Reduced fluid gain during cardiopulmonary bypass in piglets using a continuous infusion of a hyperosmolar/hyperoncotic solution

Abstract

Background: The aim of this study was to evaluate how a continuous infusion of a hyperosmolar/hyperoncotic solution influences fluid shifts and intracranial pressure during cardiopulmonary bypass in piglets. Methods: Fourteen animals, randomized to the control (CT) group or the hypertonic saline/hydroxyethyl starch (HyperHaes®) (HSH) group, received acetated Ringer's solution as prime and supplemental fluid. The HSH group received, in addition, HyperHaes® 1 ml/kg/h. After 1 h of normothermic cardiopulmonary bypass, hypothermic cardiopulmonary bypass (28°C) was initiated and continued for 90 min. Fluid balance, plasma volume, tissue water content, acid-base parameters and intracranial pressure were recorded, and protein masses and fluid extravasation rates were calculated. Results: At the start of normothermic cardiopulmonary bypass, the fluid extravasation rates (ml/kg/min) increased from 0.19 (0.06) to 1.57 (0.71) and 0.19 (0.09) to 0.82 (0.14) in the CT and HSH groups, respectively, with no between-group differences (P = 0.081) During hypothermic cardiopulmonary bypass, the fluid extravasation rates (ml/kg/min) increased from 0.19 (0.14) to 0.51 (0.10) (P < 0.01) and 0.15 (0.08) to 0.33 (0.08) (P < 0.05), respectively, with significantly lower extravasation rates in the HSH group (P < 0.01). In the HSH group, the total fluid gain during cardiopulmonary bypass decreased by about 50% (P < 0.05) and the tissue water content was significantly lower in the left and right heart as well as in the lungs. The intracranial pressure remained stable in the HSH group, but increased in the CT group. Conclusions: A continuous infusion of HSH (HyperHaes®) during cardiopulmonary bypass reduced the fluid extravasation rate and the total fluid gain during bypass. No electrolyte or acid-base disturbances were present. The intracranial pressure remained stable in the HSH group. © 2006 The Authors.