An appreciation of the nutritional status of the patient is an important part of inpatient management. A number of factors may be involved, including poor intake (anorexia associated with illness, chronic illness, neglect), malabsorption (pancreatitis, inflammatory bowel disease, following bowel resections), and increased requirements (malignancies, acute illness). A malnourished patient has a significantly impaired immune system, delayed wound healing and reduced strength that manifests itself as decreased ventilatory function.

Modern surgical management of surgical patients puts increasing importance on adequate nutrition. The current areas of intense discussion are when and how nutrition should be administrated, and how it changes outcome. From the point of view of the junior doctor, it is important to involve the dietician early on, and ideally this should be done preoperatively.

Nutritional requirements

As with fluid requirements, the nutritional status and the requirements of the patient will change according to their state of health. The aim in the surgical patient is to prevent a depletion of protein stores due to increased catabolism that leads to a negative nitrogen balance. The average carbohydrate stores are depleted in 24 hours, whereas protein and fat stores are depleted over the next month. Younger patients require a higher number of calories per kg than older ones. However in some patients, e.g. those with severe burns and trauma, the calorie requirements may increase by 100% above basal resting requirements.