Evaluation of gender differences in postoperative sore throat and hoarseness following the use of Ambu AuraGain laryngeal mask : the randomised controlled LadyLAMA trial study protocol

Abstract

Introduction Postoperative sore throat (POST) is a comparatively minor but very common side effect of general anaesthesia with a supraglottic airway device. The patient considers these side effects a mirror of the quality of anaesthesia. The aims of this study are to evaluate gender-specific differences in the incidence of POST and to assess whether the effects of known risk factors vary between genders.

Methods and analysis The LadyLAMA trial is a single-centre, patient-blinded, randomised controlled trial. Consecutive patients requiring ophthalmological surgery under general anaesthesia with a second generation Ambu AuraGain laryngeal mask are randomly allocated to either cuff pressure of 45 cmH2O or cuff pressure of 60 cmH2O. We estimate the difference in POST between the genders at 20% and we hypothesised that a reduction of cuff pressure would reduce POST by 10%. A total of 800 patients will be recruited, with each subgroup including 200 patients to achieve 80% power for detecting a difference at the 5% significance level. Primary endpoints are gender differences in the incidence of POST within 24 hours postoperatively, as well as comparison of cuff pressure 45 cmH2O to 60 cmH2O with respect to POST. The main secondary objective is the effect of cuff pressure on POST stratified by gender. Further secondary endpoints are gender-specific differences in POST and hoarseness in postanaesthesia care unit (PACU) at 48 and 72 hours (or until freedom of discomfort). The parameter cuff pressure serves as key-secondary endpoint.