A critical approach to nutritional assessment in critically ill patients

Background and aims: Nutritional assessment enhances quality of nutritional care, however, its practice bemuses professionals. This prospective study aimed to identify a feasible/informative nutritional parameter in intensive care.

Methods: 44 patients (APACHE II: 23.8+/-10.1), age 58.4+/-18.6 years, were evaluated at admission: clinical data, height, weight, body mass index (BMI), tricep skinfold thickness, mid-arm circumference (MAC), mid-arm muscle circumference (MAMC), albumin, total protein and lymphocyte count. Anthropometric parameters' performance was evaluated isolated or assembled according to Blackburn and McWhirter criteria.

Results: Oedema increased %IW and BMI (P<0.01); muscle depletion was frequent and agreed with MAC or MAMC ranked by both criteria, P=0.02. %IW and BMI overestimated well-nourished/overweight patients, whilst arm anthropometry, mostly MAC/MAMC, shifted towards +/-50% malnutrition. Patients were not equally ranked by both criteria; McWhirter's by using percentiles clarified the distribution and showed agreement between MAC and MAMC, P=0.007, unlike Blackburn's. Mortality was higher in patients with MAC<5th percentile, P=0.003; MAC;<15th percentile was able to predict mortality and major complications. In invasive ventilated patients, severe muscle depletion was associated with mortality, P=0.05.

Conclusion: In intensive care most nutritional assessment methods are useless; MAC is simple, feasible and if classified by percentiles may prove functional with prognostic value.