ABSTRACT
Sore throat is a common complication after intubation. The objective of this study,from the clinical viewpoint, is the evaluation of the local heat on postoperative sore throat. Alsothis study, from the methodological viewpoint, is an attempt to introduce the ethical andeconomical advantages of sequential analysis that was used for the first time in Iran. In this clinical trial patients were randomly assigned to eitherexperimental or control group. In the experimental group a small electrical blanket with thetemperature of 40° C was used during the general anesthesia. The sequuntial double triangulartest was used to analyse and monitor clinical trial. This study was stopped after the forth analysis [80 patients evaluated: 40 with electricalblanket and 40 without it] in favor of electric blanket. Whereas the sample size required by thesingle-stage-design was 160. Our findings showed that local heat on the tracheal area could reduce the incidenceof postoperative sore throat. Also, from methodological viewpoint, using the double triangulartest leading to a 50% reduction in sample size, which is more effective from health economicsviewpoint