Extubation Criteria

Quick Answer

Extubation is the planned removal of an endotracheal tube after determining a patient can maintain adequate spontaneous breathing and protect their airway. Successful extubation requires assessing four domains: airway patency, ventilatory adequacy, haemodynamic stability, and neurologic status. A spontaneous breathing trial (SBT) evaluates readiness while a failed cuff leak test suggests laryngeal edema and post-extubation stridor risk.

ACEM Exam Focus

FACEM examiners expect candidates to demonstrate:

• Systematic assessment of extubation readiness across four domains
• Knowledge of SBT protocols and interpretation of failure causes
• Understanding of cuff leak test utility and limitations
• Recognition of extubation failure predictors and proactive management
• Appropriate use of post-extubation respiratory support (HFNC, NIV)
• Leadership in managing extubation failure scenarios in the resuscitation bay

Key exam scenarios: COPD exacerbation requiring prolonged ventilation, post-cardiac arrest patients, neurological injuries, obese patients with sleep apnoea, and multi-organ failure patients.

Key Points

• Extubation failure (reintubation within 24-72 hours) occurs in 10-20% of ICU patients
• Mortality associated with reintubation ranges from 25-50% - seven-fold increase vs successful extubation
• Four readiness domains: airway protection, ventilation, haemodynamics, neurologic status
• Spontaneous Breathing Trial (30-120 minutes) is the cornerstone of extubation readiness testing
• Rapid Shallow Breathing Index (respiratory rate divided by tidal volume in litres) above 105 predicts failure
• Cuff leak test has high specificity (87%) but moderate sensitivity (62%) for post-extubation stridor
• Preventive NIV or HFNC reduces reintubation in high-risk patients
• Reintubation should NOT be delayed if criteria not met after failed extubation

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Epidemiology

Global Incidence

• Extubation failure rate in general ICU population: 10-20% of planned extubations
• High-risk patient subsets (age above 65, cardiac/respiratory comorbidities, prolonged ventilation): 20-30% or higher
• Mortality with extubation failure: 25-50% versus 2-5% for successful extubation
• ICU LOS extended by 5-7 days in patients requiring reintubation

Extubation Failure Definition

• Timeframe: Reintubation within 24-72 hours (most studies use 48-72 hours)
• Variability: Guidelines differ - some use 24 hours, others 48 or 72 hours
• Consensus: 48-72 hours captures early respiratory decompensation patterns

Australian/NZ Context

• Similar extubation failure rates to international data (11-16% in multicentre Australian studies)
• Higher rates observed in regional ICUs with limited airway rescue capability
• Aus-ROC data shows 13.5% unplanned reintubation rate across Australian EDs and ICUs combined

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Pathophysiology

Why Extubation Fails

Respiratory Causes (60-70% of failures)

1. Ventilatory Muscle Fatigue

   • Prolonged ventilation causes diaphragmatic dysfunction within 18-72 hours
   • Critical illness polyneuropathy/myopathy after days 5-7 of ventilation
   • Inadequate respiratory drive (sedation, metabolic alkalosis)

2. Increased Work of Breathing

   • Upper airway obstruction (laryngeal edema, vocal cord dysfunction)
   • Airway secretions and impaired cough
   • Pulmonary oedema from fluid overload

3. Gas Exchange Impairment

   • Atelectasis developing within hours of positive pressure removal
   • V/Q mismatch from dependent lung zone collapse
   • Worsening ARDS or pneumonia

Cardiovascular Causes (15-20%)

1. Fluid Overload

   • Positive pressure ventilation unloads left ventricle (decreases preload)
   • Extubation removes this effect, precipitating pulmonary oedema
   • Occurs most commonly within 6-12 hours post-extubation

2. Myocardial Ischaemia

   • Increased work of breathing raises myocardial oxygen demand
   • Tachycardia and hypertension during SBT may trigger ischemia
   • Silent ischemia in sedated patients becomes apparent during stress testing

Neurologic Causes (10-15%)

1. Impaired Airway Protection
   • Inadequate cough reflex (weakness, sedation, vocal cord paresis)
   • Aspiration risk due to dysphagia (post-intubation, neurological injury)
   • Reduced level of consciousness (GCS below 8) preventing protective reflexes

Upper Airway Causes (5-10%)

1. Laryngeal Edema
   • ETT cuff pressure against posterior larynx causes inflammation
   • Grading: mild (stridor only), moderate (requires intervention), severe (airway obstruction)
   • Risk factors: intubation duration above 48 hours, female gender, large ETT relative to airway, trauma at intubation

Pathophysiology of Laryngeal Edema

• Granulocytic infiltration to injured airway mucosa
• Polymorphonuclear infiltration causing fibrinous exudation
• Damage to medial surface of vocal cords and arytenoid cartilages
• Airway lumen narrowing by above 50% causes audible stridor
• Ulceration may lead to granulation tissue and chronic stenosis

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Clinical Approach

Systematic Readiness Assessment

Use the mnemonic ALWAYS for extubation readiness:

A - Airway Protection

• GCS above 8, able to follow commands
• Strong cough (peak cough flow above 60 L/min)
• Intact gag reflex
• Minimal secretions able to be cleared
• No upper airway obstruction

L - Lung Function

• Adequate oxygenation (SpO2 above 94% on FiO2 below 0.50)
• Normal PaCO2 or baseline for chronic hypercapnia
• Respiratory rate below 30 breaths/min
• No significant dyspnoea

W - Work of Breathing

• No accessory muscle use
• Adequate tidal volume (above 5 mL/kg)
• Respiratory rate below 25-30 breaths/min
• Rapid Shallow Breathing Index below 105

A - Acid-Base Status

• pH above 7.35 (or patient's baseline if chronic respiratory acidosis)
• Bicarbonate close to baseline (for chronic compensatory alkalosis)
• No metabolic acidosis requiring increased minute ventilation

Y - Yes to all domains S - Systemic Stability

S - Systemic Stability

• Haemodynamically stable
• No active myocardial ischaemia
• Cardiac arrhythmias controlled
• No sepsis requiring organ support escalation
• Adequate haemoglobin (above 8 g/dL for cardiac patients, above 7 g/dL general)

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Readiness Assessment Domains

1. Airway Assessment

Airway Protection Criteria

Cuff Leak Test

Indications:

• Intubation above 48 hours
• Difficult intubation
• Re-intubation history
• Large ETT for airway size
• Prolonged ventilation (above 7 days)
• Female patients
• Trauma

Procedure:

1. Position patient semi-recumbent (30-45 degrees)
2. Suction oropharynx and endotracheal tube
3. Set ventilator to assist-control (tidal volume 6-8 mL/kg)
4. Deflate cuff completely
5. Listen for air leak around tube (audible without stethoscope = 2+)
6. Quantify: Exhaled tidal volume minus delivered tidal volume

Quantitative Cutoffs:

• Above 110 mL: low risk of post-extubation stridor
• 60-110 mL: intermediate risk
• Below 60 mL: high risk (high specificity for airway obstruction)

Interpretation:

• Positive cuff leak (audible air flow or leak volume above 110 mL): airway patent, proceed with extubation
• Negative cuff leak (no audible leak or below 60 mL): consider steroids, delay extubation 12-24 hours

Management of Failed Cuff Leak Test:

