Paediatric Respiratory Failure

1. Quick Answer

Paediatric Respiratory Failure is the inability of the respiratory system to maintain adequate oxygenation (Type I/hypoxaemic) or carbon dioxide elimination (Type II/hypercapnic) in infants and children, requiring ICU-level intervention.

Key Clinical Features:

• Tachypnoea, increased work of breathing, accessory muscle use
• Grunting (auto-PEEP generation), nasal flaring, subcostal/intercostal recession
• Head bobbing (infants), tripod positioning (older children)
• Cyanosis, altered consciousness, exhaustion (late/ominous signs)

Common Aetiologies:

• Upper airway: Croup, epiglottitis, foreign body, congenital abnormalities
• Lower airway: Bronchiolitis (RSV), viral pneumonia, bacterial pneumonia, asthma
• Parenchymal: PARDS (Paediatric Acute Respiratory Distress Syndrome)
• Neuromuscular: Guillain-Barre syndrome, spinal muscular atrophy, botulism

Emergency Management:

1. Assess airway patency and work of breathing
2. High-flow oxygen therapy or HFNC (humidified 2 L/kg/min)
3. Non-invasive ventilation (CPAP/BiPAP) if deteriorating
4. Intubation with age-appropriate ETT if NIV fails
5. Lung-protective ventilation (Vt 5-8 mL/kg, plateau pressure <28 cmH2O)

ICU Mortality: PARDS mild 10%, moderate 15-20%, severe 30-35% (PMID: 25880884)

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2. CICM Exam Focus

What Examiners Expect

Second Part Written (SAQ):

Common SAQ stems:

• "A 4-month-old infant presents to PICU with bronchiolitis and respiratory failure. ABG shows pH 7.25, PaCO2 65, PaO2 55 on FiO2 0.6. Outline your management approach."
• "A 3-year-old with severe asthma is intubated. Describe your ventilation strategy and potential complications."
• "Discuss the PALICC-2 criteria for PARDS and management differences from adult ARDS."
• "A 6-month-old Indigenous infant is retrieved from remote Northern Territory with severe pneumonia. Outline specific considerations."

Expected depth:

• Knowledge of paediatric airway anatomy and physiological differences from adults
• Understanding of age-appropriate ventilation parameters
• Evidence-based approach to HFNC, NIV, and invasive ventilation
• PALICC-2 PARDS criteria and severity stratification
• Recognition of Indigenous health disparities and culturally safe care

Second Part Hot Case:

Typical presentations:

• Ventilated infant with bronchiolitis on Day 3-5 PICU
• Child with PARDS on prone positioning or ECMO
• Toddler with viral-induced wheeze/asthma requiring ventilation
• Post-operative child with respiratory failure (cardiac surgery, neurosurgery)

Examiners assess:

• Systematic A-E examination approach
• Recognition of paediatric-specific physiology
• Appropriate interpretation of ventilator waveforms and settings
• Safe ventilation strategy for age and condition
• Communication with family (often highly distressed parents)

Second Part Viva:

Expected discussion areas:

• Paediatric airway anatomy differences (large head, short neck, high larynx, floppy epiglottis)
• Respiratory physiology (horizontal ribs, compliant chest wall, diaphragm-dependent breathing)
• Higher oxygen consumption, lower FRC, faster desaturation
• ETT sizing and selection (cuffed vs uncuffed debate)
• Evidence for HFNC in bronchiolitis
• PARDS-specific ventilation strategies
• VV-ECMO indications and cannulation in children

Common Mistakes

• Forgetting paediatric-specific ETT sizing formulas
• Using adult tidal volumes (10 mL/kg) instead of paediatric (5-8 mL/kg)
• Not recognizing the rapid desaturation risk during intubation
• Failing to consider Indigenous health disparities
• Inadequate sedation/analgesia planning for children
• Poor communication with anxious parents

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3. Key Points

Must-Know Facts

1. Paediatric Airway Anatomy: Large occiput (head positioning), short neck, high larynx (C3-4 vs C5-6 adult), large tongue, floppy U-shaped epiglottis, narrowest point at cricoid (uncuffed) or glottis (cuffed ETT). (PMID: 21515694)

2. Respiratory Physiology Differences: Horizontal ribs limit bucket-handle expansion; compliant chest wall causes paradoxical breathing; diaphragm-dependent ventilation; lower FRC and closing capacity overlap with tidal breathing. (PMID: 17418741)

3. Higher Oxygen Consumption: Infants 6-8 mL/kg/min O2 consumption (vs 3-4 mL/kg/min adults). Combined with lower FRC = rapid desaturation (SpO2 falls within 60-90 seconds vs 3-5 minutes adults). (PMID: 17418741)

4. ETT Sizing (Cuffed): Age/4 + 3.5 (cuffed) or Age/4 + 4 (uncuffed). Modern practice favours cuffed ETTs even in neonates. Internal diameter (ID) in mm. (PMID: 19553830)

5. PALICC-2 PARDS Criteria: OI ≥4 or OSI ≥5 for mild, OI 8-15.9 or OSI 7.5-12.2 for moderate, OI ≥16 or OSI ≥12.3 for severe. Bilateral infiltrates on CXR, not fully explained by cardiac disease or fluid overload. (PMID: 37382423)

6. HFNC in Bronchiolitis: Flow rate 2 L/kg/min (max 20 L/min in infants). PARIS trial showed reduced treatment failure but no difference in length of stay. (PMID: 29562151)

7. Lung-Protective Ventilation: Tidal volume 5-8 mL/kg predicted body weight, plateau pressure <28-30 cmH2O, PEEP 5-15 cmH2O titrated to oxygenation. Higher respiratory rates than adults (age-appropriate). (PMID: 29280732)

8. Prone Positioning in PARDS: Consider in moderate-severe PARDS (OI ≥8). Duration 12-16 hours. Evidence extrapolated from PROSEVA (adults) - less paediatric-specific data. (PMID: 23688302)

9. VV-ECMO Indications: Refractory hypoxaemia despite optimal ventilation (OI >40, P/F ratio <60), uncompensated respiratory acidosis (pH <7.15), air leak syndromes. Survival 50-70% for respiratory ECMO. (PMID: 30371341)

10. Indigenous Health: Aboriginal and Torres Strait Islander children have 2-3x higher rates of bronchiolitis, pneumonia, and respiratory failure. Associated with overcrowding, indoor smoke exposure, and delayed access to care. (PMID: 28392343)

Memory Aids

PARDS Mnemonic - "BILATERAL":

• Bilateral infiltrates on imaging
• Impaired oxygenation (OI ≥4 or OSI ≥5)
• Lung disease onset within 7 days
• Age-appropriate definitions used
• Total exclusion of cardiogenic cause
• Epidemiological risk factors considered
• Respiratory support required (invasive or NIV)
• Acute presentation
• Left-heart failure not the primary cause

Paediatric Desaturation Risk - "FAST DROP":

• FRC low (smaller oxygen stores)
• Airway narrow (easy obstruction)
• Small tidal volume
• Thoracic compliance high (chest wall collapse)
• Diaphragm-dependent breathing
• Rate high (increased work)
• O2 consumption elevated (6-8 mL/kg/min)
• Pre-oxygenation less effective

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4. Definition & Epidemiology

Definition

Paediatric Respiratory Failure is defined as the inability of the respiratory system to meet the metabolic demands for oxygen uptake and/or carbon dioxide elimination in a child aged 1 month to 18 years.

