Cardiopulmonary function as related to intestinal mucosal lesions in experimental septic shock

The purpose of the present investigation was to explore a possible relationship between cardiopulmonary function and small intestinal mucosal lesions in experimental septic shock. The filling pressure of the left ventricle of the heart (LVEDP) and the maximal pressure change during systole (max dP/dt) were monitored continuously by a tip-transducer catheter. The pulmonary and femoral arterial pressures and pressure changes in the trachea were recorded. The aortic blood flow was measured electromagnetically. Stroke volume, external cardiac work, and the pulmonary vascular resistance could be calculated. Twenty-two cats were made septic by i.v. infusion of live E. coli bacteria. Controls received saline i.v. After 2 hours of bacteremia, preload was increased by a rapid infusion of dextran to unmask cardiac dysfunction. Small intestinal specimens were taken for microscopical examination. The occurrence and the degree of mucosal damage was established. Thirteen cats had virtually normal mucosal appearances, whereas nine disclosed severe lesions. The loading procedure revealed a more pronounced cardiac dysfunction in cats with severe mucosal damage, compared to those without. Pulmonary vasoconstriction, bronchoconstriction, and impaired ventilation-perfusion ratio were also demonstrated, but these signs of pulmonary dysfunction did not differ when comparing animals with and without mucosal damage. A correlation between impaired cardiac function on one hand and hypotension--intestinal mucosal lesions on the other, suggests cardiotoxic material released from the damaged intestine as one contributing mechanism.