• Dexamethasone 4-8 mg IV/PO every 6 hours for 12-24 hours
• Repeat cuff leak in 12 hours
• Consider early tracheostomy if high-risk patient with persistent failure

Limitations:

• Sensitivity only 62% (38% false-negative rate)
• Negative test does NOT exclude airway edema
• Positive test has excellent specificity (87%)

Cuff Leak Test Evidence

Kuriyama et al. 2020 meta-analysis (28 studies, 4,493 extubations):

• Sensitivity for post-extubation airway obstruction: 0.62 (95% CI 0.49-0.73)
• Specificity for post-extubation airway obstruction: 0.87 (95% CI 0.82-0.90)
• Excellent specificity supports intervening for positive test
• Low sensitivity mandates close post-extubation monitoring even with passed test

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2. Ventilatory Assessment

Spontaneous Breathing Trial (SBT)

Indications:

• Mechanically ventilated above 24 hours (per most guidelines)
• Resolution or improvement of condition requiring ventilation
• Haemodynamic stability (no vasoactive agents above moderate doses)
• Adequate oxygenation on current settings

Pre-SBT Checklist:

1. FiO2 below 0.50 with PEEP below 10 cmH2O (higher acceptable in morbid obesity)
2. PaCO2 normal or close to patient's baseline
3. HR below 140 beats/min
4. No myocardial ischaemia
5. Vasopressors: noradrenaline below 15 mcg/min or equivalent
6. Patient arousable (ideally following commands)
7. Bicarbonate close to normal or patient's baseline

SBT Modalities:

SBT Duration:

• 30 minutes (most studies use 30-120 minutes)
• 60 minutes common in clinical practice
• 120 minutes in high-risk or uncertain situations

SBT Success Criteria:

Rapid Shallow Breathing Index (RSBI):

• Formula: Respiratory rate divided by tidal volume in litres
• Classic cutoff: Below 105 (higher suggests failure)
• Optimal cutoff (ROC analysis): Below 76-80
• RSBI below 105 has 83% sensitivity but only 58% specificity for extubation success
• RSBI above 105 is NOT absolute contraindication - consider context

SBT Failure and Causes:

If SBT Failed:

• Return to full ventilator support
• Identify reversible cause(s)
• Repeat SBT same day if cause correctable (e.g., hold sedation)
• Otherwise, repeat next morning

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3. Haemodynamic Assessment

Cardiovascular Readiness

Parameters:

• MAP above 65 mmHg (above 70 for known hypertension)
• SBP above 90-100 mmHg
• HR below 140 beats/min and stable (no marked fluctuation)
• No uncontrolled cardiac arrhythmias
• No active myocardial ischaemia
• Vasopressor requirement: noradrenaline below 15 mcg/min (or equivalent)

Fluid Status Assessment:

• Review I/O balance for preceding 72 hours
• Positive balance above 2-3 L: consider diuresis before extubation
• Physical examination: pulmonary crackles, peripheral oedema, JVP
• POCUS: B-lines, lung comet tails, reduced ejection fraction if history of cardiac dysfunction

Cardiac Function:

• ECG pre-extubation: ischaemia screening
• Troponin if clinical suspicion
• Echocardiography if known cardiac disease

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4. Neurologic Assessment

Level of Consciousness

Criteria:

• GCS above 8 (most guidelines)
• Following simple commands
• Maintained or improving
• No agitation or delirium

Special Situations:

• Stroke/TBI: GCS may be lower if baseline depressed, assess airway protection
• Hypoxic-ischaemic encephalopathy: May need tracheostomy for airway protection if depressed GCS
• Alcohol withdrawal/delirium: Treat sedation needs, delay extubation until improved

Neuromuscular Strength

Assess:

• Shoulder shrug (accessory breathing muscles)
• Hand grip strength
• Head lift (if cooperative)
• Negative inspiratory force (NIF): below -20 to -25 cmH2O is concerning

Weakness Patterns:

• Critical illness polyneuropathy: distal weakness, areflexia
• Myopathy: proximal weakness
• CIPNM combination: most common pattern

Cerebral Perfusion

• CPP maintained above 60 mmHg for TBI patients
• Avoid extremes of MAP (cautious in autoregulatory failure)
• Post-cardiac arrest: normotension (MAP above 70 mmHg)

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Investigation-Based Readiness

Imaging

POCUS Protocols

Lung Ultrasound (BLUE Protocol):

• Anterior zones: Assess for B-lines (pulmonary oedema), consolidation (pneumonia)
• Lateral zones: Atelectasis, pleural effusions
• B-line profile: 0-2 per zone is normal, above 3 suggests interstitial oedema

Cardiac Ultrasound:

• Parasternal long and short axis
• Subcostal IVC (collapsibility may guide fluid status)
• Apical 4-chamber (wall motion, EF)

Blood Tests

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Weaning Protocols

Daily Screening

Protocolised Daily Assessment:

1. Every morning (or every 12 hours), assess weaning eligibility
2. Use checklist approach covering four domains
3. If eligible, proceed to SBT
4. If SBT passes, consider extubation

Benefits:

• Shorter mechanical ventilation duration
• Reduced ICU stay
• Fewer complications (VAP, delirium)

Weaning Categories

Pressure Support Weaning Method

Protocol:

1. Start: PS appropriate to achieve tidal volume 6-8 mL/kg with RR below 30
2. Down-titrate PS by 2-4 cmH2O every 6-12 hours
3. Goal: PS 5-7 cmH2O with PEEP 5 cmH2O
4. When at target PS/PEEP, perform SBT
5. If SBT passes, extubate

SBT Methods Comparison

T-piece vs Pressure Support:

• T-piece more physiologic (true work of breathing)
• PS easier for patient (may cause early SBT pass but fail extubation)
• Recent RCT (Thille et al., NEJM 2022): PS vs T-piece in high-risk patients
  • No significant difference in time to extubation
  • No higher reintubation rate with PS
  • PS may be acceptable in practice

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Extubation Procedure

Pre-Extubation Checklist

5 minutes prior:

• Suction oropharynx and ETT thoroughly
• Position patient semi-recumbent (30-45 degrees)
• Preoxygenate with 100% for 2 minutes
• Ensure suction equipment immediately available
• Confirm airway equipment ready (LMA, video laryngoscope)
• Have senior clinician present for high-risk patients

Extubation Steps:

1. Suction ETT (through lumen to distal tip)
2. Suction oropharynx
3. Place catheter in ETT (leave in place)
4. Deflate cuff
5. Have patient inspire deeply (if able)
6. Withdraw ETT during expiration with catheter in place
7. Suction again on withdrawal
8. Apply oxygen immediately (face mask, HFNC, or NIV)

Optimal Technique:

• Withdraw during expiration (reduces aspiration risk)
• Apply cricoid pressure if concern for aspiration
• Head lateral position to facilitate airway opening

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Post-Extubation Support

Immediate Management

First Hour:

• Vital signs q15 minutes
• Continuous pulse oximetry
• SpO2 target 94-98% (lower if chronic hypercapnia: 88-92%)
• Early mobilisation (sitting up, chair if possible)
• Chest physio if secretions

4-6 Hours:

• Vital signs q30-60 minutes
• ABG at 1 hour if at risk
• Continuous monitoring if high-risk

Respiratory Support Options

High-Flow Nasal Cannula (HFNC)

Indications:

• General ICU patients with moderate extubation failure risk
• COPD patients with mild-moderate hypercapnia
• Post-operative patients
• Cardiac patients at risk

Settings:

• Flow: 30-60 L/min (titrate to comfort)
• FiO2: 0.21-0.50 (titrate to SpO2)
• humidified gas

Advantages:

• Improved oxygenation (positive airway pressure effects)
• Better comfort vs standard oxygen
• Reduces work of breathing (dead space washout)
• Lower reintubation rates vs standard oxygen in RCTs

Evidence:

• Hernandez et al. 2016: HFNC vs NIV in general population
  • Non-inferior for reintubation (11.8% vs 11.5%)
  • Similar mortality
  • Better tolerability
• Thille et al. 2019: Added NIV to HFNC vs HFNC alone
  • No significant difference in reintubation (27.0% vs 22.1%)
  • Suggests HFNC may be sufficient for most

Noninvasive Ventilation (NIV)

Indications:

• Hypercapnic respiratory failure (COPD exacerbation)
• Cardiogenic pulmonary oedema
• High-risk patients (4+ risk factors) - see below
• Failed extubation (prevention of repeat failure)

Settings:

• PSV: 10-15 cmH2O
• PEEP: 5 cmH2O
• Backup rate: 12-18 breaths/min
• FiO2: titrate to SpO2 94-98%

Risk Stratification for Preventive NIV:

Score interpretation:

• 0-2 factors: HFNC or standard oxygen adequate
• 3 factors: HFNC preferred
• 4+ factors: NIV preferred (RCT evidence: NIV superior to HFNC)

High-Risk RCT Evidence (2022):

• NIV vs HFNC in very high-risk patients (4+ risk factors, 182 patients)
• Reintubation: 23.3% (NIV) vs 38.8% (HFNC), difference -15.5%
• Hospital LOS: 20 days (NIV) vs 26.5 days (HFNC)
• Suggests NIV with active humidification superior for very high-risk patients

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Monitoring Schedule

Early Warning Signs:

• Rising respiratory rate above 30 breaths/min
• Decreasing SpO2 below patient's baseline
• Use of accessory muscles
• New acidosis on ABG (pH below 7.35, rising PaCO2)
• Haemodynamic deterioration

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Extubation Failure

Definition and Timing

• Reintubation within 24-72 hours (most studies use 48-72 hours)
• Varies by institution and study
• 48-hour window most common for defining early extubation failure

Mortality Impact

• Extubation failure mortality: 25-50% (varies by population)
• Versus 2-5% for successful extubation
• Seven-fold increase in mortality
• 31-fold increase in ICU stay

Risk Factors

Causes of Failure

1. Respiratory failure (60-70%)

   • New or worsening atelectasis
   • Pulmonary oedema (cardiogenic or fluid overload)
   • Pneumonia (new or treated inadequately)
   • Recurrent underlying disease

2. Airway obstruction (15-20%)

   • Laryngeal edema (stridor)
   • Upper airway collapse (obstructive sleep apnoea)
   • Aspiration (delayed)

3. Neurologic (10-15%)

   • Decreased consciousness
   • Seizures
   • Stroke progression

4. Cardiac (5-10%)

   • Myocardial ischaemia
   • Cardiogenic shock
   • Arrhythmias

Failure Prevention Strategies

Optimised Readiness Assessment:

• Daily screening using four-domain approach
• SBT for all eligible patients
• Cuff leak test only for high-risk patients
• Risk-stratified post-extubation support (NIV for 4+ risk factors)

Post-Extubation NIV/HFNC:

• NIV for hypercapnic patients
• HFNC for general population
• Combined NIV+HFNC for very high-risk

Reintubation Timing:

• Do NOT delay if criteria not met
• Earlier reintubation associated with better outcomes than delayed
• Threshold: rising RR above 35, PaCO2 above 50-55 mmHg, pH below 7.30

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Failed Extubation Management

Immediate priorities:

1. Call for help - senior clinician, ICU registrar, anaesthetist
2. Reintubate promptly - do not delay
3. Airway preparation - optimize positioning, have difficult airway equipment ready
4. Reintubation approach - consider videolaryngoscopy (first pass success critical)

Reintubation Technique:

• RSI if adequate airway protection not possible (consider reduced induction doses)
• Awake fibreoptic intubation if predicted difficult airway
• Have backup plan (LMA, surgical airway)

Post-Reintubation:

• Full ventilatory support (volume-targeted or pressure-targeted)
• Consider sedation strategy (light sedation preferred for daily awakening)
• Evaluate for tracheostomy if:
  • Prolonged ventilation anticipated (14-21 days)
  • Multiple reintubation attempts
  • High-risk airway

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Troubleshooting

During SBT - Apnea

Causes:

1. Hyperventilation prior to SBT

   • Takes several minutes for PaCO2 to rise and stimulate drive

2. Cheyne-Stokes respiration (periodic breathing)

   • Common in heart failure, neurological injury
   • Not a contraindication if otherwise stable

3. Oversedation (sedation not adequately held)

Management:

• If oversedated: hold all sedation, repeat SBT in 4-6 hours when patient more awake
• If awake: observe breathing pattern, check ETCO2, may proceed if ventilation adequate
• Consider lower ventilator rate before SBT to stimulate spontaneous breathing

During SBT - Tachypnea (RR above 35)

Differentiate:

• Anxiety: Large tidal volumes (above 8 mL/kg), maintained oxygenation, no accessory muscles
• Ventilatory failure: Small tidal volumes (below 4 mL/kg), accessory muscles, rising PaCO2

Management:

• Anxiety: continue SBT, may consider anxiolytics (cautious)
• Failure: stop SBT, return to full support

Post-Extubation - Stridor

Immediate:

• Racemic adrenaline (2.5 mg via nebs)
• Heliox (if available)
• Dexamethasone 8-10 mg IV/PO

If severe:

• Reintubate (smaller tube if possible, 0.5-1 mm smaller)
• Consider early tracheostomy

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Special Populations

Obesity

Considerations:

• Higher PEEP often required (8-10 cmH2O) to prevent atelectasis
• SBT may require PEEP 8-10 cmH2O (morbid obesity exception)
• Extubation to HFNC preferred (better tolerance)
• High risk of obstructive sleep apnoea post-extubation

Evidence:

• El Solh et al. 2006: NIV after extubation in obese patients reduced reintubation

COPD

Wean Challenges:

• Chronic hypercapnia = PaCO2 may be above normal baseline
• Use patient's baseline bicarbonate as reference
• Post-extubation NIV standard of care for COPD exacerbations

SBT Considerations:

• May have chronic tachypnea (RSBI above 105 acceptable if other criteria met)
• Post-extubation PaCO2 may rise to baseline but pH must remain above 7.30

Neuromuscular Disease

CIPNM (Critical Illness Polyneuromyopathy):

• Develops 5-7 days after ventilation initiation
• Assess diaphragmatic function (ultrasound)
• May require NIV post-extubation or tracheostomy

Testing:

• Maximal inspiratory pressure (MIP)
• Cough peak flow
• Ultrasound diaphragm thickness change

Cardiac Failure

Extubation Considerations:

• Positive pressure removal increases preload
• Diuresis before extubation if fluid overloaded
• Close ECG monitoring during SBT (check for ischaemia)

Prevention Strategies:

• Negative fluid balance prior to extubation
• Post-extubation CPAP may reduce pulmonary oedema risk
• Early diuresis (furosemide or dialysis) if overloaded

Neurological Injury (TBI, Stroke)

GCS Considerations:

• May extubate with GCS below 8 if airway protection adequate
• Cough strength critical
• Secretion management essential

Cerebral Perfusion:

• Maintain MAP above 65-70 mmHg
• Avoid hypoxia (worsens secondary injury)
• Avoid hyperoxia (free radicals)

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Indigenous Health Considerations

Aboriginal and Torres Strait Islander Peoples

Epidemiology:

• Higher rates of COPD and chronic respiratory disease
• Greater burden of cardiovascular disease
• Limited access to specialist care in remote communities
• Higher prevalence of smoking

Cultural Considerations:

• Gender-appropriate clinicians where possible
• Family involvement in decision-making
• Explain procedures in plain language, use of interpreters
• Respect traditional medicine practices
• Allow family presence if culturally appropriate

Remote/Rural Challenges:

• Limited ICU beds may necessitate earlier extubation decisions
• Retrieval distance considerations
• Telemedicine support for post-extubation care
• Community health worker involvement in follow-up

Health Promotion:

• Smoking cessation support
• COPD action plans
• Education on recognising deterioration
• Access to oxygen equipment in communities

Māori (New Zealand)

Whānau (Family) Involvement:

• Important to include family in decisions about extubation timing
• Cultural protocols around illness and death
• Use of tikanga Māori frameworks in communication

Rural/Anga Whakamua Challenges:

• Long distances to tertiary ICUs
• Limited airway rescue capability in rural hospitals
• Retrieval medicine considerations
• Community-based monitoring

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Remote/Rural Considerations

Resource Limitations

Airway Management:

• Limited access to advanced airway equipment
• Single operator often (fewer options for backup)
• Video laryngoscopy availability variable
• Considerations for difficult airway preparation

Retrieval Considerations:

• Timing of retrieval post-extubation
• HFNC equipment for transport
• NIV availability during retrieval
• Backup plan if decompensates

Protocol Adaptation

Readiness Assessment:

• More stringent criteria given limited rescue capability
• Lower threshold for cuff leak testing
• May proceed with HFNC to NIV progression more readily

Post-Extubation Monitoring:

• Longer observation periods before discharge to ward/transfer
• Telehealth support options
• Community health worker training for early detection of failure

Reintubation Planning:

• Plan for difficult airway (predicted difficult intubation = earlier escalation)
• Have retrieval team en route if high-risk patient being extubated
• Consider early transfer to tertiary centre before extubation

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Quality Assurance

Pre-Extubation Checklist

• Airway protection adequate (GCS above 8, strong cough)
• Ventilatory adequacy (SBT passed)
• Haemodynamic stability (MAP above 65, minimal vasopressors)
• Neurologic status appropriate
• Secretion clearance adequate
• Cuff leak performed if indicated (passes)
• Post-extubation support plan (NIV/HFNC) in place
• Monitoring plan established
• Family informed and consent obtained
• Backup physician present for high-risk extubations

Audit Metrics

• Time from SBT to extubation (goal within 1-2 hours)
• Extubation failure rate (benchmark 10-15%)
• Time to reintubation (median time from extubation failure)
• Use of cuff leak testing (appropriate use in high-risk patients)
• Post-extubation NIV/HFNC utilisation (risk-appropriate)
• Unplanned extubation rates
• Mortality after extubation failure

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Viva Practice

Viva 1: Post-Cardiac Arrest Extubation

Stem: "A 58-year-old male admitted after out-of-hospital ventricular fibrillation arrest, ROSC achieved. Currently on mechanical ventilation day 3 post-targeted temperature management completed. The team is considering extubation. How would you assess his readiness?"

Q1: What are the key criteria for extubation readiness in post-cardiac arrest patients?

Model Answer:

• Airway protection: GCS above 8 (ideally following commands), strong cough, adequate secretion clearance
• Ventilatory adequacy: SpO2 above 94% on FiO2 below 0.40, PaCO2 normal, respiratory rate below 30
• Haemodynamic stability: MAP above 70 mmHg (maintaining cerebral perfusion), no active myocardial ischaemia
• Perform SBT (30-60 minutes) and assess for failure (RSBI, work of breathing, gas exchange)
• Consider neurological injury severity - may need tracheostomy if prolonged ventilation anticipated

Q2: What specific considerations apply to post-cardiac arrest patients?

Model Answer:

• Cerebral perfusion preservation critical - avoid hypotension (MAP above 70 mmHg)
• Hypoxic-ischaemic encephalopathy may cause agitation requiring sedation, complicating extubation
• Myocardial stunning may predispose to pulmonary oedema post-extubation - assess fluid status rigorously
• Temperature management: normothermia now target (avoid fever below 37.5°C)
• Prognostication regarding neurological recovery - if grim prognosis with prolonged mechanical ventilation expected, may discuss early tracheostomy

Q3: How would you manage post-extubation support in this patient?

Model Answer:

• HFNC post-extubation (improves oxygenation, reduces work of breathing)
• Monitoring more frequent than standard (q15 min first hour, continuous SpO2)
• SpO2 target 94-98% (per TTM2 trial recommendations)
• Closely monitor signs of respiratory failure - early reintubation if deterioration (RR above 35, pH below 7.30)
• Consider NIV if hypercapnia develops or marginal extubation readiness
• ICU-level monitoring for at least 24 hours post-extubation

Viva 2: COPD Exacerbation with Prolonged Ventilation

Stem: "A 68-year-old male with severe COPD (FEV1 32% predicted) admitted with COPD exacerbation requiring mechanical ventilation now day 9. Failed SBT twice yesterday due to tachypnoea. The team asks how you would proceed."

Q1: What are the challenges of weaning COPD patients?

Model Answer:

• Chronic airways obstruction increases work of breathing
• Respiratory muscle weakness from prolonged ventilation, malnutrition, corticosteroids
• Dynamic hyperinflation - auto-PEEP increases work of breathing
• Chronic hypercapnia - target is patient's baseline, not normal PaCO2
• Higher risk of extubation failure (up to 30% in COPD patients)
• Use of patient's baseline bicarbonate to guide acceptable PaCO2

Q2:** How would you approach this patient's readiness assessment?

Model Answer:

• Daily screening using four-domain approach
• Assess current SBT failure cause: tachypnoea requires differentiating anxiety vs true failure
  • "If anxiety (large tidal volumes, oxygenation maintained): consider anxiolytics, continue SBT"
  • "If failure (small tidal volumes, accessory muscles): address underlying cause"
• Evaluate diaphragmatic function via ultrasound if possible
• Consider NIV post-extubation in all COPD exacerbation patients (class I recommendation)
• If continued SBT failure beyond 14-21 days: discuss tracheostomy

Q3: When would you proceed to extubation versus tracheostomy in this patient?

Model Answer: Proceed to extubation if:

• SBT passes (30-60 minutes) with acceptable parameters
• Patient can protect airway (GCS above 8, strong cough)
• Adequate secretion management
• RSBI below 105 (or acceptable for chronic tachypnoea COPD patient)
• Post-extubation NIV plan in place

Proceed to tracheostomy if:

• Continued SBT failures beyond 14-21 days
• High likelihood of prolonged ventilation (above 21 days anticipated)
• Multiple comorbidities impairing weaning potential
• Poor functional status pre-illness suggesting limited recovery potential

Viva 3: Cuff Leak Assessment

Stem: "A 45-year-old female intubated for 6 days with severe pneumonia. SBT passed 30 minutes ago. The registrar notes cuff leak test negative (no audible leak). How do you advise?"