Classification:

PARDS Definition (PALICC-2 2023) (PMID: 37382423):

OI = (MAP × FiO2 × 100) / PaO2 OSI = (MAP × FiO2 × 100) / SpO2 (when SpO2 ≤97%)

Additional PARDS Criteria:

• Onset within 7 days of known clinical insult
• Bilateral infiltrates on chest radiograph consistent with acute pulmonary parenchymal disease
• Not fully explained by cardiac failure or fluid overload
• Requires positive pressure ventilation (invasive or non-invasive with PEEP ≥5 cmH2O)

Epidemiology

International Data (PMID: 26296298, 28257600):

• PARDS incidence: 2-10 per 100,000 children per year
• 2-10% of all PICU admissions
• Mechanical ventilation required: 30-65% of PARDS
• Severe PARDS: 25-35% of all PARDS cases
• Mortality: Mild 10%, Moderate 18%, Severe 33%

Australian/NZ Data (ANZPIC Registry):

• Bronchiolitis: 15-25% of PICU admissions (peak winter months)
• RSV positive in 70-80% of bronchiolitis cases
• Pneumonia: 8-12% of PICU admissions
• Indigenous children: 2-3× overrepresentation in PICU admissions
• Intubation rate for bronchiolitis: 5-15% (declining with HFNC use)

Risk Factors for Severe Disease:

Non-Modifiable:

• Prematurity (<32 weeks gestation)
• Age <3 months
• Congenital heart disease
• Chronic lung disease (bronchopulmonary dysplasia)
• Neuromuscular disease
• Immunodeficiency
• Genetic syndromes (Down syndrome, congenital airway malformations)

Modifiable/Environmental:

• Passive smoke exposure
• Indoor pollution (wood-burning stoves)
• Overcrowding (>5 people per dwelling)
• Lack of breastfeeding
• Malnutrition
• Delayed presentation to healthcare
• Incomplete immunization

High-Risk Populations:

Aboriginal and Torres Strait Islander Children (PMID: 28392343):

• 2-3× higher hospitalization rates for respiratory infections
• 5× higher rates in remote communities
• Higher rates of chronic suppurative lung disease
• Associated with housing quality, overcrowding, passive smoke
• Later presentation due to geographic isolation
• Involve Aboriginal Health Workers and family in care decisions

Maori Children (New Zealand):

• 2× higher rates of bronchiolitis and pneumonia
• Higher rates of rheumatic fever (post-streptococcal)
• Socioeconomic factors contributory
• Involve whanau (extended family) in care

Outcomes

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5. Applied Basic Sciences

Anatomy

Paediatric Airway Differences from Adults:

Surface Anatomy for ETT Depth:

• Oral ETT depth (cm) = Age/2 + 12 (or 3 × ETT internal diameter)
• Nasal ETT depth (cm) = Age/2 + 15

Radiological Anatomy:

• CXR: Thymus may mimic mediastinal mass ("sail sign" is normal)
• Tracheal bifurcation at T4 (vs T5-6 adults)
• Horizontal ribs vs downward-sloping in adults

Physiology

Normal Respiratory Physiology - Paediatric Differences (PMID: 17418741):

Key Physiological Vulnerabilities:

1. Lower FRC and Higher Closing Capacity:

• FRC provides oxygen reserve during apnoea
• Infants: Closing capacity > FRC = atelectasis during normal tidal breathing
• Rapid desaturation during apnoea (60-90 seconds vs 3-5 minutes adults)
• Pre-oxygenation less effective
• PEEP is essential to maintain FRC above closing capacity

2. Compliant Chest Wall:

• Infant chest wall highly compliant (cartilaginous ribs)
• Generates less outward recoil to oppose lung elastic recoil
• Results in lower FRC
• Causes paradoxical breathing (inward chest movement during inspiration)
• Excessive work of breathing when lung compliance decreases

3. Diaphragm-Dependent Ventilation:

• Horizontal ribs limit bucket-handle and pump-handle movement
• Intercostal muscles less effective (fatigue-prone)
• Diaphragm provides 70% of ventilation (vs 50% adults)
• Diaphragm more horizontal, shorter fibres, fewer Type I (fatigue-resistant) fibres
• Gastric distension impairs diaphragm function significantly

4. Higher Metabolic Rate:

• Oxygen consumption 6-8 mL/kg/min (double adult rate)
• Higher CO2 production
• Higher minute ventilation required
• Faster respiratory fatigue

Pathophysiology

Type I Respiratory Failure (Hypoxaemic):

Mechanisms:

1. V/Q Mismatch (most common): Perfusion of poorly ventilated lung units

   • Bronchiolitis: Small airway obstruction with mucus, oedema
   • Pneumonia: Consolidation with continued perfusion
   • Partially responsive to supplemental oxygen

2. Shunt: Blood bypasses ventilated alveoli entirely

   • Severe PARDS: Complete alveolar collapse/flooding
   • Atelectasis in infants
   • Congenital heart disease with R→L shunt
   • Refractory to supplemental oxygen (hallmark of shunt)

3. Diffusion Impairment: Thickened alveolar-capillary membrane

   • Pulmonary oedema
   • Interstitial lung disease
   • Worsens with exercise/increased cardiac output

Type II Respiratory Failure (Hypercapnic):

Mechanisms:

1. Increased Dead Space: V/Q mismatch with high V/Q units

   • Pulmonary embolism (rare in children)
   • Over-distended lung units

2. Decreased Minute Ventilation:

   • CNS depression (sedation, encephalopathy)
   • Neuromuscular disease (GBS, SMA, myopathy)
   • Severe airway obstruction (asthma, croup)
   • Respiratory muscle fatigue

3. Increased CO2 Production:

   • Fever, sepsis, hyperthyroid states
   • Excessive carbohydrate feeding (increased RQ)

PARDS-Specific Pathophysiology (PMID: 25880884):

Sequential phases:

