Introduction

Discussion of the medical management of the surgical patient is not complete unless one considers the key role that the liver plays in the body metabolism. The liver is the site of synthesis of many endogenous proteins that are involved in both the healing process as well as in the breakdown of the multitude of medications that patients receive. Unsuspected liver disease is estimated to occur in 1 in 700 otherwise healthy surgical candidates. Some of these patients may be identified before surgery by abnormalities of blood work suggesting liver dysfunction. The degree of concern raised is dependent upon the degree and type of abnormality as well as the type of surgery. In the sections to follow we will examine these issues and attempt to provide a practical approach to the evaluation, risk assessment, and management of these patients.

Abnormal liver tests

The first order of evaluation of the abnormal liver tests is to determine their time of origin. Pre-existing abnormalities suggest non-operative factors and acute development of abnormalities later suggest operative or postoperative events. The role of a careful review of presurgical records and medical history taking cannot be overemphasized. Careful review of intraoperative and postoperative medical data complement the review process. Further diagnostic testing is dictated by review of this information.

Preoperative evaluation

While many blood tests may reflect liver diseases, we will focus on the enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin, and coagulation tests.