Anesthesia Clinical Calculator

Height

Weight

Result

Your BMI:

Category:

About BMI

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m2 where kg is a person's weight in kilograms and m2 is their height in meters squared.

BMI does not directly measure body fat but it is a useful indicator of body fatness for most people.

BMI Categories:

Underweight: < 18.5
Normal weight: 18.5 - 24.9
Overweight: 25 - 29.9
Obesity: ≥ 30

Reference: World Health Organization (WHO)

`; break; case 'ibw': title = 'Ideal Body Weight Calculator'; content = ` `; break; case 'map': title = 'Mean Arterial Pressure (MAP) Calculator'; content = ` `; break; case 'gcs': title = 'Glasgow Coma Scale (GCS) Calculator'; content = ` `; break; case 'anion-gap': title = 'Anion Gap Calculator'; content = ` `; break; case 'alveolar-gas': title = 'Alveolar Gas Equation Calculator'; content = ` `; break; case 'aa-gradient': title = 'A-a Gradient Calculator'; content = ` `; break; case 'pao2-fio2': title = 'PaO2/FiO2 Ratio Calculator'; content = ` `; break; case 'creatinine-clearance': title = 'Creatinine Clearance Calculator'; content = ` `; break; case 'asa': title = 'ASA Physical Status Classification'; content = ` `; break; case 'dead-space': title = 'Dead Space Calculator'; content = ` `; break; case 'shunt-fraction': title = 'Shunt Fraction Calculator'; content = `

${title}

Calculate

Information

PaO2 (mmHg)

SaO2 (%)

Hemoglobin (g/dL)

PaCO2 (mmHg)

FiO2 (fraction)

Mixed Venous O2 (%)

Result

Shunt Fraction (Qs/Qt):

Arterial O2 Content (CaO2): mL/dL

Capillary O2 Content (CcO2): mL/dL

Mixed Venous O2 Content (CvO2): mL/dL

Interpretation:

About Shunt Fraction

Shunt fraction (Qs/Qt) is the proportion of blood flow that passes through the lungs without participating in gas exchange. It's a measure of the severity of oxygenation impairment.

Formula

Shunt Equation:

Qs/Qt = (CcO2 - CaO2) / (CcO2 - CvO2)

Where:

Qs/Qt = Shunt fraction
CcO2 = Pulmonary capillary oxygen content
CaO2 = Arterial oxygen content
CvO2 = Mixed venous oxygen content

Oxygen Content Calculation:

Content (mL O2/dL) = (Hb × 1.34 × SO2) + (PO2 × 0.0031)

Where:

Hb = Hemoglobin concentration (g/dL)
1.34 = Oxygen carrying capacity of hemoglobin (mL O2/g Hb)
SO2 = Oxygen saturation (%)
PO2 = Partial pressure of oxygen (mmHg)
0.0031 = Solubility coefficient of oxygen in plasma (mL O2/dL/mmHg)

Normal Values

Normal shunt fraction: 0.03-0.05 (3-5%)
Physiologic shunt: < 5% (bronchial circulation, Thebesian veins)

Clinical Significance

An increased shunt fraction indicates impaired oxygenation. Common causes include:

Atelectasis
Pneumonia
Pulmonary edema (cardiogenic or non-cardiogenic)
Acute respiratory distress syndrome (ARDS)
Pulmonary embolism (rarely increases shunt significantly)
Intracardiac shunts (ASD, VSD, PDA)

Interpretation

Normal: 0.03-0.05 (3-5%)
Mildly increased: 0.06-0.10 (6-10%)
Moderately increased: 0.11-0.20 (11-20%)
Severely increased: > 0.20 (>20%)

Clinical Notes

Shunt fraction is relatively unaffected by increasing FiO2 (unlike V/Q mismatch)
Requires arterial blood gas and mixed venous blood sample (or estimated SvO2)
100% oxygen ventilation test can help distinguish shunt from V/Q mismatch

Reference: West JB. Respiratory Physiology: The Essentials. 10th ed.; Nunn JF. Nunn's Applied Respiratory Physiology. 8th ed.; Tobin MJ (ed). Principles and Practice of Mechanical Ventilation. 3rd ed.

`; break; case 'oxygen-index': title = 'Oxygenation Index Calculator'; content = `

${title}

Calculate

Information

FiO2 (fraction)

Mean Airway Pressure (cmH2O)

PaO2 (mmHg)

Result

Oxygenation Index:

Interpretation:

About Oxygenation Index

The Oxygenation Index (OI) is a calculated value used to assess the severity of respiratory failure, particularly in neonates and children with acute hypoxemic respiratory failure. It's also used in adults with ARDS to evaluate the severity of lung injury and response to therapy.

Formula

Oxygenation Index:

OI = (FiO2 × Mean Airway Pressure × 100) / PaO2

Where:

FiO2 = Fraction of inspired oxygen (0.21 to 1.0)
Mean Airway Pressure = Average pressure in the airways during mechanical ventilation (cmH2O)
PaO2 = Arterial partial pressure of oxygen (mmHg)

Normal Values

Normal: < 5
Mild respiratory failure: 5-15
Moderate respiratory failure: 16-30
Severe respiratory failure: >30

Clinical Significance

The Oxygenation Index is particularly valuable because it incorporates three key components of oxygenation:

FiO2: Reflects the oxygen requirement
Mean Airway Pressure: Reflects the ventilatory support required
PaO2: Reflects the resulting arterial oxygenation

Clinical applications include:

Assessing severity of ARDS in children and adults
Evaluating eligibility for extracorporeal membrane oxygenation (ECMO)
Monitoring response to therapeutic interventions
Predicting outcomes in respiratory failure

Interpretation

Normal: < 5 - Adequate oxygenation with minimal support
Mild: 5-15 - Mild respiratory failure, may respond to conventional ventilation
Moderate: 16-30 - Moderate respiratory failure, may require advanced ventilatory strategies
Severe: >30 - Severe respiratory failure, consider ECMO or other rescue therapies

ECMO Criteria

In pediatric patients, an OI > 40 on two consecutive blood gas measurements 30 minutes apart despite optimal ventilation is often used as a criterion for ECMO consideration. In adults, OI > 30-40 is often associated with high mortality and may indicate need for ECMO.

Limitations

Requires mechanical ventilation for accurate mean airway pressure measurement
Can be affected by changes in cardiac output and oxygen consumption
May not accurately reflect oxygenation status in patients with right-to-left shunts

Reference: Kneyber MC, Brouwers AG, Caruso JA, et al. Consensus and controversies in paediatric mechanical ventilation. Intensive Care Med. 2014;40(12):1948-1963; ARDS Definition Task Force. Acute respiratory distress syndrome: the Berlin Definition. JAMA. 2012;307(23):2526-2533.