1. Exudative Phase (Days 0-7):

   • Initial insult triggers inflammation
   • Neutrophil infiltration, cytokine release
   • Type I alveolar cell injury → increased permeability
   • Protein-rich oedema floods alveoli
   • Surfactant dysfunction
   • Hyaline membrane formation

2. Proliferative Phase (Days 7-21):

   • Type II alveolar cell proliferation (repair)
   • Fibroblast activation
   • Early collagen deposition
   • Resolution or progression to fibrosis

3. Fibrotic Phase (>21 days):

   • Extensive collagen deposition
   • Loss of normal architecture
   • Chronic respiratory failure
   • Not all patients progress to this phase

Pharmacology

Key ICU Drugs for Paediatric Respiratory Failure:

1. Induction Agents for Intubation:

2. Neuromuscular Blocking Agents:

3. Sedation/Analgesia for Ventilated Children:

4. Bronchodilators:

5. Surfactant (PMID: 17714341):

• Beractant (Survanta): 100 mg/kg (4 mL/kg) intratracheally
• Poractant alfa (Curosurf): 100-200 mg/kg
• Indications in paediatrics (limited evidence):
  • Severe PARDS (compassionate use)
  • Meconium aspiration syndrome
  • Near-drowning
• Evidence: Cochrane review shows no mortality benefit in paediatric ARDS

6. Inhaled Nitric Oxide (iNO) (PMID: 28288114):

• Dose: 5-20 ppm (start 10-20 ppm, wean to 5 ppm)
• Mechanism: Selective pulmonary vasodilator, reduces V/Q mismatch
• Indications: Refractory hypoxaemia in PARDS, pulmonary hypertension
• Evidence: Improves oxygenation but no mortality benefit in PARDS
• Weaning: Gradual (rebound pulmonary hypertension risk)
• Monitoring: Methaemoglobin, NO2 levels

Pathology

Histopathology of PARDS:

Diffuse Alveolar Damage (DAD):

• Hyaline membranes (eosinophilic, proteinaceous)
• Type I alveolar cell necrosis
• Pulmonary oedema (interstitial and alveolar)
• Neutrophil infiltration
• Microthrombi in pulmonary vasculature

Bronchiolitis Histopathology:

• Bronchiolar epithelial necrosis and sloughing
• Submucosal oedema
• Mucus plugging
• Peribronchiolar lymphocytic infiltration
• Preserved alveolar architecture (distinguishes from pneumonia)

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6. Clinical Presentation

ICU Admission Scenarios

Scenario 1: Bronchiolitis in Infant

• History: 8-week-old previously well infant, 3 days coryzal symptoms, progressive feeding difficulty and tachypnoea. Born at 35 weeks, no neonatal ICU admission.
• Examination: RR 70, subcostal recession, nasal flaring, SpO2 85% room air. Fine inspiratory crackles bilaterally. Alert but irritable.
• Severity: Moderate-severe - requires HFNC or NIV

Scenario 2: Severe Asthma

• History: 6-year-old known asthmatic, 2 days URI, progressive wheeze despite salbutamol/ipratropium. Previous PICU admission.
• Examination: RR 50, unable to speak sentences, accessory muscle use, quiet wheeze bilateral. SpO2 88% on 10L NRM.
• Severity: Near-fatal asthma - requires IV salbutamol, consider intubation

Scenario 3: PARDS Secondary to Pneumonia

• History: 3-year-old previously well, 5 days fever and cough, sudden deterioration.
• Examination: Intubated in ED, bilateral crackles, P/F ratio 85, bilateral infiltrates CXR.
• Severity: Moderate PARDS - requires lung-protective ventilation, consider prone

Symptoms & Signs

History:

• Chief complaint: Difficulty breathing, fast breathing, poor feeding (infants), lethargy
• Associated symptoms: Fever, cough, wheeze, stridor, coryza
• Time course: Hours (acute epiglottitis) to days (bronchiolitis, pneumonia)
• Feeding history: Amount, duration, apnoeas during feeds (infants)
• Risk factors: Prematurity, congenital heart disease, immunodeficiency

Examination by Age:

Infants (<1 year):

Children (>1 year):

Severity Scoring

Bronchiolitis Severity Score (Wang Score):

Score interpretation: Mild 0-3, Moderate 4-8, Severe 9-12

Asthma Severity (Modified PRAM Score):

Differential Diagnosis

Upper Airway Obstruction (Stridor):

Lower Airway/Parenchymal (Wheeze/Crackles):

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7. Investigations

Laboratory Investigations

Bedside Tests:

Arterial Blood Gas (or capillary if arterial not possible):

Oxygenation Index Calculation: OI = (MAP × FiO2 × 100) / PaO2

Blood Tests:

Viral Testing:

Imaging

Chest X-Ray:

Bronchiolitis:

• Hyperinflation (>8 posterior ribs visible, flat diaphragms)
• Peribronchial thickening ("dirty" lung fields)
• Patchy atelectasis (especially right middle lobe)
• No consolidation typically

Pneumonia:

• Lobar or patchy consolidation
• Air bronchograms
• Parapneumonic effusion (may be empyema)
• Necrotizing changes (concerning)

PARDS:

• Bilateral infiltrates (essential criterion)
• Ground-glass opacities
• Consolidation
• NOT explained by cardiac failure or fluid overload

Asthma:

• Hyperinflation
• Peribronchial thickening
• May have atelectasis (mucus plugging)
• Rule out pneumothorax, pneumomediastinum

Ultrasound:

Lung Ultrasound (PMID: 30235412):

• B-lines: Interstitial syndrome (oedema, consolidation)
• Consolidation with air bronchograms: Pneumonia
• Lung sliding abolished: Pneumothorax
• Pleural effusion: Anechoic fluid between visceral/parietal pleura

Cardiac Echo:

• Exclude cardiac cause of respiratory distress (CHD, myocarditis)
• Assess RV function in PARDS (pulmonary hypertension)
• Guide fluid management

Physiological Monitoring

Non-Invasive Monitoring:

• SpO2: Continuous, target 92-97% in most conditions
• Heart rate: Tachycardia = distress, bradycardia = ominous
• Respiratory rate: Serial monitoring for trend
• EtCO2: Estimate of PaCO2, valuable in intubated patients
• Temperature: Fever management, normothermia in ARDS

Invasive Monitoring (PICU):

• Arterial line: Continuous BP, blood sampling
• Central venous pressure: Fluid status, ScvO2 monitoring
• Capnography: Continuous EtCO2, waveform analysis

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8. ICU Management

Initial Resuscitation (First Hour)

A - Airway:

Assessment:

• Stridor vs wheeze vs grunting
• Ability to maintain airway
• Level of consciousness (GCS)
• Signs of impending failure (exhaustion, apnoea)

