1. What is Potassium Replacement Calculation?

The potassium replacement calculation estimates the amount of potassium (in milliequivalents) needed to correct hypokalemia based on serum potassium level and patient's weight.

2. How Does the Calculator Work?

The calculator uses the potassium replacement formula:

Where:

• \( \text{Serum K} \) — Serum potassium level (mEq/L)
• \( \text{Weight} \) — Patient's weight in kilograms
• 0.27 — Empirical constant for distribution space

Explanation: The formula accounts for the deficit in extracellular potassium and estimates total body potassium deficit.

3. Importance of Potassium Replacement

Details: Accurate potassium replacement is crucial for treating hypokalemia while avoiding overcorrection which can lead to hyperkalemia.

4. Using the Calculator

Tips: Enter serum potassium in mEq/L (must be less than 4.0) and weight in kg. All values must be valid (potassium > 0, weight > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is 4.0 used in the formula?
A: 4.0 mEq/L is considered the lower threshold of normal serum potassium level.

Q2: How should the replacement be administered?
A: Typically given orally when possible. IV replacement should be carefully monitored and generally not exceed 20 mEq/hr in non-critical situations.

Q3: Are there limitations to this calculation?
A: This is an estimate. Actual requirements may vary based on clinical context, renal function, and ongoing losses.

Q4: What about patients with renal impairment?
A: These patients require careful monitoring and slower replacement due to reduced potassium excretion.

Q5: Should magnesium be checked?
A: Yes, hypomagnesemia can cause refractory hypokalemia and should be corrected simultaneously.