-tidal CO(2) partial pressure, and pulse oximetry were recorded. The leak fraction was calculated as the difference between the inspiratory and expiratory V(T) divided by the inspiratory V(T). Postoperative sore throat frequency was scored in the recovery room ("early") and 1 week after surgery ("late").

MAIN RESULTS

All patients were successfully ventilated through the assigned laryngeal mask. The leak fraction was 7 +/- 3% with the LMA and 7 +/- 4% with the PLMA (p = 0.731). In one patient, the PLMA drainage tube was not patent despite a leak fraction of 5%, and there was no clinically detectable air leak. During the recovery room stay, the frequency of sore throat was scored as mild in 13% and 10% of patients with the standard LMA and the PLMA, respectively, and was absent in the remaining patients (p = 0.99, between groups). There were no differences in the frequency of sore throat between the "early" and "late" evaluations (p = 0.99).

CONCLUSIONS

The PLMA and the LMA show similar airtight efficiency during laparoscopy. The patency of the PLMA drainage tube should always be confirmed. The sore throat evaluation performed in recovery room appears as reliable as later evaluations.