Comparison of hypertonic saline/dextran versus hypertonic saline/hetastarch for resuscitation of hypovolemia

In the present study, we compare resuscitation of bled sheep with hypertonic saline/dextran or hypertonic saline/hetastarch. Unanestherized sheep were subjected to 2h of hemorrhagic hypotension and then resuscitated with 200 ml of 7.5% NaCl solution made up to include either 6% dextran 70 (Macrodex) or 6% hetastarch (Hespan). Both solutions provided an immediate and sustained improvement in arterial pressure and cardiac output. The hypertonic saline/dextran provided a slightly better overall response as mean arterial pressure, cardiac output and central venous pressure were higher in the dextran group at all times post resuscitation. However, only the ddifferences in arterial pressure and initial plasma volume expansion were statistically significant. The somewhat better response to hypertonic saline/dextran may be explained by the higher oncotic pressures generated by dextran compared to equal concentrations of hetastarch

Resuscitation of hemorrhage with intraosseous infusion of hypertonic saline/dextran

We resuscitated unanesthetized bled sheep (bled volume = 1.2-1.7 liters) with 200 ml of hypetonic saline/dextran 70 infused either through a peripheral vein (n=6) or directly into the red marrow of the sternum (n = 6). Intraosseous infusion of the viscous 7.5% NaCl/6% dextran solution required 2-4 min. Plasma sodium was rapidly increased to the same level n both groups demonstrating equally rapid entry into the vascular space. Both regimens provide rapid and sustained normalization of arterial pressure and cardiac output. No significant differences between the two groups were apparent for any measured variable. Intraosseous infusion of hypertonic resuscitation fluids merits further research to evaluate the safety and efficacy for prehspital treatment of hypovolemia and trauma

Perspectives on clinical trials for hypertonic saline/dextran solutions for the treatment of traumatic shock

Animal studies with hypertonic solutins suggest that they can achieve resuscitation of hypovolemic shock with extremely small volumes. Such small volume ressuscitation might be ideal in the field treatment of injured patients. Our studies to date, with 60 patients enterd into a prospective, randomized, placebo-controlled, and double-blind clinical trial, suggest that the use of a 7.5% NaCl/Dextran 70 solution increases blood pressures during transport. The solutions have been safe, and we have encoutered no adverse side effects from their use. Survival rates to date favor use of the solutions, but we do not have convincing statistical significance yet in that regard

Cardiac performance following hypertonic saline

The present study was undertaken to examine cardiovascular function before and after either intravenous or intra-arterial infusion of hypertonic saline (7.5% NaCl) in halothane-anesthetized dogs. A high-fidelity micromanometer and ultrasonic dimension transducers were implanted to measure pressure and wall motion of the left ventricle (LV). Cardiac output (CO) was measured using an elelctromagnetic flowmeter and thermodidlution. The slop (Ees) of the linear regression of the LV pressure-diameter relationship was used as an index of cardiac contractility. Intravenous infusion of hypertonic saline (3 ml/Kg) increased mean arterial pressure (MAP, 104 ñ 6 to 116 ñ 6 mmHg), heart rate (HR, 124 ñ 21 to 140 ñ 13 bpm), CO(3.2 ñ 0.9 to 4.2 ñ 0.5 l/,) and Ees (11.6 ñ 2.1 to 14.8 ñ 1.9 mmHg/mm). Systemic vascular resistance (SVR) fell by 18%. The above responses were similar whether infusion was intravenous or intra-arterial into innervated or denervated hind limbs. While nerve blockade at T-4 (xylocaine) attenuated the changes in CO and SVR and completely prevented the tachicardia, the inotropic response remained intact. These studies suggest tht the cardiac effect of hypertonic saline infusion are not mediated by pulmonary or peripheral osmoreceptors and the increased contractility may results form a direct myocardial effect of increased osmolatity