Nutritional assessment of marginally nourished surgical patients

Anthropometric indices are known to be good indicators of nutritional status in the long term. However, there are conflicting reports about their effectiveness in short term assessments.

In 45 patients undergoing elective operations, the mid-arm circumference, biceps and triceps skin fold thickness and arm muscle area were measured. These were compared with haematological indices of nutritional status such as serum albumin, total protein and haemoglobin. The patients were divided into two groups based on their body mass index (< or > 18.5) or weight (< or > 52 kg). In another 10 patients, anthropometric and blood indices were studied pre- and postoperatively along with changes in body composition.

When patients were grouped according to weight or body mass index, the anthropometric indices studied showed significant differences between the two groups, i.e. weight < 52 kg v. > 52 kg (mid-arm circumference: 22 +/- 3.3 cm v. 10 +/- 1.8 cm, p < 0.01; triceps skin fold thickness: 5.6 +/- 1.4 mm v. 10 +/- 4.9 mm, p < 0.01) although there were no differences in the blood indices. The 10 patients studied longitudinally were on energy-deficient intakes in the first postoperative week and lost lean tissue and body fat (-43 g, -33 g and -19 g protein and -78 g, -88 g and -97 g fat on postoperative days 1, 4 and 8 respectively). There was a variable response in terms of weight and body water. The measured anthropometric indices, however, showed no significant differences.

Our results suggest that anthropometric indices are useful measures of nutritional status on a cross-sectional basis, whereas blood indices are not. Weight changes and anthropometric indices are not reliable guides to the short term nutritional course after an operation.