Hypokalaemia
Disclaimer
Hypokalaemia management guidelines are not yet well established as a dedicated, universally accepted guideline. Therefore, the information presented in this section is derived from clinical practice patterns, UK trust guidelines, and general medical literature rather than a single guideline.
The exact details of hypokalaemia management may differ between trusts, reflecting local protocols and resources. However, the fundamental management principles remain consistent.
Background Information
Definition
Hypokalaemia is defined by a serum potassium <3.5 mmol/L
Classification of severity:
| Severity | Potassium concentration (mmol/L) |
|---|---|
| Mild | 3.0-3.5 |
| Moderate | 2.5-2.9 |
| Severe | <2.5 |
Aetiology (to be added)
Clinical Features (to be added)
ECG Changes (to be added)
Management
Initial Management
- Identify any reversible causes and manage appropriately
- Stop any potassium-lowering medications if possible
Potassium Replacement
Oral potassium chloride is preferred if the GI tract is functional, and the patient is not NBM
In hypokalaemia, hypomagnesemia should be excluded and treated first if present before potassium replacement
- Hypomagnesemia commonly coexists with hypokalemia and can impair potassium reabsorption in the kidney
- Failure to correct magnesium deficiency can result in persistent or refractory hypokalemia despite potassium supplementation
Emergency treatment with IV potassium chloride is indicated if:
- Severe hypokalaemia (<2.5 mmol/L), or
- Symptomatic, or
- ECG changes present
Only use ready-made diluted potassium solution, NEVER add further potassium into a pre-made bag.
Precautions with peripheral IV potassium use:
- Maximum infusion rate WITHOUT cardiac monitoring is 10 mmol/hr
- Maximum infusion rate WITH cardiac monitoring is 20 mmol/hr
- Maximum K+ concentration of 40 mmol/L
Central venous access is necessary if the rate >20 mmol/hr (due to risk of arrhythmias/cardiotoxicity) or if the concentration is >40 mmol/L (as these concentrations are phlebitic).