[Hypertonic saline solutions in resuscitation in hemorrhagic shock. An experimental study]

The aim of the study was to evaluate the use of hypertonic solutions in restoring intravascular volume in a model of hemorrhagic shock. Eighteen pigs underwent general anesthesia and were instrumented with a carotid catheter to record mean arterial pressure (MAP), a pulmonary artery catheter for pulmonary arterial pressure (MPAP) and cardiac output (CO) monitoring and an electromagnetic flowmeter around the abdominal supraceliac aorta for aortic flow measurement (Vaor). Oxygen delivery (DO2) and oxygen consumption (VO2) data were calculated by standard formulas. The animals were hemorrhaged to a MAP of 45 mmHg, held for 1 hour. They were resuscitated during the following hour until the aortic flow regained its basal value, using three different solutions: normotonic saline (NS = NaCl 0.9%), hypertonic saline (HS = NaCl 7.5%), hypertonic saline added with dextran (HSDX = NaCl 7.5% + 6% dextran 70). An hour of autologous blood transfusion and a two hours follow-up concluded the experiment. Volumes infused were remarkably lower administering HS (13.70 +/- 1.44 ml/kg) and HSDX (9.11 +/- 1.20 ml/kg) compared to NS (90.32 +/- 24.83 ml/kg). MAP, CO and DO2 values resulted significantly higher in the HSDX animals, with lower MPAP levels. During the two hours follow-up only the animals reinfused with HSDX maintained hemodynamic and oxygen transport values at normal levels. We conclude that the administration of hypertonic saline solutions during hemorrhagic shock allows the saving of infusion volumes, thus diminishing the occurrence of interstitial edema formation. The adding of dextran to the solution prolongs the hemodynamic effects.