A client has the diagnosis of left ventricular failure and a high pulmonary capillary wedge pressure (PCWP). The physician orders dopamine to improve ventricular function. The nurse will know the medication is working if the client’s:
A. Blood pressure rises
B. Blood pressure decreases
C. Cardiac index falls
D. PCWP rises
Correct Answer: A. Blood pressure rises
If dopamine has a positive effect, it will cause vasoconstriction peripherally, but increase renal perfusion and the blood pressure will rise. The cardiac index will also rise, and the PCWP should decrease. Dopamine is a peripheral vaso stimulant used to treat low blood pressure, low heart rate, and cardiac arrest. Low infusion rates (0.5 to 2 micrograms/kg per minute) act on the visceral vasculature to produce vasodilation, including the kidneys, resulting in increased urinary flow.
Option B: Intermediate infusion rates (from 2 to 10 micrograms/kg/min) stimulate myocardial contractility and increase electrical conductivity in the heart leading to increased cardiac output. Higher doses cause vasoconstriction and increased blood pressure via the adrenergic receptors alpha-1, beta-1, and beta-2, which can lead to poor peripheral circulation.
Option C: Cardiac index should increase. Activation of the D1 receptors on smooth muscle, the proximal renal tubule, and cortical collecting duct increase diuresis. D2 receptors are located presynaptically on the renal nerves and within the glomeruli and adrenal cortex. The activation of these nerves results in decreased renal sodium and water excretion.
Option D: PCWP should decrease. Monitoring blood pressure and urine flow is necessary — monitoring of more advanced hemodynamic parameters such as cardiac output, including rhythm and pulmonary wedge pressure, is also recommended.
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