Potassium Chloride Infusion Protocol
For 40 mEq of potassium chloride administered over 4 hours, use 200 mL of 5% dextrose solution, delivering the infusion at 50 mL/hour (10 mEq/hour). 1, 2
Concentration and Rate Rationale
The standard safe concentration is 200 mEq/L (20 mEq per 100 mL), which has been extensively validated in intensive care settings without causing life-threatening arrhythmias 1, 3
For your 40 mEq dose, this translates to 200 mL of 5% dextrose (40 mEq ÷ 200 mEq/L = 0.2 L = 200 mL) 1, 2
The maximum safe infusion rate is 20 mEq/hour through either central or peripheral venous access 1, 3
Your 4-hour timeframe delivers 10 mEq/hour (50 mL/hour), which is well below the maximum safe rate and appropriate for hypokalemia correction 1, 3
Expected Outcomes
Each 20 mEq infusion typically raises serum potassium by 0.25 mmol/L, so your 40 mEq dose should increase potassium by approximately 0.5 mmol/L 1
Peak potassium levels occur within 1 hour post-infusion, with sustained elevation maintained throughout the infusion period 3
Administration Route Considerations
Both central and peripheral venous administration are safe at this concentration and rate 1, 3
Central venous administration (via subclavian catheter) of 20 mEq KCl in 100 mL 5% dextrose over 1 hour has been specifically validated without causing cardiac rhythm disturbances 2
Critical Safety Parameters
Verify serum potassium is >3.3 mEq/L before starting the infusion—if below this threshold, correct potassium first before adding to maintenance fluids 4
Confirm adequate renal function before initiating potassium replacement 4
Monitor ECG continuously during infusion, particularly watching for changes in cardiac conduction intervals 3, 5
Measure serum potassium levels at baseline, mid-infusion (2 hours), and 1 hour post-completion 1, 3
Common Pitfalls to Avoid
Do not exceed 20 mEq/hour infusion rate even if potassium is critically low, as faster rates have not been adequately studied for safety 1, 3
Avoid using normal saline as the diluent when the patient requires concurrent dextrose-containing fluids for other indications; 5% dextrose is the appropriate vehicle 2
Do not administer if potassium is <3.3 mEq/L—this requires more aggressive initial correction before maintenance replacement 4
Watch for mild hyperkalemia (occurs in approximately 2% of infusions), though this is typically transient and clinically insignificant 1
Monitoring During Infusion
Continuous ECG monitoring is essential, with particular attention to premature ventricular beats (which typically decrease during appropriate potassium replacement) 3
Vital signs every 30-60 minutes including heart rate, blood pressure, and respiratory rate 2
No new or worsening ventricular ectopy should occur with proper administration rates 2, 3