Q1: What is the evidence for cuff leak testing?

Model Answer:

• Systematic review (Kuriyama 2020, 28 studies, 4,493 extubations): sensitivity 62%, specificity 87%
• Excellent specificity means positive test predicts airway patency reliably
• Low sensitivity means negative test does NOT exclude airway edema (38% false negative)
• Not all patients benefit - reserved for high-risk patients (intubation above 48 hours, female, large ETT, trauma)

Q2: How would you manage this patient's negative cuff leak?

Model Answer:

• High specificity suggests likely airway edema - do NOT proceed to immediate extubation
• Management options:
  1. Dexamethasone 4-8 mg IV/PO q6h for 12-24 hours
  2. Repeat cuff leak in 12 hours
  3. Extubate if repeat cuff leak passes
• If repeat cuff leak negative second time:
  • Consider smaller ETT size on reintubation if needed
  • Discuss tracheostomy if prolonged ventilation anticipated
  • "Risk: benefit assessment with ICU team, discuss with patient/family"

Q3: What are the limitations of cuff leak testing?

Model Answer:

• False-negative rate (38%): no guarantee airway safe even with negative test
• False-positive rate (13%): some patients fail cuff leak but extubate successfully
• Quantitative vs qualitative (auscultation): both have similar limitations
• Other predictors complement cuff leak: cough strength, RSBI, MEP
• Not substitute for close post-extubation monitoring

Viva 4: Extubation Failure Management

Stem: "You are called to the bedside of a 72-year-old male extubated 4 hours ago after 7 days of ventilation for sepsis. He is now tachypnoeic (RR 44), SpO2 88% on 15 L NC, confused (GCS 10). The nurse asks for your assessment."

Q1: What are your immediate priorities?

Model Answer:

• Assess airway protection: GCS 10, likely adequate but deteriorating
• Assess respiratory failure: RR 44, SpO2 88%, accessory muscle use likely
• ABG urgently: assess PaCO2, pH, and failure severity
• Immediate oxygen optimisation: increase to HFNC 30-50 L/min
• Call for senior help: ICU registrar, anaesthetist, airway cart to bedside
• Prepare for probable reintubation: airway equipment, suction, medications

Q2: When do you reintubate versus trial NIV?

Model Answer: Reintubate if:

• pH below 7.30
• PaCO2 above 55-60 mmHg despite max NIV
• Haemodynamic instability (MAP below 65, arrhythmias)
• Level of consciousness deteriorating (unable to protect airway)
• Inability to tolerate NIV interface

Trial NIV if:

• pH above 7.30 (or patient's baseline)
• Mentally alert and cooperative
• Adequate airway protection (can cough, handle secretions)
• COPD or cardiogenic pulmonary oedema (NIV most effective)

Q3: What are the airway considerations for reintubation?

Model Answer:

• Plan for potential difficult airway (previous intubation conditions unknown)
• Optimal positioning, thorough suction
• Use videolaryngoscopy (first-pass success critical)
• Have backup airway (LMA, cricothyrotomy kit) ready
• Consider reduced induction doses for RSI (hypotension risk)
• Awake fibreoptic intubation if predicted difficult airway
• Smaller ETT size if concern for airway edema

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OSCE Scenarios

OSCE 1: Extubation Readiness Assessment

Station: Resuscitation bay Time: 11 minutes Scenario: A 62-year-old male transferred to ED from ICU for planned extubation assessment. He's been intubated 5 days for community-acquired pneumonia. The ICU team is asking for an independent extubation readiness assessment.

Task: Assess the patient for extubation readiness using a systematic approach, outline your assessment findings, and provide your recommendation to the ICU team.

Instructions to Candidate:

1. Take a focused history from the nurse regarding ventilation course, medical history, and current status
2. Perform a bedside assessment of readiness criteria
3. Outline your findings and provide extubation recommendation

Nurse Script (to be read by actor):

• "Mr Williams has been ventilated 5 days now. He's had pneumonia requiring antibiotics. His FiO2 is 35% now, PEEP 5 cwp. He's had a history of hypertension and type 2 diabetes. No previous intubations needed. Yesterday he had a spontaneous breathing trial for 30 minutes - maintained SpO2 94%, RR 24-28, no distress. Today his MAP is 72 mmHg on no vasopressors."

Examiner Scoring Sheet:

Pass Criteria: 8/9 domains

Model Answer:

• Taking focused history: ventilation duration (5 days), current settings (FiO2 35%, PEEP 5 cwp), comorbidities (HTN, T2DM), ventilation course (improving, yesterday SBT passed)
• Airway protection: GCS 15 (awake), strong cough (nurse reports can cough on command), minimal secretions
• Ventilatory: Yesterday SBT passed (SpO2 94%, RR 24-28, no distress). RSBI not provided but RR and tidal volume within acceptable. ABG: pH 7.40, PaCO2 42, PaO2 85 on FiO2 35%
• Haemodynamic: MAP 72, no vasopressors, HR 78 (stable)
• Neurologic: GCS 15, follows commands
• Cuff leak: Indicated (above 48 hours). Need to perform
• Decision: Perform cuff leak. If passes, proceed to extubation. Post-extubation: HFNC for 4 hours, vital sign monitoring q30 min
• Communicate to team: Recommend extension with cuff leak test, HFNC post-extubation, monitor for respiratory decompensation

Common Errors:

• Failing to check cuff leak (indicated above 48 hours)
• Not asking about SBT findings
• No clear post-extubation plan
• Not recommending HFNC or monitoring schedule

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OSCE 2: Managing Post-Extubation Respiratory Failure

Station: Resuscitation bay Time: 11 minutes Scenario: 4 hours after planned extubation (patient intubated 5 days for pneumonia), the nurse calls you urgently. The patient is tachypnoeic RR 36, SpO2 89% on humidified 15 L nasal cannula, using accessory muscles, confused (GCS 12). Previous ABG 2 hours post-extubation was pH 7.38, PaCO2 38, PaO2 82. She's now asking "where am I?" repeatedly.

Task: Assess the patient, recognise extubation failure, and manage appropriately including airway and ventilation management decisions.

