Experimental model of non-controlled hemorrhagic shock in pigs.

BACKGROUND AND OBJECTIVES A better understanding of pathophysiologic changes associated to trauma and hemorrhagic shock can help the development of therapies capable of reducing trauma-related mortality. The objective of this study was to describe a model of non-controlled hemorrhagic shock in pigs. METHODS Animals received ketamine and midazolam as pre-anesthetic medications. Anesthesia was induced with propofol, and tracheal intubation was performed with the animals on spontaneous ventilation. After intubation neuromuscular blockade was performed. Animals were maintained in controlled mechanical ventilation and normocapnia. Anesthesia was maintained with propofol and fentanyl as needed. Saline was infused during the entire preparation period. MONITORING Cardioscope, pulse oximeter, invasive blood pressure, volumetric catheter in the pulmonary artery, and urine output by cystostomy were used. Experimental model: after the initial recording of hemodynamic, metabolic, and coagulation variables, right subcostal incision and left lobe liver biopsy were performed. Anesthetic infusion was reduced while the infusion of saline was interrupted. An incision 12cm long 2cm deep was performed in the right liver lobe followed by digital divulsion of the wound. During the hemorrhagic phase, an aspiration probe was placed close to the wound and the volume of aspirated blood was recorded. When mean arterial pressure reached 40mmHg and bleeding was above 700mL the intervention phase was initiated according to the type of study. CONCLUSION The development of experimental models to reduce high mortality and costs related to trauma is important.