`; break; case 'ards-severity': title = 'ARDS Severity Calculator'; content = `

${title}

Calculate

Information

PaO2 (mmHg)

FiO2 (fraction or %)

FiO2 Unit

PEEP (cmH2O)

Timing of Onset

Cause of Respiratory Failure

Cardiac Function Assessment

Result

PaO2/FiO2 Ratio:

ARDS Classification:

Meets Berlin Definition:

Interpretation:

About ARDS Severity

Acute Respiratory Distress Syndrome (ARDS) is a life-threatening condition of fluid accumulation in the lungs that prevents adequate oxygenation. The Berlin Definition (2012) is the current standard for defining and classifying ARDS severity.

Berlin Definition Criteria

ARDS is defined by all of the following criteria:

Acute onset: Within 1 week of a known clinical insult or new/worsening respiratory symptoms
Chest imaging: Bilateral opacities not fully explained by effusions, lobar/lung collapse, or nodules
Respiratory failure not fully explained by cardiac failure or fluid overload: Requires objective assessment (e.g., echocardiography) to exclude hydrostatic edema if no risk factor present
Impaired oxygenation: Based on PaO2/FiO2 ratio with PEEP ≥ 5 cmH2O

ARDS Severity Classification

Based on PaO2/FiO2 ratio with PEEP ≥ 5 cmH2O:

Mild ARDS: 200 mmHg < PaO2/FiO2 ≤ 300 mmHg
Moderate ARDS: 100 mmHg < PaO2/FiO2 ≤ 200 mmHg
Severe ARDS: PaO2/FiO2 ≤ 100 mmHg

Clinical Significance

ARDS severity classification has important implications for:

Prognosis: Higher severity correlates with increased mortality
Treatment: Guides ventilatory strategies and consideration of rescue therapies
ECMO consideration: Severe ARDS may be an indication for extracorporeal membrane oxygenation
Clinical trials: Stratification of patients in research studies

Mortality by Severity

Mild ARDS: ~27% mortality
Moderate ARDS: ~32% mortality
Severe ARDS: ~45% mortality

Management Implications by Severity

Mild ARDS: Conventional lung-protective ventilation (tidal volume 6 mL/kg PBW, plateau pressure < 30 cmH2O)
Moderate ARDS: Consider higher PEEP, recruitment maneuvers, prone positioning
Severe ARDS: Consider all above plus neuromuscular blockade, ECMO evaluation

Limitations

Requires arterial blood gas measurement
PaO2/FiO2 ratio can be affected by changes in cardiac output and oxygen consumption
Does not account for driving pressure or other ventilatory parameters
May not predict individual outcomes as accurately as multi-parameter scores

Differential Diagnosis

Conditions that may mimic ARDS but require different management:

Cardiogenic pulmonary edema
Severe pneumonia
Aspiration pneumonitis
Diffuse alveolar hemorrhage
Acute interstitial pneumonia

Reference: ARDS Definition Task Force. Acute respiratory distress syndrome: the Berlin Definition. JAMA. 2012;307(23):2526-2533; Force ADT, Ranieri VM, Rubenfeld GD, et al. Acute respiratory distress syndrome: the Berlin Definition. JAMA. 2012;307(23):2526-2533.

`; break; case 'cardiac-output': title = 'Cardiac Output/Index Calculator'; content = `

${title}

Calculate

Information

Calculation Method

Fick Principle Method

O2 Consumption (mL/min)

Arterial O2 Content (mL/dL)

Mixed Venous O2 Content (mL/dL)

Thermodilution Method

Injectate Volume (mL)

Injectate Temperature (°C)

Blood Temperature (°C)

Area Under Curve

Calculation Constant

Estimated from Vital Signs

Heart Rate (bpm)

Systolic BP (mmHg)

Diastolic BP (mmHg)

Body Surface Area (m²)

Result

Cardiac Output: L/min

Cardiac Index: L/min/m²

Interpretation:

About Cardiac Output & Index

Cardiac Output (CO) is the volume of blood the heart pumps per minute. Cardiac Index (CI) is the CO normalized to body surface area, allowing comparison between patients of different sizes.

Calculation Methods

1. Fick Principle:

CO = O2 Consumption / (Arterial O2 Content - Mixed Venous O2 Content)

Where:

O2 Consumption = Total oxygen consumed by tissues (mL/min)
Arterial O2 Content = Oxygen content in arterial blood (mL/dL)
Mixed Venous O2 Content = Oxygen content in mixed venous blood (mL/dL)

2. Thermodilution:

CO = (Injectate Volume × Injectate Temp Difference × Calculation Constant) / Area Under Curve

This method uses a pulmonary artery catheter and requires cold injectate.

3. Estimated from Vital Signs:

Uses formulas based on heart rate, blood pressure, and body surface area. Less accurate but useful when invasive monitoring is not available.

Normal Values

Cardiac Output: 4.0-8.0 L/min
Cardiac Index: 2.5-4.2 L/min/m²

Clinical Significance

Cardiac output assessment is crucial in:

Shock states (hypovolemic, cardiogenic, distributive, obstructive)
Heart failure management
High-risk surgery monitoring
Fluid and vasopressor therapy guidance
Prognostication in critical illness

Interpretation

Normal CI: 2.5-4.2 L/min/m²
Mild decrease: 2.0-2.4 L/min/m² - May be compensated
Moderate decrease: 1.5-1.9 L/min/m² - Often symptomatic
Severe decrease: < 1.5 L/min/m² - Decompensated shock
High CI: > 4.5 L/min/m² - May indicate hyperdynamic state (sepsis, anemia, hyperthyroidism)

Factors Affecting Cardiac Output

Preload: Ventricular end-diastolic volume (Frank-Starling mechanism)

Contractility: Intrinsic force of myocardial contraction

Afterload: Resistance against which the ventricle must pump

Heart Rate: Number of contractions per minute

Limitations

Fick method requires accurate measurement of O2 consumption and mixed venous blood
Thermodilution requires pulmonary artery catheterization with associated risks
Estimated methods have limited accuracy in critical illness
All methods can be affected by arrhythmias, valvular disease, and intracardiac shunts

Reference: Pinsky MR, Payen D. Functional hemodynamic monitoring. Crit Care. 2005;9(Suppl 5):S1-S9; Vincent JL, Weil MH. Fluid challenge revisited. Crit Care Med. 2006;34(9):2253-2257.

