USMLE Prep - Medical Reference Library

Hyperkalemia - ECG First, Stabilize, Shift, and Remove

System: Metabolic Medicine • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Obtain ECG and stabilize myocardium with calcium for concerning changes, shift potassium intracellularly, and remove with diuretics, binders, or dialysis.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

Hyperkalemia threatens membrane excitability and cardiac conduction; verify with repeat lab and evaluate for hemolysis. Assess ECG for peaked T waves, QRS widening, and sine‑wave morphology; identify precipitants such as renal failure, tissue breakdown, and RAAS‑inhibiting drugs.


Treatment Strategy & Disposition

Stabilize myocardium with IV calcium for ECG changes, shift K⁺ intracellularly with insulin–dextrose and β‑agonists, and enhance elimination via loop diuretics, potassium binders, or dialysis when appropriate. Address causative agents and correct metabolic acidosis. Admit for ECG changes, ongoing tissue breakdown, or need for continuous monitoring; otherwise arrange timely outpatient follow‑up and medication reconciliation.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

Therapy Summary

ActionEffect
Calcium gluconate or chlorideMembrane stabilization
Insulin with dextroseIntracellular shift
Sodium zirconium or patiromerGI removal

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Calcium gluconate (IV)Myocardial membrane stabilizationMinutesECG changes or K ≥6.5Extravasation risk
Sodium bicarbonate (IV)Buffers acidosisMinutesIf severe acidemiaVolume/Na load
Albuterol (neb)β2-agonistMinutesAdjunct shiftTachycardia
Insulin + dextroseCellular K⁺ shiftMinutesTemporizingHypoglycemia
Loop diuretic / dialysisK⁺ removalHoursDefinitive removalVolume depletion / access

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

Notes

Recheck potassium 30 to 60 minutes after shift therapies. Watch for hypoglycemia after insulin.


References

  1. AHA ACLS and electrolyte emergencies — Link
  2. KDIGO potassium disorder statements — Link