Cri Calculator Veterinary

Professional Grade Drug Infusion & Fluid Bag Supplementation

Calculation Results:

Drug Delivery Rate: mL/hr

Drug Dosage: mg/hr

To supplement a mL bag:
Add mL of drug to the bag.

Please enter valid positive numbers for Weight, Concentration, Dose, and Rate.

Understanding Veterinary Constant Rate Infusions (CRI)

A Constant Rate Infusion (CRI) is a method of drug delivery where a medication is administered at a slow, continuous rate to maintain a steady concentration in the bloodstream. In veterinary medicine, this is crucial for managing pain (analgesia), anesthesia, or controlling seizures and cardiac arrhythmias.

Common Clinical Applications

• FLK/MLK Combinations: Fentanyl, Lidocaine, and Ketamine (or Morphine) used for perioperative pain management.
• Propofol: Used for maintenance of anesthesia or refractory status epilepticus.
• Dopamine/Dobutamine: Blood pressure support and inotropic therapy in critical care settings.
• Metoclopramide: Used as a prokinetic for GI motility disorders.

The CRI Formula Explained

To calculate the rate of a CRI, we first determine the amount of drug the patient needs per minute, convert it to an hourly dose, and then calculate the volume of the drug based on its concentration:

1. Total mcg/hr = Dose (mcg/kg/min) × Weight (kg) × 60 min
2. Total mg/hr = Total mcg/hr ÷ 1000
3. Rate (mL/hr) = Total mg/hr ÷ Drug Concentration (mg/mL)

Practical Example

Scenario: A 20kg dog requires a Lidocaine CRI at 50 mcg/kg/min. Your Lidocaine bottle is 20 mg/mL.

• Step 1: 50 mcg × 20 kg × 60 min = 60,000 mcg/hr.
• Step 2: 60,000 mcg ÷ 1000 = 60 mg/hr.
• Step 3: 60 mg ÷ 20 mg/mL = 3 mL/hr.
• Result: If using a syringe pump, set the rate to 3 mL/hr. If adding to a 500mL fluid bag running at 50 mL/hr, you would add 30 mL of Lidocaine to the bag.

Disclaimer: This tool is for educational purposes for veterinary professionals. Always double-check calculations before administering medications. The user assumes all responsibility for clinical decisions.