Please enter valid positive numbers for all fields.
IV Pump Rate:0 mL/hr
Solution Concentration:0 mcg/mL
Total Drug (mg/hr):0 mg/hr
function calculateDopamineRate() {
var weightInput = document.getElementById('pt_weight');
var doseInput = document.getElementById('desired_dose');
var amountInput = document.getElementById('drug_amount');
var volumeInput = document.getElementById('total_volume');
var errorDiv = document.getElementById('error_message');
var resultDiv = document.getElementById('results_display');
var weight = parseFloat(weightInput.value);
var dose = parseFloat(doseInput.value);
var amountMg = parseFloat(amountInput.value);
var volumeMl = parseFloat(volumeInput.value);
// Validation
if (isNaN(weight) || weight <= 0 ||
isNaN(dose) || dose <= 0 ||
isNaN(amountMg) || amountMg <= 0 ||
isNaN(volumeMl) || volumeMl <= 0) {
errorDiv.style.display = 'block';
resultDiv.style.display = 'none';
return;
}
errorDiv.style.display = 'none';
// Calculation Logic
// 1. Calculate concentration in mcg/mL
// Concentration (mg/mL) = Amount (mg) / Volume (mL)
// Concentration (mcg/mL) = Concentration (mg/mL) * 1000
var concMgPerMl = amountMg / volumeMl;
var concMcgPerMl = concMgPerMl * 1000;
// 2. Calculate Rate in mL/hr
// Formula: (Dose (mcg/kg/min) * Weight (kg) * 60 min/hr) / Concentration (mcg/mL)
var numerator = dose * weight * 60;
var infusionRate = numerator / concMcgPerMl;
// 3. Calculate total drug delivered per hour in mg
// mg/hr = (Rate mL/hr * Concentration mg/mL)
var mgPerHour = infusionRate * concMgPerMl;
// Display Results
document.getElementById('res_rate').innerHTML = infusionRate.toFixed(1) + ' mL/hr';
document.getElementById('res_conc_mcg').innerHTML = concMcgPerMl.toFixed(0) + ' mcg/mL';
document.getElementById('res_mg_hr').innerHTML = mgPerHour.toFixed(2) + ' mg/hr';
resultDiv.style.display = 'block';
}
Understanding Dopamine Infusion Calculations
Dopamine is a catecholamine neurotransmitter used medically to treat hemodynamic instability, such as severe hypotension (low blood pressure), bradycardia (slow heart rate), and cardiac arrest. Accurate calculation of the infusion rate is critical for patient safety, as the physiological effects of dopamine are highly dose-dependent.
The Infusion Rate Formula
To determine the flow rate for an IV pump (in mL/hr), you need the patient's weight, the desired dose, and the concentration of the drug solution. The standard formula used in critical care settings is:
Dose: The order prescribed by the physician (e.g., 5 mcg/kg/min).
Weight: Patient weight in kilograms.
Concentration: The strength of the admixture, converted to micrograms per milliliter (mcg/mL).
Dose-Dependent Effects
Dopamine exhibits distinct pharmacological effects depending on the dosage range administered. While individual patient response varies, the general guidelines are:
Dose Range (mcg/kg/min)
Primary Receptor
Physiological Effect
Low (1-3 mcg)
Dopaminergic
Renal and mesenteric vasodilation. Historically referred to as the "Renal Dose," though clinical efficacy for renal protection is debated.
Intermediate (3-10 mcg)
Beta-1 Adrenergic
Increases cardiac contractility (inotropic effect), stroke volume, and heart rate. Used to improve cardiac output.
High (10-20+ mcg)
Alpha Adrenergic
Systemic vasoconstriction. Increases systemic vascular resistance (SVR) and blood pressure. Similar to norepinephrine effects.
Standard Concentrations
To minimize fluid overload and standardize calculations, hospitals often use "Standard Concentrations." Common preparations include:
Standard: 400 mg in 250 mL D5W (1600 mcg/mL)
Concentrated: 800 mg in 250 mL D5W (3200 mcg/mL)
Always verify the concentration on the IV bag before initiating therapy. Using the wrong concentration variable in your calculation can lead to a massive overdose or underdose.
Step-by-Step Calculation Example
Scenario: A 75 kg patient requires Dopamine at 5 mcg/kg/min. The pharmacy sends a bag containing 400 mg of Dopamine in 250 mL of solution.
Calculate Concentration: 400 mg / 250 mL = 1.6 mg/mL.
Convert to mcg: 1.6 mg/mL × 1000 = 1600 mcg/mL.
Calculate Numerator (Total mcg needed per hour): 5 mcg × 75 kg × 60 min = 22,500 mcg/hr.
Divide by Concentration: 22,500 / 1600 = 14.1 mL/hr.
Medical Disclaimer: This calculator is intended for educational and verification purposes only. It does not replace professional clinical judgment. Always double-check calculations and verify infusion pump settings against institutional protocols before administering medication.