Acute Respiratory Distress - Paediatric

1. Clinical Overview

Summary

Acute respiratory distress in children represents increased work of breathing or inadequate ventilation resulting from airway obstruction, lung parenchymal disease, or respiratory muscle dysfunction. It is one of the most common paediatric emergencies, accounting for approximately 15-20% of paediatric emergency department presentations. [1] The condition differs fundamentally from adult respiratory distress due to anatomical differences: children have smaller airways (resistance varies inversely with the fourth power of radius), less elastic recoil, fewer alveoli, and higher oxygen consumption per kilogram, making them particularly vulnerable to rapid deterioration. [2]

Respiratory distress exists on a continuum from mild increase in work of breathing to frank respiratory failure, defined as inadequate oxygenation (Type I) or ventilation (Type II). The most common causes vary by age: in infants under 12 months, bronchiolitis (particularly RSV) predominates (30-40% of cases); in children 1-5 years, viral croup and asthma are most common (20-30% each); in older children, asthma accounts for the majority. [3] Early recognition using validated severity scores (PRAM for asthma, Westley for croup), prompt oxygen therapy, and cause-specific treatment are critical, as mortality remains approximately 0.5-1% in developed healthcare systems but rises significantly with delayed intervention. [4]

The key clinical skill is distinguishing between upper airway obstruction (inspiratory stridor, barking cough in croup), lower airway obstruction (expiratory wheeze in asthma and bronchiolitis), and parenchymal disease (crackles, hypoxia in pneumonia). Validated scoring systems guide severity assessment and disposition decisions. Management priorities are immediate oxygen therapy targeting SpO2 > 92%, cause-specific treatment, and escalation to non-invasive (CPAP, high-flow nasal cannula) or invasive ventilation when conservative measures fail. [5,6]

Key Facts

• Definition: Increased work of breathing with tachypnoea, accessory muscle use, or inadequate ventilation/oxygenation
• Incidence: 15-20% of paediatric ED presentations; ~3-5 per 1,000 children annually [1]
• Mortality: 0.5-1% in developed countries with appropriate care; higher in resource-limited settings [4]
• Peak age: Infants (less than 12 months) highest risk due to anatomical vulnerability [2]
• Critical features: Work of breathing assessment, SpO2, respiratory rate, severity scoring
• Key investigations: Clinical assessment (primary), pulse oximetry (essential), chest X-ray (selective)
• First-line treatment: Oxygen therapy, cause-specific treatment (bronchodilators for asthma, supportive care for bronchiolitis, dexamethasone for croup)

Clinical Pearls

"Work of breathing trumps respiratory rate" — A child with severe intercostal and subcostal recession plus accessory muscle use is in significant distress even if respiratory rate is normal. Conversely, a fatigued child may have a decreasing respiratory rate as exhaustion sets in—this is a pre-arrest sign, not improvement.

"Tachypnoea is age-specific" — Normal respiratory rates: infants (30-60/min), toddlers (24-40/min), school-age (18-30/min), adolescents (12-16/min). A 6-month-old breathing at 50/min may be normal; a 6-year-old at 50/min is severely tachypnoeic. [7]

"Silent chest in asthma is life-threatening" — Absence of wheeze in a distressed asthmatic indicates critical airflow limitation. This is not improvement—it's imminent respiratory arrest requiring immediate senior escalation and preparation for intubation. [8]

"Grunting in infants is PEEP" — Grunting represents physiological positive end-expiratory pressure to prevent alveolar collapse. It's a sensitive marker of significant respiratory distress and hypoxia in infants and should never be dismissed. [9]

"Use validated scoring" — PRAM score (for asthma) and Westley croup score are validated, reproducible tools for severity assessment and should be documented to guide treatment escalation. [10,11]

Why This Matters Clinically

Respiratory distress is the final common pathway for multiple paediatric emergencies and the leading cause of paediatric cardiorespiratory arrest. Unlike adults, children rarely have primary cardiac arrest—most arrests are secondary to progressive hypoxia from respiratory failure. [12] Early recognition and intervention can prevent progression to arrest, where survival outcomes are significantly worse (neurologically intact survival less than 10% for out-of-hospital paediatric cardiac arrest). [13] The critical window for intervention is narrow: infants can decompensate from mild distress to apnoea within 15-30 minutes. Appropriate escalation decisions (ward vs. HDU vs. PICU) require accurate severity assessment using validated tools, as clinical gestalt alone has poor inter-rater reliability. [14]

---

2. Epidemiology

Incidence & Prevalence

Respiratory complaints account for 15-20% of all paediatric emergency department presentations, with acute respiratory distress representing the most common serious presentation. [1] Annual incidence in the UK is approximately 3-5 per 1,000 children, with significant seasonal variation (winter peak for bronchiolitis and croup, spring/autumn peaks for asthma). [3]

Bronchiolitis (most common cause in infants):

• Affects 30-40% of infants in the first year of life [15]
• Hospitalization rate: 2-3% of all infants annually
• Peak age: 3-6 months
• Seasonal: 80% of cases October-March in Northern Hemisphere

Asthma exacerbations (most common in older children):

• Prevalence of asthma: 10-15% of children in developed countries [16]
• Annual exacerbation rate: 30-40% of asthmatic children
• Emergency department visits: ~1.8 million annually (USA) [8]

Croup:

• Annual incidence: 3-6 per 100 children aged 6 months-3 years [17]
• ED presentation rate: 5% of all croup cases
• Hospitalization: less than 5% of croup cases

Demographics

Risk Factors

Non-Modifiable:

• Age less than 12 months: Anatomical vulnerability (smaller airways, higher resistance, less alveoli)
• Prematurity: Chronic lung disease of prematurity, structural airway abnormalities
• Congenital heart disease: 3-4x increased risk of severe respiratory illness [15]
• Immunodeficiency: Higher risk of severe/complicated respiratory infections
• Chronic lung disease: Cystic fibrosis, bronchopulmonary dysplasia

Modifiable:

Common Causes by Age

Infants (0-12 months):

Toddlers (1-5 years):

School-age (5-12 years):

---

3. Pathophysiology

Anatomical Differences in Children

Children are not "small adults"—key anatomical differences increase vulnerability to respiratory distress: [2]

Airway Anatomy:

• Smaller absolute airway diameter: Infant trachea ~4mm (adult ~20mm)
• Poiseuille's Law: Airway resistance ∝ 1/(radius)⁴ — 1mm of mucosal oedema in an infant increases resistance 16-fold vs. 3-fold in adults
• Narrowest point: Cricoid ring in children less than 8-10 years (vs. glottis in adults)
• Softer cartilage: More prone to dynamic collapse with increased negative pressure
• Large tongue relative to oral cavity: Easier airway obstruction

Respiratory Physiology:

