HEMODYNAMIC ADVANTAGE OF LEFT ATRIAL EPINEPHRINE ADMINISTRATION AFTERCARDIAC OPERATIONS

Cardiac surgical patients frequently require catecholamines, typically administered via the central venous circulation. Potential. disadvant ages of this route of administration include catecholamine metabolism by the pulmonary vascular bed before gaining access to the heart and p ulmonary vasoconstriction producing increased pulmonary vascular resis tance. We therefore prospectively compared administration of epinephri ne via the left atrium versus central venous administration of epineph rine with particular interest in: cardiac output, mean pulmonary arter y pressure, and pulmonary vascular resistance. Fifteen consecutive aor tocoronary bypass patients were studied after cardiopulmonary bypass. Epinephrine (mean dose, 0.07 +/- 0.02 mu g.kg(-1) min(-1)) was adminis tered via the central venous route, then via the left atrium, then via the central venous route again. Hemodynamic data were collected 10 mi nutes after changing the route of administration. Left atrial administ ration of epinephrine produced a 35% greater cardiac output, 25% lower pulmonary artery pressure, and 32% lower pulmonary vascular resistanc e when compared with central venous administration (all significant; p < 0.05). Left atrial epinephrine administration may offer hemodynamic advantage in cardiac surgical patients in whom central venous adminis tration does not produce an adequate cardiac output or in patients wit h pulmonary hypertension to avoid any further increase in pulmonary va scular resistance.