Name the following arterial blood gas (ABG) values: pH 7.47, PaCO2 32, HCO3- 23

Choice A reason: Drugs with a narrow therapeutic range, like digoxin, require plasma level monitoring to ensure concentrations remain within a safe and effective range. This prevents toxicity (e.g., arrhythmias) or subtherapeutic effects, as small dose changes can significantly alter blood levels, making monitoring critical for patient safety and efficacy.

Choice B reason: Intravenous administration does not inherently address the risks of a narrow therapeutic range. While it ensures rapid delivery, it increases toxicity risk due to immediate bioavailability. Monitoring plasma levels is more critical than the route to maintain safe and effective drug concentrations, making this choice less appropriate.

Choice C reason: Administering at intervals longer than the half-life may lead to subtherapeutic levels for drugs with a narrow therapeutic range, reducing efficacy. Consistent dosing and plasma level monitoring are needed to maintain steady-state concentrations within the therapeutic window, making this choice incorrect for managing such drugs.

Choice D reason: Teaching that maximum effects occur quickly is inaccurate for most narrow therapeutic range drugs, which often require steady-state concentrations over time. Without monitoring, toxicity or inefficacy risks increase. Patient education should focus on adherence and monitoring, not rapid effects, making this choice inappropriate.

Choice A reason: Mannitol, an osmotic diuretic, reduces intracranial pressure by drawing fluid from brain tissue into the bloodstream. This is its primary use in head injuries, making it correct.

Choice B reason: Mannitol is not primarily for peripheral edema; it targets cerebral edema. Furosemide is used for peripheral fluid, so this is incorrect for mannitol’s purpose.

Choice C reason: Mannitol removes fluid, not restores it. extracellular fluid, aiming to reduce brain swelling. Restoring fluid is opposite its effect, so this is incorrect.

Choice D reason: Mannitol increases renal perfusion by promoting diuresis, not reducing it. Its main goal is intracranial pressure reduction, so this is incorrect.