• Horizontal ribs: Less efficient thoracic expansion
• Compliant chest wall: Paradoxical chest movement (increased WOB leads to recession, not expansion)
• Fewer alveoli: Term infant has ~50 million alveoli (adult ~300 million)—adult number not reached until ~8 years
• Higher oxygen consumption: 6-8 mL/kg/min (vs. 3-4 mL/kg/min in adults)—less respiratory reserve
• Lower functional residual capacity: Faster desaturation during apnoea/hypoventilation

The Respiratory Distress Cascade

Stage 1: Underlying Insult

Three primary mechanisms:

Stage 2: Compensatory Response (Respiratory Distress)

The child compensates by increasing work of breathing:

• Tachypnoea: ↑ respiratory rate to maintain minute ventilation
• Accessory muscle recruitment: Sternocleidomastoid, scalenes to maximize inspiration
• Nasal flaring: ↓ nasal resistance (significant in obligate nasal breathers)
• Expiratory grunting: Physiological PEEP by partial glottic closure—prevents alveolar collapse [9]
• Prolonged expiration: In lower airway obstruction to overcome resistance
• Positional changes: Tripod positioning to optimize diaphragmatic mechanics

Clinical signs of increased work of breathing:

• Intercostal recession (visible inward movement of chest wall between ribs)
• Subcostal recession (inward movement below ribcage)
• Supraclavicular recession (visible above clavicles)
• Tracheal tug (downward movement of trachea with inspiration)
• Head bobbing (in infants—accessory muscle use)

Stage 3: Decompensation (Respiratory Failure)

When work of breathing exceeds metabolic capacity, compensation fails:

Type I Respiratory Failure (Hypoxaemic):

• PaO₂ less than 8 kPa (60 mmHg) on room air
• Normal or low PaCO₂ (hyperventilation)
• Mechanism: V/Q mismatch (pneumonia, pulmonary oedema)
• Clinical: ↓ SpO₂, tachypnoea, cyanosis

Type II Respiratory Failure (Hypercapnic):

• PaCO₂ > 6.5 kPa (50 mmHg)
• PaO₂ may be normal (if on oxygen) or low
• Mechanism: Alveolar hypoventilation (fatigue, airway obstruction, neuromuscular)
• Clinical: ↓ conscious level, ↓ respiratory effort (exhaustion), bradycardia (late sign)

Stage 4: Cardiorespiratory Arrest

Progressive hypoxia and acidosis lead to:

• Bradycardia (PaO₂ less than 4 kPa or SpO₂ less than 60%)
• Hypotension
• Asystole/PEA arrest [12]

Cause-Specific Pathophysiology

Bronchiolitis:

• Viral infection (80% RSV) → bronchiolar epithelial necrosis → lymphocytic infiltration + oedema + mucus plugging
• Result: ↑ airway resistance, ↓ lung compliance, V/Q mismatch
• Clinical: Expiratory wheeze, crackles, hypoxia [15]

Asthma:

• Airway inflammation + bronchospasm + mucus hypersecretion
• Result: ↑ expiratory resistance, air trapping, dynamic hyperinflation
• Clinical: Expiratory wheeze, prolonged expiration, silent chest if severe [8]

Croup:

• Viral infection (parainfluenza) → subglottic oedema
• Result: ↑ inspiratory resistance at narrowest point (cricoid)
• Clinical: Inspiratory stridor, barking cough, worse with agitation [17]

---

4. Clinical Presentation

Symptom Recognition

Cardinal Symptoms:

Age-Specific Presentations:

Infants (less than 12 months):

• Grunting (physiological PEEP—sign of significant distress) [9]
• Nasal flaring (reduces nasal resistance in obligate nasal breathers)
• Head bobbing (accessory muscle use)
• Poor feeding (work of breathing incompatible with feeding)
• Irritability or lethargy
• Apnoea in bronchiolitis (especially less than 6 weeks, ex-preterm)—10-20% of hospitalized infants [15]

Older Children (1-12 years):

• Ability to verbalize dyspnoea (if old enough)
• Preference for sitting upright (tripod position in severe asthma)
• Difficulty speaking full sentences (severe asthma indicator)
• Barking cough (croup—characteristic) [17]
• Chest pain (pneumonia, pneumothorax)

Clinical Signs: Structured Assessment

A. Vital Signs (Age-Specific Normal Ranges) [7]

SpO₂ Thresholds:

• Normal: ≥95% (room air at sea level)
• Mild hypoxia: 92-94%
• Moderate hypoxia: 88-91%
• Severe hypoxia: less than 88%
• Target on oxygen: ≥92% (BTS/SIGN recommendation) [8]

B. Work of Breathing Assessment

C. Auscultation Findings

D. Signs of Exhaustion (Pre-Arrest) [12]

[!CAUTION] Imminent Respiratory Arrest Indicators:

• Decreasing respiratory rate (not improvement—exhaustion)
• Decreased depth of breathing (shallow, ineffective)
• Reduced work of breathing (appears "better" but is fatigued)
• Altered consciousness (GCS less than 13, confusion, drowsiness)
• Bradycardia (ominous—extreme hypoxia; normal HR does NOT exclude severe distress)
• Cyanosis persisting despite oxygen
• "See-saw" breathing (paradoxical chest/abdominal movement)
• Action: Immediate senior escalation, prepare for intubation, alert anaesthetics/PICU

---

5. Severity Assessment & Scoring Systems

PRAM Score (Preschool Respiratory Assessment Measure)

Validated for asthma exacerbation severity in children 2-17 years. [10]

Assesses 5 parameters (0-12 points total):

Interpretation:

• 0-3: Mild (discharge candidate if improving)
• 4-7: Moderate (admission, frequent bronchodilators)
• 8-12: Severe (HDU/PICU, continuous therapy, consider IV therapy) [10]

Evidence: Validated against hospitalization (AUC 0.84), validated inter-rater reliability (κ = 0.82), correlates with hospital length of stay. Recommended by Canadian Paediatric Society and increasingly adopted internationally. [10]

Westley Croup Score

Validated for croup severity in children 6 months-6 years. [11]

Assesses 5 parameters (0-17 points total):

Interpretation:

• 0-2: Mild (outpatient management, single dose dexamethasone)
• 3-7: Moderate (ED observation, dexamethasone, consider nebulized adrenaline)
• 8-11: Severe (admission, dexamethasone + nebulized adrenaline, high-dependency monitoring)
• ≥12: Impending respiratory failure (PICU, prepare for intubation) [11]

Evidence: Validated in multiple studies, correlates with need for adrenaline (score ≥3 has 85% sensitivity, 82% specificity), predicts hospitalization (score ≥4: positive predictive value 79%). [11,17]

Respiratory Failure Criteria (Blood Gas)

Indications for arterial/capillary blood gas: [8]

• SpO₂ less than 92% despite oxygen therapy
• Severe distress (PRAM ≥8, Westley ≥8)
• Altered consciousness
• Signs of exhaustion
• Clinical suspicion of hypercapnia (acidosis, drowsiness)

Lactate > 2 mmol/L suggests tissue hypoxia and increased WOB (metabolic load).

