الفهرس 
Haemodynamic monitoring of the Cardiac
Dopamine hydrochlorideOnly 14 pages are availabe for public view
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Abstract
Despite Advances in Cardiac surgery and perioperative care, the prevention and treatment of postoperative complications continue to be an integral part of the care of the cardiac surgery patients. As older and sicker adult patients undergo suregry with greater frequencies, the incidence of complications has increased.
Patients recovering from cardiac surgery involving cadiopulmonary bypass often exhibit systemic and regional haemodynamic disturbances.
Common features are low cardiac output with increased left ventricular afterload, increased vascular resistance and inadequate renal and hepatosplanchnic perfusion.
The aim of therapy after cardiopulmonary bypass surgery is therefore to maintain cardiac output and to reduce vasoconstriction which assists in restoring blood fow to vital organs.
It has been suggested that the optimal drug should combine systemic vasodilation, renal vasodilation, augmentation of myocardial relaxation and should not have too strong positive inotropic effect. Various drugs optimize cardiac output through their effects on myocardial contractility (inotropic effect), effects on the peripheral resistance (afterload effect) or both. Positive inotropic agents act to increase the force and speed of myocardial fiber contraction.
The sympathetic amines (epinephrine - norepinephrine -isoproternol - Dopamine) improve cardiac output by a direct beta-adrenergic inotropic effect and have selectively different effects on the peripheral vasculature. Their effects are mediated through the adrenergic receptors. Beta receptors exist predominantly in the myocardium, their activation results in increased speed and force of myocardial contraction, increased rate of automaticity of the sinoatrial node and faster atrioventricular conduction. The Beta-2 receptors are present predominantly in the smooth muscles of blood vessels and bronchi, their activiation results in vasodilation and bronchodilation. Alpha adrenrgic receptors exist primarily in the peripheral and pulmonary vasculature, their stimulation causes vasoconstriction.
Dopexamine hydrochloride is a newly developed synthetic catecholamine structurally related to dopamine. Dopexamine possesses a combination of agonist activity at B2-adrenoceptor and dopamine DA1-receptor which produces renal and hepato-splanchnic vasodilation. Dopexamine has a mild positive intoropic effect resulting from stimulation of cardiac B2-adrenoceptors and from indirect stimulation of B1-adrenoceptors via inhibition of the active neuronal reuptake of noradrenaline (uptake I) and from baroreflex activation. Dopexamine is not an a-adrenergic agonist and therefore does not cause vasoconstriction which would antagonize the effects produced by activity at other receptors.
On a total number of thirty patients this study was conducted to compare the haemodynamic effects of dopexamine hydrochloride and dopamine hydrochloride for up to 12 hours following surgery for coronary artery bypass grafting (CABG) or valve replacment. The patients were divided into two main groups, each consisted of 15 pateints.