Cardiac contractile effects of ethanolism and hemorrhagic shock

Abstract

Moderate ethanol consumption, associated with cardiac depression, occurs in greater than 50% of trauma. Hemorrhagic shock, a significant component of trauma in the clinical setting, causes intrinsic cardiac contractile dysfunction. In this study, we used an isolated heart model to determine whether acute ethanolism increases the cardiovascular risk associated with hemorrhagic shock. We hypothesized that hemorrhagic shock in the acutely intoxicated subject would cause significantly greater cardiac dysfunction compared with that observed in a nonintoxicated subject. A total of 116 guinea pigs was divided into four groups: control (no ethanol, no shock), ethanol intoxication alone (1 mg/kg iv), hemorrhagic shock alone (mean arterial blood pressure, 30 mmHg for 2 h), and a combination of hemorrhagic shock plus ethanol. Half of the hearts in each group were used for isolated heart studies, and half were used to assess myocardial cell membrane integrity. Ethanol alone reduced peak isovolumic pressure by 36%, maximal rate of left ventricular pressure (LVP) rise by 27%, and maximal rate of LVP fall by 35%; however, contractile depression was significantly greater in the intoxicated, hemorrhaged, group compared with the nonintoxicated, hemorrhaged, group (P less than 0.05). Both ethanol and hemorrhage independently altered myocardial cell volume regulation; however, abnormalities in myocardial cell volume regulation induced by hemorrhage were similar in the intoxicated and nonintoxicated groups. Our data show that hemorrhagic shock causes significantly greater cardiac contractile dysfunction in the intoxicated subject.