---

6. Differential Diagnosis

Clinical Differentiation: Asthma vs. Bronchiolitis vs. Croup

Key distinguishing manoeuvres:

• Trial of bronchodilator: Improvement in wheeze suggests asthma (not bronchiolitis) [21]
• Quality of breath sounds: Stridor (harsh, inspiratory) vs. wheeze (musical, expiratory)
• Age + season: Infant in winter with coryzal prodrome + wheeze = bronchiolitis until proven otherwise

"Must Not Miss" Differentials

---

7. Investigations

First-Line (Immediate Bedside)

1. Pulse Oximetry (Essential) [6]

• Indication: All children with respiratory distress
• Interpretation: Target SpO₂ ≥92% (BTS/SIGN guideline) [8]
• Caution: Falsely reassuring if on oxygen (may have normal SpO₂ but rising CO₂)
• Action: Continuous monitoring if moderate-severe distress

2. Clinical Severity Scoring [10,11]

• PRAM score (asthma): Documents objective severity, guides escalation
• Westley score (croup): Predicts need for adrenaline and admission
• Respiratory rate: Age-adjusted tachypnoea thresholds [7]
• Work of breathing: Systematic documentation of recession, accessory muscles

3. Temperature

• Fever suggests infective cause (pneumonia, bronchiolitis)
• High fever (> 39°C) + toxicity suggests bacterial (pneumonia, tracheitis)

Laboratory Investigations

When NOT to investigate:

• Bronchiolitis: NPA not routinely required (NICE NG9)—clinical diagnosis sufficient [6]
• Croup: Diagnosis is clinical; investigations may agitate child and worsen obstruction [17]
• Mild asthma: No blood tests needed in uncomplicated exacerbation [8]

Imaging

Chest X-Ray:

Indications (selective): [20]

• Focal signs (pneumonia suspected)
• Severe distress not responding to treatment
• Suspicion of complication (pneumothorax, effusion)
• Foreign body aspiration suspected (inspiratory + expiratory films)
• Diagnostic uncertainty

NOT routinely indicated:

• Uncomplicated bronchiolitis (NICE guideline) [6]
• Typical viral croup (clinical diagnosis) [17]
• Asthma responding to treatment (BTS guideline) [8]

Typical findings:

Lateral neck X-ray:

• Only if suspected epiglottitis/retropharyngeal abscess
• Shows "thumb sign" (swollen epiglottis) or prevertebral soft tissue swelling
• Do not send child unaccompanied to radiology if high suspicion

---

8. Management

Management Algorithm

    ACUTE RESPIRATORY DISTRESS (CHILD)
  (Increased work of breathing + tachypnoea)
                  ↓
┌──────────────────────────────────────────────┐
│      IMMEDIATE ASSESSMENT (ABCDE)            │
│  • Airway: Patent? Stridor? Drooling?        │
│  • Breathing: SpO₂, RR, WOB, auscultation    │
│  • Circulation: HR, BP, CRT                  │
│  • Disability: AVPU/GCS                      │
│  • Exposure: Temperature, rash               │
│  • SEVERITY SCORE: PRAM (asthma) or Westley (croup) │
└──────────────────────────────────────────────┘
                  ↓
┌──────────────────────────────────────────────┐
│      OXYGEN THERAPY (if SpO₂ less than 92%)           │
│  • Target SpO₂ ≥92%                          │
│  • Delivery: Nasal cannula (1-2 L/min)       │
│    or face mask (5-10 L/min) or high-flow    │
│  • Continuous monitoring                     │
└──────────────────────────────────────────────┘
                  ↓
┌──────────────────────────────────────────────┐
│      IDENTIFY CAUSE (Clinical Diagnosis)     │
├──────────────────────────────────────────────┤
│  WHEEZE (lower airway) → Asthma/Bronchiolitis│
│  STRIDOR (upper airway) → Croup              │
│  CRACKLES (parenchymal) → Pneumonia          │
│  + Age, season, tempo, history               │
└──────────────────────────────────────────────┘
                  ↓
┌──────────────────────────────────────────────┐
│      CAUSE-SPECIFIC TREATMENT                │
├──────────────────────────────────────────────┤
│  ASTHMA                                      │
│  → Salbutamol (10 puffs via spacer or neb)  │
│  → Ipratropium (if severe)                   │
│  → Prednisolone 1-2 mg/kg PO (or IV hydrocortisone) │
│  → Reassess PRAM q20 min                     │
│  → Escalate if PRAM ≥8: consider IV Mg²⁺, salbutamol IV │
│                                              │
│  BRONCHIOLITIS                               │
│  → Supportive care (no bronchodilators)      │
│  → Oxygen if SpO₂ less than 92%                       │
│  → NG/IV fluids if poor feeding              │
│  → Consider HFNC if increasing WOB [22]      │
│                                              │
│  CROUP                                       │
│  → Dexamethasone 0.15 mg/kg PO (single dose) │
│  → Nebulized adrenaline if Westley ≥3        │
│    (5 mL of 1:1000 nebulized)                │
│  → Observe 2-4 hours post-adrenaline         │
│                                              │
│  PNEUMONIA                                   │
│  → Amoxicillin 50 mg/kg/day PO (if mild)     │
│  → Co-amoxiclav or ceftriaxone IV (if severe)│
│  → Oxygen, fluids                            │
└──────────────────────────────────────────────┘
                  ↓
┌──────────────────────────────────────────────┐
│      ESCALATION (if not responding)          │
│  • High-flow nasal cannula (HFNC)            │
│  • CPAP or BiPAP (if Type II failure)        │
│  • Intubation and invasive ventilation       │
│    (if signs of exhaustion, apnoea, arrest)  │
│  • PICU referral                             │
└──────────────────────────────────────────────┘
                  ↓
┌──────────────────────────────────────────────┐
│      DISPOSITION                             │
│  DISCHARGE: Mild, improving, SpO₂ ≥94%       │
│  WARD: Moderate, stable, needs O₂/monitoring │
│  HDU: Severe, high-flow O₂, frequent nebs    │
│  PICU: Respiratory failure, NIV/invasive vent│
└──────────────────────────────────────────────┘

Acute Management - First 20 Minutes

Immediate Actions (Parallel):

1. Airway Assessment

   • Patent? Can the child speak/cry?
   • Stridor + drooling + tripod position = epiglottitis (do NOT examine throat, call anaesthetics)
   • If obstructed: Airway opening manoeuvres, consider airway adjunct, call for help

2. Oxygen Therapy [5,6]

   • Indication: SpO₂ less than 92%
   • Target: ≥92% (BTS/SIGN recommendation) [8]
   • Delivery methods:

High-Flow Nasal Cannula (HFNC):

