Potassium (K+)
The major intracellular cation essential for cellular and cardiac function
Definition
Potassium (K+) is the predominant intracellular cation, critical for membrane potential, nerve conduction, cardiac rhythm, skeletal and smooth muscle function, and acid-base balance.
Normal and Critical Values
- Normal: 3.5 to 5.0 mEq/L
- Hypokalemia: less than 3.5
- Hyperkalemia: greater than 5.0
- Critically low: less than 2.5
- Critically high: greater than 6.5
Safety Rules for IV Potassium
- NEVER administer IV push. Cardiac arrest risk
- Always dilute
- Maximum peripheral rate: 10 mEq/hr
- Maximum central rate: 20 mEq/hr
- Always use infusion pump
- Monitor ECG during rapid replacement
- Assess for phlebitis and infiltration
Nursing Considerations
Monitor kidney function before and during replacement. Assess for digoxin therapy (hypokalemia causes digoxin toxicity). Teach patients food sources (bananas, oranges, spinach, potatoes) and to avoid salt substitutes containing K+ if on K-sparing drugs.
NCLEX Relevance
NEVER push IV potassium.