**Core Concept**
The patient is experiencing septic shock due to lobar pneumonia, which is not adequately responding to antibiotics, despite initial improvement in fever. The patient's blood pressure is low, and the presence of warm skin and full peripheral pulses suggests a vasodilatory component to the shock.

**Why the Correct Answer is Right**
The patient's condition suggests a severe inflammatory response to the infection, which is causing vasodilation and leading to hypotension. The use of vasopressors such as norepinephrine has helped to maintain a perfusing blood pressure, but the patient's vasodilatory shock is likely due to the release of inflammatory mediators such as nitric oxide and prostacyclin. The administration of corticosteroids, specifically hydrocortisone, can help to mitigate this vasodilatory response by inhibiting the production of these inflammatory mediators and thereby improving blood pressure.

**Why Each Wrong Option is Incorrect**
**Option A:** Administering more norepinephrine would not address the underlying cause of the vasodilatory shock and may lead to tachyphylaxis.
**Option B:** The patient's condition does not suggest a need for mechanical ventilation weaning, as the SpO2 is still 92% on room air.
**Option C:** There is no indication that the patient has acute respiratory distress syndrome (ARDS), as the SpO2 is still within a relatively normal range.

**Clinical Pearl / High-Yield Fact**
In septic shock, particularly in the context of vasodilatory shock, corticosteroids such as hydrocortisone can be a game-changer in improving blood pressure and potentially reducing mortality.

**Correct Answer:** C. Administer hydrocortisone 50 mg IV every 6 hours.