• Delivers heated, humidified oxygen at high flow rates (up to 2 L/kg/min)
• Mechanisms: Washes out dead space, provides low-level PEEP (3-5 cmH₂O), reduces work of breathing, improves mucociliary clearance
• Evidence: RCT in bronchiolitis showed HFNC reduced escalation to intubation vs. standard oxygen (NNT ~14) [22]
• Indications: Moderate-severe bronchiolitis, pneumonia not responding to standard O₂
• Contraindications: Upper airway obstruction, undrained pneumothorax
• Settings: Start at 2 L/kg/min (max 60 L/min in older children), FiO₂ titrated to SpO₂ ≥92%
• Monitoring: HDU-level monitoring required (risk of delayed recognition of deterioration)

Comparison of Oxygen Delivery Devices:

Humidification:

• Essential for flows > 4 L/min (prevents mucosal drying, thick secretions)
• Heated humidification preferred over cold (better tolerance, improved mucociliary function)

3. Severity Scoring [10,11]
   • PRAM (if wheeze): Guides asthma treatment intensity
   • Westley (if stridor): Guides croup treatment (adrenaline if ≥3)
   • Document work of breathing: Recession, accessory muscles, mental status
   • Serial assessment: Reassess severity scores every 20-30 min to guide escalation

Cause-Specific Treatment

ASTHMA EXACERBATION [8]

First-Line (All Severities):

Severe Asthma (PRAM ≥8, life-threatening features):

Life-Threatening Asthma Features: [8]

• Silent chest (absent breath sounds)
• Cyanosis despite oxygen
• Exhaustion, poor respiratory effort
• Altered consciousness
• SpO₂ less than 92% despite high-flow oxygen
• → Call senior/anaesthetics, prepare for intubation, transfer to PICU

Bronchodilator Response Assessment:

• Reassess PRAM score 20 min after salbutamol
• If improving (PRAM decreasing): Continue q4h, consider discharge if PRAM less than 4 and sustained response
• If static/worsening: Escalate to ipratropium + consider IV magnesium

BRONCHIOLITIS [6,15]

Core Principle: Supportive Care Only (NICE Guideline NG9) [6]

Evidence-Based Management:

High-Flow Nasal Cannula (HFNC) in Bronchiolitis:

• RCT (Franklin et al.): HFNC vs. standard oxygen in moderate-severe bronchiolitis → reduced treatment failure (7% vs. 18%, NNT = 14) [22]
• Indications: Persistent SpO₂ less than 92% on standard O₂, increasing work of breathing despite supportive care
• Settings: 2 L/kg/min, FiO₂ titrated to SpO₂ ≥92%
• Requires HDU/PICU monitoring

Admission Criteria (Bronchiolitis): [6]

• SpO₂ less than 92% on room air (sustained)
• Apnoea (any episode, especially if less than 6 weeks or ex-preterm)
• Poor feeding (less than 50-75% normal intake) or clinical dehydration
• Significant respiratory distress (marked recession, RR > 60-70)
• Social factors (inability to observe at home, distance from hospital)

CROUP [17]

First-Line (All Croup):

Alternative: Budesonide 2 mg nebulized (if cannot tolerate oral; not superior to dexamethasone)

Severe Croup (Westley ≥3, stridor at rest):

Critical Points:

• Observe 2-4 hours post-adrenaline (rebound effect possible as adrenaline wears off)
• Admit if adrenaline required (indicates severe croup)
• Do not agitate child (crying worsens obstruction): avoid IV access, throat examination, unnecessary procedures unless essential
• Oxygen if SpO₂ less than 92% (but croup rarely causes hypoxia unless very severe)

PNEUMONIA [20]

Antibiotic Therapy:

Mild Community-Acquired Pneumonia (CAP) - Outpatient:

Moderate-Severe CAP - Inpatient:

Atypical Cover (if Mycoplasma suspected - age > 5y, dry cough):

• Add Azithromycin 10 mg/kg OD PO/IV (max 500 mg)

Supportive Care:

• Oxygen if SpO₂ less than 92%
• IV fluids if poor oral intake or shock
• Analgesia (paracetamol/ibuprofen for pain/fever)

Escalation to Ventilatory Support

Indications for Non-Invasive Ventilation (NIV):

Indications for Intubation and Invasive Ventilation: [12]

• Apnoea or gasping respirations
• Exhaustion (decreasing respiratory effort despite ongoing distress)
• Persistent hypoxia (SpO₂ less than 90%) despite maximal non-invasive support
• Hypercapnia with altered consciousness (pH less than 7.25, PaCO₂ > 8 kPa with drowsiness)
• Cardiorespiratory arrest
• Upper airway obstruction requiring airway control (epiglottitis, severe croup)

Intubation Considerations:

• Senior anaesthetist/intensivist
• Pre-oxygenate (avoid desaturation during intubation)
• Rapid sequence induction (beware cardiovascular collapse in severe asthma due to dynamic hyperinflation)
• Post-intubation: Gentle ventilation (low tidal volumes in asthma to avoid barotrauma)

Disposition Decisions

Discharge Criteria:

• SpO₂ ≥94% on room air (sustained for ≥4 hours)
• Feeding adequately (≥75% normal intake)
• Minimal work of breathing
• No concerning apnoeas (if bronchiolitis)
• Parent/carer confident with management
• Safety-netting advice provided
• Follow-up arranged if indicated (e.g., asthma clinic)

Safety-Netting Advice:

• Return if: increasing work of breathing, blue lips/tongue, breathing much faster, unusually sleepy, unable to feed, parents very worried
• Asthma: Written asthma action plan, GP follow-up within 48 hours, complete steroid course

---

9. Complications

Immediate (Minutes-Hours)

Early (Days-Weeks)

Late (Months-Years)

---

10. Prognosis & Outcomes

Natural History (Without Treatment)

Respiratory distress is a progressive condition:

• Untreated mild distress: 30-50% progress to moderate-severe [14]
• Untreated severe distress: > 90% progress to respiratory failure
• Respiratory failure: 50-70% mortality without ventilatory support [12]

Historical context: Pre-modern era mortality for severe croup ~50%; with dexamethasone and adrenaline, now less than 0.5%. [17]

Outcomes with Modern Treatment

Prognostic Factors

Good Prognosis:

• Early presentation and treatment
• Mild-moderate severity (PRAM less than 8, Westley less than 8)
• No comorbidities (normal immune system, no chronic lung disease)
• Good response to initial treatment
• Age > 6 months (if bronchiolitis)

Poor Prognosis (Higher Risk of Complications):

• Delayed presentation (> 24 hours severe symptoms)
• Comorbidities: Congenital heart disease, chronic lung disease, immunodeficiency, neuromuscular disease
• Age less than 6 weeks (bronchiolitis—higher apnoea risk) [15]
• Prematurity (less than 32 weeks)
• Severe presentation (PRAM ≥8, respiratory failure)

Long-Term Respiratory Outcomes

Post-Bronchiolitis Respiratory Function:

• Longitudinal studies: 40-50% of infants hospitalized with severe bronchiolitis have recurrent wheeze in the first 5 years [15]
• By age 11 years: 20-30% still have asthma/wheeze
• Lung function: Small but significant reduction in FEV₁ detectable into adolescence (unclear if causal or shared genetic predisposition)

Asthma Trajectory:

• Most childhood asthma improves with age: 30-50% "outgrow" asthma by late adolescence [16]
• Predictors of persistent asthma: Early onset (less than 3 years), atopy, severe exacerbations, impaired lung function

---

11. Evidence & Guidelines

Key Guidelines

1. BTS/SIGN British Guideline on the Management of Asthma (2019) [8]

Key Recommendations:

• Oxygen to maintain SpO₂ ≥92%
• Salbutamol (10 puffs via spacer or nebulized) first-line
• Prednisolone 1-2 mg/kg for all but mild exacerbations
• Ipratropium for severe/life-threatening asthma
• IV magnesium sulfate (40 mg/kg) for severe asthma not responding to initial treatment
• Evidence Level: 1A (systematic reviews, RCTs)

2. NICE Bronchiolitis in Children: Diagnosis and Management (NG9, 2015) [6]

Key Recommendations:

• Clinical diagnosis (do not routinely perform nasopharyngeal aspirate or CXR)
• Oxygen if SpO₂ less than 92%
• NG/IV fluids if oral intake less than 50-75%
• Do NOT use: Salbutamol, ipratropium, corticosteroids, antibiotics (unless secondary bacterial infection), hypertonic saline
• Consider HFNC for escalating respiratory distress
• Evidence Level: 1A (Cochrane reviews, RCTs)

3. Cochrane Review: Glucocorticoids for Croup (2018) [17]

Findings:

• Dexamethasone 0.15 mg/kg reduces return visits (RR 0.52, 95% CI 0.36-0.75) and hospitalization (RR 0.79, 95% CI 0.65-0.96)
• Effective across all severities
• Oral route as effective as IM
• Evidence Level: 1A

4. WHO Pocket Book of Hospital Care for Children (2013)

Key Points:

• Age-specific respiratory rate thresholds for tachypnoea [7]
• Danger signs requiring immediate treatment
• Oxygen therapy protocols

Landmark Evidence

Bronchodilators in Bronchiolitis:

• Cochrane Review (Gadomski et al., 2014): 30 trials, n=1,992 infants. Bronchodilators (salbutamol, ipratropium) showed no significant benefit on hospitalization, oxygen requirement, or length of stay. [21]
• Clinical Impact: Changed practice from routine bronchodilator use to supportive care only

High-Flow Nasal Cannula:

• Franklin et al. (2018): RCT, n=1,472 infants with bronchiolitis. HFNC vs. standard oxygen → treatment failure 12% vs. 23% (pless than 0.001), NNT = 14. [22]
• Clinical Impact: Established HFNC as effective rescue therapy, reduces intubation

Magnesium in Severe Asthma:

• Cochrane Review (Griffiths et al., 2016): IV magnesium sulfate in severe asthma reduced hospitalization (OR 0.32, 95% CI 0.21-0.50, NNT ~10). [8]
• Clinical Impact: Standard of care in life-threatening asthma

Evidence Summary Table

---

12. Clinical Pearls & Common Pitfalls

High-Yield Clinical Pearls

Assessment Pearls:

1. "Oxygen saturations can lie" — A child on high-flow oxygen may have normal SpO₂ (e.g., 95%) but rising CO₂ and worsening respiratory failure. Always assess work of breathing and conscious level, not just SpO₂. If work of breathing is increasing despite oxygen, get a blood gas. [14]

2. "Tachycardia is sensitive, bradycardia is specific" — Tachycardia is expected in respiratory distress (sympathetic response). Bradycardia in a distressed child is an ominous pre-arrest sign indicating severe hypoxia—immediate intervention required. [12]

3. "The quiet asthmatic is the dangerous asthmatic" — Silent chest (absence of wheeze + distress) = critical airflow obstruction. This child needs immediate senior escalation, IV access, magnesium, and preparation for intubation. Do NOT interpret silent chest as improvement. [8]

4. "Bronchiolitis peaks at day 3-5" — Parents (and junior doctors) often expect improvement after 1-2 days. Bronchiolitis typically worsens over the first 3-5 days before plateau, then slow improvement over 7-10 days. Set realistic expectations and safety-net appropriately. [15]

5. "Apnoea in bronchiolitis is unpredictable" — Occurs in 10-20% of hospitalized infants, especially less than 6 weeks or ex-preterm. Can occur suddenly without warning even in improving infants. Any infant with bronchiolitis + apnoea requires continuous monitoring and low threshold for PICU. [15]

6. "Recessions > respiratory rate for severity" — A child with marked subcostal and intercostal recessions is in severe distress even if RR is "only" mildly elevated. Work of breathing assessment is more sensitive than RR alone. [14]

7. "Grunting = hypoxia until proven otherwise" — Expiratory grunting in infants is physiological PEEP to prevent alveolar collapse. It indicates significant respiratory distress and usually hypoxia. Check SpO₂ and give oxygen. [9]

8. "One-sided wheeze = think foreign body" — Unilateral wheeze or decreased air entry in a previously well toddler with sudden onset suggests foreign body aspiration, not asthma or bronchiolitis. Arrange urgent rigid bronchoscopy—do NOT delay for X-ray if high suspicion.

Management Pearls:

9. "Salbutamol works in asthma, not bronchiolitis" — If a wheezing infant improves with salbutamol, it's asthma (or viral wheeze responsive to bronchodilators), not bronchiolitis. Bronchiolitis does not respond to bronchodilators (Cochrane review level 1A evidence). [21] Use response to trial of salbutamol to differentiate.

10. "Steroids for croup work across all severities" — Even mild croup benefits from a single dose of dexamethasone 0.15 mg/kg (reduces return visits by 50%, Cochrane review). Give it to everyone with croup unless absolute contraindication. [17]

11. "Adrenaline in croup is temporary (2 hours)" — Nebulized adrenaline gives rapid relief in severe croup but wears off within 2 hours. Always observe for 2-4 hours post-adrenaline and admit the child. Rebound worsening is common. [17]

12. "Magnesium in severe asthma: give it early" — Don't wait until the child is in extremis. PRAM ≥8 or life-threatening features = indication for IV magnesium sulfate 40 mg/kg. It reduces hospitalization and intubation (NNT ~10). [8]

13. "High-flow nasal cannula is not just 'more oxygen'" — HFNC provides multiple benefits beyond FiO₂: dead space washout, PEEP effect (~3-5 cmH₂O), reduced work of breathing. In bronchiolitis RCTs, it reduced intubation rates vs. standard oxygen at same FiO₂. [22] But it requires HDU-level monitoring.

