Decompensated Heart Failure with Hyperkalaemia and Borderline Perfusion
Mr A is a 71-year-old man with heart failure with reduced ejection fraction (LVEF 28%), permanent atrial fibrillation, stage 3b chronic kidney disease (baseline creatinine 1.6 mg/dL), type 2 diabetes, and a prior inferior myocardial infarction. His regimen is sacubitril/valsartan 97/103 mg twice daily, carvedilol 6.25 mg twice daily, spironolactone 25 mg daily, empagliflozin 10 mg daily, and apixaban 5 mg twice daily. He presents after 10 days of worsening dyspnoea with a 6 kg weight gain, orthopnoea, and bibasal crackles to the mid-zones. Supine blood pressure is 96/58 mmHg, heart rate 104 irregular, respiratory rate 24, and oxygen saturation 91% on room air. Laboratory results: creatinine 2.1 mg/dL, potassium 5.8 mmol/L, sodium 131 mmol/L, bicarbonate 21 mmol/L, NT-proBNP 8,900 pg/mL. The ECG shows atrial fibrillation at 100–110 bpm with QRS 96 ms and no peaked T waves. Chest radiography confirms pulmonary oedema. He is alert, not in shock, and has passed 30 mL/h of urine.
1. How would you initiate decongestion and manage the potassium of 5.8 mmol/L in this haemodynamically borderline patient? Give specific agents, doses and monitoring.
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Start intravenous furosemide 40 mg now. He is loop-naïve, so this is roughly 1–2 times an equivalent oral dose; reassess urine output and symptoms at 2–4 hours and, if output is under 100–150 mL/h, double the dose to 80 mg IV rather than adding a second agent prematurely. Do not wait for the creatinine to improve - a modest creatinine rise during effective decongestion is common and usually transient.
For potassium 5.8 mmol/L with a normal QRS and no peaked T waves, there is no indication for intravenous calcium. Stop spironolactone, start a potassium binder such as sodium zirconium cyclosilicate 10 g three times daily, restrict dietary potassium, and recheck potassium and creatinine at 6 and 24 hours. Avoid NSAIDs and trimethoprim.
He does not need inotropes: he is alert, perfusing and making urine. Escalate to a second diuretic or ultrafiltration only if he remains congested with poor output after adequate loop doses. The judgement point is to treat congestion aggressively while respecting the low blood pressure rather than reflexively stopping all heart failure therapy.
2. Which of his heart failure drugs would you continue, reduce or stop today, and why?
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Apply a hierarchy of risk rather than stopping everything at once.
- Apixaban 5 mg twice daily: continue. He meets only one of the three dose-reduction criteria (creatinine ≥1.5 mg/dL), so the full dose is correct, and interrupting anticoagulation in permanent AF with this stroke risk is more dangerous than continuing while he is not bleeding.
- Carvedilol 6.25 mg twice daily: continue unless he becomes shocked or persistently symptomatic with hypotension. Abrupt beta-blocker withdrawal can precipitate tachycardia and ischaemia, and a heart rate of 104 suggests he is not over-blocked.
- Spironolactone: stop. Potassium 5.8 mmol/L is an absolute contraindication to continuing a mineralocorticoid receptor antagonist and it is the most likely contributor.
- Sacubitril/valsartan: reduce to 49/51 mg twice daily rather than stopping, because systolic pressure is under 100 mmHg and creatinine has risen. Re-titrate once decongested and pressures allow.
- Empagliflozin: reasonable to hold during this acute illness with hypotension and AKI, then restart before discharge if he is eating and stable.
The principle is to remove only what is immediately dangerous, document a plan for re-titration, and avoid the common error of discharging patients on a permanently de-escalated regimen.
3. What would make you move to inotropes or renal replacement therapy, and what common interventions would you avoid?
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Escalate on the basis of perfusion, not the blood pressure number.
- Inotropes: consider dobutamine 2.5–5 micrograms/kg/min if he develops cold extremities, rising lactate, worsening confusion, or urine output below 0.3 mL/kg/h despite adequate diuresis. Low blood pressure alone with clear mentation and good urine output is not an indication; inotropes increase myocardial oxygen demand and arrhythmia risk and do not treat congestion.
- Renal replacement therapy or ultrafiltration: indicated for diuretic resistance with persistent congestion, refractory hyperkalaemia, severe acidosis, or uraemic complications. It removes fluid but does not improve survival, so it is a rescue strategy.
- Avoid: fluid boluses for the low blood pressure, nephrotoxins such as NSAIDs, contrast and aminoglycosides, routine intravenous calcium for a potassium of 5.8 without ECG changes, and permanently discontinuing neurohormonal therapy because of a transient creatinine rise.
Reassess after 24 hours with weight, urine output, electrolytes and renal function. The trap is treating the monitor rather than the patient: a pressure of 96/58 mmHg with preserved mentation and urine output is compensated, whereas a normal pressure with rising lactate and oliguria is not.