Albumin bolus administration versus continuous infusion in critically ill hypoalbuminemic pediatric patients.

OBJECTIVE

To test the hypothesis that the rate of degradation of exogenously administered albumin is faster with bolus administration than with continuous infusion and thus that a bolus administration is less efficacious in restoring blood albumin concentration (BAC) in the hypoalbuminemic critically ill pediatric patient.

DESIGN

A prospective, controlled study of two groups of patients.

SETTING

Pediatric intensive care unit (PICU) of a children's hospital.

PATIENTS

37 critically ill hypoalbuminemic patients (BAC < or = 2.8 g/dl), in whom no overt protein-losing disease was identified, were divided into two treatment groups and included in a 60-h study.

INTERVENTIONS

18 patients were given an i.v. bolus of 1 g/kg of 25% albumin over 4 h. This treatment was repeated after 24 and 48 h. Nineteen other patients were given the same dose of 1 g/kg of 25% albumin as a continuous 24-h infusion throughout the 60-h study period. BAC along with sodium, potassium, and total and ionized calcium were measured in the serum of blood samples obtained at predetermined intervals.

MEASUREMENTS AND MAIN RESULTS

A 4 h bolus of albumin resulted in an acute rise in BAC, which declined to baseline within 24 h. A continuous infusion resulted in a steady rise in BAC with 24-h levels significantly higher than baseline. The percent change in mean BAC from baseline, calculated at 12-h intervals during the 60-h study period, showed a steady increase in the continuous infusion group with a 34% increase after the first 24 h. In contrast, the 4-h bolus method resulted in major fluctuations in the BAC values with only a 14% increase (p < 0.05) after 24 h. Albumin's volume of distribution, half-life and elimination constant, calculated based on blood albumin values during the first 24 h after the bolus administration, were 0.12 +/- 0.03 l/kg, 4.6 +/- 1.8 h and 0.17 +/- 0.06 h-1, respectively. This half-life did not apply to the continuous infusion group as a steady state was not achieved after 30 h (6 half-lives), and BAC continued to rise throughout the 60-h study period. No significant changes in blood electrolytes were observed with either method.

CONCLUSIONS

The half-life of exogenous albumin in the critically ill hypoalbuminemic pediatric patient is short if given as a bolus. Continuous infusion therapy appears to be more efficacious in increasing BAC over time, as the half-life with this method appears to be longer.