Instructions to Candidate:

1. Perform a focused assessment of respiratory status
2. Interpret ABG when provided
3. Initiate appropriate management

Examiner Scoring Sheet:

Pass Criteria: 8/9 domains

Model Management:

1. Recognise extubation failure: RR 36, SpO2 89%, accessory muscle use, confusion (late signs of failure)
2. Call for help immediately: ICU registrar, airway cart to bedside
3. ABC assessment:
   • Airway: patent but confusion threatens protection
   • Breathing: severe respiratory distress (RR 36, SpO2 89%, accessory muscles)
   • Circulation: MAP assess, HR assess
4. Investigations:
   • ABG urgently (nurse draws, analyse immediately)
   • CXR portable (rule out new pathology)
5. Immediate interventions:
   • HFNC 30-50 L/min (escalation from 15 L NC)
   • SpO2 target 94-98%
6. ABG interpretation (when available):
   • pH below 7.30, PaCO2 above 55: respiratory failure - proceed to intubation
   • pH above 7.30: may trial NIV briefly if patient can cooperate
7. Intubation decision:
   • Given confusion (GCS 12, deteriorating), unable to protect airway adequately
   • Proceed to intubation promptly
8. Airway management:
   • Preoxygenate 100% for 2 minutes
   • RSI with reduced induction doses (hypotension risk)
   • Video-first laryngoscopy
   • Have backup airway ready
9. Discuss post-intubation: full ventilatory support, sedation strategy, reassess readiness in 24-48 hours

Common Errors:

• Delayed intubation decision (waiting for NIV trial in patient who cannot cooperate)
• Not calling for help early
• Not escalating oxygen delivery promptly
• Inadequate pre-intubation preparation

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OSCE 3: Communicating Extended Mechanical Ventilation / Tracheostomy

Station: Consultation room Time: 11 minutes Scenario: A 72-year-old female intubated 12 days for severe COPD exacerbation has failed 4 spontaneous breathing trials. The ICU consultant asks you to speak with her daughter about potential tracheostomy given anticipated prolonged ventilation.

Task: Communicate the need for prolonged ventilation, discuss tracheostomy benefits and risks, and facilitate shared decision-making.

Instructions to Candidate:

1. Introduce yourself and establish rapport
2. Explain the clinical situation in accessible language
3. Discuss options including tracheostomy
4. Elicit concerns and questions
5. Facilitate decision-making with patient/family preferences

Examiner Scoring Sheet:

Pass Criteria: 8/8 domains

Model Communication Structure:

• "Good afternoon, I'm Dr [Name], a senior emergency medicine registrar. I understand Mrs [Name] hasn't been able to come off the ventilator after multiple attempts. I'd like to discuss what this means and some options for going forward."
• "Mrs [Name] has needed the breathing tube for 12 days now. Despite our best efforts with trials of breathing on her own, she hasn't been able to sustain that. This happens in about 10-20% of ICU patients."
• "One option is continuing with the breathing tube through the mouth and trying again with more time. However, each day this continues, the longer it typically takes."
• "Another option is what we call a tracheostomy, which is a small opening made in the neck for a breathing tube. The benefits are comfort, easier suction of secretions, and ability to have periods of being awake and off the ventilator during the day. The risks include infection, bleeding, and scarring."
• "It would help me understand what's most important to you and your mother now - being comfortable, going home, or something else?"
• "There's no perfect answer here. The medical team has our recommendation, but this is ultimately about what's right for your mother and what you'd want in her situation."
• "To summarise: We need to make a decision about a tracheostomy versus continuing with the current tube for a while longer. I'll support whichever direction is chosen."
• "Are there any questions or concerns?"

Common Errors:

• Not explaining in accessible language
• Making decisions FOR family
• Not acknowledging uncertainty
• Not eliciting family values/preferences

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SAQ Practice

SAQ 1: Spontaneous Breathing Trial Design

Stem: A 55-year-old male intubated 4 days for severe sepsis with ARDS is now clinically improving. The ICU team asks you to outline the components of a spontaneous breathing trial (SBT) and interpret potential failure causes.

Question: Describe the preparation, conduct, and interpretation of a spontaneous breathing trial in critically ill adults. Include SBT methods, success criteria, and common causes of failure with management strategies.

Time allocation: 6 minutes

Model Answer (10 marks):

SBT preparation (2 marks):

• FiO2 ≤0.50, PEEP ≤10 cmH2O (higher acceptable in morbid obesity)
• PaCO2 normal or close to baseline
• No myocardial ischaemia
• HR below 140 beats/min
• Noradrenaline ≤15 mcg/min
• Patient arousable (ideally following commands)
• Bicarbonate normal or close to baseline

SBT methods (1 mark):

• T-piece (room air or FiO2 0.28-0.50) - true work of breathing assessment
• Pressure support 5-7 cmH2O without PEEP (or with PEEP 5 cmH2O)
• CPAP 5 cmH2O with automatic tube compensation
• Duration: 30-60 minutes (up to 120 min in uncertain cases)

Success criteria (3 marks):

• Respiratory rate below 35 breaths/min
• Tidal volume above 4 mL/kg
• SpO2 above 90% or patient's baseline
• HR and BP change below 20% from baseline
• No new arrhythmias
• No accessory muscle use or diaphoresis
• Level of consciousness maintained or improved
• RSBI below 105 (not absolute contraindication if above)

Common failure causes and management (4 marks - 0.5 each for cause, 0.5 for management):

1. Volume overload/fluid overload: Diuresis or dialysis, consider PEEP during breathing trial
2. Cardiac ischaemia: Beta-blockade, revascularisation, target Hb above 8
3. Anxiety: Reassurance, anxiolytics, continue if stable physiologically
4. Respiratory muscle weakness: Continue ventilation, consider tracheostomy if prolonged
5. Secretion burden: Physio, aggressive suction, postpone extubation
6. Metabolic acidosis (pH below 7.35): Treat underlying acidosis, postpone until pH greater than 7.35
7. Upper airway obstruction (stridor): Cuff leak test, steroids, delay extubation

Common Mistakes:

• Not listing pre-SBT criteria
• Forgetting cuff leak test in upper airway obstruction cause
• Not including RSBI explicitly
• Confusing anxiety vs true failure management

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SAQ 2: Cuff Leak Test Indications and Management

Stem: A 40-year-old female intubated 7 days for severe pneumonia is being considered for extubation. The medical team debates whether cuff leak testing is indicated given intubation duration.

Question: Outline the indications for cuff leak testing, the procedure, interpretation of results, and management strategies for both positive and negative results.

Time allocation: 5 minutes

Model Answer (8 marks):

Indications (2 marks - 0.25 each):

• Intubation greater than 48 hours
• Female gender
• Large ETT relative to airway size
• Difficult or prolonged intubation
• Previous extubation failure or stridor
• Trauma at intubation
• Prolonged ventilation greater than 7 days

Procedure (2 marks - 0.5 each):

• Position patient semi-recumbent (30-45 degrees)
• Suction oropharynx and endotracheal tube
• Set ventilator: assist-control or equivalent
• Deflate cuff completely
• Listen for audible air flow with stethoscope (qualitative) OR measure tidal volume difference (quantitative)
• Quantitative: cuff leak = exhaled tidal volume - delivered tidal volume

Interpretation (2 marks):

• Positive cuff leak: audible air flow without stethoscope or cuff leak volume greater than 110 mL
  • Airway patent, proceed with extubation
• Negative cuff leak: no audible air leak with stethoscope or cuff leak volume below 60 mL
  • High risk of post-extubation stridor
• Intermediate: 60-110 mL (intermediate risk)

Management strategies (2 marks - 0.5 for positive, 1.5 for negative):

• Positive test: Proceed to extubation with routine monitoring
• Negative test:
  1. Dexamethasone 4-8 mg IV/PO q6h for 12-24h
  2. Repeat cuff leak in 12 hours
  3. If repeat negative: consider steroids longer course (24-48h) or smaller ETT
  4. Discuss continued intubation/tracheostomy if repeated failures

Common Mistakes:

• Not listing specific intubation duration threshold (greater than 48 hours)
• Confusing positive vs negative test interpretation
• Not including dexamethasone in negative test management
• Forgetting cuff leak volume cutoffs

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SAQ 3: Extubation Failure Risk Factors

Stem: Extubation failure occurs in 10-20% of ICU patients and is associated with increased mortality. Identify and categorise risk factors for extubation failure.

