Albumin plays an important role in maintaining physiological homeostasis. Although decreased albumin concentration has been well described as an acute-phase response following injury, it is unclear whether the decrease is due to compromised synthesis of albumin, dilution, or imbalance between synthesis and breakdown rates, particularly after injury. We investigated changes in albumin synthesis in severely burned patients using stable isotope infusion techniques. Five patients (29 ± 3 years; 80 ± 7 kg) with burn of 48% ± 4% total body surface area (TBSA) were enrolled and studied in the ICU at the Burn Unit of the US Army Institute of Surgical Research. Five age-and sex-matched healthy volunteers (33 ± 5 years; 81 ± 6 kg) were included as controls. On the study day (13 ± 3 days after burn), a primed constant infusion (4 h) of stable isotope d5-phenlylalanine and d3-ketoisocaproic acid was given. Hourly arterial blood samples were drawn during the infusion to determine albumin synthesis rates, using gas chromatography-mass spectrometry analysis. Burned patients had higher heart and respiration rates. Plasma total protein in burn patients (4.5 ± 0.3 g • dL-1) was lower compared with controls (6.8 ± 0.2 g • dL-1). Plasma albumin concentration in burn patients (1.1 ± 0.1 g • dL-1) was also lower compared with controls (3.8 ± 0.1 g • dL-1; both P < 0.05). Albumin synthesis rate in burn patients (4.6 ± 0.2 mg • kg-1 • h) was enhanced compared with controls (2.2 ± 0.2 mg • kg-1 • h; P < 0.05). Despite the decrease in albumin concentration, albumin synthesis was enhanced in severely burned patients during the flow phase.
- Burn injury
- gas chromatography and mass spectrometry
- stable isotopes