Learning objectives

• Definition, diagnosis, and management of hyperkalemia

Definition

• Hyperkalemia is an elevated level of potassium (K+) in the blood:
  • Mild: a serum K+ 5.5 – 5.9 mmol/L
  • Moderate: a serum K+6.0-6.4 mmol/L
  • Severe: a serum K+  ≥ 6.5  mmol/L

Signs and symptoms

• Gastro-intestinal
  • Nausea
  • Vomiting
  • Diarrhea
• Neuromuscular 
  • Paresthesias
  • Muscle fasciculations
  • Ascending paralysis of the extremities (quadriplegia)
• Cardiac
  • Dyspnea
  • Progressive ECG changes with increasing severity of hyperkalemia
    • Peaked T wave
    • Wide PR interval
    • Wide QRS duration
    • Loss of P wave
    • Sinusoidal wave

Causes

Management

• First, ensure that the lab result is correct and rule out pseudohyperkalemia
• Typical examples:
  • Poor storage of blood specimens
  • Long transport time from blood draw of the sample to processing in the lab

Suggested reading

• Lott C, Truhlář A, Alfonzo A, et al. European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances [published correction appears in Resuscitation. 2021 Oct;167:91-92]. Resuscitation. 2021;161:152-219.
• Palmer BF, Carrero JJ, Clegg DJ, et al. Clinical Management of Hyperkalemia. Mayo Clin Proc. 2021;96(3):744-762.
• Palmer BF, Clegg DJ. Diagnosis and treatment of hyperkalemia. Cleve Clin J Med. 2017;84(12):934-942. doi:10.3949/ccjm.84a.17056

Clinical updates

Jessen et al. (Resuscitation, 2025) conducted a systematic review and meta-analysis showing that insulin with glucose lowers serum potassium by about 0.7 mmol/L within 60 minutes, while inhaled or IV beta₂-agonists (e.g., salbutamol) reduce potassium by 0.9–1.0 mmol/L, with combination therapy achieving up to a 1.2 mmol/L reduction. In contrast, bicarbonate showed no meaningful potassium-lowering effect, and there is no high-quality evidence that calcium improves outcomes beyond membrane stabilization. These findings support insulin–glucose and beta₂-agonists as first-line therapies for acute hyperkalemia and call for re-evaluation of routine bicarbonate and calcium use.

• Read more about this study HERE.
• Listen to NYSORA’s podcast discussing this HERE.

Glahn et al. (British Journal of Anaesthesia, 2025) highlight in the updated 2024 EMHG guidelines that severe hyperkalemia is a key life-threatening feature of malignant hyperthermia (MH) and requires immediate treatment alongside dantrolene. Recommended management includes IV insulin with dextrose, IV calcium chloride or gluconate for membrane stabilization, beta₂-agonists, and dialysis in refractory cases, with close potassium and ECG monitoring. The guideline reinforces structured, protocol-driven hyperkalemia treatment as a core component of MH crisis management to prevent arrhythmias and cardiac arrest.

• Read more about this study HERE.

Zhou et al. (Anesthesiology, 2026) emphasize that hyperkalemia during massive transfusion is driven not only by patient factors but also by the potassium load and delivery rate of stored pRBCs: extracellular potassium rises roughly 1 mEq/L per storage day and may exceed 40 mEq/L near expiration, with irradiated units accumulating even higher concentrations. They recommend prevention through shorter-storage blood when feasible and, in patients with impaired potassium clearance or anticipated supramassive transfusion, early use of intraoperative pRBC washing, which can remove > 90% of extracellular potassium when appropriately performed, plus tailored CRRT and pharmacologic therapy; importantly, actual CRRT potassium clearance may be substantially lower than theoretical estimates and may require aggressive flow and dialysate adjustments. 

• Read more about this study HERE.