`; break; default: title = 'Calculator'; content = ` `; break; } return content; } // Function to add event listeners to modal function addModalEventListeners(modal, type) { // Close modal when clicking on X const closeBtn = modal.querySelector('.close-modal'); closeBtn.addEventListener('click', function() { modal.style.display = 'none'; document.body.style.overflow = 'auto'; }); // Close modal when clicking outside of it window.addEventListener('click', function(event) { if (event.target === modal) { modal.style.display = 'none'; document.body.style.overflow = 'auto'; } }); // Tab functionality const tabs = modal.querySelectorAll('.tab'); tabs.forEach(tab => { tab.addEventListener('click', function() { const tabId = this.getAttribute('data-tab'); // Remove active class from all tabs and contents tabs.forEach(t => t.classList.remove('active')); const tabContents = modal.querySelectorAll('.tab-content'); tabContents.forEach(content => content.classList.remove('active')); // Add active class to clicked tab and corresponding content this.classList.add('active'); const activeContent = modal.querySelector(`#${tabId}-tab`); if (activeContent) { activeContent.classList.add('active'); } }); }); // Add calculator-specific functionality switch(type) { case 'bmi': setupBMICalculator(modal); break; case 'ibw': setupIBWCalculator(modal); break; case 'map': setupMAPCalculator(modal); break; case 'gcs': setupGCSCalculator(modal); break; case 'anion-gap': setupAnionGapCalculator(modal); break; case 'alveolar-gas': setupAlveolarGasCalculator(modal); break; case 'aa-gradient': setupAAGradientCalculator(modal); break; case 'pao2-fio2': setupPaO2FiO2Calculator(modal); break; case 'creatinine-clearance': setupCreatinineClearanceCalculator(modal); break; case 'asa': setupASACalculator(modal); break; case 'dead-space': setupDeadSpaceCalculator(modal); break; case 'shunt-fraction': setupShuntFractionCalculator(modal); break; case 'oxygen-index': setupOxygenIndexCalculator(modal); break; case 'ards-severity': setupARDSSeverityCalculator(modal); break; case 'cardiac-output': setupCardiacOutputCalculator(modal); break; } } // Setup BMI Calculator function setupBMICalculator(modal) { const calculateBtn = modal.querySelector('#calculate-bmi'); const resetBtn = modal.querySelector('#reset-bmi'); const resultBox = modal.querySelector('#bmi-result'); calculateBtn.addEventListener('click', function() { const height = parseFloat(modal.querySelector('#height').value); const heightUnit = modal.querySelector('#height-unit').value; const weight = parseFloat(modal.querySelector('#weight').value); const weightUnit = modal.querySelector('#weight-unit').value; if (isNaN(height) || isNaN(weight)) { alert('Please enter valid height and weight values'); return; } // Convert to metric if needed let heightInMeters = height; if (heightUnit === 'cm') { heightInMeters = height / 100; } else if (heightUnit === 'in') { heightInMeters = height * 0.0254; } else if (heightUnit === 'ft') { heightInMeters = height * 0.3048; } let weightInKg = weight; if (weightUnit === 'lb') { weightInKg = weight * 0.453592; } // Calculate BMI const bmi = weightInKg / (heightInMeters * heightInMeters); // Determine category let category = ''; if (bmi < 18.5) { category = 'Underweight'; } else if (bmi < 25) { category = 'Normal weight'; } else if (bmi < 30) { category = 'Overweight'; } else { category = 'Obesity'; } // Display result modal.querySelector('#bmi-value').textContent = bmi.toFixed(1); modal.querySelector('#bmi-category').textContent = category; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#height').value = ''; modal.querySelector('#weight').value = ''; resultBox.style.display = 'none'; }); } // Setup IBW Calculator function setupIBWCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-ibw'); const resetBtn = modal.querySelector('#reset-ibw'); const resultBox = modal.querySelector('#ibw-result'); calculateBtn.addEventListener('click', function() { const gender = modal.querySelector('#gender').value; const height = parseFloat(modal.querySelector('#ibw-height').value); const heightUnit = modal.querySelector('#ibw-height-unit').value; if (isNaN(height)) { alert('Please enter a valid height value'); return; } // Convert to cm if needed let heightInCm = height; if (heightUnit === 'in') { heightInCm = height * 2.54; } // Calculate IBW let ibw; if (gender === 'male') { ibw = 50 + 0.91 * (heightInCm - 152.4); } else { ibw = 45.5 + 0.91 * (heightInCm - 152.4); } // Display result modal.querySelector('#ibw-value').textContent = ibw.toFixed(1) + ' kg'; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#gender').selectedIndex = 0; modal.querySelector('#ibw-height').value = ''; resultBox.style.display = 'none'; }); } // Setup MAP Calculator function setupMAPCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-map'); const resetBtn = modal.querySelector('#reset-map'); const resultBox = modal.querySelector('#map-result'); calculateBtn.addEventListener('click', function() { const systolic = parseFloat(modal.querySelector('#systolic').value); const diastolic = parseFloat(modal.querySelector('#diastolic').value); if (isNaN(systolic) || isNaN(diastolic)) { alert('Please enter valid blood pressure values'); return; } // Calculate MAP const map = ((2 * diastolic) + systolic) / 3; // Determine interpretation let interpretation = ''; if (map < 60) { interpretation = 'Low - Inadequate tissue perfusion'; } else if (map <= 100) { interpretation = 'Normal'; } else { interpretation = 'High'; } // Display result modal.querySelector('#map-value').textContent = map.toFixed(1); modal.querySelector('#map-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#systolic').value = ''; modal.querySelector('#diastolic').value = ''; resultBox.style.display = 'none'; }); } // Setup GCS Calculator function setupGCSCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-gcs'); const resetBtn = modal.querySelector('#reset-gcs'); const resultBox = modal.querySelector('#gcs-result'); calculateBtn.addEventListener('click', function() { const eyeOpening = modal.querySelector('#eye-opening').value; const verbalResponse = modal.querySelector('#verbal-response').value; const motorResponse = modal.querySelector('#motor-response').value; if (eyeOpening === '' || verbalResponse === '' || motorResponse === '') { alert('Please select values for all components'); return; } // Calculate total GCS let totalGCS = 0; let severity = ''; if (eyeOpening !== 'NT') totalGCS += parseInt(eyeOpening); if (verbalResponse !== 'NT') totalGCS += parseInt(verbalResponse); if (motorResponse !