Interventions:

• Patent airway: Position, suction secretions, jaw thrust
• Upper airway obstruction (croup):
  • "Nebulized adrenaline 0.5-1 mL of 1:1000"
  • Dexamethasone 0.15-0.6 mg/kg PO/IV
  • "Consider heliox (70:30) if severe"
• Indications for intubation:
  • Apnoea or irregular respirations
  • Exhaustion, altered consciousness
  • SpO2 <85% despite maximal support
  • Severe hypercapnia (pH <7.15, PaCO2 >80)
  • HFNC/NIV failure

ETT Selection:

Formula (cuffed): (Age/4) + 3.5

B - Breathing:

Oxygen Therapy Escalation:

1. Low-flow nasal cannulae: 0.5-2 L/min (FiO2 ~0.3-0.4)
2. High-flow nasal cannulae (HFNC): 2 L/kg/min (max 60 L/min children)
   • Provides PEEP effect (2-4 cmH2O)
   • Heated humidified oxygen
   • Reduces work of breathing
   • PARIS trial: Reduced treatment failure vs standard O2 (PMID: 29562151)
3. Non-invasive ventilation:
   • CPAP: 5-10 cmH2O (bronchiolitis, ARDS)
   • BiPAP: IPAP 10-16, EPAP 5-8 cmH2O (neuromuscular, asthma)
4. Invasive mechanical ventilation: See below

Initial Ventilator Settings (Post-Intubation):

C - Circulation:

• Fluid assessment: Avoid over-hydration (worsens pulmonary oedema)
• Maintenance fluids: 2/3 maintenance if PARDS/pneumonia (SIADH common)
• Inotropes: Rarely needed unless septic shock or myocarditis
• Haemodynamic targets:
  • MAP >age-appropriate lower limit
  • CVP 8-12 mmHg if monitored
  • ScvO2 >70%

D - Disability:

• GCS/AVPU: Altered consciousness may indicate hypoxia/hypercapnia
• Sedation for ventilated children:
  • Morphine 10-40 mcg/kg/hr + Midazolam 1-4 mcg/kg/min
  • Or Fentanyl 1-4 mcg/kg/hr + Dexmedetomidine 0.2-0.7 mcg/kg/hr
• Glucose: Maintain 4-10 mmol/L (hypoglycaemia common in sick infants)

Definitive Management

HFNC for Bronchiolitis (PMID: 29562151, 31266260):

NIV for PARDS/Bronchiolitis Failure (PMID: 28288114):

Mechanical Ventilation in PARDS (PMID: 29280732, 37382423):

Lung-Protective Ventilation Goals:

• Tidal volume: 5-8 mL/kg predicted body weight
• Plateau pressure: <28 cmH2O (ideally <25 cmH2O)
• Driving pressure: <15 cmH2O
• PEEP: 10-15 cmH2O (titrate to oxygenation and compliance)
• Permissive hypercapnia: pH >7.20, PaCO2 up to 60-70 acceptable
• Permissive hypoxaemia: SpO2 88-92%, PaO2 55-80 mmHg

PEEP Titration in PARDS (PALICC-2 Recommendations):

Prone Positioning (PMID: 23688302, adapted for paediatrics):

• Indication: Moderate-severe PARDS (OI ≥8, P/F <150)
• Duration: 12-16 hours per session
• Timing: Within 24-36 hours of PARDS diagnosis
• Contraindications: Spinal instability, open abdomen, intracranial hypertension
• Evidence: Extrapolated from PROSEVA (adults); limited paediatric RCT data

Neuromuscular Blockade in Severe PARDS (PMID: 30626584):

• Indication: Refractory hypoxaemia, ventilator dyssynchrony despite sedation
• Agent: Rocuronium infusion 0.3-0.6 mg/kg/hr or Vecuronium 0.1 mg/kg/hr
• Duration: Limit to 24-48 hours when possible
• Monitoring: Train-of-four (TOF), depth 1-2/4

Inhaled Nitric Oxide (iNO) (PMID: 28288114):

• Dose: Start 10-20 ppm, wean to 5 ppm, then discontinue
• Indication: Refractory hypoxaemia (OI >25), confirmed pulmonary hypertension
• Response: 50-60% have oxygenation improvement
• Evidence: Improves oxygenation, no mortality benefit in PARDS
• Weaning: Gradual (rebound pulmonary hypertension if stopped abruptly)

Surfactant Therapy (PMID: 17714341):

• Evidence: Limited in paediatric ARDS (no proven mortality benefit)
• Consideration: Severe PARDS, especially post-near-drowning, meconium aspiration
• Dose: Beractant 100 mg/kg or Poractant alfa 100-200 mg/kg
• Administration: Intratracheal via ETT

VV-ECMO for Refractory PARDS (PMID: 30371341):

Indications:

• OI >40 despite optimal ventilation
• P/F ratio <50-60 on optimal settings
• Uncompensated respiratory acidosis (pH <7.15)
• Reversible underlying cause

Cannulation:

• Weight <15 kg: Often VV-DL (dual-lumen) via IJ
• Weight >15 kg: Femoral-IJ or femoral-femoral

Settings:

• Blood flow: 80-120 mL/kg/min
• Sweep gas: Titrate to PaCO2 target
• Target: SpO2 >85%, adequate oxygen delivery

Outcomes:

• Survival to discharge: 55-65% (respiratory ECMO) (PMID: 30371341)
• Higher in isolated respiratory failure vs multi-organ

Condition-Specific Management

Bronchiolitis (PMID: 31266260, Australasian Guidelines):

Severe Asthma (PMID: 31055897):

Ventilation Strategy in Asthma:

• Mode: Pressure control or volume control
• Goal: Minimize dynamic hyperinflation
• I:E ratio: 1:3 to 1:4 (long expiratory time)
• Low respiratory rate: 12-15/min (allow complete exhalation)
• Permissive hypercapnia: pH >7.20 acceptable
• PEEP: Low (3-5 cmH2O) unless intrinsic PEEP is high

Australian-Specific Protocols

ANZPIC Ventilation Guidelines:

• Lung-protective ventilation is standard of care
• PEEP optimization emphasized
• iNO available in tertiary PICUs
• VV-ECMO available at designated centres (RCH Melbourne, CHW Sydney, LCCH Brisbane, Perth Children's, Starship Auckland)

Retrieval Considerations:

• NETS (Newborn and Paediatric Emergency Transport Service): NSW 1300 362 500
• PIPER (Paediatric Infant Perinatal Emergency Retrieval): Victoria 1300 137 650
• RSQ (Retrieval Services Queensland): 1300 799 127
• MedSTAR Kids: South Australia
• RFDS: For remote retrievals

