Initial treatment of autoimmune hemolytic anemia is with:

Correct Answer: C

Rationale: Initial AIHA treatment is corticosteroids (C e.g., prednisone 1 mg/kg), suppressing antibody production, raising Hb (e.g., >10 g/dL) in 70% of warm cases. Splenectomy (A) is second-line. Myelosuppressives (B) are later (e.g., rituximab). Plasma (D) is coagulopathy-related. None' denies. Steroids' rapid effect is key, guiding nursing for taper and side effect watch.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: PCO2, or partial pressure of carbon dioxide, reflects the concentration of CO2 in blood, highest where metabolic waste accumulates and lowest where gas exchange removes it. The superior vena cava (SVC) carries deoxygenated blood from the upper body back to the heart, rich in CO2 from tissue metabolism, typically with a PCO2 of 45-46 mmHg, making it the highest among the options. Pulmonary veins carry oxygenated blood from the lungs to the heart after CO2 is offloaded in the alveoli, so their PCO2 is low (around 40 mmHg, arterial level). The midportion of pulmonary capillaries is where gas exchange occurs, transitioning from high venous PCO2 to lower arterial levels, averaging less than the SVC. Carotid bodies are chemoreceptors sensing blood gases, not a blood-containing structure, but even arterial blood they monitor has a PCO2 of about 40 mmHg. The SVC, as a major venous return vessel, consistently has the highest PCO2 due to its role in collecting metabolically produced CO2 before pulmonary gas exchange, distinguishing it from the other options.

Correct Answer: B

Rationale: Atmospheric air contains approximately 21% oxygen (O2) and 0.04% carbon dioxide (CO2), meaning O2's percentage is much higher than CO2's, reflecting their natural abundances. Solubility in blood, governed by Henry's law, depends on the solubility coefficient of each gas. O2 has a solubility coefficient of about 0.024 ml O2/mmHg/L blood, while CO2's is much higher at 0.51 ml CO2/mmHg/L blood over 20 times greater. This means CO2 is far more soluble in solution than O2, despite its lower atmospheric presence. In blood, O2 relies heavily on hemoglobin binding (98% of transport), with only ~1-2% dissolved, whereas CO2 is transported dissolved (~7%), as bicarbonate (~70%), and bound to hemoglobin (~23%), leveraging its high solubility. Thus, O2's higher atmospheric percentage contrasts with its lower solubility compared to CO2, driving distinct transport mechanisms critical for respiration and acid-base balance.