INTRODUCTION

Outcomes after surgery are influenced by:

• preoperative physiological status,

• operative severity,

• the provision of appropriate care.

Surgeons can minimize the deleterious effects of the surgical insult by careful preoperative planning, meticulous intraoperative technique and by accurate postoperative care.

Preoperative Physiological status

Preoperative co-existing medical problems translate into increased operative risk. The simplest tool to assess patient risk factors is the American Society of Anesthetists (ASA) scale. This is a subjective assessment of the patient's operative risk based on the presence and severity of co-existing medical problems, which are detected by routine history and physical examination.

The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) was developed in 1991. POSSUM variables include physiological markers and other factors related to operative severity. These variables have been tested extensively and have resulted in a central database of over 200,000 patients. POSSUM scoring has been used to predict the outcome of patients undergoing a broad range of operations and has been recognized as being the most appropriate available score for assessing risk in surgical patients. However, POSSUM over-predicts mortality for those patients at the low-risk end of the spectrum. The Portsmouth group revised the scoring and the so-called P-POSSUM is now widely used.

Operative severity

Surgery (or trauma from injury) has been shown to result in immune suppression and organ failure is the leading cause of death in surgical patients.