ABSTRACT
Patients with coronary artery disease undergoing coronary artery bypass grafting can develop perioperative low cardiac output failure requiring positive inotropic support. Commonly, the sympathetic amines, dopamine, dobutamine or adrenaline are used in low-output state. However, patients on long-term cardioselective beta-blocking therapy may experience problems with such a treatment. Dopexamine, a new synthetic amine, possesses positive inotropic effects by indirect stimulation of the beta 1-receptors and direct stimulation of the beta 2-receptors. We therefore studied the hemodynamic efficacy of dopexamine in patients with and without beta-receptor blockade. In 12 patients with coronary artery disease classed as NYHA II or III, six without any beta-blocker medication, and six with beta 1-blocker medication (bisoprolol 5 mg), anesthesia was induced with high-dose fentanyl (0.05 mg/kg) and pancuronium (0.1 mg/kg). The patients were normoventilated with a mask (O2:air 1:1, tidal volume 10 ml/kg with a rate of 10/min) for 5 min and then intubated. Following intubation anesthesia was continued with 0.025 mg/kg/h fentanyl. In anesthesia steady state the patients of both groups were treated with 2 micrograms/kg/min dopexamine over a period of 15 min and then with 4 micrograms/kg/min dopexamine over a further period of 15 min. Measurements of cardiovascular dynamics included heart rate (HR), cardiac index (CI), stroke volume index (SVI), mean arterial blood pressure (MAP), coronary perfusion pressure (CPP), systemic vascular resistance (SVR), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), right atrium pressure (RAP), pressure work index (PWI) and arterial-mixed venous oxygen content difference (AVDO2), which were monitored or calculated by standard formulas.(ABSTRACT TRUNCATED AT 250 WORDS)