Pre-transport Stabilization:

• Secure airway before transport
• Adequate sedation and muscle relaxation
• Blood gas prior to departure
• Portable ventilator with appropriate settings
• Blood products available if needed

Indigenous Health Considerations

Aboriginal and Torres Strait Islander Children (PMID: 28392343):

Higher Risk Factors:

• 2-3× higher rates of bronchiolitis and pneumonia hospitalization
• Associated with overcrowding, passive smoke exposure, malnutrition
• Later presentation due to geographic isolation
• Higher rates of chronic suppurative lung disease
• Bronchiectasis more common

Cultural Considerations:

• Involve Aboriginal Health Worker/Aboriginal Liaison Officer
• Extended family involvement in care decisions
• Allow time for family consultation before major decisions
• Respect traditional healing practices alongside Western medicine
• Language interpreters as needed
• Discharge planning with Aboriginal Medical Service

Maori Children (New Zealand):

• 2× higher rates of respiratory infections
• Involve whanau (extended family)
• Respect tikanga (cultural protocols)
• Involve Maori Health Worker
• Consider social determinants (housing, income, access)

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9. Monitoring & Complications

ICU-Specific Monitoring

Daily Parameters:

Ventilation Monitoring:

Complications

Early Complications (First 48 Hours):

1. Intubation-Related Complications:

• Incidence: 10-15%
• Risk factors: Inexperience, difficult airway, emergency setting
• Complications: Oesophageal intubation, mainstem intubation, hypoxic arrest, aspiration
• Prevention: Video laryngoscopy, pre-oxygenation, expert operator
• Management: Immediate recognition, re-intubation

2. Pneumothorax/Air Leak Syndromes:

• Incidence: 5-10% in PARDS, higher with high PEEP/Vt
• Risk factors: Necrotizing pneumonia, high ventilator pressures, asthma
• Presentation: Sudden desaturation, hypotension, unilateral absent breath sounds
• Management: Needle decompression → chest drain

3. Dynamic Hyperinflation (Asthma):

• Incidence: Common in severe asthma
• Risk factors: High respiratory rate, short expiratory time, bronchospasm
• Presentation: Increasing airway pressures, hypotension, auto-PEEP
• Management: Disconnect from ventilator briefly, reduce RR, increase I:E ratio

Late Complications (Beyond 48 Hours):

4. Ventilator-Associated Pneumonia (VAP):

• Incidence: 5-20% of ventilated paediatric patients
• Risk factors: Duration of ventilation, aspiration, immunocompromise
• Prevention: Head elevation, oral care, subglottic suctioning
• Management: Antibiotics based on culture, source control

5. Ventilator-Induced Lung Injury (VILI):

• Mechanisms: Volutrauma (overdistension), barotrauma (high pressure), atelectrauma (repeated opening/closing), biotrauma (inflammation)
• Prevention: Lung-protective ventilation, PEEP optimization, limit driving pressure

6. ICU-Acquired Weakness:

• Incidence: 25-40% of prolonged ventilation
• Risk factors: Corticosteroids + NMB, immobility, sepsis
• Prevention: Early mobilization, minimize sedation, limit NMB duration

7. Subglottic Stenosis (Post-Extubation):

• Incidence: 1-2% of intubated children
• Risk factors: Traumatic intubation, oversized ETT, prolonged intubation, multiple reintubations
• Prevention: Appropriate ETT size, cuff pressure <25 cmH2O
• Management: Laryngoscopy, may need surgical intervention

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10. Prognosis & Outcome Measures

Mortality

Short-Term Outcomes:

Prognostic Factors in PARDS (PMID: 26296298):

Good Prognosis:

• Isolated respiratory failure
• OI <16 at 24 hours
• Improvement in OI by Day 3
• No immunocompromise
• Age >1 year

Poor Prognosis:

• Multi-organ failure (≥2 organ failures)
• Immunocompromise
• OI >20 at 24 hours
• Worsening OI over first 72 hours
• PELOD-2 score >10
• Age <1 year

Morbidity and Long-Term Outcomes

Bronchiolitis Long-Term (PMID: 31266260):

• Recurrent wheeze: 30-50% in first 2 years
• Asthma diagnosis by age 7: 15-25%
• Lung function generally normal
• Neurodevelopmental outcomes excellent

PARDS Long-Term (PMID: 33432426):

• Pulmonary function: 70-80% normal at 1 year
• Mild restrictive disease: 10-20%
• Exercise limitation: 15-25%
• Quality of life: Generally good but may be reduced

ECMO Survivors (PMID: 30371341):

• Neurodevelopmental concerns: 25-40%
• Learning difficulties: 20-30%
• Need for ongoing rehabilitation: 30-40%
• Pulmonary function: Usually recovers

Paediatric Severity Scores

PIM-3 (Paediatric Index of Mortality 3) (PMID: 24253048):

• Calculated at PICU admission
• Variables: SBP, pupil reactions, PaO2/FiO2, base excess, mechanical ventilation, elective admission, bypass, cardiac arrest, risk diagnosis
• Predicts PICU mortality risk

PELOD-2 (Paediatric Logistic Organ Dysfunction 2) (PMID: 23838678):

• Daily organ dysfunction score
• Variables: GCS, pupil reactions, lactatemia, MAP, creatinine, PaO2/FiO2, PaCO2, invasive ventilation, WCC, platelets
• Higher scores = higher mortality risk

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11. SAQ Practice (CICM Second Part Standard)

SAQ 1: Severe Bronchiolitis Management

Time Allocation: 10 minutes
Total Marks: 20

Stem:

A 6-week-old previously well male infant is referred to the PICU from a regional hospital 300 km away. He was born at 38 weeks gestation with no neonatal issues.

He has had 3 days of coryzal symptoms with increasing work of breathing and poor feeding. He is currently on HFNC at 2 L/kg/min with FiO2 0.6.

Observations:

• Weight: 4.5 kg
• RR: 75/min with moderate subcostal recession
• HR: 180 bpm
• BP: 70/45 mmHg
• SpO2: 88% on HFNC FiO2 0.6
• Temperature: 38.2°C

Capillary blood gas:

• pH: 7.25
• PCO2: 65 mmHg
• HCO3: 26 mmol/L
• Lactate: 2.1 mmol/L

CXR: Hyperinflation, bilateral perihilar infiltrates, no focal consolidation.

Nasopharyngeal aspirate: RSV positive.

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Question 1.1 (8 marks)

Outline your approach to the immediate management of this infant in the first hour after arrival to your PICU.

Question 1.2 (6 marks)

Discuss the risk factors that make this infant at higher risk of severe disease and the indications for intubation and mechanical ventilation.

