Breathing Rate & Pattern Calculator

ANA›Life Services Authority›National Calculator Authority›Breathing Rate & Pattern Calculator

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Breathing Rate & Pattern Calculator

Calculate breathing rate, minute ventilation, inspiratory-to-expiratory ratio, and identify breathing patterns (normal, tachypnea, bradypnea, Kussmaul, Cheyne-Stokes indicators).

Number of Breaths Counted

Count breaths observed during the measurement period

Observation Time (seconds)

Duration over which breaths were counted (10–300 s)

Tidal Volume (mL) (optional)

Volume of air per breath; typical adult ~500 mL

Inspiratory Time (seconds) (optional)

Duration of each inhalation phase

Expiratory Time (seconds) (optional)

Duration of each exhalation phase

Age Group

Adult (≥18 years) Adolescent (12–17 years) School-age child (6–11 years) Preschool child (3–5 years) Toddler (1–2 years) Infant (0–12 months)

Calculate

function breCalc() { var breathsVal = document.getElementById('bre-breaths').value.trim(); var obsTimeVal = document.getElementById('bre-obs-time').value.trim(); var tidalVal = document.getElementById('bre-tidal').value.trim(); var inspVal = document.getElementById('bre-insp-time').value.trim(); var expVal = document.getElementById('bre-exp-time').value.trim(); var ageGroup = document.getElementById('bre-age-group').value; var resultDiv = document.getElementById('bre-result');

// --- Validation --- if (breathsVal === '' || obsTimeVal === '') { resultDiv.innerHTML = 'Please enter the number of breaths and observation time.'; return; }

var breaths = parseFloat(breathsVal); var obsTime = parseFloat(obsTimeVal);

if (isNaN(breaths) || breaths 200 || !Number.isInteger(breaths)) { resultDiv.innerHTML = 'Breaths counted must be a whole number between 1 and 200.'; return; } if (isNaN(obsTime) || obsTime 300) { resultDiv.innerHTML = 'Observation time must be between 10 and 300 seconds.'; return; }

var tidal = null, insp = null, exp = null;

if (tidalVal !== '') { tidal = parseFloat(tidalVal); if (isNaN(tidal) || tidal 3000) { resultDiv.innerHTML = 'Tidal volume must be between 50 and 3000 mL.'; return; } } if (inspVal !== '') { insp = parseFloat(inspVal); if (isNaN(insp) || insp 10) { resultDiv.innerHTML = 'Inspiratory time must be between 0.1 and 10 seconds.'; return; } } if (expVal !== '') { exp = parseFloat(expVal); if (isNaN(exp) || exp 20) { resultDiv.innerHTML = 'Expiratory time must be between 0.1 and 20 seconds.'; return; } }

// --- Core Calculations ---

// 1. Breathing Rate (breaths per minute) // RR = (breaths_counted / observation_time_seconds) × 60 var rr = (breaths / obsTime) * 60;

// 2. Breath cycle time (seconds per breath) // T_cycle = 60 / RR var tCycle = 60 / rr;

// 3. Minute Ventilation (L/min) — only if tidal volume provided // MV = RR × V_T (V_T in litres) var mv = null; if (tidal !== null) { mv = rr * (tidal / 1000); // convert mL → L }

// 4. I:E Ratio — only if both insp and exp times provided // I:E = T_I : T_E (normalised so I = 1) var ieRatio = null, ieNorm = null; if (insp !== null && exp !== null) { ieRatio = insp / exp; // e.g. 0.6 means 1:1.67 ieNorm = exp / insp; // expiratory multiple relative to inspiratory // Validate: insp + exp should not exceed cycle time by more than 20% if ((insp + exp) > tCycle * 1.2) { resultDiv.innerHTML = 'Inspiratory + expiratory time (' + (insp + exp).toFixed(1) + ' s) exceeds the calculated breath cycle time (' + tCycle.toFixed(1) + ' s). Please check your inputs.'; return; } }

// 5. Normal RR ranges by age group (breaths/min) var normalRanges = { adult: { min: 12, max: 20, label: 'Adult (≥18 yr)' }, adolescent: { min: 12, max: 20, label: 'Adolescent (12–17 yr)' }, school: { min: 18, max: 30, label: 'School-age (6–11 yr)' }, preschool: { min: 22, max: 34, label: 'Preschool (3–5 yr)' }, toddler: { min: 24, max: 40, label: 'Toddler (1–2 yr)' }, infant: { min: 30, max: 60, label: 'Infant (0–12 mo)' } }; var range = normalRanges[ageGroup];

