TPN Infusion Rate Calculator
Calculated Results
Hourly Infusion Rate: mL/hr
Drip Rate: gtts/min
How to Calculate TPN Infusion Rates
Total Parenteral Nutrition (TPN) is a complex intravenous solution designed to provide all the necessary nutrients for patients who cannot use their digestive systems. Calculating the correct infusion rate is critical to prevent metabolic complications such as hyperglycemia or fluid overload.
The Basic Infusion Rate Formula
To find the hourly infusion rate in milliliters per hour (mL/hr), you use the following formula:
Calculating the Drip Rate (gtts/min)
If you are using manual gravity tubing rather than an infusion pump, you must calculate the drip rate based on the tubing's drop factor. The formula is:
Practical Example
A physician orders 1,800 mL of TPN to be infused over 24 hours. The tubing has a drop factor of 15 gtts/mL.
- Step 1: Calculate mL/hr: 1,800 mL ÷ 24 hours = 75 mL/hr.
- Step 2: Calculate gtts/min: (1,800 × 15) ÷ (24 × 60) = 27,000 ÷ 1,440 = 18.75 gtts/min.
Common Infusion Standards
| Typical Patient Type | Standard Duration | Average Rate (Estimate) |
|---|---|---|
| Standard Hospitalized Adult | 24 Hours | 80 – 125 mL/hr |
| Home Care (Cyclic TPN) | 12 – 14 Hours | 150 – 200 mL/hr |
| Critically Ill (Fluid Restricted) | 24 Hours | 40 – 60 mL/hr |
Critical Safety Considerations
When managing TPN rates, healthcare providers must monitor blood glucose levels frequently (often every 6 hours) and check electrolytes daily. Sudden changes in the infusion rate can cause severe shifts in insulin levels and fluid balance. Always use an electronic infusion pump for TPN when possible to ensure accuracy and prevent "free-flow" accidents.