Resuscitation from hemorrhagic shock: Experimental model comparing normal saline, dextran, and hypertonic saline solutions

Objective: To compare the effectiveness of normal saline, dextran, hypertonic, and hypertonic-hyperoncotic solutions in hemorrhagic shock. Design: Laboratory investigation. Setting: University hospital, Emergency Surgery and Intensive Care staff. Subjects: Thirty-two large white female pigs. Interventions: Routine care included: anesthesia and sedation (ketamine 10 mg/kg, droperidol 0.25 mg/kg, diazepam 0.7 mg/kg, fentanyl 0.006 mgtkg, 2% enflurane, 20% nitrous oxide, pancuronium bromide 0.13 mg/kg); volume-controlled ventilation (Paco(2) 35-40 torr, 4.7-5.4 kPa); cannulation of right carotid artery and pulmonary artery. Three flow probes (subdiaphragmatic aorta, superior mesenteric artery, right renal artery) and regional venous catheters (superior mesenteric vein, right renal vein) were positioned. Animals were bled to 45 mm Hg for 1 hr and resuscitated with four different fluids and blood to normal aortic blood flow and hemoglobin. Measurements and Main Results: Mean arterial pressure and blood flow through abdominal aorta (V-aor) mesenteric artery (V-mes), and renal artery (V-ren) were continuously monitored. Cardiac output, systemic and regional oxygen delivery (DO2, DO2mes, DO2ren), and consumption (VO2 VO2mes, VO2ren) were recorded every 30 mins. Baseline V-aor was restored with different amounts of fluids in the four groups: normal saline (91.35 +/- 22.18 mL/kg); dextran (16.24 +/- 4.42 mL/kg); hypertonic (13.70 +/- 1.44 mL/kg); and hypertonic-hyperoncotic (9.11 +/- 1.20 mL/kg). The amount of sodium load was less using dextran and hypertonic-hyperoncotic and sodium levels were only transiently increased after hypertonic infusion. Mean arterial pressure and cardiac output were normalized in all groups. Animals resuscitated with normal saline and dextran showed increased pulmonary artery pressures. DO2 Was significantly higher after hypertonic-hyperoncotic infusion, because of reduced hemodilution. Hypertonic and hypertonic-hyperoncotic normalized V-mes, DO2mes, VO2mes, V-ren, and DO2ren, whereas normal saline and dextran did not achieve this result. At the end of the experiment, hypertonic-hyperoncotic maintained mean arterial pressure, cardiac output, and DO2 until the end of observation in contrast to normal saline, dextran, and hypertonic. Conclusions: Resuscitation with a small volume of hypertonic-hyperoncotic solution allows systemic and splanchnic hemodynamic and oxygen transport recovery, without an increase in pulmonary artery pressure. It only transiently increased sodium concentration.