Aim: To study the relationship between the changes in protein repletion indicators and calorie and nitrogen balance in undernourished patients receiving enteral nutrition.
Patients and methods: Fourteen patients (11 female, age range 55-85 years old) with an initial serum albumin below 3.5 g/dl or serum transferrin below 200 mg/dl, which received enteral nutrition, were studied. On days one and ten of nutritional support, indirect calorimetry, nitrogen balance and serum levels of albumin, transferrin, pre-albumin and total lymphocyte count were measured.
Results: Initial resting energy expenditure was 25.1 +/- 5 Kcal/kg/day (115.4 +/- 20% of that predicted by Harris Benedict equations) and urinary urea nitrogen 5.4 +/- 3.7 g/day. Initial and final nitrogen balances were 66.9 +/- 71 and 81.4 +/- 105.9 mg N/kg/day and mean energy balance throughout the study was +9.0 +/- 7.2 Kcal/kg/day. During the ten days of nutritional support, albumin improved significantly in 0.35 +/- 0.43 g/dl (15.2 +/- 19.8%). Transferrin, pre-albumin and total lymphocyte count did not change significantly. The changes in these last parameters did not correlate with nitrogen or calorie balance.
Conclusions: Probably other factors, besides nutritional balances, influence serum protein levels and these may not change despite an adequate nutritional repletion.