The calculator helps healthcare professionals determine the right dose of norepinephrine by considering the patient's weight, the drug’s concentration in the infusion solution, and the infusion rate. Accurate dosing is crucial, as too little norepinephrine may not adequately treat hypotension or shock, while too much can lead to dangerous side effects, including severe hypertension and arrhythmias.
Formula of Norepinephrine Dose mcg/kg/min Calculator
The formula to calculate the norepinephrine dose in micrograms per kilogram per minute (mcg/kg/min) is straightforward:
Dose (mcg/kg/min) = (Infusion rate (mL/hr) * Concentration (mcg/mL)) / (Weight (kg) * 60)
- Infusion rate (mL/hr): The volume of the infusion solution administered per hour.
- Concentration (mcg/mL): The amount of norepinephrine in each milliliter of the solution.
- Weight (kg): The body weight of the patient, which is critical in calculating the dose per kg.
- Number 60: This converts the rate from per hour to per minute, as there are 60 minutes in an hour.
Clinical Guidelines for Norepinephrine Dosing
Norepinephrine dosing must be tailored to the individual patient's needs and closely monitored. Here are general guidelines:
- Hypotension:
- Initial dose: 8-12 mcg/min
- Maintenance dose: 2-4 mcg/min
- Sepsis (Society of Critical Care Medicine):
- Dose range: 0.01-3 mcg/kg/min
- Cardiac Arrest (American Heart Association):
- Initial dose: 8-12 mcg/min
- Maintenance dose: 2-4 mcg/min
- Titration: 0.1-0.5 mcg/kg/min, adjusted based on patient response
It is essential to start with a lower dose and titrate up based on clinical effect and blood pressure monitoring.
Usage Table
Here is a quick reference table for healthcare providers:
| Patient Weight (kg) | Condition | Infusion Rate (mL/hr) | Concentration (mcg/mL) | Calculated Dose (mcg/kg/min) |
|---|---|---|---|---|
| 70 | Hypotension | 50 | 4 | 0.48 |
| 70 | Sepsis | 100 | 0.1 | 0.024 |
| 70 | Cardiac Arrest | 25 | 16 | 0.96 |
Example of Norepinephrine Dose mcg/kg/min Calculator
Example 1: Hypotension
Consider a 70 kg patient needing norepinephrine for hypotension:
- Infusion rate: 50 mL/hr
- Concentration: 4 mcg/mL
Using the formula:
Dose = (50 * 4) / (70 * 60) = 0.48 mcg/kg/min
This dose should be monitored and adjusted based on the patient's blood pressure and clinical response.
Example 2: Sepsis
For the same patient in a septic condition:
- Infusion rate: 100 mL/hr
- Concentration: 0.1 mcg/mL
Calculation:
Dose = (100 * 0.1) / (70 * 60) = 0.024 mcg/kg/min
This low dose reflects the cautious approach needed in sepsis to avoid exacerbating the condition.
Most Common FAQs
To calculate the dose, multiply the infusion rate by the concentration, then divide by the product of the patient's weight in kilograms and 60 (to convert hours to minutes).
Incorrect dosing can lead to under-treatment or potentially fatal overdose. It's critical to use precise calculations and continuous monitoring.
This calculator is designed for adult patients. Pediatric dosing of norepinephrine should be handled with specific formulas and guidelines tailored to children.
