Potassium Chloride Dosing for a 1-Month-Old Infant with Hypokalemia
For a 1-month-old infant weighing 2.8 kg with hypokalemia, administer potassium chloride at 2-3 mmol/kg/day (5.6-8.4 mmol/day total) with careful monitoring of serum levels and cardiac function. 1
Initial Potassium Replacement
- For severe hypokalemia (serum K+ <2.5 mEq/L), administer KCl at 2-4 mmol/kg/day divided into multiple doses 1
- For a 2.8 kg infant, this translates to 5.6-11.2 mmol/day total 1
- Using KCl 2 mEq/mL concentration, this equals 2.8-5.6 mL/day of the solution 1
- Divide the total daily dose into 4-6 administrations to avoid rapid potassium shifts 2
Administration Method
- For mild to moderate hypokalemia (K+ 2.5-3.5 mEq/L), oral replacement is preferred when bowel function is normal 3
- For severe hypokalemia (K+ <2.0 mEq/L) or when ECG changes are present, IV administration is necessary 4
- IV administration should be done at a controlled rate not exceeding 0.25 mmol/kg/hour (0.7 mmol/hour for this infant) 5
- Central venous access is preferred for concentrations above 40 mEq/L to avoid peripheral vein irritation 4
- For peripheral IV administration, ensure adequate dilution (usually to ≤40 mEq/L) 4
Monitoring Requirements
- Monitor serum potassium levels every 4-6 hours during initial replacement 1
- Ensure adequate urine output (>1 mL/kg/hour) before administering potassium 1
- Monitor ECG for signs of hypo/hyperkalemia, especially during IV administration 5
- Check for signs of fluid overload, particularly important in this young infant 1
Maintenance Dosing
- Once serum potassium normalizes, transition to maintenance dosing of 2-3 mmol/kg/day 2
- For this 2.8 kg infant, maintenance dose would be 5.6-8.4 mmol/day 2
- Adjust fluid intake based on weight (140-160 mL/kg/day for infants >1500g) 2
Special Considerations
- Avoid rapid IV administration as it may cause cardiac arrhythmias 4
- Consider "Cl-free" potassium salts (like potassium acetate) if metabolic acidosis is present 6
- Ensure adequate nutrition with 120 kcal/kg/day to support growth and electrolyte utilization 7
- Be vigilant for rebound hyperkalemia, especially in premature infants 1
Practical Administration
- For oral administration: Divide daily dose (5.6-8.4 mmol) into 4-6 doses (approximately 1-2 mmol per dose) 3
- For IV administration: Maximum rate should not exceed 0.7 mmol/hour for this 2.8 kg infant 5
- Using 2 mEq/mL concentration, this equals 0.35 mL/hour maximum infusion rate 5
- Always administer with a calibrated infusion device when giving IV potassium 4