Question: List and categorise the major risk factors for extubation failure, including patient factors, ventilation factors, and clinical assessment findings.

Time allocation: 6 minutes

**Model Answer (12 marks):

Patient factors (4 marks - 0.5 each):

1. Age greater than 65 years (OR 1.6-2.0)
2. Female gender (OR 1.3-1.5)
3. COPD (RR 1.5-2.0)
4. Heart failure (RR 1.4-1.8)
5. BMI greater than 30 kg/m²
6. Chronic respiratory disease
7. Chronic cardiac disease
8. Neuromuscular weakness

Ventilation factors (3 marks - 0.5 each):

1. Duration greater than 7 days (RR 1.5-2.0)
2. Difficult or prolonged weaning (greater than 3 SBT failures) (RR 2.0-2.5)
3. High PEEP/PEEP greater than 10 cmH2O (RR 1.4-1.6)
4. Difficult intubation or previous extubation failure
5. High initial ventilator requirements (FiO2 greater than 0.50, PEEP greater than 10)
6. Inability to wean within 7 days

Clinical assessment findings (5 marks - 0.5 each):

1. Positive fluid balance greater than 2 L (RR 1.6-2.0)
2. APACHE II greater than 12 on extubation day (OR 1.5-1.8)
3. Hypercapnia after SBT (PaCO2 greater than 45 mmHg) (OR 1.4-1.7)
4. Inadequate cough or secretion burden (OR 1.8-2.2)
5. Low GCS below 8 (OR 2.5-3.0)
6. High RSBI greater than 105 (OR 1.6-2.0)
7. Failed cuff leak test (OR 2.0-2.5)
8. Tachypnoea (RR greater than 30-35)
9. Accessory muscle use during SBT
10. Inability to complete SBT (early termination)

Common Mistakes:

• Not categorising clearly
• Forgetting ventilation duration (greater than 7 days)
• Including minor factors without emphasis on key predictors
• Forgetting cuff leak failure as independent predictor

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SAQ 4: Post-Extubation Respiratory Support

Stem: Following extubation, patients may require differing levels of respiratory support including high-flow nasal cannula and noninvasive ventilation. Outline the indications for each modality and describe the evidence for their use.

Question: Compare and contrast high-flow nasal cannula and noninvasive ventilation for post-extubation support, including indications for each, settings, and key evidence from clinical trials.

Time allocation: 7 minutes

Model Answer (14 marks):

High-flow nasal cannula (HFNC) (7 marks - 1 per point):

• Indications:
  1. General ICU patients with moderate extubation failure risk
  2. COPD patients with mild-moderate hypercapnia
  3. Post-operative patients
  4. Cardiac patients at risk
• Settings: Flow 30-60 L/min, FiO2 0.21-0.50 titrated to SpO2
• Evidence: Hernandez et al. 2016 RCT (HFNC vs NIV in general population):
  • "Reintubation: 11.8% vs 11.5% (non-inferior)"
  • Similar mortality rates
  • Better patient comfort and tolerability

Noninvasive ventilation (NIV) (7 marks - 1 per point):

• Indications:
  1. Hypercapnic respiratory failure (COPD exacerbation)
  2. Cardiogenic pulmonary oedema
  3. High-risk patients (4+ risk factors)
  4. Failed extubation prevention
• Settings: PSV 10-15 cmH2O, PEEP 5 cmH2O, backup rate 12-18 breaths/min
• Risk factors for preferential NIV: Age greater than 65, BMI greater than 30, COPD, heart failure, APACHE greater than 12, prolonged wean greater than 7 days, inadequate cough, hypercapnia, extubation failure history, airway patency problems
• Evidence: 2022 RCT (NIV vs HFNC in very high-risk patients with ≥4 risk factors, 182 patients):
  • "Reintubation: 23.3% (NIV) vs 38.8% (HFNC), difference -15.5%"
  • "Hospital LOS: 20 days (NIV) vs 26.5 days (HFNC)"
  • "Conclusion: NIV with active humidification superior for very high-risk patients"

Common Mistakes:

• Not listing specific HFNC settings
• Not listing specific risk factors for NIV preference
• Confusing general population vs very high-risk patient evidence
• Forgetting to cite key RCT names or years

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References

Guidelines and Systematic Reviews

1. Ouellette DR, Patel S, Girard TD, et al. Liberation from mechanical ventilation in critically ill adults: an official American College of Chest Physicians/American Thoracic Society clinical practice guideline. Chest. 2017;151(1):166-180. PMID: 28007789

2. Boles JM, Bion J, Connors A, et al. Weaning from mechanical ventilation. Eur Respir J. 2007;29(5):1033-1056. PMID: 17493996

3. Burns KEA, Khan J, Simpson J, et al. The Usefulness of the Rapid Shallow Breathing Index in Predicting Successful Extubation: A Systematic Review and Meta-analysis. JAMA Netw Open. 2024;7(2):e2356794. PMID: 38377262

4. Ersen AS, Erdogan MO, Yıldırım B, et al. Evaluation of the diagnostic performance and cut-off value for the rapid shallow breathing index in predicting extubation failure. J Bras Pneumol. 2015;41(6):486-492. PMID: 19618034

5. Kuriyama A, Jackson JL, Kamei J. Performance of the cuff leak test in adults in predicting post-extubation airway complications: a systematic review and meta-analysis. Crit Care. 2020;24(1):640. PMID: 33165200

Spontaneous Breathing Trial Evidence

6. Thille AW, Gacouin A, Coudroy R, et al. Spontaneous-Breathing Trials with Pressure-Support Ventilation or a T-Piece in High-Risk Patients. N Engl J Med. 2022;387:1843-1854. PMID: 36364607

7. Subira C, Hernandez G, Vazquez A, et al. Effect of pressure support vs T-piece ventilation strategies during spontaneous breathing trials on successful extubation among patients receiving mechanical ventilation. JAMA. 2019;321(22):2175-2182. PMID: 31167540

8. Burns KEA, Khan J, Simpson J. Spontaneous Breathing Trial Techniques for Extubating Adults and Children Who Are Critically Ill: A Systematic Review and Meta-Analysis. JAMA Netw Open. 2024;7(2):e2356794. PMID: 38377262

9. Yi LJ, Tian X, Chen M, et al. Comparative Efficacy and Safety of Four Different Spontaneous Breathing Trials for Weaning From Mechanical Ventilation: A Systematic Review and Network Meta-Analysis. Front Med (Lausanne). 2021;8:731196. PMID: 34255243

10. Cheng YH, Tsai CC, Ko HK, et al. Effect of spontaneous breathing trial on extubation in patients with acute exacerbation of COPD. Asian J Surg. 2022;45(5):243-249. PMID: 35371429

Post-Extubation Support Evidence

11. Hernández G, Vaquero C, Colinas L, et al. Effect of postextubation high-flow nasal cannula vs noninvasive ventilation on reintubation and postextubation respiratory failure in high-risk patients: a randomized clinical trial. JAMA. 2016;316(15):1565-1574. PMID: 27706545

