The nurse evaluates the effects of warfarin by monitoring what lab test?

Choice A rationale

Heart failure occurs when the heart muscle cannot pump blood effectively, leading to a backup of blood and fluid buildup in the lungs, legs, and other parts of the body. This explanation is accurate and helps the patient understand the nature of their condition.

Choice B rationale

Reduced oncotic pressure due to increased protein levels is not a primary factor in heart failure. Heart failure is related to the heart’s inability to pump effectively, not protein levels affecting oncotic pressure.

Choice C rationale

Hydrostatic pressure pushing fluids out of the capillaries is not directly related to heart failure. In heart failure, the issue lies in the heart’s inability to pump blood efficiently, leading to fluid buildup rather than fluid being pushed out of capillaries.

Choice D rationale

The decrease in venous pressure from the backup of blood does not cause heart failure. Heart failure results from the heart’s inability to pump blood effectively, leading to increased pressure and fluid buildup, not a decrease in venous pressure.

Choice A rationale

This choice is incorrect. Cholinergic agonists primarily affect acetylcholine receptors, not GABA receptors. GABA receptors are involved in the inhibitory neurotransmission in the central nervous system and are the target of different drug classes, such as benzodiazepines and barbiturates, which are not related to cholinergic agonists.

Choice B rationale

This choice is incorrect. Cholinergic agonists do not decrease norepinephrine activity. Norepinephrine is a neurotransmitter involved in the sympathetic nervous system response, which is different from the cholinergic system. Drugs that decrease norepinephrine activity would have a different mechanism of action, such as adrenergic antagonists.

Choice C rationale

This choice is incorrect. The primary action of cholinergic agonists is not to increase dopamine activity. Dopamine is another neurotransmitter involved in various brain functions, including reward and motor control. Cholinergic agonists specifically target acetylcholine receptors, enhancing their activity, which is not related to dopamine receptors.

Choice D rationale

This choice is correct. Cholinergic agonists increase the activity of acetylcholine receptor sites throughout the body. These drugs mimic the action of acetylcholine, a neurotransmitter that plays a key role in the parasympathetic nervous system, which regulates functions such as muscle contraction, gland secretion, and heart rate. Enhancing acetylcholine activity helps in conditions like myasthenia gravis and certain types of glaucoma.