Assessment of outcome of perioperative nutritional interventions

It is 60 years since malnutrition was first recognized as contributing significantly to the development of postoperative complications.’ This observation has since been confirmed in many studies. The attractiveness of this association has been the suggestion that, in contrast to many other surgical risk factors, impaired nutritional status can be treated. Nutritional support has indeed been shown to reduce weight loss and improve nitrogen balance and serum protein parameters.*J Furthermore, clinical evidence indicates that nutritional support restores tissue function, reflected by improved skeletal muscle force, decreased fatiguability, improvement of ventilatory function4 and the reversal of skin anergy, presumably equivalent to improved immune function. These observations have led to high expectations with regard to the ability of nutritional intervention to decrease morbidity and mortality from surgical therapy. However, it has been difficult to demonstrate a positive effect on clinical outcome since this is influenced by so many other factors, including the quality of anesthesia and surgery, age, and cardiorespiratory disease. Furthermore, a large number of studies investigating the effects of