1. What is Potassium Deficit?

The total body potassium deficit represents the estimated amount of potassium that needs to be replaced to correct hypokalemia, accounting for age-related differences in total body potassium distribution.

2. How Does the Calculator Work?

The calculator uses the potassium deficit equation:

Where:

• \( K \) — Serum potassium level (mmol/L)
• \( TBW \) — Total body water (liters)
• \( \text{Age Factor} \) — 1.2 (children), 1.0 (adults), or 0.8 (elderly)

Explanation: The equation estimates the potassium deficit based on the difference from normal potassium levels (4 mmol/L), adjusted for body water content and age-related distribution.

3. Importance of Potassium Deficit Calculation

Details: Accurate potassium deficit estimation is crucial for safe and effective correction of hypokalemia, preventing both under- and over-replacement.

4. Using the Calculator

Tips: Enter serum potassium in mmol/L, total body water in liters, and select the appropriate age factor. All values must be valid (K > 0, TBW > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why use different age factors?
A: Children have higher intracellular potassium per kg body weight, while elderly have reduced total body potassium stores.

Q2: How is total body water estimated?
A: TBW can be estimated as 60% of body weight in young men, 50% in young women, and lower percentages in elderly.

Q3: What are normal potassium levels?
A: Normal serum potassium is typically 3.5-5.0 mmol/L, with 4.0 mmol/L used as the reference for deficit calculation.

Q4: Are there limitations to this calculation?
A: This provides only an estimate. Actual deficits may vary based on acid-base status, renal function, and medications.

Q5: How should potassium be replaced?
A: Replacement should be guided by serial potassium measurements, with most of the deficit replaced intravenously in symptomatic patients.