body {
font-family: -apple-system, BlinkMacSystemFont, “Segoe UI”, Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background-color: #f4f7f6;
}
.calculator-container {
background: #ffffff;
padding: 30px;
border-radius: 12px;
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
margin-bottom: 40px;
border-top: 5px solid #007bff;
}
.calculator-title {
font-size: 24px;
font-weight: 700;
margin-bottom: 25px;
color: #2c3e50;
text-align: center;
}
.input-group {
margin-bottom: 20px;
}
.input-row {
display: flex;
gap: 20px;
margin-bottom: 15px;
}
.input-col {
flex: 1;
}
label {
display: block;
font-weight: 600;
margin-bottom: 8px;
color: #555;
font-size: 14px;
}
input[type=”number”], select {
width: 100%;
padding: 12px;
border: 1px solid #ddd;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.3s;
}
input[type=”number”]:focus, select:focus {
border-color: #007bff;
outline: none;
}
.btn-calculate {
display: block;
width: 100%;
padding: 15px;
background-color: #007bff;
color: white;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: 700;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 20px;
}
.btn-calculate:hover {
background-color: #0056b3;
}
.result-box {
margin-top: 25px;
padding: 20px;
background-color: #e3f2fd;
border-radius: 8px;
border-left: 5px solid #007bff;
display: none;
}
.result-value {
font-size: 32px;
font-weight: 700;
color: #007bff;
}
.result-label {
font-size: 14px;
color: #555;
text-transform: uppercase;
letter-spacing: 1px;
}
.error-msg {
color: #dc3545;
font-size: 14px;
margin-top: 5px;
display: none;
}
.info-section {
background: #fff;
padding: 30px;
border-radius: 12px;
box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
h2 {
color: #2c3e50;
margin-top: 0;
font-size: 22px;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
margin-bottom: 20px;
}
h3 {
font-size: 18px;
color: #333;
margin-top: 25px;
}
p, ul {
color: #666;
font-size: 16px;
}
ul {
padding-left: 20px;
}
li {
margin-bottom: 10px;
}
.disclaimer {
font-size: 12px;
color: #888;
margin-top: 30px;
padding-top: 15px;
border-top: 1px solid #eee;
font-style: italic;
}
@media (max-width: 600px) {
.input-row {
flex-direction: column;
gap: 15px;
}
}
Standard (mcg/min)
Weight-Based (mcg/kg/min)
Guide to Nitroglycerin IV Calculations
Nitroglycerin (NTG) is a potent vasodilator commonly used in critical care settings for managing conditions such as angina pectoris, myocardial infarction, and severe hypertension. Because of its potency, accurate calculation of the infusion rate is vital for patient safety. This calculator helps nursing and medical professionals convert ordered doses into pump settings (flow rates).
Common Dosing Strategies
Nitroglycerin can be administered using two primary dosing methods:
- Standard Dosing (mcg/min): This is the most common method. The physician orders a specific amount of micrograms to be delivered per minute (e.g., “Start NTG at 5 mcg/min”). The patient’s weight does not affect the calculation.
- Weight-Based Dosing (mcg/kg/min): Used less frequently for NTG but common in pediatrics or specific protocols. The dose is calculated based on the patient’s body weight in kilograms.
Calculation Formulas
To determine the infusion pump setting in milliliters per hour (mL/hr), the calculator uses the following logic:
1. Determine Concentration
First, calculate the concentration of the drug in the IV bag:
Concentration (mcg/mL) = [Total Drug (mg) × 1000] / Total Volume (mL)
2. Calculate Flow Rate
For Standard Dosing (mcg/min):
Flow Rate (mL/hr) = [Dose (mcg/min) × 60 min/hr] / Concentration (mcg/mL)
For Weight-Based Dosing (mcg/kg/min):
Flow Rate (mL/hr) = [Dose (mcg/kg/min) × Weight (kg) × 60 min/hr] / Concentration (mcg/mL)
Example Calculation
Scenario: You have a premixed bag containing 50 mg of Nitroglycerin in 250 mL of D5W. The physician orders an infusion to start at 10 mcg/min.
- Convert mg to mcg: 50 mg = 50,000 mcg.
- Find Concentration: 50,000 mcg / 250 mL = 200 mcg/mL.
- Calculate Rate: (10 mcg/min × 60 min) / 200 mcg/mL = 600 / 200 = 3 mL/hr.
function toggleWeightInput() {
var doseType = document.getElementById(“dosingUnit”).value;
var weightDiv = document.getElementById(“weightContainer”);
var doseLabel = document.getElementById(“doseUnitLabel”);
if (doseType === “mcg_kg_min”) {
weightDiv.style.display = “block”;
doseLabel.innerText = “mcg/kg/min”;
} else {
weightDiv.style.display = “none”;
doseLabel.innerText = “mcg/min”;
}
}
function calculateNitroglycerinRate() {
// Clear previous results and errors
document.getElementById(“resultBox”).style.display = “none”;
document.getElementById(“errorDisplay”).style.display = “none”;
// Get Input Values
var mg = parseFloat(document.getElementById(“drugAmount”).value);
var vol = parseFloat(document.getElementById(“totalVolume”).value);
var dose = parseFloat(document.getElementById(“orderedDose”).value);
var doseType = document.getElementById(“dosingUnit”).value;
var weight = 0;
// Validation
if (isNaN(mg) || mg <= 0 || isNaN(vol) || vol <= 0 || isNaN(dose) || dose < 0) {
document.getElementById("errorDisplay").style.display = "block";
return;
}
// Calculate Concentration
// 1 mg = 1000 mcg
var totalMcg = mg * 1000;
var concentrationMcgPerMl = totalMcg / vol;
// Display Concentration Preview (Optional helpful UI)
document.getElementById("concentrationDisplay").innerText =
"Concentration: " + concentrationMcgPerMl.toFixed(2) + " mcg/mL (" + mg + " mg / " + vol + " mL)";
var flowRate = 0;
if (doseType === "mcg_kg_min") {
weight = parseFloat(document.getElementById("patientWeight").value);
if (isNaN(weight) || weight <= 0) {
document.getElementById("errorDisplay").style.display = "block";
document.getElementById("errorDisplay").innerText = "Please enter a valid patient weight.";
return;
}
// Formula: (Dose * Weight * 60) / Concentration
flowRate = (dose * weight * 60) / concentrationMcgPerMl;
} else {
// Formula: (Dose * 60) / Concentration
flowRate = (dose * 60) / concentrationMcgPerMl;
}
// Check for infinite or NaN results
if (!isFinite(flowRate) || isNaN(flowRate)) {
document.getElementById("errorDisplay").style.display = "block";
document.getElementById("errorDisplay").innerText = "Calculation Error. Check inputs.";
return;
}
// Display Result
document.getElementById("resultBox").style.display = "block";
document.getElementById("finalRate").innerText = flowRate.toFixed(1) + " mL/hr";
document.getElementById("concentrationResult").innerText =
"Based on concentration: " + concentrationMcgPerMl.toFixed(1) + " mcg/mL";
}