Can serum potassium level be used as a criterion to terminate resuscitation in cardiac arrest?

NO - Serum Potassium Should NOT Be Used as a Criterion to Stop Resuscitation in Cardiac Arrest

Serum potassium levels should not be used as a criterion to terminate resuscitation efforts in cardiac arrest, as current guidelines do not support this practice and evidence shows that even markedly elevated potassium levels do not reliably predict futility of resuscitation.

Guideline Position

The 2025 American Heart Association guidelines 1 and the 2025 International Liaison Committee on Resuscitation (ILCOR) consensus 2 make no mention of using potassium levels as termination criteria. In fact, the guidelines emphasize that the utility of therapies intended to lower potassium concentrations during cardiac arrest is unclear when weighing their possible benefits against the risk of interrupting well-established interventions like CPR 1. This statement implicitly suggests that potassium management is secondary to high-quality CPR, not a criterion for stopping it.

Evidence Against Using Potassium as a Termination Criterion

Hyperkalemia Does Not Predict Futility

While hyperkalemia is associated with worse outcomes, it does not preclude successful resuscitation:

• In a 2025 Danish study of 4,894 OHCA survivors with ROSC, patients with severe hyperkalemia (>6.0 mmol/L) still achieved 22.7% survival at 30 days 3. This demonstrates that even markedly elevated potassium levels are compatible with meaningful survival.

• A 2020 Korean study found that 54.4% of OHCA patients had hyperkalemia on arrival, yet many achieved good neurological outcomes 4. The presence of hyperkalemia was common and did not automatically indicate futility.

• In a 2018 Chinese study, patients with hyperkalemia had shorter survival duration but many still achieved ROSC 5, indicating that elevated potassium does not preclude initial resuscitation success.

Hypokalemia May Actually Predict Better Outcomes

Paradoxically, hypokalemia appears associated with better neurological outcomes:

• The 2020 Korean study found that hypokalemia (<3.5 mEq/L) was associated with significantly better neurological outcomes (26.1% good outcomes) compared to normokalemia and hyperkalemia 4. This had an odds ratio of 4.45 for neurologically favorable survival.

• A 2025 Danish study confirmed that hypokalemia was NOT associated with reduced 30-day survival 3, contrary to what might be expected.

Special Consideration: Hypothermic Cardiac Arrest

The only context where potassium has been studied as a prognostic marker is hypothermic cardiac arrest, where it serves as a triage tool:

• A 1995 canine study found that very high potassium following prolonged hypothermic cardiac arrest may suggest inability to resuscitate, but potassium after brief CPR was not a good predictor 6.

• A 2017 systematic review explained that hypothermia initially causes hypokalemia, but the final stage of hypothermic cardiac arrest can induce hyperkalemia due to cell lysis 7. This makes potassium a potential marker of irreversible cell death specifically in hypothermia.

However, this is specific to hypothermic arrest and should not be extrapolated to normothermic cardiac arrest.

Clinical Algorithm for Potassium Management During Cardiac Arrest

Rather than using potassium as a termination criterion, follow this approach:

1. Continue high-quality CPR regardless of potassium level - This is the priority per guidelines 1, 2

2. If hyperkalemia is suspected as the cause:

   • Administer IV insulin with glucose (weak recommendation) 2
   • Consider calcium and sodium bicarbonate, though evidence is insufficient 2
   • Do NOT interrupt CPR to administer these therapies

3. If hypokalemia is identified as the cause:

   • Rapidly administer IV potassium (10 mEq/100 mL over 5 minutes) 8, 9
   • This is a reversible cause that warrants aggressive treatment
   • A 2026 case report demonstrated successful resuscitation from hypokalemic VT cardiac arrest using rapid IV potassium 8

4. Use standard termination of resuscitation criteria - Not potassium-based

Common Pitfalls to Avoid

• Do not delay or terminate resuscitation based on elevated potassium alone - Even levels >6.0 mmol/L are compatible with survival 3

• Do not assume hyperkalemia means futility - It is associated with worse outcomes but not absolute futility

• Do not overlook hypokalemia as a reversible cause - This requires rapid, aggressive potassium replacement 8, 9

• Do not extrapolate hypothermia data to normothermic arrest - Potassium physiology differs markedly 7

The Bottom Line

Standard termination of resuscitation criteria should guide decisions to stop CPR, not serum potassium levels. Potassium abnormalities should be treated as potentially reversible causes of cardiac arrest, with continued high-quality CPR taking priority over all other interventions 1, 2.