MYOCARDIAL PERFORMANCE AFTER CONTUSION WITH CONCURRENT HYPOVOLEMIA

Myocardial contusion may present as a benign nonclinical event or a li fe-threatening emergency. Although cardiac output is recognized to be decreased with major contusion, the contribution of hypovolemic shock to myocardial dysfunction is unclear. This study was designed to evalu ate the relationship between myocardial contusion and hypovolemic shoc k. After Sprague-Dawley rats were anesthetized, contusions were admini stered at either 80 psi or 120 psi. Half of each group then underwent hypovolemic shock. After 24 hours of recovery, cardiac hemodynamics we re studied in each subgroup using the Neely-Langendorff apparatus. Iso enzymes and histology were evaluated as well. The data showed that rat s undergoing hypovolemic shock in each subgroup had a significant decr ease in cardiac output when compared with their controls. This decreas e was more pronounced in the 120-psi group. Cardiac isoenzyme levels w ere elevated in all groups. Microscopic evaluations showed contusion i n the controls and necrosis in the shock groups. Patients whose injuri es are compatible with myocardial contusion and hypovolemic shock shou ld be resuscitated quickly and evaluated for myocardial dysfunction se condary to infarction.