From the Guidelines
Hyperkalemia becomes critical when serum potassium levels exceed 6.0 mmol/L, as levels above this threshold are considered severe and potentially life-threatening. At these elevated levels, patients face significant risk of cardiac arrhythmias and sudden cardiac death due to the effect of potassium on cardiac membrane potentials 1.
Classification of Hyperkalemia
The severity of hyperkalemia can be classified as mild (>5.0 to <5.5 mEq/L) to moderate (5.5 to 6.0 mEq/L) and to severe at thresholds (>6.0 mEq/L) 1.
Treatment of Hyperkalemia
Immediate treatment is necessary and typically includes calcium gluconate 10% (10 mL IV over 2-3 minutes) to stabilize cardiac membranes, followed by insulin (10 units regular insulin IV) with glucose (25-50g IV) to shift potassium intracellularly 1. Sodium bicarbonate (50 mEq IV over 5 minutes) may be used in acidotic patients, and nebulized albuterol (10-20 mg) can also help shift potassium into cells. These temporizing measures should be accompanied by interventions to remove potassium from the body, such as sodium polystyrene sulfonate (15-30g orally or rectally), loop diuretics if kidney function permits, or hemodialysis in severe cases or renal failure.
Monitoring
ECG monitoring is essential during treatment, with typical hyperkalemic changes including peaked T waves, widened QRS complexes, and eventual sine wave pattern in extreme cases 1.
Key Considerations
It's crucial to evaluate the patient's diet, use of supplements, salt substitutes, and nutraceuticals that contain K+ as well as concomitant medications that may contribute to hyperkalemia 1. Kidney function must be determined and monitored, and a low-K+ diet and loop or thiazide diuretics that increase K+ excretion may be considered to reduce the occurrence of hyperkalemia.
From the Research
Definition and Critical Level of Hyperkalemia
- Hyperkalemia is defined as a condition where a serum potassium level is >5.5 mmol/l 2
- However, other studies suggest that hyperkalemia occurs when serum potassium levels are greater than 5.0 mEq per L 3
- The critical level of hyperkalemia that requires immediate treatment is generally considered to be a serum potassium concentration >6.0 mEq/l, especially when accompanied by EKG changes 4
Clinical Considerations and Treatment
- Hyperkalemia can be deadly and requires specific measures, including membrane stabilization, cellular shift, and excretion 5
- Treatment options include glucose and insulin, bicarbonate, calcium gluconate, beta-2 agonists, hyperventilation, and dialysis 2
- The combination of nebulised beta agonists with IV insulin-and-glucose may be more effective than either alone in managing emergency hyperkalaemia 6
Severity and Emergency Interventions
- Severe hyperkalemia can lead to fatal dysrhythmias and muscular dysfunction 2
- Emergency interventions for hyperkalaemia include intravenous calcium, insulin, sodium bicarbonate, diuretics, and beta agonists 3
- Dialysis may be considered in the presence of end-stage renal disease, severe renal impairment, or ongoing potassium release 3