14. "NG fluids in bronchiolitis: start early" — Infants with bronchiolitis tire easily and feeding becomes difficult (increased WOB incompatible with suck-swallow-breathe). If intake less than 75% normal, start NG fluids early—don't wait for dehydration. [6]

15. "Pneumothorax risk in severe asthma" — Occurs in 1-5% of severe asthma exacerbations due to air trapping and high intrathoracic pressures. If sudden deterioration during asthma exacerbation (unilateral decreased air entry, sudden drop in SpO₂), think pneumothorax. [8]

Common Pitfalls & How to Avoid Them

Pitfall 1: "Missing exhaustion for improvement"

• Error: Child appears "better" because respiratory rate is decreasing and less agitated
• Reality: This is respiratory exhaustion—pre-arrest sign
• How to avoid: Always assess work of breathing AND conscious level together. Decreased effort + altered consciousness = exhaustion, not improvement. Escalate immediately. [12]

Pitfall 2: "Over-relying on SpO₂ in a child on oxygen"

• Error: SpO₂ is 95% on high-flow oxygen, so the child must be OK
• Reality: May have rising CO₂ (Type II respiratory failure) with normal SpO₂ on supplemental oxygen
• How to avoid: If work of breathing is not improving despite oxygen, or if conscious level is deteriorating, get a blood gas (capillary or arterial). Don't be falsely reassured by normal SpO₂ on oxygen. [14]

Pitfall 3: "Giving bronchodilators for bronchiolitis"

• Error: Infant with wheeze → reflexively give salbutamol
• Reality: Bronchodilators have NO benefit in bronchiolitis (Cochrane review, level 1A evidence) and delay appropriate supportive care [21]
• How to avoid:
  • Age less than 12 months + coryzal prodrome + winter = bronchiolitis (not asthma) until proven otherwise
  • Trial of salbutamol is acceptable (if improves = likely viral wheeze/asthma; if no improvement = bronchiolitis, stop salbutamol)
  • "Follow NICE NG9 guideline: supportive care only for bronchiolitis [6]"

Pitfall 4: "Missing Type II respiratory failure in severe asthma"

• Error: Treating severe asthma but not monitoring for hypercapnia
• Reality: Severe asthma can progress to Type II failure (CO₂ retention), which is life-threatening
• How to avoid: Get a blood gas in severe asthma (PRAM ≥8, life-threatening features). Rising CO₂ + acidosis (pH less than 7.25) = impending respiratory arrest. Alert PICU, prepare for intubation. [8]

Pitfall 5: "Agitating a child with croup"

• Error: Attempting IV access, throat examination, or forced procedures in a distressed child with croup
• Reality: Agitation worsens upper airway obstruction and can precipitate complete obstruction
• How to avoid: Keep child calm—sit on parent's lap, minimal intervention. Give oral dexamethasone (as effective as IM). Only do essential procedures. If suspected epiglottitis, do NOT examine throat—call senior ENT/anaesthetics. [17]

Pitfall 6: "Discharging a child too soon after nebulized adrenaline for croup"

• Error: Child improves dramatically after adrenaline → discharge home
• Reality: Adrenaline effect is temporary (~2 hours). Rebound worsening common after 2-4 hours.
• How to avoid: Mandatory 2-4 hour observation post-adrenaline. Admit if adrenaline was required (indicates severe croup). [17]

Pitfall 7: "Missing foreign body aspiration"

• Error: Toddler with "asthma" not responding to bronchodilators → escalate asthma treatment
• Reality: Foreign body causing unilateral airway obstruction masquerading as asthma
• How to avoid:
  • Sudden onset in previously well child + no asthma history + unilateral signs = foreign body until proven otherwise
  • Ask about choking episode (but absence doesn't exclude—witnessed choking in only 50-70%)
  • Arrange rigid bronchoscopy urgently; do NOT delay for imaging if high suspicion

Pitfall 8: "Not recognizing bacterial tracheitis"

• Error: Treating as severe croup, child not responding to dexamethasone + adrenaline
• Reality: Bacterial tracheitis (rare but serious—Staph aureus superinfection of viral croup)
• How to avoid: Croup not responding to standard treatment + high fever + toxic appearance = bacterial tracheitis. Needs IV antibiotics (ceftriaxone), airway management, PICU. [17]

Pitfall 9: "Sending an unstable child to radiology alone"

• Error: Child with severe respiratory distress sent unaccompanied to X-ray department
• Reality: Risk of deterioration during transport; delays in recognition and intervention
• How to avoid:
  • Most respiratory distress is a clinical diagnosis (don't routinely X-ray bronchiolitis, croup, typical asthma)
  • If imaging essential in unstable child, send with senior clinician, portable monitoring, oxygen
  • Never send suspected epiglottitis to X-ray—call anaesthetics/ENT to assess at bedside

Pitfall 10: "Inadequate safety-netting for bronchiolitis discharge"

• Error: Discharging infant with bronchiolitis without explaining natural history and red flags
• Reality: Parents expect improvement; bronchiolitis worsens over 3-5 days. Preventable re-presentations or delayed escalation.
• How to avoid:
  • Explain timeline: "Will get worse over next 3-5 days before improving"
  • "Red flags: Return if breathing much faster, working much harder to breathe, blue lips, very sleepy, not feeding, apnoeas, parents very worried"
  • Written safety-netting advice
  • Follow-up plan (e.g., GP review day 3-5, or open access to paediatric assessment unit)

Medicolegal Pitfalls

"Failure to escalate"

• Delayed PICU referral in deteriorating child with respiratory distress
• Document repeated assessments, severity scores (PRAM, Westley), and clear escalation plans
• If in doubt, call senior/PICU early—it's easier to step down than catch up

"Inadequate monitoring"

• Child on high-flow oxygen or NIV on general ward without appropriate monitoring
• HFNC/CPAP/BiPAP requires HDU minimum (continuous SpO₂, frequent observations, trained staff)

"Missed diagnosis of non-accidental injury"

• Recurrent presentations with "asthma" or "respiratory distress" in young infant
• Consider fabricated/induced illness if atypical presentations, only occurs with one parent, or inconsistent history
• Document carefully, involve safeguarding team if concerns

---

13. Patient/Layperson Explanation

What is Respiratory Distress?

Respiratory distress means your child is having difficulty breathing or is not getting enough oxygen into their body. Breathing should be easy and effortless—when your child has respiratory distress, you can see they're working hard to breathe. This might show as fast breathing, using their neck and stomach muscles to breathe, or making grunting noises.

In simple terms: Your child's body isn't getting enough oxygen, or they're working too hard to breathe. This is a medical emergency, but most children recover fully with prompt treatment.

Why Does It Happen?

The most common causes depend on your child's age:

• Babies under 1 year: Usually a viral infection called bronchiolitis (especially in winter)
• Toddlers (1-3 years): Often viral croup (causing a barking cough and noisy breathing) or asthma (wheezing)
• Older children: Usually asthma (wheezing) or chest infections (pneumonia)

How Will I Know My Child Has Respiratory Distress?

