A sample of 82 patients was estimated, considering the level of significance (alpha) of unilateral 2.5%, the power of the study (1-beta) of 80%, the non-inferiority limit of 4%, and success percentages in the groups control and experimental studies of 92% and 100%, respectively. Once the high mortality rate of the study site (about 60%, according to unpublished administrative information), it was decided to increase this number by 30% to compensate for possible losses, totaling 106 patients, 53 in each arm.