Resuscitation with 7.5% NaCl in 6% dextran-70 during hemorrhagic shock in swine: effects on organ blood flow.

We previously reported that small volume infusions of 7.5% NaCl in 6% dextran-70 (HSD) are superior to equal volumes of normal saline (NS) or 7.5% NaCl in the ability to resuscitate animals from an otherwise lethal hemorrhage. In the present experiment, we evaluated organ blood flow in unanesthetized swine bled 46 ml/kg in 15 min and subsequently infused with a volume of HSD (n = 5) or NS (n = 5) equal to 25% of the shed blood. Radiomicrospheres were injected before hemorrhage, immediately after hemorrhage, and 5 and 30 min after treatment. At the end of hemorrhage, cardiac output had fallen to one-third of baseline values. Five minutes after the infusion of HSD, cardiac output had returned to baseline levels, while cardiac output in the NS-treated controls had increased to only one-half of prehemorrhage values. Blood flows to the brain, diaphragm, skin, muscle, and fat were not different between the two groups. Infusion with HSD, however, produced flows to the myocardium, kidneys, liver, small intestine, and pancreas that were significantly greater than post-hemorrhage and NS-treated control values. NS was unable to increase these flows significantly above post-hemorrhage levels. We conclude that small volumes of HSD can significantly improve organ blood flow after hemorrhagic shock. This improvement in flow may explain the increased survival observed with this solution and may attenuate some of the later complications of hemorrhagic shock.