.uf-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
color: #333;
line-height: 1.6;
}
.uf-calc-container {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
margin-bottom: 40px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.uf-calc-title {
text-align: center;
color: #0056b3;
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.uf-form-group {
margin-bottom: 20px;
}
.uf-form-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #495057;
}
.uf-input-row {
display: flex;
gap: 20px;
flex-wrap: wrap;
}
.uf-col {
flex: 1;
min-width: 200px;
}
.uf-form-group input {
width: 100%;
padding: 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.15s ease-in-out;
}
.uf-form-group input:focus {
border-color: #0056b3;
outline: 0;
box-shadow: 0 0 0 0.2rem rgba(0,86,179,.25);
}
.uf-calc-btn {
display: block;
width: 100%;
padding: 15px;
background-color: #0056b3;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: 600;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 10px;
}
.uf-calc-btn:hover {
background-color: #004494;
}
.uf-results {
margin-top: 30px;
background-color: #ffffff;
border: 1px solid #dee2e6;
border-radius: 6px;
padding: 20px;
display: none;
}
.uf-result-row {
display: flex;
justify-content: space-between;
align-items: center;
padding: 12px 0;
border-bottom: 1px solid #f1f3f5;
}
.uf-result-row:last-child {
border-bottom: none;
}
.uf-result-label {
font-weight: 500;
color: #6c757d;
}
.uf-result-value {
font-weight: 700;
font-size: 18px;
color: #212529;
}
.uf-metric-highlight {
color: #0056b3;
font-size: 22px;
}
.uf-alert-box {
padding: 15px;
margin-top: 15px;
border-radius: 4px;
font-size: 14px;
display: none;
}
.uf-alert-safe {
background-color: #d4edda;
color: #155724;
border: 1px solid #c3e6cb;
}
.uf-alert-warning {
background-color: #f8d7da;
color: #721c24;
border: 1px solid #f5c6cb;
}
.uf-article-content h2 {
color: #333;
margin-top: 30px;
font-size: 22px;
}
.uf-article-content p {
margin-bottom: 15px;
color: #555;
}
.uf-article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.uf-article-content li {
margin-bottom: 8px;
color: #555;
}
.formula-box {
background-color: #eef2f5;
padding: 15px;
border-left: 4px solid #0056b3;
font-family: "Courier New", Courier, monospace;
margin: 20px 0;
}
function calculateUFRate() {
// Get inputs
var preWeight = parseFloat(document.getElementById('preWeight').value);
var targetWeight = parseFloat(document.getElementById('targetWeight').value);
var hours = parseFloat(document.getElementById('treatmentTime').value);
var extraFluid = parseFloat(document.getElementById('extraFluid').value);
var resultsArea = document.getElementById('resultsArea');
var safetyAlert = document.getElementById('safetyAlert');
// Reset display
resultsArea.style.display = 'none';
safetyAlert.style.display = 'none';
safetyAlert.className = 'uf-alert-box';
// Validation
if (isNaN(preWeight) || isNaN(targetWeight) || isNaN(hours) || hours = preWeight && extraFluid === 0) {
alert("Target Weight must be lower than Pre-Dialysis Weight, or fluid intake must be added.");
return;
}
// Calculations
// 1. Calculate weight difference in kg
var weightDiffKg = preWeight – targetWeight;
// 2. Convert to mL (assuming 1kg = 1L = 1000mL)
var weightDiffmL = weightDiffKg * 1000;
// 3. Add extra fluid (washback, saline prime, oral intake during session)
var totalVolumeToRemove = weightDiffmL + extraFluid;
// 4. Calculate Hourly Rate
var hourlyRate = totalVolumeToRemove / hours;
// 5. Calculate Normalized Rate (mL/hr per kg of dry weight)
var normalizedRate = hourlyRate / targetWeight;
// Update DOM
document.getElementById('resTotalVolume').innerText = (totalVolumeToRemove / 1000).toFixed(2) + " L (" + Math.round(totalVolumeToRemove) + " mL)";