== 'NT') totalGCS += parseInt(motorResponse); // Determine severity if (totalGCS <= 8) { severity = 'Severe'; } else if (totalGCS <= 12) { severity = 'Moderate'; } else { severity = 'Mild'; } // Display result modal.querySelector('#gcs-value').textContent = totalGCS; modal.querySelector('#gcs-severity').textContent = severity; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#eye-opening').selectedIndex = 0; modal.querySelector('#verbal-response').selectedIndex = 0; modal.querySelector('#motor-response').selectedIndex = 0; resultBox.style.display = 'none'; }); } // Setup Anion Gap Calculator function setupAnionGapCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-anion-gap'); const resetBtn = modal.querySelector('#reset-anion-gap'); const resultBox = modal.querySelector('#anion-gap-result'); calculateBtn.addEventListener('click', function() { const sodium = parseFloat(modal.querySelector('#sodium').value); const chloride = parseFloat(modal.querySelector('#chloride').value); const bicarbonate = parseFloat(modal.querySelector('#bicarbonate').value); if (isNaN(sodium) || isNaN(chloride) || isNaN(bicarbonate)) { alert('Please enter valid electrolyte values'); return; } // Calculate Anion Gap const anionGap = sodium - (chloride + bicarbonate); // Determine interpretation let interpretation = ''; if (anionGap < 8) { interpretation = 'Low - May indicate laboratory error, hypoalbuminemia, or multiple myeloma'; } else if (anionGap <= 16) { interpretation = 'Normal'; } else { interpretation = 'High - Suggests metabolic acidosis (lactic acidosis, ketoacidosis, renal failure, toxins)'; } // Display result modal.querySelector('#anion-gap-value').textContent = anionGap.toFixed(1); modal.querySelector('#anion-gap-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#sodium').value = ''; modal.querySelector('#chloride').value = ''; modal.querySelector('#bicarbonate').value = ''; resultBox.style.display = 'none'; }); } // Setup Alveolar Gas Equation Calculator function setupAlveolarGasCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-alveolar-gas'); const resetBtn = modal.querySelector('#reset-alveolar-gas'); const resultBox = modal.querySelector('#alveolar-gas-result'); calculateBtn.addEventListener('click', function() { const fio2 = parseFloat(modal.querySelector('#fio2').value); const paco2 = parseFloat(modal.querySelector('#paco2').value); const r = parseFloat(modal.querySelector('#r').value); if (isNaN(fio2) || isNaN(paco2) || isNaN(r)) { alert('Please enter valid values for all fields'); return; } // Constants const patm = 760; // Atmospheric pressure at sea level (mmHg) const ph2o = 47; // Water vapor pressure at 37°C (mmHg) // Calculate PAO2 using alveolar gas equation const pao2 = (fio2 * (patm - ph2o)) - (paco2 / r); // Display result modal.querySelector('#pao2-value').textContent = pao2.toFixed(1); resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#fio2').value = ''; modal.querySelector('#paco2').value = ''; modal.querySelector('#r').value = '0.8'; resultBox.style.display = 'none'; }); } // Setup A-a Gradient Calculator function setupAAGradientCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-aa-gradient'); const resetBtn = modal.querySelector('#reset-aa-gradient'); const resultBox = modal.querySelector('#aa-gradient-result'); calculateBtn.addEventListener('click', function() { const pao2 = parseFloat(modal.querySelector('#pao2-aa').value); const paco2 = parseFloat(modal.querySelector('#paco2-aa').value); const fio2 = parseFloat(modal.querySelector('#fio2-aa').value); const age = parseFloat(modal.querySelector('#age').value); if (isNaN(pao2) || isNaN(paco2) || isNaN(fio2) || isNaN(age)) { alert('Please enter valid values for all fields'); return; } // Constants const patm = 760; // Atmospheric pressure at sea level (mmHg) const ph2o = 47; // Water vapor pressure at 37°C (mmHg) const r = 0.8; // Respiratory quotient // Calculate PAO2 using alveolar gas equation const PAO2 = (fio2 * (patm - ph2o)) - (paco2 / r); // Calculate A-a gradient const aaGradient = PAO2 - pao2; // Calculate expected A-a gradient const expectedAA = (age / 4) + 4; // Determine interpretation let interpretation = ''; if (aaGradient <= expectedAA) { interpretation = 'Normal A-a gradient for age'; } else { interpretation = 'Increased A-a gradient - suggests problem with oxygenation'; } // Display result modal.querySelector('#aa-gradient-value').textContent = aaGradient.toFixed(1); modal.querySelector('#expected-aa-value').textContent = expectedAA.toFixed(1); modal.querySelector('#aa-gradient-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#pao2-aa').value = ''; modal.querySelector('#paco2-aa').value = ''; modal.querySelector('#fio2-aa').value = '0.21'; modal.querySelector('#age').value = ''; resultBox.style.display = 'none'; }); } // Setup PaO2/FiO2 Ratio Calculator function setupPaO2FiO2Calculator(modal) { const calculateBtn = modal.querySelector('#calculate-pao2-fio2'); const resetBtn = modal.querySelector('#reset-pao2-fio2'); const resultBox = modal.querySelector('#pao2-fio2-result'); calculateBtn.addEventListener('click', function() { const pao2 = parseFloat(modal.querySelector('#pao2-pf').value); const fio2 = parseFloat(modal.querySelector('#fio2-pf').value); const fio2Unit = modal.querySelector('#fio2-unit').value; if (isNaN(pao2) || isNaN(fio2)) { alert('Please enter valid values for all fields'); return; } // Convert FiO2 to fraction if in percentage let fio2Fraction = fio2; if (fio2Unit === 'percent') { fio2Fraction = fio2 / 100; } // Calculate P/F ratio const pfRatio = pao2 / fio2Fraction; // Determine interpretation let interpretation = ''; if (pfRatio > 400) { interpretation = 'Normal oxygenation'; } else if (pfRatio > 300) { interpretation = 'Mild hypoxemia'; } else if (pfRatio > 200) { interpretation = 'Moderate hypoxemia / Mild ARDS'; } else if (pfRatio > 100) { interpretation = 'Severe hypoxemia / Moderate ARDS'; } else { interpretation = 'Extreme hypoxemia / Severe ARDS'; } // Display result modal.querySelector('#pf-ratio-value').textContent = pfRatio.toFixed(0); modal.querySelector('#pf-ratio-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#pao2-pf').value = ''; modal.querySelector('#fio2-pf').value = ''; modal.querySelector('#fio2-unit').selectedIndex = 0; resultBox.style.display = 'none'; }); } // Setup Creatinine Clearance Calculator function setupCreatinineClearanceCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-creatinine-clearance'); const resetBtn = modal.querySelector('#reset-creatinine-clearance'); const resultBox = modal.querySelector('#creatinine-clearance-result'); calculateBtn.addEventListener('click', function() { const serumCreatinine = parseFloat(modal.querySelector('#serum-creatinine').value); const age = parseFloat(modal.querySelector('#age-cc').value); const weight = parseFloat(modal.querySelector('#weight-cc').value); const gender = modal.querySelector('#gender-cc').value; if (isNaN(serumCreatinine) || isNaN(age) || isNaN(weight)) { alert('Please enter valid values for all fields'); return; } // Calculate creatinine clearance using Cockcroft-Gault formula let crCl = ((140 - age) * weight) / (72 * serumCreatinine); // Adjust for gender if (gender === 'female') { crCl = crCl * 0.85; } // Determine interpretation let interpretation = ''; if (crCl > 90) { interpretation = 'Normal kidney function'; } else if (crCl > 60) { interpretation = 'Mildly decreased kidney function'; } else if (crCl > 30) { interpretation = 'Moderately decreased kidney function'; } else if (crCl > 15) { interpretation = 'Severely decreased kidney function'; } else { interpretation = 'Kidney failure'; } // Display result modal.querySelector('#creatinine-clearance-value').textContent = crCl.toFixed(1); modal.querySelector('#creatinine-clearance-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#serum-creatinine').value = ''; modal.querySelector('#age-cc').value = ''; modal.querySelector('#weight-cc').value = ''; modal.querySelector('#gender-cc').selectedIndex = 0; resultBox.style.display = 'none'; }); } // Setup ASA Physical Status Calculator function setupASACalculator(modal) { const showBtn = modal.querySelector('#show-asa-details'); const resetBtn = modal.querySelector('#reset-asa'); const resultBox = modal.querySelector('#asa-result'); showBtn.addEventListener('click', function() { const asaClass = modal.querySelector('#asa-class').value; const emergency = modal.querySelector('#emergency').value; if (asaClass === '') { alert('Please select an ASA class'); return; } // Get ASA description let description = ''; switch(asaClass) { case 'I': description = 'Normal healthy patient'; break; case 'II': description = 'Patient with mild systemic disease'; break; case 'III': description = 'Patient with severe systemic disease'; break; case 'IV': description = 'Patient with severe systemic disease that is a constant threat to life'; break; case 'V': description = 'Moribund patient who is not expected to survive without the operation'; break; case 'VI': description = 'Declared brain-dead patient whose organs are being removed for donor purposes'; break; } // Add emergency modifier if needed let classification = asaClass; if (emergency === 'yes') { classification += 'E'; } // Display result modal.querySelector('#asa-classification').textContent = classification; modal.querySelector('#asa-description').textContent = description; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#asa-class').selectedIndex = 0; modal.querySelector('#emergency').selectedIndex = 0; resultBox.style.display = 'none'; }); } // Setup Dead Space Calculator function setupDeadSpaceCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-dead-space'); const resetBtn = modal.querySelector('#reset-dead-space'); const resultBox = modal.querySelector('#dead-space-result'); calculateBtn.addEventListener('click', function() { const paco2 = parseFloat(modal.querySelector('#paco2-ds').value); const petco2 = parseFloat(modal.querySelector('#petco2').value); const tidalVolume = modal.querySelector('#tidal-volume').value; // Input validation if (isNaN(paco2) || isNaN(petco2)) { alert('Please enter valid values for PaCO2 and PetCO2'); return; } // Validate PaCO2 range (20-80 mmHg) if (paco2 < 20 || paco2 > 80) { alert('PaCO2 value is outside the realistic range (20-80 mmHg). Please check your input.'); return; } // Validate PetCO2 range (10-50 mmHg) if (petco2 < 10 || petco2 > 50) { alert('PetCO2 value is outside the realistic range (10-50 mmHg). Please check your input.'); return; } // Validate that PaCO2 > PetCO2 if (paco2 <= petco2) { alert('PaCO2 must be greater than PetCO2. Please check your input values.'); return; } // Calculate dead space fraction const deadSpaceFraction = (paco2 - petco2) / paco2; // Calculate dead space volume if tidal volume is provided let deadSpaceVolume = ''; if (tidalVolume !== '') { const tv = parseFloat(tidalVolume); // Validate tidal volume (100-1500 mL) if (isNaN(tv) || tv < 100 || tv > 1500) { alert('Tidal volume must be between 100 and 1500 mL. Please check your input.'); return; } deadSpaceVolume = (tv * deadSpaceFraction).toFixed(0) + ' mL'; } // Determine interpretation let interpretation = ''; if (deadSpaceFraction < 0.20) { interpretation = 'Low - May indicate measurement error or unusual physiological state'; } else if (deadSpaceFraction <= 0.35) { interpretation = 'Normal'; } else if (deadSpaceFraction <= 0.45) { interpretation = 'Mildly increased - May indicate early lung disease or mild V/Q mismatch'; } else if (deadSpaceFraction <= 0.60) { interpretation = 'Moderately increased - Suggests significant V/Q mismatch or lung disease'; } else { interpretation = 'Severely increased - Indicates severe V/Q mismatch, consider pulmonary embolism or ARDS'; } // Display results modal.querySelector('#dead-space-fraction').textContent = (deadSpaceFraction * 100).toFixed(1) + '%'; modal.querySelector('#dead-space-volume').textContent = deadSpaceVolume || 'Not calculated (tidal volume not provided)'; modal.querySelector('#dead-space-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#paco2-ds').value = ''; modal.querySelector('#petco2').value = ''; modal.querySelector('#tidal-volume').value = ''; resultBox.style.display = 'none'; }); } // Setup Shunt Fraction Calculator function setupShuntFractionCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-shunt-fraction'); const resetBtn = modal.querySelector('#reset-shunt-fraction'); const resultBox = modal.querySelector('#shunt-fraction-result'); calculateBtn.addEventListener('click', function() { const pao2 = parseFloat(modal.querySelector('#pao2-sf').value); const sao2 = parseFloat(modal.querySelector('#sao2').value); const hemoglobin = parseFloat(modal.querySelector('#hemoglobin').value); const paco2 = parseFloat(modal.querySelector('#paco2-sf').value); const fio2 = parseFloat(modal.querySelector('#fio2-sf').value); const mixedVenousO2 = parseFloat(modal.querySelector('#mixed-venous-o2').value); // Input validation if (isNaN(pao2) || isNaN(sao2) || isNaN(hemoglobin) || isNaN(paco2) || isNaN(fio2) || isNaN(mixedVenousO2)) { alert('Please enter valid values for all fields'); return; } // Validate PaO2 range (40-600 mmHg) if (pao2 < 40 || pao2 > 600) { alert('PaO2 value is outside the realistic range (40-600 mmHg). Please check your input.'); return; } // Validate SaO2 range (70-100%) if (sao2 < 70 || sao2 > 100) { alert('SaO2 value is outside the realistic range (70-100%). Please check your input.'); return; } // Validate hemoglobin range (5-20 g/dL) if (hemoglobin < 5 || hemoglobin > 20) { alert('Hemoglobin value is outside the realistic range (5-20 g/dL). Please check your input.'); return; } // Validate PaCO2 range (20-80 mmHg) if (paco2 < 20 || paco2 > 80) { alert('PaCO2 value is outside the realistic range (20-80 mmHg). Please check your input.'); return; } // Validate FiO2 range (0.21-1.0) if (fio2 < 0.21 || fio2 > 1.0) { alert('FiO2 value is outside the realistic range (0.21-1.0). Please check your input.'); return; } // Validate mixed venous O2 range (40-90%) if (mixedVenousO2 < 40 || mixedVenousO2 > 90) { alert('Mixed venous O2 value is outside the realistic range (40-90%). Please check your input.'); return; } // Constants const huffnerConstant = 1.34; // mL O2 per gram of hemoglobin const o2Solubility = 0.0031; // mL O2 per dL per mmHg const patm = 760; // Atmospheric pressure at sea level (mmHg) const ph2o = 47; // Water vapor pressure at 37°C (mmHg) const r = 0.8; // Respiratory quotient // Calculate PAO2 using alveolar gas equation const pao2Alveolar = (fio2 * (patm - ph2o)) - (paco2 / r); // Calculate oxygen contents // Arterial oxygen content (CaO2) const sao2Fraction = sao2 / 100; const cao2 = (hemoglobin * huffnerConstant * sao2Fraction) + (pao2 * o2Solubility); // Capillary oxygen content (CcO2) - assuming 100% saturation const cco2 = (hemoglobin * huffnerConstant * 1.0) + (pao2Alveolar * o2Solubility); // Mixed venous oxygen content (CvO2) const mixedVenousO2Fraction = mixedVenousO2 / 100; // Estimate PvO2 from SvO2 using a rough approximation let pvO2; if (mixedVenousO2 >= 70) { pvO2 = 40 + (mixedVenousO2 - 70) * 0.5; // Rough approximation } else { pvO2 = 30 + (mixedVenousO2 - 60) * 0.4; // Rough approximation } const cvo2 = (hemoglobin * huffnerConstant * mixedVenousO2Fraction) + (pvO2 * o2Solubility); // Calculate shunt fraction let shuntFraction; if (cco2 - cvo2 > 0) { shuntFraction = (cco2 - cao2) / (cco2 - cvo2); } else { alert('Unable to calculate shunt fraction. CcO2 must be greater than CvO2.'); return; } // Validate shunt fraction result if (shuntFraction < 0 || shuntFraction > 1) { alert('Calculated shunt fraction is outside the valid range (0-1). Please check your input values.'); return; } // Determine interpretation let interpretation = ''; if (shuntFraction < 0.03) { interpretation = 'Low - May indicate measurement error or unusual physiological state'; } else if (shuntFraction <= 0.05) { interpretation = 'Normal'; } else if (shuntFraction <= 0.10) { interpretation = 'Mildly increased - May indicate mild lung disease or early atelectasis'; } else if (shuntFraction <= 0.20) { interpretation = 'Moderately increased - Suggests significant lung pathology such as pneumonia, atelectasis, or ARDS'; } else { interpretation = 'Severely increased - Indicates severe intrapulmonary shunting, consider massive atelectasis, ARDS, or intracardiac shunt'; } // Display results modal.querySelector('#shunt-fraction-value').textContent = (shuntFraction * 100).toFixed(1) + '%'; modal.querySelector('#cao2-value').textContent = cao2.toFixed(2); modal.querySelector('#cco2-value').textContent = cco2.toFixed(2); modal.querySelector('#cvo2-value').textContent = cvo2.toFixed(2); modal.querySelector('#shunt-fraction-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#pao2-sf').value = ''; modal.querySelector('#sao2').value = ''; modal.querySelector('#hemoglobin').value = ''; modal.querySelector('#paco2-sf').value = ''; modal.querySelector('#fio2-sf').value = '0.21'; modal.querySelector('#mixed-venous-o2').value = '75'; resultBox.style.display = 'none'; }); } // Setup Oxygenation Index Calculator function setupOxygenIndexCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-oxygen-index'); const resetBtn = modal.querySelector('#reset-oxygen-index'); const resultBox = modal.querySelector('#oxygen-index-result'); calculateBtn.addEventListener('click', function() { const fio2 = parseFloat(modal.querySelector('#fio2-oi').value); const meanAirwayPressure = parseFloat(modal.querySelector('#mean-airway-pressure').value); const pao2 = parseFloat(modal.querySelector('#pao2-oi').value); // Input validation if (isNaN(fio2) || isNaN(meanAirwayPressure) || isNaN(pao2)) { alert('Please enter valid values for all fields'); return; } // Validate FiO2 range (0.21-1.0) if (fio2 < 0.21 || fio2 > 1.0) { alert('FiO2 value is outside the realistic range (0.21-1.0). Please check your input.'); return; } // Validate Mean Airway Pressure range (5-40 cmH2O) if (meanAirwayPressure < 5 || meanAirwayPressure > 40) { alert('Mean Airway Pressure value is outside the realistic range (5-40 cmH2O). Please check your input.'); return; } // Validate PaO2 range (40-500 mmHg) if (pao2 < 40 || pao2 > 500) { alert('PaO2 value is outside the realistic range (40-500 mmHg). Please check your input.'); return; } // Calculate Oxygenation Index const oxygenIndex = (fio2 * meanAirwayPressure * 100) / pao2; // Validate calculated OI if (oxygenIndex < 0 || oxygenIndex > 200) { alert('Calculated Oxygenation Index is outside the valid range (0-200). Please check your input values.'); return; } // Determine interpretation let interpretation = ''; if (oxygenIndex < 5) { interpretation = 'Normal - Adequate oxygenation with minimal support'; } else if (oxygenIndex <= 15) { interpretation = 'Mild respiratory failure - May respond to conventional ventilation strategies'; } else if (oxygenIndex <= 30) { interpretation = 'Moderate respiratory failure - May require advanced ventilatory strategies'; } else { interpretation = 'Severe respiratory failure - Consider ECMO or other rescue therapies'; } // Display results modal.querySelector('#oxygen-index-value').textContent = oxygenIndex.toFixed(1); modal.querySelector('#oxygen-index-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#fio2-oi').value = '0.21'; modal.querySelector('#mean-airway-pressure').value = ''; modal.querySelector('#pao2-oi').value = ''; resultBox.style.display = 'none'; }); } // Setup ARDS Severity Calculator function setupARDSSeverityCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-ards-severity'); const resetBtn = modal.querySelector('#reset-ards-severity'); const resultBox = modal.querySelector('#ards-severity-result'); calculateBtn.addEventListener('click', function() { const pao2 = parseFloat(modal.querySelector('#pao2-ards').value); const fio2 = parseFloat(modal.querySelector('#fio2-ards').value); const fio2Unit = modal.querySelector('#fio2-unit-ards').value; const peep = parseFloat(modal.querySelector('#peep').value); const timing = modal.querySelector('#timing').value; const cause = modal.querySelector('#cause').value; const cardiac = modal.querySelector('#cardiac').value; // Input validation if (isNaN(pao2) || isNaN(fio2) || isNaN(peep)) { alert('Please enter valid values for PaO2, FiO2, and PEEP'); return; } // Validate PaO2 range (40-500 mmHg) if (pao2 < 40 || pao2 > 500) { alert('PaO2 value is outside the realistic range (40-500 mmHg). Please check your input.'); return; } // Validate FiO2 range (0.21-1.0 or 21-100%) if (fio2 < 0.21 || fio2 > 1.0) { if (fio2Unit === 'percent' && (fio2 < 21 || fio2 > 100)) { alert('FiO2 value is outside the realistic range (21-100%). Please check your input.'); return; } else if (fio2Unit === 'fraction') { alert('FiO2 value is outside the realistic range (0.21-1.0). Please check your input.'); return; } } // Validate PEEP range (5-25 cmH2O) if (peep < 5 || peep > 25) { alert('PEEP value is outside the realistic range (5-25 cmH2O). Please check your input.'); return; } // Convert FiO2 to fraction if in percentage let fio2Fraction = fio2; if (fio2Unit === 'percent') { fio2Fraction = fio2 / 100; } // Calculate P/F ratio const pfRatio = pao2 / fio2Fraction; // Validate P/F ratio result if (pfRatio < 40 || pfRatio > 600) { alert('Calculated P/F ratio is outside the valid range (40-600). Please check your input values.'); return; } // Determine ARDS classification let ardsClassification = ''; let meetsBerlin = 'No'; let interpretation = ''; // Check if meets Berlin Definition criteria const timingAcute = timing === 'acute'; const respiratoryCause = cause === 'respiratory'; const cardiacNormal = cardiac === 'normal'; const peepAdequate = peep >= 5; if (timingAcute && respiratoryCause && cardiacNormal && peepAdequate) { if (pfRatio > 300) { ardsClassification = 'No ARDS'; meetsBerlin = 'No'; interpretation = 'Does not meet ARDS criteria. Consider other causes of respiratory failure.'; } else if (pfRatio > 200) { ardsClassification = 'Mild ARDS'; meetsBerlin = 'Yes'; interpretation = 'Meets criteria for mild ARDS. Mortality ~27%. Consider conventional lung-protective ventilation.'; } else if (pfRatio > 100) { ardsClassification = 'Moderate ARDS'; meetsBerlin = 'Yes'; interpretation = 'Meets criteria for moderate ARDS. Mortality ~32%. Consider higher PEEP, recruitment maneuvers, and prone positioning.'; } else { ardsClassification = 'Severe ARDS'; meetsBerlin = 'Yes'; interpretation = 'Meets criteria for severe ARDS. Mortality ~45%. Consider all advanced therapies including ECMO evaluation.'; } } else { ardsClassification = 'Cannot classify'; meetsBerlin = 'No'; interpretation = 'Does not meet all Berlin Definition criteria. '; if (!timingAcute) { interpretation += 'Onset is not acute. '; } if (!respiratoryCause) { interpretation += 'Primary cause may not be respiratory. '; } if (!cardiacNormal) { interpretation += 'Cardiac function may be impaired. '; } if (!peepAdequate) { interpretation += 'PEEP is inadequate (< 5 cmH2O). '; } interpretation += 'Consider alternative diagnoses or reassess when criteria are met.'; } // Display results modal.querySelector('#pf-ratio-ards').textContent = pfRatio.toFixed(0); modal.querySelector('#ards-classification').textContent = ardsClassification; modal.querySelector('#meets-berlin').textContent = meetsBerlin; modal.querySelector('#ards-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { modal.querySelector('#pao2-ards').value = ''; modal.querySelector('#fio2-ards').value = ''; modal.querySelector('#fio2-unit-ards').selectedIndex = 0; modal.querySelector('#peep').value = ''; modal.querySelector('#timing').selectedIndex = 0; modal.querySelector('#cause').selectedIndex = 0; modal.querySelector('#cardiac').selectedIndex = 0; resultBox.style.display = 'none'; }); } // Setup Cardiac Output Calculator function setupCardiacOutputCalculator(modal) { const calculateBtn = modal.querySelector('#calculate-cardiac-output'); const resetBtn = modal.querySelector('#reset-cardiac-output'); const resultBox = modal.querySelector('#cardiac-output-result'); const methodSelect = modal.querySelector('#co-method'); // Method content elements const fickMethod = modal.querySelector('#fick-method'); const thermodilutionMethod = modal.querySelector('#thermodilution-method'); const estimatedMethod = modal.querySelector('#estimated-method'); // Show/hide method content based on selection methodSelect.addEventListener('change', function() { const selectedMethod = this.value; fickMethod.style.display = selectedMethod === 'fick' ? 'block' : 'none'; thermodilutionMethod.style.display = selectedMethod === 'thermodilution' ? 'block' : 'none'; estimatedMethod.style.display = selectedMethod === 'estimated' ? 'block' : 'none'; }); calculateBtn.addEventListener('click', function() { const selectedMethod = methodSelect.value; let cardiacOutput = 0; let isValid = true; if (selectedMethod === 'fick') { const o2Consumption = parseFloat(modal.querySelector('#o2-consumption').value); const arterialO2 = parseFloat(modal.querySelector('#arterial-o2').value); const mixedVenousO2 = parseFloat(modal.querySelector('#mixed-venous-o2-co').value); // Input validation for Fick method if (isNaN(o2Consumption) || isNaN(arterialO2) || isNaN(mixedVenousO2)) { alert('Please enter valid values for all Fick method fields'); return; } if (o2Consumption < 100 || o2Consumption > 500) { alert('O2 consumption is outside the realistic range (100-500 mL/min)'); return; } if (arterialO2 < 10 || arterialO2 > 25) { alert('Arterial O2 content is outside the realistic range (10-25 mL/dL)'); return; } if (mixedVenousO2 < 8 || mixedVenousO2 > 20) { alert('Mixed venous O2 content is outside the realistic range (8-20 mL/dL)'); return; } if (arterialO2 <= mixedVenousO2) { alert('Arterial O2 content must be greater than mixed venous O2 content'); return; } // Calculate using Fick principle const aVDiff = arterialO2 - mixedVenousO2; cardiacOutput = o2Consumption / aVDiff / 10; // Convert to L/min } else if (selectedMethod === 'thermodilution') { const injectateVolume = parseFloat(modal.querySelector('#injectate-volume').value); const injectateTemp = parseFloat(modal.querySelector('#injectate-temp').value); const bloodTemp = parseFloat(modal.querySelector('#blood-temp').value); const areaUnderCurve = parseFloat(modal.querySelector('#area-under-curve').value); const calculationConstant = parseFloat(modal.querySelector('#calculation-constant').value); // Input validation for thermodilution method if (isNaN(injectateVolume) || isNaN(injectateTemp) || isNaN(bloodTemp) || isNaN(areaUnderCurve) || isNaN(calculationConstant)) { alert('Please enter valid values for all thermodilution method fields'); return; } if (injectateVolume < 5 || injectateVolume > 20) { alert('Injectate volume is outside the realistic range (5-20 mL)'); return; } if (injectateTemp < 0 || injectateTemp > 25) { alert('Injectate temperature is outside the realistic range (0-25°C)'); return; } if (bloodTemp < 35 || bloodTemp > 39) { alert('Blood temperature is outside the realistic range (35-39°C)'); return; } if (areaUnderCurve <= 0) { alert('Area under curve must be greater than 0'); return; } // Simplified thermodilution calculation const tempDifference = bloodTemp - injectateTemp; cardiacOutput = (injectateVolume * tempDifference * calculationConstant) / areaUnderCurve; } else if (selectedMethod === 'estimated') { const heartRate = parseFloat(modal.querySelector('#heart-rate').value); const systolicBP = parseFloat(modal.querySelector('#systolic-bp').value); const diastolicBP = parseFloat(modal.querySelector('#diastolic-bp').value); const bsa = parseFloat(modal.querySelector('#bsa').value); // Input validation for estimated method if (isNaN(heartRate) || isNaN(systolicBP) || isNaN(diastolicBP) || isNaN(bsa)) { alert('Please enter valid values for all estimated method fields'); return; } if (heartRate < 40 || heartRate > 180) { alert('Heart rate is outside the realistic range (40-180 bpm)'); return; } if (systolicBP < 70 || systolicBP > 250) { alert('Systolic BP is outside the realistic range (70-250 mmHg)'); return; } if (diastolicBP < 30 || diastolicBP > 150) { alert('Diastolic BP is outside the realistic range (30-150 mmHg)'); return; } if (systolicBP <= diastolicBP) { alert('Systolic BP must be greater than diastolic BP'); return; } if (bsa < 1.0 || bsa > 2.5) { alert('Body surface area is outside the realistic range (1.0-2.5 m²)'); return; } // Estimated cardiac output using a simplified formula // This is a rough estimation based on heart rate and blood pressure const map = (systolicBP + 2 * diastolicBP) / 3; cardiacOutput = (heartRate * map * 0.001) + 2.0; // Very rough estimation } // Validate cardiac output if (cardiacOutput < 1 || cardiacOutput > 15) { alert('Calculated cardiac output is outside the valid range (1-15 L/min). Please check your input values.'); return; } // Calculate cardiac index const bsa = parseFloat(modal.querySelector('#bsa').value) || 1.73; const cardiacIndex = cardiacOutput / bsa; // Determine interpretation let interpretation = ''; if (cardiacIndex < 1.5) { interpretation = 'Severely decreased - Indicates decompensated shock requiring immediate intervention'; } else if (cardiacIndex < 2.0) { interpretation = 'Moderately decreased - Often symptomatic, requires hemodynamic support'; } else if (cardiacIndex < 2.5) { interpretation = 'Mildly decreased - May be compensated, monitor closely'; } else if (cardiacIndex <= 4.2) { interpretation = 'Normal - Adequate cardiac output'; } else if (cardiacIndex <= 4.5) { interpretation = 'Mildly increased - May be normal in some conditions (e.g., pregnancy)'; } else { interpretation = 'Markedly increased - Suggests hyperdynamic state (e.g., sepsis, anemia, hyperthyroidism)'; } // Display results modal.querySelector('#co-value').textContent = cardiacOutput.toFixed(2); modal.querySelector('#ci-value').textContent = cardiacIndex.toFixed(2); modal.querySelector('#co-interpretation').textContent = interpretation; resultBox.style.display = 'block'; }); resetBtn.addEventListener('click', function() { // Reset all inputs modal.querySelectorAll('input').forEach(input => { if (input.type === 'number') { if (input.id === 'injectate-volume') input.value = '10'; else if (input.id === 'injectate-temp') input.value = '4'; else if (input.id === 'blood-temp') input.value = '37'; else if (input.id === 'calculation-constant') input.value = '1'; else if (input.id === 'bsa') input.value = '1.73'; else input.value = ''; } }); // Reset method selection methodSelect.selectedIndex = 0; fickMethod.style.display = 'block'; thermodilutionMethod.style.display = 'none'; estimatedMethod.style.display = 'none'; // Hide result box resultBox.style.display = 'none'; }); } });

