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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, METHODS, METHODS, RESULTS. Meshes: Acid-Base Equilibrium, Anticoagulants, Blood Gas Analysis, Blood Pressure, Cardiopulmonary Bypass, Electrolytes, Hematocrit, Hemodynamics, Heparin, Humans, Injections, Intravenous, Prospective Studies, Vascular Resistance, Vasodilator Agents.
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Is intravenous heparin for cardiopulmonary bypass an acute vasodilator? Context: To investigate the changes in hemodynamic profile during cardiopulmonary bypass, and determine the effect of intravenous (IV) heparin on serum chemistry and acid-base status. Prospective study. Three Canadian hospitals. 43 consecutive patients undergoing elective aortocoronary bypass. Anesthetic technique was standarized. Hemodynamic profile, blood gases, and serum electrolytes were measured immediately before IV heparin for cardiopulmonary bypass, and 5 minutes after. Mean arterial pressure (MAP) decreased by a mean of 11.2 mmHg (12.5%, p = 0.0001) in all patients, of whom 28% were treated with vasoactive drugs to restore MAP. Mean systemic vascular resistance decreased by 418 dyne sec/cm(5) (25%, p = 0.0001), and mean serum potassium increased by 0.14 meq/L (p = 0.0002). The reduction in MAP correlated strongly with the reduction in SVR (p = 0.004), but not with changes in potassium or other variables.
assistant
Mean arterial pressure is significantly affected by IV heparin for cardiopulmonary bypass. The hemodynamic mechanism is systemic vasodilation, implying that treatment with a short-acting vasoconstrictor is appropriate, if necessary. Unlike earlier studies, the increase in serum potassium observed, although reproducible, was trivial. Final Decision: yes