Question 1.3 (6 marks)

The infant is intubated. Describe your initial ventilator settings and the targets you are aiming for.

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Model Answer - SAQ 1

Question 1.1 (8 marks total)

A - Airway and Breathing Assessment (3 marks):

• Assess work of breathing, air entry, chest expansion (0.5 mark)
• Continue HFNC at current settings initially (0.5 mark)
• If deteriorating: Trial increase HFNC to 2.5 L/kg/min (max ~12 L/min) (0.5 mark)
• Prepare for intubation (equipment, drugs, personnel) given high-risk features (0.5 mark)
• Calculate ETT size: Cuffed 3.0-3.5 mm ID, depth 10 cm oral (0.5 mark)
• If intubating: Ketamine 1-2 mg/kg + Rocuronium 1 mg/kg for RSI (0.5 mark)

C - Circulation and Fluid Assessment (2 marks):

• IV access if not already established (0.5 mark)
• Judicious fluid bolus if hypovolaemic (10 mL/kg) (0.5 mark)
• Maintenance fluids at 2/3 rate (risk of SIADH) (0.5 mark)

D - Disability and Supportive Care (2 marks):

• Glucose check (hypoglycaemia risk in sick infants) (0.5 mark)
• Temperature management (antipyretics for fever) (0.5 mark)
• Nasogastric feeding: Consider NG feeds or TPN if intubated (0.5 mark)
• Minimal handling to reduce oxygen consumption (0.5 mark)

Investigations (1 mark):

• FBC, UEC, blood gas post-intervention (0.5 mark)
• Consider blood culture if concerned about secondary infection (0.5 mark)

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Question 1.2 (6 marks total)

High-Risk Features in This Infant (3 marks):

• Age <8 weeks (peak age for apnoea, severe disease) (0.5 mark)
• Young chronological age (6 weeks - immature immune response) (0.5 mark)
• Respiratory acidosis with hypercapnia (pH 7.25, PCO2 65) (0.5 mark)
• Hypoxaemia despite FiO2 0.6 (SpO2 88%) (0.5 mark)
• Tachycardia (HR 180) indicating significant physiological stress (0.5 mark)
• Tachypnoea (RR 75) with increased work of breathing (0.5 mark)

Indications for Intubation (3 marks):

• Apnoea or irregular respirations (0.5 mark)
• Exhaustion/impending respiratory arrest (0.5 mark)
• Worsening hypoxaemia (SpO2 <88%) despite maximal non-invasive support (0.5 mark)
• Worsening hypercapnia (PCO2 >70, pH <7.20) (0.5 mark)
• Altered level of consciousness (0.5 mark)
• Failure to improve after 1-2 hours of maximal HFNC (0.5 mark)
• Recurrent apnoeas (especially in young infants) (0.5 mark)

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Question 1.3 (6 marks total)

ETT and Intubation (1 mark):

• Cuffed ETT 3.0-3.5 mm ID (Age/4 + 3.5 for cuffed) (0.5 mark)
• Oral depth ~10 cm (3 × ETT ID) (0.5 mark)

Initial Ventilator Settings (3 marks):

• Mode: Pressure-controlled ventilation (PC-CMV) or Volume-controlled (0.5 mark)
• Tidal volume: 6-8 mL/kg (~27-36 mL) if volume mode (0.5 mark)
• Respiratory rate: 25-35/min (age-appropriate) (0.5 mark)
• PEEP: 5-8 cmH2O (maintain FRC, prevent atelectasis) (0.5 mark)
• FiO2: Start 0.6, titrate to SpO2 92-97% (0.5 mark)
• Inspiratory pressure/PIP: 18-25 cmH2O (limit plateau <28) (0.5 mark)

Targets (2 marks):

• SpO2: 92-97% (0.5 mark)
• PaCO2: 45-60 mmHg (permissive hypercapnia acceptable) (0.5 mark)
• pH: >7.25 (0.5 mark)
• Plateau pressure: <28 cmH2O (0.5 mark)

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SAQ 2: PARDS Ventilation Strategy

Time Allocation: 10 minutes
Total Marks: 20

Stem:

A 3-year-old previously healthy girl is admitted to PICU with community-acquired pneumonia progressing to PARDS.

She was intubated in the Emergency Department and is now 24 hours into her PICU admission.

Current ventilator settings:

• Mode: PC-CMV
• PIP: 28 cmH2O, PEEP: 12 cmH2O
• FiO2: 0.8
• RR: 28/min
• Vt: 140 mL (predicted body weight 14 kg)

ABG (FiO2 0.8, MAP 20 cmH2O):

• pH: 7.28
• PaCO2: 55 mmHg
• PaO2: 62 mmHg
• HCO3: 24 mmol/L
• Lactate: 1.8 mmol/L

CXR: Bilateral diffuse infiltrates, no pneumothorax, ETT in good position.

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Question 2.1 (8 marks)

Calculate the Oxygenation Index, classify the severity of PARDS according to PALICC-2 criteria, and outline your ventilation strategy for the next 24 hours.

Question 2.2 (6 marks)

The child fails to improve after 24 hours of optimized ventilation. Discuss additional therapies you would consider and the indications for VV-ECMO.

Question 2.3 (6 marks)

The child's parents are Indigenous Australians from a remote community. Discuss specific considerations for communication and family support.

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Model Answer - SAQ 2

Question 2.1 (8 marks total)

Oxygenation Index Calculation (2 marks):

• OI = (MAP × FiO2 × 100) / PaO2 (0.5 mark)
• OI = (20 × 0.8 × 100) / 62 = 1600 / 62 = 25.8 (0.5 mark)
• PARDS Severity: Severe (OI ≥16) (1 mark)

Current Assessment (2 marks):

• Tidal volume: 140 mL / 14 kg = 10 mL/kg - TOO HIGH (0.5 mark)
• Need to reduce Vt to 5-6 mL/kg (70-84 mL) (0.5 mark)
• Plateau pressure 28 cmH2O - at upper limit (0.5 mark)
• Permissive hypercapnia appropriate (pH 7.28, PCO2 55) (0.5 mark)

Ventilation Strategy for Next 24 Hours (4 marks):

• Reduce tidal volume to 5-6 mL/kg (70-84 mL) (0.5 mark)
• Increase PEEP to 14-16 cmH2O (moderate-severe PARDS) (0.5 mark)
• Limit plateau pressure <28 cmH2O (ideally <25) (0.5 mark)
• Target driving pressure <15 cmH2O (0.5 mark)
• Prone positioning for 12-16 hours (OI >16 indication) (0.5 mark)
• Consider neuromuscular blockade for 24-48 hours (ventilator synchrony) (0.5 mark)
• Permissive hypercapnia: Accept pH >7.20, PCO2 55-70 (0.5 mark)
• Permissive hypoxaemia: Target SpO2 88-92%, PaO2 55-80 (0.5 mark)

