Medical Disclaimer: This calculator is a support tool. Always double-check calculations and follow your institution's protocols.
function calculateNoradRate() {
// 1. Get input values
var weight = parseFloat(document.getElementById('ptWeight').value);
var dose = parseFloat(document.getElementById('targetDose').value);
var drugMg = parseFloat(document.getElementById('drugAmount').value);
var volumeMl = parseFloat(document.getElementById('totalVolume').value);
var resultsDiv = document.getElementById('noradResults');
// 2. Validation
if (isNaN(weight) || isNaN(dose) || isNaN(drugMg) || isNaN(volumeMl) || volumeMl === 0) {
alert("Please enter valid numerical values for all fields. Volume cannot be zero.");
resultsDiv.style.display = 'none';
return;
}
// 3. Calculation Logic
// Calculate Concentration in mcg/mL
// Formula: (mg * 1000) / mL
var totalMcg = drugMg * 1000;
var concentration = totalMcg / volumeMl;
// Calculate Total Dose required per minute in mcg
// Formula: mcg/kg/min * kg
var totalDosePerMin = dose * weight;
// Calculate Flow Rate in mL/hr
// Formula: (Total Dose mcg/min / Concentration mcg/mL) * 60 min/hr
var flowRateMlPerHr = (totalDosePerMin / concentration) * 60;
// 4. Update UI
document.getElementById('resConcentration').innerText = concentration.toFixed(1) + " mcg/mL";
document.getElementById('resTotalDose').innerText = totalDosePerMin.toFixed(2) + " mcg/min";
document.getElementById('resFlowRate').innerText = flowRateMlPerHr.toFixed(2) + " mL/hr";
resultsDiv.style.display = 'block';
}
Clinical Guide to Noradrenaline Infusion Calculation
Noradrenaline (Norepinephrine) is a potent vasopressor predominantly used in critical care environments such as Intensive Care Units (ICU) and operating theaters. It functions as an alpha-1 adrenergic agonist, causing peripheral vasoconstriction to increase blood pressure in hypotensive states, particularly septic shock. Accurate calculation of the infusion rate is critical for patient safety and hemodynamic stability.
How to Calculate Noradrenaline Infusion Rates
Calculating the infusion rate for a syringe driver or volumetric pump involves three main steps: determining the concentration of the solution, calculating the patient's total minute requirement, and converting that into an hourly flow rate.
The Mathematical Formula
The standard equation used in critical care pharmacology is:
Let's assume a clinical scenario with the following parameters:
Patient Weight: 75 kg
Prescribed Dose: 0.1 mcg/kg/min
Preparation: 4 mg of Noradrenaline in 50 mL of 5% Dextrose (Single Strength)
Step 1: Determine Concentration
First, convert milligrams to micrograms and divide by the total volume. 4 mg = 4,000 mcg 4,000 mcg / 50 mL = 80 mcg/mL
Step 2: Determine Total Minute Dose
Multiply the weight-based dose by the patient's weight. 0.1 mcg/kg/min × 75 kg = 7.5 mcg/min
Step 3: Calculate Hourly Rate
Divide the minute dose by the concentration and multiply by 60 (minutes in an hour). (7.5 mcg/min / 80 mcg/mL) × 60 = 5.625 mL/hr
Standard Concentrations
To reduce the risk of calculation errors, many hospitals utilize standard concentrations:
Single Strength: 4 mg in 50 mL (80 mcg/mL)
Double Strength: 8 mg in 50 mL (160 mcg/mL)
Quad Strength: 16 mg in 50 mL (320 mcg/mL)
Higher concentrations (Double or Quad strength) are typically reserved for patients requiring high doses or those who are fluid-restricted, to minimize the volume of fluid delivered.
Safety Considerations
Noradrenaline is a high-alert medication. Extravasation can cause severe tissue necrosis. It should ideally be administered via a central venous catheter. While this calculator provides a mathematical aid, all infusion pump settings should be double-checked by two qualified healthcare professionals according to local hospital policy.