In order to facilitate the data collection and to get a more homogeneous sample of patients, only patients scheduled for surgery at the San Ignacio University Hospital between 7 a.m. and 2 p.m. as of June 2006 were included, until the calculated sample of 550 patients was completed. The patient distribution was as follows: 200 general anesthesia, 200 regional neuroaxial anesthesia epidural or spinal anesthesia, 100 regional peripheral anesthesia in the upper or lower limb and 50 combined anesthesia procedures regional neuroaxial plus general anesthesia.
Se decidió, por comodidad para recolectar la información y obtener mayor homogeneidad de los pacientes, incluir únicamente a aquellos programados para cirugía en el Hospital Universitario de San Ignacio, en el horario de 7 a.m. a 2 p.m., a partir de julio de 2006, hasta completar la muestra calculada de 550 pacientes, distribuidos en 200 procedimientos de anestesia general, 200 procedimientos de anestesia regional del neuroeje anestesia peridural o espinal, 100 procedimientos de anestesia regional periférica en miembro superior o inferior y 50 procedimientos de anestesia combinada anestesia regional del neuroeje más anestesia general.