A client has a central venous access device (CVAD) with a gauze dressing that was last changed 48 hours ago and appears to be clean and dry. According to standard protocol, how soon should the dressing be changed again?

Angina pectoris occurs when myocardial oxygen demand exceeds oxygen supply, often triggered by physical exertion or stress. This imbalance leads to transient chest pain due to myocardial ischemia without irreversible myocardial damage. Acute management focuses on rapidly relieving ischemia by improving coronary blood flow and reducing cardiac workload. Immediate symptom relief is essential to prevent progression to myocardial infarction.

Rationale:
A. Metoprolol is a beta-blocker that decreases heart rate and myocardial oxygen demand, making it useful for long-term angina management and prevention of episodes. However, it is not the first-line medication for immediate relief of acute anginal pain because it does not act quickly enough to terminate ongoing ischemia. It is more appropriate for chronic control rather than acute symptom resolution.

B. Aspirin is important in acute coronary syndromes because it inhibits platelet aggregation and helps prevent clot formation. However, it does not provide immediate relief of chest pain because it does not directly improve coronary blood flow or reduce myocardial oxygen demand. It is an adjunct therapy rather than the primary agent for acute angina relief.

C. Clopidogrel is an antiplatelet agent used to prevent further thrombus formation in clients with coronary artery disease. It works by inhibiting ADP-induced platelet aggregation but has no immediate effect on chest pain or myocardial oxygen supply-demand balance. It is used for secondary prevention rather than acute symptom management.

D. Nitroglycerin is the priority treatment for acute angina because it rapidly dilates coronary arteries and reduces myocardial oxygen demand. It works by relaxing vascular smooth muscle, improving blood flow to ischemic myocardium, and decreasing preload. This leads to quick relief of chest pain and is the first-line medication for acute anginal episodes.

Parkinson’s disease is caused by decreased dopamine activity in the brain, leading to motor symptoms such as tremors, rigidity, and bradykinesia. Treatment commonly includes Entacapone in combination with levodopa to improve dopamine availability. Entacapone works by inhibiting the breakdown of levodopa in the periphery, allowing more of the drug to reach the brain. This enhances and prolongs the therapeutic effect of levodopa, improving motor control.

Rationale:
A. Inhibiting dopamine receptor activity in the CNS is incorrect because entacapone does not block dopamine receptors. Instead, it supports dopamine activity by increasing the amount of levodopa available for conversion into dopamine in the brain. Dopamine receptor blockade would actually worsen Parkinsonian symptoms.

B. Decreasing the side effects of levodopa therapy is not the primary mechanism of entacapone. Although it may allow for lower doses of levodopa and indirectly reduce some side effects such as “wearing off,” its main action is pharmacokinetic enhancement of levodopa availability rather than direct side effect reduction.

C. Enhancing the metabolism of levodopa in peripheral tissues is incorrect because entacapone actually inhibits, rather than enhances, levodopa metabolism. It blocks catechol-O-methyltransferase (COMT), an enzyme responsible for breaking down levodopa in the periphery. This increases the amount of levodopa that can cross the blood-brain barrier.

D. Inhibiting the enzyme that breaks down levodopa is correct because entacapone selectively inhibits peripheral COMT. This prevents the conversion of levodopa into inactive metabolites before it reaches the central nervous system. As a result, more levodopa is available to be converted into dopamine in the brain, improving symptom control in Parkinson’s disease.