Anesthesia Clinical Calculator

Clinical Calculators for Anesthesia Trainees

Airway & Breathing

Cardiovascular

Pharmacology

Fluid & Electrolytes

Renal

Pediatric

Risk Assessment

Scores & Scales

Body Metrics

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Transfusion

Critical Care

Result

About BMI

BMI Categories:

Anesthesia Clinical Calculator

Clinical Calculators for Anesthesia Trainees

Airway & Breathing

Cardiovascular

Pharmacology

Fluid & Electrolytes

Renal

Pediatric

Risk Assessment

Scores & Scales

Body Metrics

Equipment & Technical

Transfusion

Critical Care

Result

About BMI

BMI Categories:

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About Ideal Body Weight

Formulas:

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About Mean Arterial Pressure

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Clinical Significance:

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About Glasgow Coma Scale

Components:

Interpretation:

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About Anion Gap

Formula:

Normal Range:

Clinical Significance:

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About Alveolar Gas Equation

Formula:

Clinical Significance:

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About A-a Gradient

Formula:

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Clinical Significance:

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About PaO2/FiO2 Ratio

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ARDS Berlin Definition:

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About Creatinine Clearance

Cockcroft-Gault Formula:

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ASA Physical Status

About ASA Physical Status Classification

ASA Classes:

Emergency Modifier:

Limitations:

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About Dead Space

Formula

Normal Values

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About Shunt Fraction

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Normal Values

Clinical Significance

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