Hemodynamic and Renal Effects of Dopexamine and Dobutamine in Patients With Reduced Cardiac Output Following Coronary Artery Bypass Grafting: Methods

This study was approved by the Institutional Review Board prior to the recruitment of patient subjects. Twenty-eight patients undergoing elective CABG with preoperative left ventricular ejection fraction of at least 40 percent (determined by contrast ventriculography at the time of cardiac catheterization) provided written informed consent. Patients excluded from the study included those with acute myocardial infarction within 1 month of surgery, diabetes, severe peripheral vascular disease, creatinine >2.2 mg/dl, thrombocytopenia (<100,000/mm), liver disease (SGOT >98 U/L, alkaline phosphatase >210 U/L, or total bilirubin >2.1 mg/dl), or uncontrolled hypertension (>150/95 mm Hg). Patients were also excluded if they had received diuretics within 1.5 h of surgery, monoamine oxidase inhibitors or dopamine antagonists (metoclopramide, chlorpromazine, trifluoperazine, droperidol, etc) within 2 weeks of surgery, or had received any investigational drug within 28 days of surgery. No patients expressed known or suspected allergies to dopexamine, dobutamine, or any catecholamines, including dopamine.
Of the 28 patients recruited into the study, 10 had Cl<2.5 L/min/m2 immediately after separation from cardiopulmonary bypass without inotropic support despite fluid administration to keep pulmonary capillary wedge pressure (PCWP) >10 mm Hg. These patients received a starting dose of either dobutamine (5^g/kg/min) (n=5) or dopexamine (2^g/kg/min) (n=5) and were studied for a period of 24 h following surgery. The operating room (OR) loading phase of the study included the first 30 min after initiation of the study drugs, during which time dosages were titrated incrementally to maintain Cl >3.0 L/min/m2. Initial doses were 2^g/kg/min of dopexamine and 5 jiig/kg/min of dobutamine. If the Cl did not increase to <3.0 L/min/m2 the initial dose was doubled. ventolin inhaler

This entry was posted in Cardiac Surgery and tagged Cardiac surgery (CABG), dobutamine, dopexamine, inotropic support (inotropy).