Acute Care Nurse Practitioner Acute Kidney Injury and Renal Replacement Therapy 2 — Questions and Answers
Question 1: Which indication for renal replacement therapy (RRT) is considered an EMERGENCY requiring immediate initiation?
- BUN >80 mg/dL
- Creatinine >4 mg/dL
- Severe hyperkalemia with ECG changes (Correct answer)
- Urine output <0.5 mL/kg/hr for 6 hours
Correct answer: Severe hyperkalemia with ECG changes
Severe hyperkalemia causing ECG changes (peaked T waves, wide QRS, sine wave pattern) is a life-threatening emergency requiring immediate RRT.
Question 2: Which modality of RRT is preferred for hemodynamically unstable ICU patients?
- Intermittent hemodialysis (IHD)
- Continuous renal replacement therapy (CRRT) (Correct answer)
- Peritoneal dialysis
- Sustained low-efficiency dialysis (SLED)
Correct answer: Continuous renal replacement therapy (CRRT)
CRRT is preferred in hemodynamically unstable patients because it provides slow, continuous fluid and solute removal without causing rapid osmotic shifts.
Question 3: Which anticoagulation is MOST commonly used in CRRT to prevent circuit clotting while minimizing systemic bleeding risk?
- Systemic heparin infusion
- Citrate regional anticoagulation (Correct answer)
- Warfarin
- Enoxaparin
Correct answer: Citrate regional anticoagulation
Regional citrate anticoagulation confines anticoagulation to the extracorporeal circuit, minimizing systemic bleeding risk in high-risk patients.
Question 4: A patient on CRRT receiving citrate anticoagulation develops rising total calcium with decreasing ionized calcium. What does this indicate?
- Adequate anticoagulation
- Citrate toxicity/accumulation (Correct answer)
- Hypocalcemia from calcium chelation
- Equipment malfunction
Correct answer: Citrate toxicity/accumulation
Rising total calcium with low ionized calcium (high total/ionized ratio >2.5) indicates citrate accumulation, usually from hepatic failure impairing citrate metabolism.
Question 5: Which condition is MOST likely to cause a false elevation in serum creatinine without true reduction in GFR?
- High protein diet
- Rhabdomyolysis
- Trimethoprim use (Correct answer)
- Hypoalbuminemia
Correct answer: Trimethoprim use
Trimethoprim (and cimetidine) blocks tubular secretion of creatinine, raising serum creatinine without changing GFR or true kidney function.
Question 6: Recovery of renal function after AKI in the ICU is BEST predicted by which factor?
- Peak creatinine level
- Duration of oliguria before RRT initiation
- Underlying cause of AKI (reversibility) (Correct answer)
- Patient age
Correct answer: Underlying cause of AKI (reversibility)
The underlying etiology and its reversibility is the strongest predictor of renal recovery; pre-renal and ATN from reversible causes recover more reliably than CKD-related AKI.
Acute Care Nurse Practitioner Acute Kidney Injury and Renal Replacement Therapy 2
Which indication for renal replacement therapy (RRT) is considered an EMERGENCY requiring immediate initiation?