Signs to look for:

• Breathing faster than normal (see chart below for age-specific normal rates)
• Working hard to breathe: You can see their chest pulling in between the ribs, below the ribs, or at the neck
• Noisy breathing: Wheezing (a whistling sound when breathing out) or stridor (a harsh sound when breathing in)
• Flaring nostrils: Their nose widens with each breath
• Grunting: Small grunting noises with each breath (in babies)
• Blue lips or tongue (this is very serious—call 999 immediately)
• Very sleepy or floppy
• Not feeding normally (babies)

Normal breathing rates by age:

• Babies (0-12 months): 24-50 breaths/minute
• Toddlers (1-5 years): 20-30 breaths/minute
• School-age children (5-12 years): 15-25 breaths/minute

Count for 30 seconds and double it to get breaths per minute.

What Will Happen at the Hospital?

1. Immediate Assessment (First 10 minutes):

• Doctor/nurse will check your child's breathing, oxygen levels (using a small clip on the finger), and heart rate
• They'll listen to your child's chest with a stethoscope
• They may give oxygen immediately (through a small tube in the nose or a mask)

2. Finding the Cause:

• The doctor will ask about symptoms (cough, fever, how quickly it started)
• They'll examine your child to work out what's causing the breathing difficulty
• Most of the time, they can diagnose the cause by examination alone (no X-rays or blood tests needed)

3. Treatment (Depends on the Cause):

If it's asthma/wheezing:

• Medicine to open the airways (called salbutamol—given through an inhaler with a spacer, or a nebulizer mask)
• Steroid medicine (prednisolone) to reduce inflammation in the airways
• Your child will be reassessed every 20 minutes to see if the treatment is working

If it's bronchiolitis (viral infection in babies):

• There's no medicine that treats the virus directly
• Treatment is supportive: oxygen (if needed), fluids (if not feeding well)
• Most babies improve within 3-5 days

If it's croup (barking cough, noisy breathing):

• Steroid medicine (dexamethasone) given once—helps reduce swelling in the airway
• Sometimes adrenaline through a nebulizer (if severe)
• Usually improves within a few hours

If it's a chest infection (pneumonia):

• Antibiotics (if bacterial infection suspected)
• Oxygen and fluids

4. Monitoring:

• Your child will be monitored closely
• Oxygen levels checked regularly
• If they're not getting better, they may need more intensive support (e.g., a special oxygen delivery system called high-flow nasal cannula, or rarely, a breathing machine in intensive care)

What to Expect - Recovery Time

• Asthma: Usually improves within 1-2 hours of treatment; may go home same day if mild
• Croup: Improves within 2-4 hours of steroid medicine; usually go home same day
• Bronchiolitis: Gets worse over 3-5 days, then slowly improves over 1-2 weeks; may need to stay in hospital for oxygen and feeding support
• Pneumonia: Improves over 2-5 days with antibiotics; may need hospital stay for a few days

When to Call 999 (Emergency)

Call 999 immediately if your child has ANY of these:

• Blue lips or tongue (cyanosis)
• Struggling to breathe or gasping for air
• Becoming very sleepy or floppy or difficult to wake
• Breathing very fast and getting worse
• Stopped breathing or has long pauses in breathing
• You are extremely worried about your child

When to see a doctor urgently (same day):

• Breathing faster than normal (see rates above)
• Working harder to breathe (chest pulling in)
• Not feeding well (less than half normal amount)
• Wheezing or noisy breathing
• Cough that's getting worse
• Fever with fast breathing

After Going Home - What to Watch For

Return to hospital/call 999 if:

• Breathing becomes difficult again or gets worse
• Blue lips or tongue
• Very sleepy or not responding normally
• Not drinking (or breastfeeding) and no wet nappies for 12 hours
• You're very worried

Follow-up:

• Asthma: See your GP within 48 hours to review asthma control and inhaler technique
• Bronchiolitis: Symptoms may last 2-3 weeks; cough can persist for 4 weeks
• Croup: May recur with future viral infections; usually outgrown by age 3

Can It Be Prevented?

• Vaccinations: Keep your child's vaccinations up-to-date (prevents some causes of pneumonia)
• Asthma: If your child has asthma, use preventer inhalers regularly as prescribed
• Avoid smoke: Don't smoke around your child (makes respiratory infections worse)
• Hand hygiene: Wash hands regularly, especially during winter (reduces spread of viruses)
• RSV prevention: High-risk babies (very premature, heart conditions) may be offered RSV antibody injections (palivizumab) in winter

Key Message for Parents

Trust your instincts. You know your child best. If you're worried about their breathing, seek medical help. Respiratory distress in children can get worse quickly, but with prompt treatment, the vast majority of children recover fully. It's always better to get checked out—healthcare professionals would rather see your child and reassure you than have you wait at home and worry.

Remember: Fast breathing + working hard to breathe + blue lips = call 999 immediately.

---

13. Common Exam Questions & Model Answers

Q1: "Describe your approach to a 9-month-old with respiratory distress in the emergency department."

Model Answer:

"I would use a structured ABCDE approach. First, I'd assess the airway—is it patent? Any stridor suggesting upper airway obstruction? Then breathing: I'd assess work of breathing by looking for intercostal and subcostal recession, nasal flaring, and grunting (which is physiological PEEP in infants and indicates significant distress). I'd count the respiratory rate—tachypnoea in a 9-month-old is > 50 breaths per minute. I'd check SpO₂ immediately using pulse oximetry—the target is ≥92% based on BTS guidelines. I'd auscultate the chest: wheeze suggests lower airway obstruction (bronchiolitis or asthma), crackles suggest parenchymal disease (pneumonia), and stridor suggests upper airway obstruction (croup).

For circulation, I'd assess heart rate and capillary refill time—tachycardia is expected compensatory response. For disability, I'd assess conscious level (AVPU)—altered consciousness suggests hypercapnia or severe hypoxia. For exposure, I'd check temperature (fever suggests infection) and look for any rash.

Based on the season (winter makes bronchiolitis most likely), presence of coryzal symptoms, and examination findings (widespread wheeze and crackles), I'd make a clinical diagnosis—most likely bronchiolitis at this age. I'd give oxygen if SpO₂ less than 92%, assess feeding and hydration status, and provide supportive care. I'd not use bronchodilators as Cochrane review evidence shows no benefit in bronchiolitis. I'd monitor closely and consider admission if SpO₂ less than 92% persistently, poor feeding, or significant apnoeas."

Examiner Follow-Up: "When would you consider escalation to HDU or PICU?"

"I'd escalate to HDU if there's increasing work of breathing despite standard oxygen therapy, or if high-flow nasal cannula is needed—this has been shown in RCTs to reduce intubation rates in bronchiolitis. PICU referral would be indicated for respiratory failure: Type I (hypoxia despite maximal oxygen) or Type II (hypercapnia with altered consciousness), signs of exhaustion (decreasing respiratory effort despite ongoing distress—a pre-arrest sign), recurrent apnoeas, or if intubation and invasive ventilation are required."

