Correct Answer: D

Rationale: The correct answer is D, Leucovorin. Leucovorin is administered with methotrexate to protect normal cells from methotrexate toxicity by acting as a "rescue" agent. Methotrexate inhibits dihydrofolate reductase, leading to decreased levels of tetrahydrofolate needed for DNA synthesis. Leucovorin bypasses this step by directly providing the reduced form of folic acid, thus preventing toxicity in normal cells. Probenecid (choice A) is not used to protect normal cells during methotrexate therapy. Cytarabine (choice B) and Thioguanine (choice C) are not rescue agents for methotrexate toxicity.

Correct Answer: B

Rationale: The correct answer is B. A semiprivate room with one or two consistent caregivers is the most therapeutic setting for an agitated head-injured patient. Here's the rationale: 1. Consistency: Having one or two consistent caregivers provides the patient with a stable and familiar environment, which can help reduce agitation. 2. Privacy: A semiprivate room offers more privacy compared to a day room or a ward, which can help minimize external stimuli and promote relaxation. 3. Individualized care: In a semiprivate room, caregivers can focus more on the specific needs of the patient, leading to better management of agitation. 4. Reduced distractions: Being in a semiprivate room minimizes distractions and noise, which can be overwhelming for an agitated head-injured patient. Summary: A, C, and D are incorrect because they do not offer the same level of consistency, privacy, individualized care, and reduced distractions as a semiprivate room with one

Correct Answer: B

Rationale: The correct answer is B because air conduction is less efficient than bone conduction due to the sound waves traveling through the air in the ear canal, which can be hindered by factors like blockages or obstructions. This results in a weaker and less clear sound transmission compared to bone conduction, where sound waves are transmitted directly through the bones of the skull, bypassing any potential obstructions in the ear canal. Incorrect choices: A: This statement is incorrect as air conduction of sound in the ear is not caused by the vibration of bones in the skull. C: This statement is incorrect as air conduction is typically heard for a shorter duration than bone conduction. D: This statement is incorrect as air conduction of sound in the ear is not caused by the transmission of heat through the air, but rather by sound waves traveling through the ear canal.

Correct Answer: B

Rationale: The correct answer is B: To prevent cerebrospinal fluid (CSF) leakage. Rationale: During a spinal block, the anesthesiologist injects anesthesia into the subarachnoid space, which contains CSF. Proper positioning ensures that the anesthesia stays in place and prevents leakage of CSF, which could lead to complications such as post-dural puncture headache. Incorrect choices: A: To prevent confusion - Irrelevant to the procedure. C: To prevent seizures leakage - Seizures are not a concern with spinal blocks. D: To prevent cardiac arrhythmias - Cardiac arrhythmias are not directly related to spinal blocks.

Correct Answer: D

Rationale: The correct answer is D: The client is experiencing a mild overdosage. Tinnitus is a common symptom of aspirin toxicity. Aspirin overdose can lead to tinnitus due to its ototoxic effects. This occurrence indicates that the client may be taking too much aspirin, resulting in toxicity. The other choices (A, B, C) are incorrect because tinnitus is not a normal side effect of aspirin working correctly, upper GI bleed, or a metallic taste in the mouth.