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Question 2.2 (6 marks total)

Additional Therapies (3 marks):

• Inhaled Nitric Oxide (iNO): 10-20 ppm, selective pulmonary vasodilator (0.5 mark)
  • "Indication: Refractory hypoxaemia, confirmed pulmonary hypertension (0.5 mark)"
  • "Evidence: Improves oxygenation, no mortality benefit (0.5 mark)"
• High-frequency oscillatory ventilation (HFOV): Rescue if failing conventional (0.5 mark)
• Surfactant therapy: Consider in severe PARDS (limited evidence) (0.5 mark)
• Recruitment manoeuvres: Stepwise PEEP increase with observation (0.5 mark)

ECMO Indications (3 marks):

• OI >40 despite optimal ventilation for 6+ hours (0.5 mark)
• P/F ratio <50-60 despite optimal settings (0.5 mark)
• Uncompensated respiratory acidosis (pH <7.15, rising PCO2) (0.5 mark)
• Potentially reversible underlying condition (0.5 mark)
• Air leak syndromes unresponsive to management (0.5 mark)
• Expected ECMO survival >50% (no contraindications) (0.5 mark)

Contraindications to ECMO:

• Irreversible underlying disease
• Severe neurological injury
• Uncontrolled bleeding
• Prolonged mechanical ventilation (>14 days with high settings)

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Question 2.3 (6 marks total)

Cultural Considerations (3 marks):

• Involve Aboriginal Health Worker (AHW) or Aboriginal Liaison Officer (ALO) from admission (1 mark)
• Family is broadly defined - extended family, Elders may be decision-makers (0.5 mark)
• Allow time for family consultation before major decisions (0.5 mark)
• Collective decision-making rather than individual autonomy model (0.5 mark)
• Offer interpreter services even if English spoken (0.5 mark)

Communication Strategies (2 marks):

• Use plain language, avoid medical jargon (0.5 mark)
• Visual aids helpful for explaining procedures (0.5 mark)
• Check understanding ("Can you tell me what you understood?") (0.5 mark)
• Respect silence - family may need thinking time (0.5 mark)

Practical Considerations (1 mark):

• Remote family - facilitate accommodation, transport support (0.5 mark)
• If death occurs, respect "Sorry business" protocols (0.5 mark)
• Discharge planning: Coordinate with Aboriginal Medical Service (0.5 mark)

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12. Viva Scenarios

Viva Scenario 1: Intubation of a Child with Respiratory Failure

Stem: "You are called to the Emergency Department to intubate a 2-year-old child with severe bronchiolitis. The child weighs 12 kg and has been on HFNC for 4 hours but is now exhausted with SpO2 85% on FiO2 0.7, RR 70, and poor air entry bilaterally."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Opening Question:

"What are your immediate priorities and how would you prepare for intubation?"

Expected Answer (2-3 minutes):

Immediate Assessment:

• Confirm need for intubation: SpO2 85%, exhaustion, worsening despite maximal HFNC
• Call for experienced help (anaesthetist, consultant)
• Prepare resuscitation equipment

Equipment Preparation:

• ETT: Cuffed 4.0 mm ID (Age/4 + 3.5 = 2/4 + 3.5 = 4.0), have 3.5 and 4.5 ready
• Blade: Miller 2 (straight) or Macintosh 2 (curved)
• Depth: 12-13 cm oral (Age/2 + 12 = 13)
• Suction, bag-valve-mask, two laryngoscopes, bougie, LMA backup

Pre-oxygenation:

• Apnoeic oxygenation with nasal cannulae during laryngoscopy
• High-flow or bag-mask pre-oxygenation
• Remember: Children desaturate rapidly (60-90 seconds)

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Follow-up Question 1 (2-3 minutes):

"What drugs would you use and why?"

Expected Answer:

Induction Agent:

• Ketamine 2 mg/kg IV (24 mg)
  • Bronchodilator properties beneficial in bronchiolitis
  • Maintains respiratory drive and airway reflexes
  • Cardiovascular stability
  • "Alternative: Propofol 2-3 mg/kg if haemodynamically stable"

Neuromuscular Blocker:

• Rocuronium 1.2 mg/kg IV (14 mg)
  • Rapid onset (60 seconds at this dose)
  • Sugammadex reversal available
  • Avoids suxamethonium-related complications

Atropine:

• 0.02 mg/kg (0.24 mg) - pretreatment to prevent bradycardia
• Essential in infants/young children

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Follow-up Question 2 (2-3 minutes):

"Explain the anatomical differences in the paediatric airway that make intubation challenging."

Expected Answer:

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Follow-up Question 3 (2-3 minutes):

"The intubation is successful. What are your initial ventilator settings?"

Expected Answer:

Post-Intubation:

• Confirm ETT position (CXR, EtCO2)
• Sedation: Morphine + Midazolam or Fentanyl + Dexmedetomidine
• NG tube for gastric decompression
• ABG in 30-60 minutes

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Viva Scenario 2: HFNC Failure and Escalation

Stem: "A 4-month-old infant with bronchiolitis has been on HFNC at 2 L/kg/min for 12 hours. Initially improved, but over the last 2 hours has deteriorated with increasing work of breathing. SpO2 is now 90% on FiO2 0.5, RR 65, with moderate recession."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Opening Question:

"How do you assess whether this infant is failing HFNC, and what are your options?"

Expected Answer:

Signs of HFNC Failure:

• Increasing work of breathing despite HFNC
• Rising FiO2 requirement (>0.5)
• Persistent tachypnoea (RR >60 in infants)
• Worsening hypoxaemia (SpO2 <92%)
• Apnoea or irregular respirations
• Altered consciousness, exhaustion
• Rising PaCO2, falling pH

Options for Escalation:

1. Optimize HFNC (if not already maximal):

   • Increase flow to 2.5 L/kg/min
   • Ensure appropriate interface fit
   • Clear secretions

2. Non-Invasive Ventilation (NIV):

   • CPAP 6-10 cmH2O
   • Requires appropriate interface (nasal prongs, mask)
   • Monitor closely for failure

3. Intubation and Mechanical Ventilation:

   • If NIV fails or contraindicated
   • If signs of impending arrest

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Follow-up Question 1:

"What is the evidence for HFNC in bronchiolitis?"