Q2: "What is the PRAM score and why is it useful?"

Model Answer:

"The PRAM score is the Preschool Respiratory Assessment Measure, a validated severity scoring tool for asthma exacerbations in children aged 2-17 years. It assesses five parameters: SpO₂ on room air, suprasternal retractions, scalene muscle contraction, air entry, and wheeze. The score ranges from 0-12.

Interpretation: 0-3 is mild, 4-7 is moderate, and 8-12 is severe. A PRAM score ≥8 indicates severe asthma and is an indication for escalation to ipratropium bromide, IV magnesium sulfate, and consideration of HDU or PICU admission.

It's useful because it provides objective, reproducible assessment of severity (validated inter-rater reliability), guides treatment decisions (when to add ipratropium, when to give IV magnesium), and allows monitoring of response to treatment (you can reassess PRAM every 20 minutes after bronchodilator therapy). It correlates with important outcomes like hospitalization and length of stay, so it's better than clinical gestalt alone for disposition decisions."

Q3: "A 2-year-old with croup is not improving after oral dexamethasone. What would you do next?"

Model Answer:

"First, I'd reassess using the Westley croup score to objectively quantify severity—this looks at level of consciousness, cyanosis, stridor (at rest vs. with agitation), air entry, and retractions. If the Westley score is ≥3, this indicates moderate-severe croup and is an indication for nebulized adrenaline (5 mL of 1:1,000).

Adrenaline works by causing vasoconstriction, which reduces subglottic oedema. The effect is rapid (within 10-30 minutes) but temporary (lasts ~2 hours), so there's a risk of rebound deterioration. For this reason, the child must be observed for 2-4 hours post-adrenaline, and admission is required if adrenaline has been needed.

If the child is still not improving despite adrenaline, or if there are signs of severe obstruction (Westley ≥8, significant stridor at rest with marked recession and desaturation), I'd escalate immediately: call senior ENT and anaesthetics, consider transfer to PICU, and prepare for potential intubation. I'd ensure the child is kept calm—agitation worsens upper airway obstruction—so I'd minimize interventions like IV access unless absolutely necessary.

Differential diagnoses to consider if not responding to typical croup treatment include bacterial tracheitis (high fever, toxic appearance, not responding to steroids), epiglottitis (rare post-Hib vaccine but still possible—drooling, tripod positioning), or foreign body aspiration (sudden onset, choking history)."

---

14. References

1. Florin TA, et al. Reliability of examination findings in suspected community-acquired pneumonia. Pediatrics. 2017;140(3):e20170310. doi:10.1542/peds.2017-0310

2. Hammer J, Eber E. The peculiarities of infant respiratory physiology. Paediatr Respir Rev. 2005;6(2):83-90. doi:10.1016/j.prrv.2005.02.003

3. O'Brien S, et al. Epidemiology of respiratory tract infections in infants. Arch Dis Child. 2019;104(6):542-546. doi:10.1136/archdischild-2018-315039

4. Schindler MB, et al. Respiratory emergencies in children. Emerg Med Clin North Am. 2018;36(2):473-492. doi:10.1016/j.emc.2017.12.002

5. World Health Organization. Pocket Book of Hospital Care for Children: Guidelines for the Management of Common Childhood Illnesses. 2nd ed. Geneva: WHO; 2013.

6. National Institute for Health and Care Excellence. Bronchiolitis in children: diagnosis and management. NICE guideline [NG9]. London: NICE; 2015. Available at: https://www.nice.org.uk/guidance/ng9

7. Fleming S, et al. Normal ranges of heart rate and respiratory rate in children from birth to 18 years: a systematic review of observational studies. Lancet. 2011;377(9770):1011-1018. doi:10.1016/S0140-6736(10)62226-X

8. British Thoracic Society, Scottish Intercollegiate Guidelines Network. British guideline on the management of asthma. Edinburgh: SIGN; 2019. Available at: https://www.brit-thoracic.org.uk/quality-improvement/guidelines/asthma/

9. Corwin DJ, et al. Significance of grunting respirations in infants with bronchiolitis. Pediatr Emerg Care. 2016;32(8):509-511. doi:10.1097/PEC.0000000000000505

10. Ducharme FM, et al. The Pediatric Respiratory Assessment Measure (PRAM): a responsive index of acute asthma severity. J Pediatr. 2008;152(4):476-480. doi:10.1016/j.jpeds.2007.08.034

11. Bjornson C, et al. A randomized trial of a single dose of oral dexamethasone for mild croup. N Engl J Med. 2004;351(13):1306-1313. doi:10.1056/NEJMoa033534

12. Atkins DL, et al. Epidemiology and outcomes from out-of-hospital cardiac arrest in children: the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest. Circulation. 2009;119(11):1484-1491. doi:10.1161/CIRCULATIONAHA.108.802678

13. Donoghue AJ, et al. Out-of-hospital pediatric cardiac arrest: an epidemiologic review and assessment of current knowledge. Ann Emerg Med. 2005;46(6):512-522. doi:10.1016/j.annemergmed.2005.05.028

14. McCallum GB, et al. Clinical assessment versus standardised scores for diagnosing severity of respiratory distress. Arch Dis Child. 2015;100(6):539-541. doi:10.1136/archdischild-2014-307396

15. Ralston SL, et al. Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics. 2014;134(5):e1474-e1502. doi:10.1542/peds.2014-2742

16. Martinez FD, Vercelli D. Asthma. Lancet. 2013;382(9901):1360-1372. doi:10.1016/S0140-6736(13)61536-6

17. Russell KF, et al. Glucocorticoids for croup. Cochrane Database Syst Rev. 2018;8:CD001955. doi:10.1002/14651858.CD001955.pub4

18. Burke H, et al. Prenatal and passive smoke exposure and incidence of asthma and wheeze: systematic review and meta-analysis. Pediatrics. 2012;129(4):735-744. doi:10.1542/peds.2011-2196

19. American Academy of Pediatrics Committee on Infectious Diseases. Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection. Pediatrics. 2014;134(2):415-420. doi:10.1542/peds.2014-1665

20. Harris M, et al. British Thoracic Society guidelines for the management of community acquired pneumonia in children: update 2011. Thorax. 2011;66(Suppl 2):ii1-ii23. doi:10.1136/thoraxjnl-2011-200598

21. Gadomski AM, Scribani MB. Bronchodilators for bronchiolitis. Cochrane Database Syst Rev. 2014;(6):CD001266. doi:10.1002/14651858.CD001266.pub4

22. Franklin D, et al. A randomized trial of high-flow oxygen therapy in infants with bronchiolitis. N Engl J Med. 2018;378(12):1121-1131. doi:10.1056/NEJMoa1714855

---

Last Reviewed: 2026-01-10 | MedVellum Editorial Team

---

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists and follow local guidelines. This information is not a substitute for professional medical advice, diagnosis, or treatment. In emergency situations, always activate emergency services immediately.