Chris asks the nurse whether all donor blood products are cross-matched with the recipient to prevent a transfusion reaction. Which of the following always require cross-matching?

Correct Answer: D

Rationale: Packed red blood cells (PRBCs) always require cross-matching to ensure compatibility between the donor and recipient blood types. Cross-matching involves testing the recipient's serum against the donor's red cells to detect antibodies that could cause a transfusion reaction. Granulocytes, platelets, and plasma do not require cross-matching in the same way, although they may undergo other compatibility tests. PRBCs are the most critical to match correctly due to the risk of hemolytic reactions, which can be life-threatening.

Correct Answer: B

Rationale: Diazepam, a benzodiazepine, has active metabolites (e.g., desmethyldiazepam) with longer half-lives, contributing to its effects, so that's false. Activated charcoal is effective in overdose by adsorbing diazepam, reducing absorption, a true statement and standard intervention. It undergoes minimal, not extensive, enterohepatic recirculation, making that false. It's a GABA agonist, enhancing chloride influx via benzodiazepine receptors, not an antagonist, so that's incorrect. It also inhibits spinal reflexes, aiding muscle relaxation. The overdose utility of charcoal highlights its role in emergency management, binding unabsorbed drug in the gut, a key pharmacokinetic intervention distinct from flumazenil reversal.

Correct Answer: A

Rationale: Hypogonadism in males, marked by low testosterone, delays secondary sexual characteristics, like facial hair, which remains minimal, soft, and light due to insufficient androgen stimulation of follicles. Absent pubic hair aligns with this, reflecting poor pubertal development from gonadal dysfunction. Decreased subcutaneous fat is less typical-hypogonadism often increases fat due to estrogen dominance from low testosterone. Small testicles directly indicate testicular failure, a hallmark of primary hypogonadism, reducing hormone and sperm output. Minimal facial hair is a visible, assessable sign tied to androgen deficiency, distinguishing it from normal variation, and supports the diagnosis alongside other findings like testicular size, reflecting the condition's impact on masculinization and reproductive maturity.

Correct Answer: D

Rationale: Lithium's narrow therapeutic range (0.6-1.2 mEq/L) requires frequent blood draws to ensure levels stay safe and effective, preventing toxicity (e.g., tremors) or subtherapeutic dosing. Side effects are monitored clinically, not just by blood. Effectiveness and response tie to levels, but ‘correct amount' is precise, addressing the patient's query directly about monitoring's purpose.

Correct Answer: A

Rationale: Long half-life drugs (e.g., diazepam) linger, risking fetal exposure post-conception, a pharmacokinetic worry for serious conditions. No active metabolites reduce risk. High protein-binding limits free drug, less concern. As-needed use minimizes exposure. Long half-life heightens teratogenic potential, critical in planning.