Intravenous heparin for cardiopulmonary bypass is an acute vasodilator

• Published in: Journal of clinical anesthesia 2002-05, Vol.14 (3), p.179-182
• Main Authors: Jacka, Michael J., Clark, Andrew G.
• Format: Article
• Language: English
• Subjects: Acid-Base Equilibrium - drug effects; Anesthesia; Anesthesia depending on type of surgery; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anticoagulants - administration & dosage; Anticoagulants - pharmacology; Biological and medical sciences; Blood Gas Analysis; Blood Pressure - drug effects; Cardiopulmonary Bypass; electrolytes; Electrolytes - blood; Hematocrit; Hemodynamics - drug effects; Heparin - administration & dosage; Heparin - pharmacology; heparin hemodynamics; Humans; Injections, Intravenous; Medical sciences; Prospective Studies; Thoracic and cardiovascular surgery. Cardiopulmonary bypass; Vascular Resistance - drug effects; vasodilator; Vasodilator Agents - administration & dosage; Vasodilator Agents - pharmacology
• ISSN: 0952-8180; 1873-4529
• DOI: 10.1016/S0952-8180(01)00380-4

Study Objectives: 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. Design: Prospective study. Setting: Three Canadian hospitals. Patients: 43 consecutive patients undergoing elective aortocoronary bypass. Interventions: Anesthetic technique was standarized. Hemodynamic profile, blood gases, and serum electrolytes were measured immediately before IV heparin for cardiopulmonary bypass,, and 5 minutes after. Results: 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. Implications: 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.