// 6. Pattern Classification var pattern = '', patternClass = '', patternDesc = ''; if (rr >= range.min && rr range.max) { if (ageGroup === 'adult' || ageGroup === 'adolescent') { if (rr > 30) { pattern = 'Severe Tachypnea'; patternClass = 'calc-high'; patternDesc = 'Markedly elevated respiratory rate. May indicate severe respiratory distress, sepsis, or metabolic acidosis.'; } else { pattern = 'Tachypnea'; patternClass = 'calc-high'; patternDesc = 'Elevated respiratory rate above normal. Common causes include fever, anxiety, pain, hypoxia, or pulmonary disease.'; } } else { pattern = 'Tachypnea'; patternClass = 'calc-high'; patternDesc = 'Elevated respiratory rate above normal for age group ' + range.label + '.'; } } else { pattern = 'Bradypnea'; patternClass = 'calc-low'; patternDesc = 'Respiratory rate below normal. May indicate CNS depression, opioid use, hypothyroidism, or metabolic alkalosis.'; }

// 7. I:E pattern assessment var ieAssessment = ''; if (ieRatio !== null) { if (ieRatio > 1) { ieAssessment = 'Inverse I:E ratio (I > E) — may indicate inverse-ratio ventilation or obstructive pathology.'; } else if (ieNorm >= 1.5 && ieNorm 2.5) { ieAssessment = 'Prolonged expiratory phase (I:E = 1:' + ieNorm.toFixed(2) + '). Suggests obstructive pattern (e.g., asthma, COPD).'; } else { ieAssessment = 'Short expiratory phase (I:E = 1:' + ieNorm.toFixed(2) + '). May indicate restrictive pattern or rapid shallow breathing.'; } }

// 8. Kussmaul / Cheyne-Stokes indicators (heuristic flags) var specialPattern = ''; if (ageGroup === 'adult' || ageGroup === 'adolescent') { if (rr > 20 && tidal !== null && tidal > 700) { specialPattern = '- Kussmaul breathing indicator: High rate combined with large tidal volume may suggest metabolic acidosis (e.g., diabetic ketoacidosis). Clinical correlation required.'; } if (rr 0 && tidal !== null && tidal 0) { alveolarVent = (effectiveTidal / 1000) * rr; // L/min } }

// --- Build Output --- var statusColor = patternClass === 'calc-normal' ? '#2e7d32' : (patternClass === 'calc-high' ? '#c62828' : '#e65100');

var html = '### Results '; html += ''; html += 'ParameterValue'; html += 'Breathing Rate (RR)' + rr.toFixed(1) + ' breaths/min'; html += 'Normal Range (' + range.label + ')' + range.min + '–' + range.max + ' breaths/min'; html += 'Breath Cycle Time' + tCycle.toFixed(2) + ' s/breath';

if (mv !== null) { html += 'Minute Ventilation (MV)' + mv.toFixed(2) + ' L/min'; } if (alveolarVent !== null) { html += 'Estimated Alveolar Ventilation' + alveolarVent.toFixed(2) + ' L/min'; html += 'Estimated Dead Space Used' + deadSpaceEst[ageGroup] + ' mL (anatomical estimate)'; } if (ieRatio !== null) { html += 'I:E Ratio1 : ' + ieNorm.toFixed(2) + ' (' + insp.toFixed(1) + ' s : ' + exp.toFixed(1) + ' s)'; } html += '';

html += ''; html += 'Pattern: ' + pattern + ''; html += '' + patternDesc + ''; html += '';

if (ieAssessment) { html += ''; html += 'I:E Assessment: ' + ieAssessment; html += ''; }

if (specialPattern) { html += ''; html += 'Special Pattern Flags:' + specialPattern + ''; html += ''; }

html += '⚠ This tool is for educational purposes only. Clinical assessment by a qualified healthcare professional is required for diagnosis and treatment decisions.

';

resultDiv.innerHTML = html; }

#### Formulas Used

1. Breathing Rate (RR): RR (breaths/min) = (Breaths Counted ÷ Observation Time in seconds) × 60

2. Breath Cycle Time: Tcycle (s) = 60 ÷ RR

3. Minute Ventilation (MV): MV (L/min) = RR × VT (L) where VT = tidal volume in litres

4. Alveolar Ventilation (V̇A): V̇A (L/min) = (VT − VD) × RR where VD = anatomical dead space (estimated: ~150 mL adult, scaled by age group)

5. I:E Ratio: I:E = TI : TE (normalised to 1 : TE/TI) Normal physiological range: 1:1.5 to 1:2

6. Pattern Classification thresholds (adults): Eupnea: 12–20 breaths/min | Tachypnea: >20 | Severe Tachypnea: >30 | Bradypnea: <12

#### Assumptions & References

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