Calculator Inputs
Example Data Table
| Scenario | Weight (kg) | Glucose (mg/dL) | Bag | Start Rate | Pump Rate | Reduced Rate |
|---|---|---|---|---|---|---|
| Adult DKA example | 70 | 350 | 100 units in 100 mL | 0.1 units/kg/hour | 7 mL/hour | 0.05 units/kg/hour |
| Higher weight example | 95 | 420 | 100 units in 100 mL | 0.1 units/kg/hour | 9.5 mL/hour | 0.05 units/kg/hour |
| Custom rate review | 80 | 300 | 50 units in 50 mL | 6 units/hour | 6 mL/hour | 4 units/hour equivalent |
Formula Used
1) Bag concentration: Concentration = Total insulin units ÷ Total bag volume.
2) Starting hourly insulin: Units/hour = Weight × starting units/kg/hour, unless a custom hourly rate is chosen.
3) Pump delivery: mL/hour = Units/hour ÷ Concentration.
4) Reduced infusion phase: Reduced units/hour = Weight × reduced units/kg/hour once the dextrose threshold is reached.
5) Estimated glucose fall: Hourly glucose reduction = Units/hour × user-selected insulin sensitivity estimate.
6) Timing estimate: Hours = Glucose difference ÷ estimated hourly glucose reduction for each phase.
7) Bag usage: Estimated delivered units ÷ Concentration = estimated mL consumed.
How to Use This Calculator
- Enter weight, current glucose, target glucose, and serum potassium.
- Enter the insulin bag strength and total volume exactly as mixed.
- Select weight-based mode for protocol review or custom mode for an existing hourly order.
- Set the starting rate and the reduced rate used after the dextrose threshold is reached.
- Use a realistic insulin sensitivity estimate for projection only, not for ordering.
- Press calculate to display the result above the form, review the chart, and export CSV or PDF.
- Cross-check all outputs against institutional guidance before any bedside use.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates insulin units per hour, pump mL per hour, reduced infusion rates, projected bag use, and approximate glucose decline. The output is for structured review and education, not prescribing.
2. Why is patient weight important?
Many hospital infusion pathways start with weight-based dosing. Weight directly changes the calculated units per hour and therefore the pump rate when the insulin solution concentration is fixed.
3. Why does the tool ask for potassium?
Insulin shifts potassium into cells and can worsen hypokalemia. The tool flags potassium ranges because low potassium often changes the treatment sequence and monitoring intensity.
4. What is the dextrose threshold?
It is the glucose level where many protocols add dextrose and reduce the insulin infusion rate. This helps continue ketone clearance while lowering hypoglycemia risk.
5. Is the glucose fall prediction exact?
No. It is a simplified projection based on your selected sensitivity estimate. Real-world glucose response changes with fluids, insulin resistance, infection, steroids, renal function, and sampling timing.
6. Can I use a custom hourly rate?
Yes. Custom mode is useful when reviewing an existing infusion order or a local protocol that does not use the default weight-based start. The pump rate still depends on bag concentration.
7. Why include an optional bolus field?
Some protocols or legacy pathways reference a starting bolus, while others avoid it. The checkbox lets you estimate total insulin exposure without forcing that assumption.
8. Is this suitable for direct patient care?
No. Use it only as a supplemental review aid. Direct patient care requires current institutional policy, physician oversight, bedside reassessment, and frequent laboratory confirmation.