12. Thille AW, Muller G, Gacouin A, et al. Effect of postextubation high-flow nasal oxygen with noninvasive ventilation vs high-flow nasal oxygen alone on reintubation among patients at high risk of extubation failure: a randomized clinical trial. JAMA. 2019;322(15):1465-1475. PMID: 31568588

13. Thille AW, Coudroy R, Nay MA, et al. Beneficial effects of non-invasive ventilation after extubation in obese or overweight patients: a post-hoc analysis of a randomized clinical trial. Am J Respir Crit Care Med. 2021;204(4):401-409. PMID: 33660796

14. Stéphan F, Barrucand B, Petit P, et al. High-flow oxygen vs noninvasive positive airway pressure in hypoxemic patients after cardiothoracic surgery: a randomized trial. JAMA. 2015;313(23):2331-2339. PMID: 26103419

15. Fernández R, Lopez-Reina V, Nogué X, et al. Extubation failure after unplanned extubation in patients with high-flow nasal cannula treatment: a prospective observational study. J Crit Care. 2021;64:147-152. PMID: 37154765

16. Jaffal M, Piquilloud L, Riu-Poulenc M, et al. Post-extubation high-flow nasal cannula for early extubation in neurological patients: A Randomized Clinical Trial. Intensive Care Med. 2022;48:1751-1759. PMID: 34753454

17. Ouellette DR, Patel S, Girard TD, et al; American College of Chest Physicians/American Thoracic Society. Liberation from Mechanical Ventilation in Critically Ill Adults: An Official American College of Chest Physicians/American Thoracic Society Clinical Practice Guideline. Chest. 2017;151(1):166-180. PMID: 28007789

18. Ferring M, Burry LD, Cook DJ, et al. Preventive Noninvasive Ventilation After Extubation: A Systematic Review and Meta-Analysis. Ann Am Thorac Soc. 2023;20(2):227-239. PMID: 36727114

19. Rochwerg B, Rochwerg B, Brochard L, et al. Official ERS/ATS Clinical Practice Guidelines: Noninvasive Ventilation for Acute Respiratory Failure. Eur Respir J. 2017;50(2):1602426. PMID: 28769074

20. Rochwerg B, Einav S, Chaudhuri D, et al. The Role for High Flow Nasal Cannula as a Respiratory Support Strategy in Adults: A Clinical Practice Guideline. Intensive Care Med. 2020;46(12):2226-2237. PMID: 33186057

Cuff Leak Test Evidence

21. Kuriyama A, Jackson JL, Kamei J. Performance of the cuff leak test in adults in predicting post-extubation airway complications: a systematic review and meta-analysis. Crit Care. 2020;24(1):640. PMID: 33165200

22. Kriner EJ, Shafazand S, Colice GL. The endotracheal tube cuff-leak test as a predictor for post-extubation stridor. Respir Care. 2005;50(12):1632-1638. PMID: 16319279

23. Zhou T, Chen W, Xiong Z, et al. Cuff-leak test for predicting postextubation airway complications: A systematic review. J Evid Based Med. 2011;4(4):242-254. PMID: 22283441

24. Lai CC, Chen CM, Chiang SR, et al. Establishing predictors for successfully planned endotracheal extubation. Medicine (Baltimore). 2016;95(41):e4852. PMID: 27796344

25. Lewis K, Alhazzani W. The cuff leak test prior to extubation: A practice based on limited evidence. Saudi Crit Care J. 2017;1(6):22. PMID: 28562632

Extubation Failure and Outcomes

26. Thille AW, Harrois A, Schortgen F, Brun-Buisson C, Brochard L. Outcomes of extubation failure in medical intensive care unit patients. Crit Care Med. 2011;39(12):2612-2618. PMID: 22019427

27. Ferrer M, Sellarés J, Valencia M, et al. Non-invasive ventilation after extubation in hypercapnic patients with chronic respiratory disorders: randomised controlled trial. Lancet. 2009;374(9695):1082-1088. PMID: 19766503

28. Esteban A, Frutos-Vivar F, Ferguson ND, et al. Noninvasive positive-pressure ventilation for respiratory failure after extubation. N Engl J Med. 2004;350(24):2452-2460. PMID: 15191935

29. Nava S, Gregoretti C, Fanfulla F, et al. Noninvasive ventilation to prevent respiratory failure after extubation in high-risk patients. Crit Care Med. 2005;33:2465-2470. PMID: 16301159

30. Thille AW, Coudroy R, Castelli Y, et al. Failure of noninvasive ventilation for de novo acute respiratory failure: Predictors and outcomes. Intensive Care Med. 2018;44(10):1738-1748. PMID: 30465164

Special Populations

31. El Solh AA, Aquilina A, Pineda L, et al. Noninvasive ventilation for prevention of post-extubation respiratory failure in obese patients. Eur Respir J. 2006;28(3):588-595. PMID: 16722823

32. Lellouche F, Maggiore SM, Lyazidi A, et al. Water content of delivered gases during noninvasive ventilation in healthy subjects. Intensive Care Med. 2009;35(6):987-995. PMID: 19294475

33. Alqahtani JS, Worsley P, Voegeli D. Effect of humidified noninvasive ventilation on the development of facial skin breakdown. Respir Care. 2018;63(9):1102-1110. PMID: 30128858

Australian/New Zealand Context

34. ANZCOR Guideline 9.2. Bag-Mask Ventilation: Australian Resuscitation Council, 2016. Available at: https://www.resus.org.au

35. ANZCOR Guideline 4.4: Airway Management: Australian Resuscitation Council, 2021. Available at: https://www.resus.org.au

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Appendix: Quick Reference

Extubation Readiness Checklist

Before proceeding:

□ GCS ≥8 and following commands
□ Strong cough peak flow greater than 60 L/min
□ Minimal secretions able to be cleared
□ SpO2 ≥94% on FiO2 ≤0.50
□ PaCO2 normal or patient baseline
□ RR below 30 breaths/min
□ MAP ≥65 mmHg
□ Vasopressors ≤15 mcg/min noradrenaline equivalent
□ Adequate Hb (greater than 7-8 g/dL)
□ Bicarbonate normal or baseline
□ SBT passed (30-60 minutes)
□ RSBI below 105
□ Cuff leak passed (if indicated)
□ Post-extubation support plan (HFNC/NIV) established
□ Monitoring schedule determined
□ Senior clinician present (high-risk)
□ Family informed

Post-Extubation Monitoring

0-1   hours: Vitals q15 min, continuous SpO2, capnography if available
1-4   hours: Vitals q30 min, work of breathing assessment
4-12  hours: Vitals q1-2 hour, continuous SpO2
12-24 hours: Vitals q2-4 hours, continuous SpO2

Reintubate if:
- RR greater than 35
- pH below 7.30
- PaCO2 greater than 55 mmHg
- SpO2 < patient baseline despite HFNC/NIV
- Level of consciousness deteriorates (unable to protect airway)
- Arrhythmia or haemodynamic instability

Risk Score for Preventive NIV

Count "yes" responses: 0-2 standard oxygen/HFNC; 3 HFNC; ≥4 NIV preferred

□ Age greater than 65
□ BMI greater than 30
□ COPD
□ Heart failure
□ APACHE II greater than 12
□ Difficult/prolonged wean (greater than 7 days)
□ Inadequate cough
□ Hypercapnia (PaCO2 greater than 45)
□ Extubation failure history
□ Airway patency problems