Expected Answer:

PARIS Trial (2018) (PMID: 29562151):

• Multicentre RCT in Australian/NZ EDs
• HFNC vs standard O2 for bronchiolitis
• Primary outcome: Treatment failure (escalation to other support)
• Results: HFNC reduced treatment failure (12% vs 23%, p<0.001)
• No difference in length of stay, intubation rate, duration of O2
• HFNC is rescue therapy for standard O2 failure

Other Evidence:

• HFNC generates PEEP effect (2-5 cmH2O)
• Reduces work of breathing
• Provides humidified, heated gas
• Well-tolerated in infants
• No mortality benefit demonstrated

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Follow-up Question 2:

"The infant requires intubation. The family are from a remote Indigenous community and grandmother is the primary carer. How do you approach this?"

Expected Answer:

Communication Approach:

• Involve Aboriginal Health Worker/Liaison Officer immediately
• Explain situation clearly using plain language, interpreter if needed
• Grandmother may be primary decision-maker - respect this
• Allow time for family consultation (phone family members if needed)
• Explain what intubation involves, expected course, prognosis

Cultural Considerations:

• Extended family involvement is expected and welcome
• Decision-making may be collective
• Allow time for discussion - don't rush
• Ask about any specific cultural concerns or practices
• Reassure that family can stay with child

Practical Support:

• Arrange accommodation for family
• Facilitate contact with home community
• Involve social worker for travel/financial support
• Plan for retrieval back to home when recovered

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13. Hot Case Scenario

Hot Case: Ventilated Child with PARDS

Setting: PICU Bed 5
Duration: 20 minutes (10 min assessment + 10 min discussion)
Equipment: Ventilator, monitors, IV pumps, charts available

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Actor/Simulator Briefing (Not given to candidate):

Patient Details:

• Age: 18 months
• Gender: Female
• Admission diagnosis: Influenza B pneumonia → PARDS
• Day of PICU stay: Day 4

History (available from nurse):

• Previously well, fully immunized
• Presented with 4 days fever, cough, progressive respiratory distress
• Intubated Day 1 for respiratory failure
• Cultures negative, NPA positive for Influenza B
• Oseltamivir started Day 1
• Required prone positioning Day 2-3

Current Examination Findings:

• General: Sedated (RASS -3), ETT 4.0 cuffed in situ
• Airway: ETT secure, good position
• Breathing: Bilateral coarse crackles, no wheeze, symmetrical expansion
• Circulation: HR 130, BP 85/50, CRT 2 sec, warm peripheries
• Disability: Sedated on morphine/midazolam infusions
• Exposure: T 37.8°C, NG in situ, IDC draining clear urine

Charts/Data Available:

Ventilator Settings:

• Mode: PC-CMV
• PIP: 24 cmH2O, PEEP: 10 cmH2O
• RR: 28/min, Vt: 90 mL (7.5 mL/kg, weight 12 kg)
• FiO2: 0.5
• SpO2: 93-95%

ABG (today):

• pH: 7.34
• PaCO2: 48 mmHg
• PaO2: 75 mmHg
• HCO3: 25 mmol/L
• Lactate: 1.2 mmol/L

CXR (today): Bilateral infiltrates improving, no pneumothorax

Infusions:

• Morphine 20 mcg/kg/hr
• Midazolam 2 mcg/kg/min
• Maintenance fluids 40 mL/hr (2/3 maintenance)

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Candidate Task:

"You are the ICU registrar. This 18-month-old girl was admitted 4 days ago with influenza pneumonia and PARDS. She has been ventilated throughout. Please assess the patient, review the charts, and present your findings to the consultant. You have 10 minutes to examine and review, then 10 minutes for discussion."

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Expected Performance:

Assessment Phase (10 minutes)

History Review (3 marks):

• Collateral from nurse: Current concerns, overnight events
• Review admission notes: Severity at presentation, interventions needed
• Oseltamivir course (5-10 days for severe influenza)

Examination - A-E Approach (10 marks):

• A (Airway): ETT position, cuff pressure, oral hygiene (1 mark)
• B (Breathing): Chest expansion, breath sounds, work of breathing, ventilator settings and waveforms, calculate OI (3 marks)
• C (Circulation): HR, BP, perfusion, fluid balance, lines, infusions (2 marks)
• D (Disability): Sedation level (RASS), pupils, CAM-ICU deferred if sedated (2 marks)
• E (Exposure): Temperature, skin, NG position, IDC output, nutrition (2 marks)

Chart Review (2 marks):

• Trend of OI over 4 days
• Ventilator settings progression
• Fluid balance
• Medications

One-Minute Summary (2 marks):

"This is [name], an 18-month-old previously well girl, Day 4 of PICU admission with influenza B pneumonia complicated by PARDS.

Currently she is ventilated on PC-CMV with improving oxygenation - OI has decreased from [X] on admission to [current]. She is on moderate sedation with morphine and midazolam.

Key issues are:

1. PARDS - improving, plan to wean ventilation
2. Sedation weaning
3. Nutrition (check if NG feeds established)
4. Oseltamivir course completion

Plan: Continue current ventilation, consider daily spontaneous breathing trial, begin sedation weaning, family update."

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Discussion Phase (10 minutes)

Q1: "What are your weaning criteria and how would you approach weaning from the ventilator?"

Expected Answer:

• Weaning Criteria:

  • FiO2 <0.4, PEEP <8 cmH2O
  • Improving OI (<8)
  • Minimal sedation, patient triggering ventilator
  • Haemodynamically stable
  • Afebrile or low-grade fever
  • Adequate nutrition

• Approach:

  • Daily sedation interruption (if appropriate)
  • "Spontaneous Breathing Trial (SBT): PSV 5-10 cmH2O + PEEP 5"
  • Assess for 30-120 minutes
  • "If passes: Consider extubation"
  • Extubation to HFNC (2 L/kg/min)

Q2: "What are the criteria for extubation failure and how would you manage it?"

Expected Answer:

• Extubation Failure Criteria:

  • Reintubation within 24-48 hours
  • Need for NIV within 24 hours (some definitions)

• Risk Factors for Failure:

  • Age <2 years
  • Failed SBT
  • Excessive secretions
  • Upper airway oedema (cuff leak test)
  • Prolonged intubation

• Management if Fails:

  • Re-intubate if in distress
  • Consider NIV if borderline
  • Dexamethasone for stridor (croup-like presentation post-extubation)
  • Investigate cause (secretions, laryngeal oedema, atelectasis)

Q3: "The family wants to know about long-term outcomes. What do you tell them?"

Expected Answer:

• Short-term: Expect full recovery from influenza
• Pulmonary function: Usually returns to normal within 6-12 months
• Recurrent wheeze: 20-30% may have episodes in first 1-2 years
• Neurodevelopment: Generally excellent if no hypoxic injury
• Follow-up: Paediatric respiratory clinic, immunization counselling (influenza vaccine)