Comparison of the standard laryngeal mask airway and the ProSeal laryngeal mask airway in obese patients

Background. The ProSeal(TM) laryngeal mask airway (PLMA) may have advantages over the laryngeal mask airway (LMA(dagger)) in obese patients. We tested this hypothesis in a clinical setting. Methods. Sixty obese patients (BMI >30) were randomized to receive mechanical ventilation (tidal volume 7 ml kg(-1), PEEP 10 cm H2O), through either the PLMA or the LMA. A gastric tube was used in all patients. Cuff pressure was set at 60 cm H2O and increased progressively until excessive leak occurred. The incidence of sore throat was assessed at recovery and after 1 week. Results. The mean leak fraction was 6.1 (sd 2.9)% with the LMA and 6.4 (3.5)% with the PLMA (P=0.721). With the PLMA, with no sign of ventilation problems, the drainage tube was not patent in three patients. The cuff pressure was >100 cm H2O in 38% of the LMA group and 7% of the PLMA group (P=0.05). The incidence of sore throat was similar in both groups and it was similarly scored in the recovery room and 1 week after surgery. Conclusions. Both the PLMA and the LMA can be used for mechanical ventilation of obese patients. The patency of the PLMA drainage tube needs to be checked constantly even when an optimal airtight seal is present. In obese patients the LMA requires a greater cuff pressure than the PLMA, but sore throat is not related to the cuff pressure. Sore throat assessment in the recovery room appears as reliable as assessment later.