The scope of this work is to analyze the usefulness and indications of preoperative evaluation.
Patients and methods: 791 consecutive patients candidate for surgical treatment, were studied prospectively under the next inclusion criteria: 40 years old or less than 40 years old. Blood count cell, glucose, urea, creatinine, sodium, potassium, prothrombin time, partial thromboplastin time, platelets count, liver function tests, chest x-ray and electrocardiograph made before entry. In the the post liver, lung, bleeding, infectious or metabolic complications was done, while visiting the patients every day until discharge. Relative risk (RR) was calculated for every variable, analyzing differences with X2 and Fisher's Test. Those variables with statistical significance value were analyzed with logistic regression. Only 751 patients were studied, there were 335 male (44%) and 416 female (56%), with mean age of 63.9 years. Metabolic disorders (16.9%) and postoperative infections (7.0%) were the more frequent complications. Hemorrhage during of after surgery occurred in 2.2% of the patients. There were seventeen deaths (2.2%) related directly with surgery, with systemic illness or with postoperative complications. Selection of auxiliary tests for preoperative evaluation must be agree with clinical evaluation. The major objective of clinical evaluation is to estimate risk factors for surgery.