What is the concentration of a potassium chloride (KCl) solution in milliequivalents per milliliter (mEq/mL) for an 18-month-old child with severe hypokalemia, given that 1 milliliter (mL) of the solution contains 150 milligrams (mg) of potassium chloride?

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Potassium Chloride Solution Concentration Conversion

A solution containing 150 mg potassium chloride per 1 mL equals 2 mEq/mL.

Calculation Method

The conversion is based on the molecular weight and valence of potassium chloride 1:

  • Molecular weight of KCl: 74.5 mg/mEq
  • Calculation: 150 mg ÷ 74.5 mg/mEq = 2.01 mEq/mL (rounded to 2 mEq/mL)

This represents a highly concentrated potassium solution that requires extreme caution in preparation and administration 2.

Critical Safety Considerations for Pediatric Use

For an 18-month-old child with severe hypokalemia, this concentration is dangerously high and must be diluted before administration 2, 3:

Standard Pediatric Dilution Protocol

  • Maximum safe concentration: ≤40 mEq/L (0.04 mEq/mL) for peripheral IV administration 4, 3
  • This solution is 50 times more concentrated than the maximum safe peripheral concentration
  • Never administer undiluted - concentrated potassium chloride must be removed from clinical areas and stored only in locked cupboards in critical care settings 5

Recommended Approach for Severe Pediatric Hypokalemia

If the child has severe hypokalemia with ECG changes 4, 3:

  • Initial bolus: 0.25 mEq/kg IV over 30 minutes (diluted to ≤40 mEq/L concentration) 4
  • Continuous infusion: 0.25 mEq/kg/hour with continuous cardiac monitoring 4, 3
  • Verify adequate urine output (≥0.5 mL/kg/hour) before starting potassium replacement 4
  • Check and correct magnesium first (target >0.6 mmol/L), as hypomagnesemia makes hypokalemia resistant to correction 4

Critical Safety Measures

  • Institute double-check policy for all potassium administration 5
  • Use pre-prepared IV infusions containing potassium when available 5
  • Continuous cardiac monitoring is mandatory during rapid correction 4, 3
  • Recheck potassium levels within 1-2 hours after initial bolus 4

Common Pitfall to Avoid

Never use this 2 mEq/mL concentration directly for IV administration - accidental bolus administration of concentrated potassium can cause cardiac arrest 2, 6. The solution must be diluted at least 50-fold before peripheral IV use 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

IV Potassium Correction for Severe Pediatric Hypokalemia

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Guideline

Potassium Supplementation for Hypokalemia

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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