Dose Response Characteristics of Hypertonic Saline Dextran Solutions

In an effort to find the best hypertonic saline-dextran solution (HSD) for prehospital use, 33 chronically catheterized sheep were bled using a fixed pressure shock model (50 mm Hg x 2 hours) and resuscitated with 4 ml/kg of HSD solution (2-minute bolus). In the first set of experiments colloid was varied and sodium chloride was held constant, as 7.5% NaCl was paired with either 0%, 6%, or 12% dextran 70. A dose-response relationship existed, with cardiac output increasing 20% with each sequential dextran 70 concentration. Mean arterial blood pressure was higher in animals that were resuscitated with either the 7.5% NaCl/6% dextran 70 or 7.5% NaCl/12% dextran 70 solution (p less than 0.05). Using the optimal dextran 70 concentration from the first set of experiments (i.e., 12%), solute was varied in a second set of experiments comparing 0.9%, 3.8%, 7.5%, or 10% NaCl/12% dextran 70. Again, dose-response features were demonstrated, as cardiac output increased as a function of NaCl concentration. However, this response plateaued with the 7.5% NaCl concentration and no advantage was obtained by increasing the NaCl concentration to 10%. We conclude that a 4-ml/kg bolus of 7.5% NaCl/12% dextran 70 solution may be a more effective form of therapy than those previously evaluated. This new solution is now being included in our ongoing clinical trials.