Central hemodynamic changes in experimental muscle crush injury in pigs

To investigate central and pulmonary hemodynamics in a standardized normovo lemic experimental muscle injury model, 8 anesthetized and mechanically ven tilated test pigs were intracavally infused with 100 mi of autologous muscl e extract over a period of 100 min; 8 control pigs received Ringer's soluti on. The cardiac index decreased 20% and the heart rate decreased 10% within 30 min of starting the infusion in the muscle extract group and remained d epressed. Mean arterial pressure increased significantly in both groups. Th e pulmonary capillary wedge pressure and central venous pressure remained r elatively unchanged during the 5-hour study. A 2-fold increase in mean pulm onary arterial pressure and a nearly 4-fold increase in the pulmonary vascu lar resistance index was seen in the muscle extract infusion group, which h owever returned to normal. Arterial hemoglobin concentration and systemic v ascular resistance index remained fairly stationary in both groups. Immedia te significant decreases in both arterial oxygen saturation and arterial ox ygen tension were observed in the muscle extract group, however both variab les recovered towards the end of the experiment. A slight increase in arter ial blood pH value was noted during the experiment. In conclusion, autologo us muscle extract infusion causes decreases in heart rate and cardiac index , as well as a significant increase in pulmonary vascular tone and systemic hypoxemia, emphasizing the detrimental effects of skeletal muscle injury f ollowing severe trauma.