Enter the serum sodium, normal sodium, total fluid intake, and desired sodium into the calculator to determine the maintenance fluid rate using the Abbott formula.
Abbott Formula
The following formula is used to calculate the maintenance fluid rate:
MFR = (TFI * (NS - SS)) / (DS - SS)
Variables:
- MFR is the maintenance fluid rate (mL/hr)
- TFI is the total fluid intake (L/day)
- NS is the normal sodium level (mEq/L)
- SS is the serum sodium level (mEq/L)
- DS is the desired sodium level (mEq/L)
To calculate the maintenance fluid rate, multiply the total fluid intake by the difference between the normal sodium level and the serum sodium level, then divide by the difference between the desired sodium level and the serum sodium level. The result is then converted from L/day to mL/hr by multiplying by 1000 and dividing by 24.
What is the Abbott Formula?
The Abbott formula is a medical calculation used to determine the maintenance fluid rate for patients, especially in cases of hyponatremia where the sodium level in the blood is lower than normal. It helps in planning the appropriate fluid therapy to correct the sodium imbalance without causing rapid shifts that could lead to complications.
How to Calculate Maintenance Fluid Rate?
The following steps outline how to calculate the Maintenance Fluid Rate using the Abbott Formula.
- First, determine the serum sodium level (SS) in mEq/L.
- Next, determine the normal sodium level (NS) in mEq/L, typically around 140 mEq/L.
- Then, determine the total fluid intake (TFI) in liters per day.
- Next, determine the desired sodium level (DS) in mEq/L.
- Use the formula to calculate the Maintenance Fluid Rate (MFR) in mL/hr.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
Serum Sodium (SS) = 125 mEq/L
Normal Sodium (NS) = 140 mEq/L
Total Fluid Intake (TFI) = 2 L/day
Desired Sodium (DS) = 130 mEq/L
