The constant rate infusion (CRI) calculator
Vet Radar has a constant rate infusion (CRI) calculator that can calculate the infusion rate of fluid therapy medication. Vet Radar calculates the necessary infusion rate to give the medication to the patient at the specified dose. Vet Radar can calculate an undiluted dose and a diluted dose.
You can only calculate one medication to a patient at one time. If a patient must have more than one IV infusion treatment, you must calculate each medication each time.
How Vet Radar calculates an undiluted dose
An undiluted dose is a dose that you give directly to the patient (for example, with a syringe pump). To calculate the undiluted dose, Vet Radar uses these equations:
| Equation | Result |
|---|---|
| Dose rate (mg/ kg/ hr) × Weight (kg) | Dosage rate (mg/ hr) |
| Dosage rate (mg/ hr) ÷ Concentration (mg/ mL) | Infusion rate (mL/ hr) |
To calculate the undiluted dose, Vet Radar uses three values:
- Patient weight
- A rate value
- The medication's concentration
Vet Radar always automatically enters the patient weight and the medication's concentration. You must enter the remaining value. The other value is one of:
- Dose rate
- Dosage rate
- Infusion rate
ExampleA nurse admits a patient with a broken leg. The attending veterinarian makes the decision to prescribe fentanyl CRI through a syringe pump to treat the patient's pain. The veterinarian uses Vet Radar to calculate the infusion rate of the fentanyl for the patient. They select the fentanyl and the related products. Vet Radar automatically enters the patient's weight, and the veterinarian enters the dose rate. Vet Radar:
- Calculates the dosage rate (dose rate × patient weight)
- Calculates the infusion rate (concentration ÷ dosage rate)
The veterinarian uses the infusion rate information to treat the patient's pain.
How Vet Radar calculates a diluted dose
A diluted dose is a dose that you must first add to a diluent (for example, a saline fluid bag). You can use a diluted dose if:
- The necessary dose is small (for example, if the patient is less than 1 kg)
- You want to give the treatment for a longer period
To calculate a diluted dose, Vet Radar uses these equations:
| Equation | Result |
|---|---|
| Concentration (mg/ mL) × Medication volume (mL) | Diluted concentration (mg/ mL) × Final volume (mL) |
| Dose rate (mg/ kg/ hr) × weight (kg) | Dosage rate (mg/ hr) |
| Dosage rate (mg/ hr) ÷ diluted concentration (mg/ mL) | Infusion rate (mL/ hr) |
To calculate the undiluted dose, Vet Radar uses four values:
- Patient weight
- A rate value
- A volume value
- The medication's concentration
Vet Radar automatically enters the patient's weight and the medication's concentration. You must manually enter the remaining values. You must enter one of these rate values:
- Dose rate
- Dosage rate
- Infusion rate
And you must enter one of these volume values:
- Medication volume
- Final volume
ExampleA nurse admits a patient with a broken leg. The attending veterinarian makes a decision to prescribe a fentanyl CRI through a fluid bag to treat the patient's pain. The veterinarian uses Vet Radar to calculate the infusion rate of the fentanyl for the patient. They select the fentanyl and the related products. Vet Radar automatically enters the patient's weight and the veterinarian manually enters the dose rate. Vet Radar:
- Calculates the dosage rate (dose rate × patient weight)
- (Medication volume × concentration) ÷ final volume = diluted concentration
- Calculates the infusion rate (diluted concentration × dosage rate)
The veterinarian uses the infusion rate information to treat the patient's pain.
Note: If you dilute the medication, (for example, if you add a 20 mL medication to a 1000 mL fluid bag) you must remove the same quantity of diluent before you add the medication to the fluid bag.