Assessment of protein nutrition in surgical patients—the value of anthropometrics

Abstract

To evaluate the reliability of anthropometry in assessing protein stores measurements of weight/height, arm circumference, arm muscle circumference and arm muscle area with direct measurements of body N using in vivo neutron activation analysis were compare in 10 normal adults and 82 surgical patients with varying degrees of weight loss. Anthropometry is reliable for the assessment of protein nutrition in groups of patients (for 100 patients 95% confidence limits are .+-. 30 g N) but the magnitude of variance shown makes it inappropriate for assessing the individual as a single measurement (95% confidence limits are .+-. 300 g N). Repeat measurements were made after 2 wk on 35 patients and their was no correlation between changes in body N and changes in the anthropometric measurements. Anthropometry is not reliable in following changes in body N in individual patients over short periods of time.