Several controlled, experimental, hypotensive models of hemorrhagic shock have evaluated the effects of timing, rate, and types of fluid replacement. In a near-fatal experimental model we evaluated the hemodynamic and metabolic effects of two types of solutions for fluid resuscitation. In this study, 30 young Large-White pigs were randomly assigned to three groups: Group I (control, n= 10), not bled; Group II (hydroxyethyl starch, HES, n = 10), submitted to controlled hemorrhage to a mean arterial blood pressure (MAP) of 30 mmHg and blood lactate >10 mM/L, at which time resuscitation was initiated with 7 mL/kg of HES 130/0.4 6% followed by 33 mL/kg of lactated Ringer's solution (LR) and retransfusion; Group III (LR, n = 10), submitted to controlled hemorrhage to a MAP of 30 mmHg and blood lactate >10 mM/L, at which time resuscitation was initiated with 40 mL/kg of LR followed by retransfusion. The resuscitation with HES 130/0.4 proved to be superior to LR, expressed by hemodynamic and perfusion variables. Despite improvement in tissue perfusion, MAP did not totally return to baseline values. In conclusion, early colloid infusion resulted in prompt recovery of tissue perfusion when compared with infusion with an equal volume of crystalloid.

PURPOSE: To compare the hemodynamic repercussions following a toxic dose of levobupivacaine and bupivacaine intravascularly injected in swines. Methods: Large White pigs were anesthetized with thiopental, tracheal intubation was performed and mechanical ventilation was instituted. Hemodynamic variables were recorded with invasive pressure monitoring and pulmonary artery catheterization (Swan-Ganz catheter). After a 30-minute resting period, the animals were randomly divided into two groups in a double-blinded fashion and received a bolus injection of 4 mg/kg of either agent for intoxication. Hemodynamic results were then evaluated at 1, 5, 10, 15, 20 and 30 minutes. RESULTS: Levobupivacaine had greater hemodynamic repercussions than racemic bupivacaine. These results disagree with those found when the levorotatory isomer of bupivacaine was used in humans, but are in agreement with recently reported findings in animals. CONCLUSION: Levobupivacaine was shown to be more toxic in pigs than racemic bupivacaine when large doses are injected intravenously.

These results contradict those found in human beings regarding the pure levorotatory isomer, but confirm recent animal studies. One must be very careful when extrapolating animal data to human beings. Further studies involving larger samples and more homogeneous groups are necessary.