Volume Kinetics of Gelofusine 4% During Vascular Surgery

The volume kinetics of a commercially available colloid fluid, Gelofusine, have not been studied previously.

Intravenous Gelofusine 10 mL/kg was infused over 30 min in 15 patients undergoing vascular surgery. Of the 15 patients, 14 were classified as American Society of Anesthesiologists (ASA) class III status. The distribution and elimination of the infused volume was calculated with mixed-model kinetics based on 280 measurements of the hemoglobin-derived plasma dilution (19 per patient) collected over 180 min.

The expanded central fluid space volume (V_c, the plasma) amounted to 2.16 L (95% confidence interval [CI] 1.06-2.35) at baseline. The maximum volume expansion of V_c was 706 mL (95% CI 599-812) after infusing Gelofusine 800 mL. Elimination occurred with a half-life of 115 min (95% CI 110-124). Noradrenaline was infused in eight of the 15 patients, leading to a dose-dependent reduction in elimination half-life. For example, an infusion rate of 3 µg/min decreased the half-life to 60 min (- 48%). Distribution of the infused volume to the extravascular space was small (15%), and redistribution to the plasma was accelerated by noradrenaline. Mean arterial pressure and urinary creatinine were not statistically significant covariates, and the model was not strengthened by considering the urine output. Infusion protocols aiming to achieve steady state plasma volume expansion during surgery can begin with a fast infusion over 20 min, then decreasing the rate by 80%.

The kinetics of Gelofusine was predictable in patients of American Society of Anesthesiologists class III status undergoing vascular surgery, with the fluid expanding the vascular space and the half-life shortened by noradrenaline.

Retrospectively registered with ClinicalTrials.gov NCT06474052, June 24, 2024.