document.getElementById('resHourlyRate').innerText = Math.round(hourlyRate) + " mL/hr";
document.getElementById('resNormalizedRate').innerText = normalizedRate.toFixed(2) + " mL/kg/hr";
// Safety Logic (Threshold usually 10-13 mL/kg/hr)
safetyAlert.style.display = 'block';
if (normalizedRate > 13) {
safetyAlert.className = 'uf-alert-box uf-alert-warning';
safetyAlert.innerHTML = "Warning: High UF Rate. A rate > 13 mL/kg/hr is associated with higher mortality risks and myocardial stunning. Please verify with a clinician.";
} else if (normalizedRate > 10) {
safetyAlert.className = 'uf-alert-box uf-alert-warning';
safetyAlert.style.backgroundColor = '#fff3cd';
safetyAlert.style.color = '#856404';
safetyAlert.style.borderColor = '#ffeeba';
safetyAlert.innerHTML = "Caution: Moderate UF Rate. The rate is between 10-13 mL/kg/hr. Monitor patient for hypotension.";
} else {
safetyAlert.className = 'uf-alert-box uf-alert-safe';
safetyAlert.innerHTML = "Safe Range. The calculated UF rate is below the common safety threshold of 10 mL/kg/hr.";
}
resultsArea.style.display = 'block';
}
Hemodialysis Ultrafiltration (UF) Rate Calculator
Total Fluid to Remove:
0 mL
Hourly UF Rate:
0 mL/hr
Normalized UF Rate:
0 mL/kg/hr
Understanding Ultrafiltration (UF) Rates in Hemodialysis
The Ultrafiltration (UF) Rate is a critical parameter in hemodialysis prescription. It represents the speed at which fluid is removed from the patient's blood during a dialysis session. Managing this rate is essential for preventing intradialytic hypotension (low blood pressure during treatment) and ensuring long-term cardiovascular health.
How the UF Rate Calculator Works
This calculator determines both the absolute hourly fluid removal rate and the normalized rate relative to the patient's body weight. The calculation follows these steps:
1. Total Fluid Goal (mL) = (Pre-Dialysis Weight – Target Weight) × 1000 + Additional Fluids
2. Hourly UF Rate (mL/hr) = Total Fluid Goal / Treatment Time
3. Normalized UF Rate (mL/kg/hr) = Hourly UF Rate / Target Dry Weight
2. Hourly UF Rate (mL/hr) = Total Fluid Goal / Treatment Time
3. Normalized UF Rate (mL/kg/hr) = Hourly UF Rate / Target Dry Weight
Why Normalized UF Rate Matters (mL/kg/hr)
While the total volume of fluid removed is important, the rate at which it is removed relative to body size is the most significant predictor of outcomes. Clinical studies suggest that:
- Rate < 10 mL/kg/hr: Generally considered the safest zone, allowing sufficient time for plasma refill (fluid moving from tissues back into the blood vessels).
- Rate 10 – 13 mL/kg/hr: A grey zone that requires careful monitoring.
- Rate > 13 mL/kg/hr: Associated with a significantly higher risk of all-cause mortality and cardiovascular events. High rates can outpace the plasma refill rate, leading to hypovolemia and organ stunning.
Optimizing Fluid Removal
To reduce a high UF rate, clinicians may consider:
- Extending Treatment Time: Increasing the duration of the dialysis session allows the same amount of fluid to be removed more slowly.
- Reducing Interdialytic Weight Gain (IDWG): Helping patients manage their fluid intake between sessions reduces the total volume that needs to be removed.
- Adjusting Dry Weight: Ensuring the target weight is accurate and not set too low.
Disclaimer: This calculator is a tool for educational and estimation purposes only. It does not replace professional medical advice or the specific protocols of a dialysis clinic. Always verify calculations and prescription settings with a qualified nephrologist or renal nurse.