Hemodialysis is absolutely indicated in –
**Core Concept**
Hemodialysis is a life-sustaining treatment for patients with end-stage renal disease (ESRD) or acute kidney injury (AKI), primarily aimed at removing waste products, excess fluids, and electrolytes from the blood when the kidneys are no longer capable of performing these functions.
**Why the Correct Answer is Right**
The correct answer is **Hyperkalemia with cardiac arrest**. Hemodialysis is an effective way to rapidly lower serum potassium levels in patients with severe hyperkalemia, especially when cardiac arrest is imminent or has already occurred. During hemodialysis, the potassium is removed from the blood through the dialysis membrane, which helps to normalize the serum potassium levels and prevent further cardiac complications.
**Why Each Wrong Option is Incorrect**
**Option A:** In cases of acute kidney injury (AKI), hemodialysis may be indicated, but it's not the only option and is typically reserved for more severe cases or when there's a need for rapid fluid removal or electrolyte correction.
**Option B:** In cases of chronic kidney disease (CKD) stage 4 or 5, hemodialysis is indicated, but it's not the only option; peritoneal dialysis or conservative management may also be considered, depending on the patient's overall health and preferences.
**Option C:** In cases of acute kidney injury (AKI), hemofiltration or continuous renal replacement therapy (CRRT) may be used as an alternative to hemodialysis, especially in critically ill patients.
**Clinical Pearl / High-Yield Fact**
In patients with severe hyperkalemia, the initial treatment should aim to stabilize cardiac membranes with calcium gluconate, followed by the administration of insulin and glucose to drive potassium into cells, and finally, hemodialysis to remove excess potassium from the blood.
**Correct Answer: D. Hyperkalemia with cardiac arrest**