Addisonian crisis requires rapid replacement of both circulating volume and cortisol. The immediate priority is to stabilize the patient’s hemodynamics and metabolic stress because cortisol deficiency contributes to hypotension, shock, and electrolyte disturbances. Initiating IV isotonic fluids, usually normal saline, quickly expands intravascular volume, corrects dehydration, and helps normalize blood pressure and sodium balance. At the same time, providing steroids—typically hydrocortisone given IV—replaces the missing cortisol and also offers some mineralocorticoid activity, which supports vascular responsiveness and sodium retention during this acute crisis. This combination addresses the underlying deficiency and the life-threatening instability. Desmopressin is not indicated for adrenal crisis; it treats ADH-related disorders, not cortisol deficiency. Relying on electrolyte repletion alone won’t resolve the crisis because the primary issue is cortisol deficiency. Oral hydration is insufficient in this acute setting where rapid stabilization is needed. After stabilization, ongoing management includes careful electrolyte monitoring and transitioning to longer-term adrenal replacement as appropriate.

Prioritize airway first because nothing else can help if air can’t reach the lungs. An open airway allows rescue breaths to actually enter the lungs and begin oxygenating the blood. If the airway is blocked or collapsed, ventilation won’t occur and oxygen delivery to tissues stops, even if you’re delivering breaths or performing compressions. Once the airway is clear, focus on breathing to ensure ventilation is happening effectively. Providing breaths helps move oxygen into the lungs and into the bloodstream, supporting oxygen delivery to the brain and other vital organs. If the person isn’t breathing adequately on their own, give rescue breaths to establish ventilation. Only after establishing an open airway and ensuring ventilation should you address circulation. Chest compressions move oxygenated blood to the heart and brain, sustaining perfusion while you continue airway and breathing support. If there’s no detectable pulse, start compressions to maintain circulation as you continue airway management and breathing. This sequence minimizes time where the brain and heart are not getting oxygen, making it the most effective order for basic life support.

The key idea is the time window for giving intravenous tPA in acute ischemic stroke. IV tPA is most beneficial when given as early as possible after onset, but safety limits the treatment to a specific timeframe. For eligible adults, the approved window extends up to 4.5 hours from symptom onset, with the standard 3-hour window applying to broader eligibility and a 4.5-hour extension for select patients who meet additional criteria. This explains why the best choice is the 3-4.5 hour window. Treating beyond 4.5 hours increases the risk of harm without meaningful benefit. Remember that aiming for rapid treatment is crucial, though door-to-needle time is a separate performance goal from the onset-to-treatment window.

In heart failure management, drugs that both relieve symptoms and improve outcomes are essential. Loop diuretics like furosemide address fluid overload and edema quickly, helping to reduce congestion and improve breathing and comfort. ACE inhibitors counter the harmful activation of the renin-angiotensin-aldosterone system, decreasing afterload and preventing adverse remodeling of the heart, which translates to better survival and fewer hospitalizations in many patients with systolic dysfunction. These two classes together represent a core pharmacologic approach to treating heart failure. Other options don’t fit the typical treatment goals. Antibiotics treat infection, not heart failure itself, and insulin is used for diabetes management, not HF treatment. Calcium channel blockers are not the primary therapy for heart failure and, depending on the type of HF, may not provide the same mortality and symptom-relief benefits as the combination of diuretics and ACE inhibitors.