DOES HEMODILUTION EXIST - EFFECTS OF SALINE INFUSION ON HEMATOLOGIC PARAMETERS IN EUVOLEMIC SUBJECTS

The effects of intravenous fluids on hematocrit are debated. We sought to determine whether maintenance or bolus fluid therapy causes a sign ificant change in the hematocrit and other hematologic parameters incl uded in the complete blood count. Nine subjects completed a randomized three-period crossover designed trial in which they were given no flu id, maintenance fluid, or a bolus of fluid followed by maintenance flu id. We measured complete blood counts at baseline, 1 hour, 4 hours, an d 8 hours. In the bolus fluid trial, the hemoglobin and hematocrit val ues (mean +/- SEM) decreased by a maximum of 1.5 +/- 0.1 g/dL and 4.1 +/- 0.3% at 1 hour. There was no difference in hemoglobin or hematocri t during the no fluid or maintenance fluid treatments. No significant changes occurred in white blood cell or platelet counts. We demonstrat ed that maintenance fluid infusions do not significantly alter the com plete blood count. Saline bolus is associated with a significant decre ase in hemoglobin and hematocrit, but these parameters trend toward ba seline over time.