[Assessment of changes in body composition in critically ill patients]

Critically ill patients are especially prone to malnutrition because their hypermetabolic state produces an increase in nutritional requirements that often are not covered with the formulae supplied. Evaluation of the body composition (BC) makes it possible to quantify the main structural components of the body: muscle, bone and fat. An anthropometry study was made for the assessment of these elements to obtain information on the protein-calorie nutritional status of critically ill patients. We have aimed to describe the variations in the BC of the critical ill patient during the first seven days after ICU admission. The observational study included 50 critically ill patients, of whom 78% were male and 22% women with a mean age of 56 years. Height, weight, body mass index (BMI), bone diameters, muscle perimeters and skinfolds of patients were recorded. The body composition (BC) calculations were performed using the Faulkner, Rocha, Wurch and Matiegka formulae. We obtained the baseline energy expenditure of each patient with the Harris-Benedict formula. After analyzing the data, a decrease was found in the percentage of muscle mass (mean+/-SD: 3+/-0.76), an increase in the percentage of body fat (2+/-0.76) and an increase in BMI at the expense of an augment of weight. We have concluded that during the first week of ICU admission patients lose critical muscle mass and have an increase in fat mass. Awareness of these changes in the BC of patients may be useful to determine the appropriate nutrition for critically ill patients.