ECMO/ECPR

Quick Answer

Extracorporeal Membrane Oxygenation (ECMO) is a modified heart-lung machine providing temporary cardiopulmonary support for reversible respiratory or cardiac failure. Two main types: Veno-venous (VV) for respiratory failure, Veno-arterial (VA) for cardiogenic shock or refractory cardiac arrest (ECPR). ECPR (Extracorporeal Cardiopulmonary Resuscitation) uses VA-ECMO during refractory cardiac arrest.

Key thresholds for ECMO:

• Refractory respiratory failure: PaO2/FiO2 below 80 despite optimal ventilation
• Refractory cardiac arrest: No ROSC after high-quality CPR ≥10 minutes with reversible cause
• Cardiogenic shock: Persistent hypotension despite ≥2 vasopressors, lactate ≥4 mmol/L

Time-critical: ECPR initiation within 60 minutes of arrest improves survival.

ACEM Exam Focus

FACEM examiners expect you to:

1. Distinguish ECMO types and indications (VV vs VA vs VAV)
2. Understand ECPR selection criteria and contraindications
3. Recognise complications (bleeding, thrombosis, limb ischemia, Harlequin syndrome)
4. Know Australian retrieval pathways (NSW ECLS, VECMOS, EXCEL registry)
5. Apply ELSO guidelines for anticoagulation and management
6. Demonstrate knowledge of LV unloading strategies in VA-ECMO
7. Understand Indigenous health considerations in remote areas (access, cultural safety)

Common exam questions:

• ECPR patient selection - who is suitable?
• VA-ECMO complications and management
• Harlequin syndrome recognition and treatment
• Indigenous patient considerations for ECMO retrieval

Key Points

• ECMO is NOT first-line for cardiac arrest; ECPR requires ECMO centre proximity and systems-based care
• VV-ECMO supports oxygenation without hemodynamic support; VA-ECMO provides both
• ECPR outcomes: 20-40% survival to discharge in carefully selected patients
• Anticoagulation typically with heparin (ACT 180-220 or aPTT 60-80); bivalirudin for HIT
• Femoral cannulation risks limb ischemia (13-21%); distal perfusion cannula recommended
• Harlequin syndrome: Differential oxygenation with VA-ECMO if native LV recovery
• Australian ECMO centres: NSW ECLS (RPA, St Vincent's), VECMOS (Alfred, Austin, Box Hill), Qld (Prince Charles)
• Retrieval services: NSW ECLS retrieval 24/7, VECMOS via ARV
• EXCEL registry monitors national ECMO outcomes
• Remote/rural areas: Longer transport times impact ECPR eligibility

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Clinical Overview

Definition

ECMO (Extracorporeal Membrane Oxygenation): Modified heart-lung machine providing temporary cardiopulmonary support when conventional therapy fails. Blood drained from venous system passes through an oxygenator (adds oxygen, removes CO2) and is returned to patient.

ECPR (Extracorporeal Cardiopulmonary Resuscitation): VA-ECMO initiated during refractory cardiac arrest to restore circulation while treating reversible cause.

Indications

VV-ECMO:

• Severe ARDS with PaO2/FiO2 below 80
• Refractory hypoxaemia despite optimal ventilation
• PaCO2 ≥60 mmHg with respiratory acidosis
• Lung-protective ventilation intolerance (plateau ≥30 cmH2O)

VA-ECMO:

• Refractory cardiogenic shock (persistent hypotension despite ≥2 vasopressors, lactate ≥4 mmol/L)
• Acute myocardial infarction with mechanical complications
• Post-cardiotomy shock
• ECPR for refractory cardiac arrest (see below)

ECPR Criteria:

• Age 18-75 years
• Witnessed cardiac arrest
• High-quality CPR initiated within 10 minutes
• No ROSC after ≥10 minutes ACLS
• Reversible cause identified (MI, PE, hypothermia, poisoning)
• ECMO initiation achievable within 60 minutes of arrest
• No major comorbidities or severe neurological injury

Contraindications

Absolute:

• Severe irreversible neurological injury
• Advanced directives prohibiting invasive support
• Prolonged cardiac arrest greater than 60-90 minutes without ECMO
• Severe terminal illness with limited life expectancy
• Uncontrolled active bleeding

Relative:

• Advanced age (greater than 75 years)
• High-risk frailty
• Severe chronic lung disease (VV-ECMO)
• Significant comorbidities (end-stage renal failure, advanced malignancy)
• BMI greater than 35 kg/m² (cannulation challenges)

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ECMO Types and Cannulation

Veno-Venous (VV-ECMO)

Configuration:

• Drainage: Inferior vena cava via right femoral vein
• Return: Right atrium via right internal jugular or second femoral vein
• Blood flow: 3-5 L/min typical

Indications: Pure respiratory failure with preserved cardiac function

Cannulation sites:

1. Femoro-femoral: Right femoral drain, left femoral return
2. Jugulo-femoral: Right internal jugular return, right femoral drainage (often preferred for mobility)

Veno-Arterial (VA-ECMO)

Configuration:

• Drainage: Right femoral vein
• Return: Right femoral artery
• Blood flow: 3-6 L/min typical

