CENTRAL AND REGIONAL HEMODYNAMICS DURING UNCONTROLLED BLEEDING USING HYPERTONIC SALINE DEXTRAN FOR RESUSCITATION

The effects of hypertonic (7.5%) saline/6% dextran 70 (HSD) on central and regional hemodynamics were studied during uncontrolled intra-abdo minal bleeding in 16 anesthetized pigs. Ultrasonic flow probes were pl aced proximally and distally to an aortic injury to indicate the incid ence and extent of rebleeding after injecting 4 mt kg(-1) (N = 8) and 2.65 mL kg(-1) (N = 8) of HSD 10 min after the vascular injury was ind uced. The initial aortic bleeding reduced the blood flow rates to 71% of baseline in the skin, 53% in the splanchnic region, 42% in the uppe r aorta, and 15% in the kidney. Cardiac output dropped to 46% and the mean arterial pressure to 57% of baseline. The injection of HSD was fo llowed by a prompt increase in all blood flow rates, but rebleeding st arted within 2 min in 13 of the pigs (81%). A second period of rebleed ing occurred in six of them. The rebleeding averaged 300 mL, which is 62% of the blood lost when the aortic injury was induced, There was no significant difference between the treatment groups with respect to t hese blood losses or to the oxygen consumption, which was not restored by HSD. Five animals in each treatment group died after about 70 min, while the remaining six pigs (38%) survived the 120 min study period. These results suggest that HSD in the recommended dose, and even two- thirds thereof, promotes rebleeding when given shortly after a low ene rgy intra-abdominal aortic injury. The fluid seems to have no benefici al effect on this type of uncontrolled hemorrhage.