Indications: Cardiogenic shock, cardiac arrest

Special configurations:

Hybrid (VAV)-ECMO:

• VV plus atrial return for combined cardiac/respiratory failure
• Allows transitioning from VA to VV

Peripheral vs Central Cannulation:

• Peripheral: Femoral percutaneous (most common ECMO in ED)
• Central: Sternotomy with direct atrial/aortic cannulation (cardiac surgery)

Cannulation Technique

Peripheral femoral cannulation (Seldinger technique):

1. Preparation: Ultrasound guidance, local anaesthesia
2. Venous cannula: 21-25 Fr (guided to right atrium)
3. Arterial cannula: 15-19 Fr (limited to distal common femoral)

Distal Perfusion Cannula (DPC):

• Recommended for VA-ECMO to prevent limb ischemia
• 6-8 Fr retrograde into superficial femoral artery

Confirmation:

• Chest X-ray for position
• Ultrasound confirmation of flow
• Transesophageal echocardiography for central cases

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Clinical Approach to ECMO Decision

ED Assessment

Step 1: Confirm ECMO Indication

VV-ECMO checklist:

• Refractory hypoxaemia (PaO2/FiO2 below 80)?
• Optimal ventilation: volume 4-6 mL/kg PBW, PEEP 10-15, plateau below 30?
• pH below 7.2 or PaCO2 above 60?
• Lung-protective ventilation limited?

VA-ECMO checklist:

• MAP below 65 despite ≥2 vasopressors?
• Lactate greater than 4 mmol/L?
• Echocardiogram: EF below 25%, severe mitral regurgitation, RV failure?
• Reversible cause?

ECPR checklist:

• Witnessed arrest?
• High-quality CPR ≥10 minutes without ROSC?
• ECMO within 60 minutes?
• No major comorbidities?

Step 2: Assess Contraindications

Screen for:

• Uncontrolled active bleeding
• Terminal illness/severe frailty
• Advanced neurological injury
• Advanced directives

Step 3: Contact ECMO Centre

NSW: NSW ECLS Retrieval Service (1300 number or referral portal)

Victoria: VECMOS / Adult Retrieval Victoria (ARV) (1300 368 661)

Step 4: Prepare for ECMO Initiation or Retrieval

While awaiting:

• Continue high-quality resuscitation
• Ensure vascular access
• Confirm blood products available
• Prepare anticoagulation

Investigation of ECMO Candidate

Immediate (ED/Urgent):

• ABG, electrolytes, lactate, glucose
• CBC, coagulation profile (PT, aPTT, fibrinogen)
• Troponin, BNP
• Chest X-ray
• ECG
• Point-of-care ultrasound (FAST, lung, cardiac)
• Blood cultures

Urgent (within 1 hour):

• CT chest (PE, ARDS pattern)
• Echo (transthoracic or transoesophageal)
• CT head if neurological concern
• Sputum, viral PCR (if respiratory failure)

Specialist tests:

• HIT antibodies if prior heparin exposure
• Type and screen (crossmatch)

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ECMO Management

Anticoagulation

Unfractionated Heparin (UFH):

• Loading: 50-100 U/kg bolus
• Infusion: 15-20 U/kg/hr
• Target:
  • "ACT: 180-220 seconds (standard)"
  • aPTT: 60-80 seconds
  • "Anti-Xa: 0.3-0.7 IU/mL"

Alternative agents:

• Bivalirudin: HIT, contraindication to heparin
  • "Start: 0.15 mg/kg/hr, adjust to aPTT 60-80"
  • "Advantage: Short half-life, no HIT risk"
• Argatroban: Alternative in HIT with renal failure

Monitoring:

• ACT every 1 hour (initially)
• aPTT or anti-Xa every 4-6 hours
• CBC, fibrinogen, D-dimer daily
• Circuit inspection for thrombosis

Ventilator Strategy (VV-ECMO)

Lung-protective ventilation:

• FiO2: 21-40% (target post-oxygenator saturation 88-92%)
• Tidal volume: 4 mL/kg PBW
• PEEP: 5-10 cmH2O
• Respiratory rate: 4-10 bpm
• Plateau pressure: ≤25 cmH2O
• Driving pressure: ≤15 cmH2O

Prone positioning: Consider every 12-24 hours if compatible

Vasoactive Support (VA-ECMO)

Target endpoints:

• MAP ≥65 mmHg
• ScvO2 ≥65%
• Cardiac index 2.2-3.0 L/min/m²
• Lactate clearance

Typical agents:

• Noradrenaline 0.05-0.5 mcg/kg/min
• Vasopressin 0.03 U/min (if required)
• Adrenaline infusion in refractory shock

Weaning from ECMO

VV-ECMO weaning criteria:

• FiO2 ≤40%, flow ≤2 L/min
• PaO2 ≥60 mmHg on 40% FiO2
• PaCO2 35-45 mmHg
• Low-level PEEP (5-10 cmH2O)
• Lung compliance improved

VA-ECMO weaning criteria:

• Cardiac index ≥2.2 L/min/m²
• EF ≥30-35%
• Lactate clearing
• MAP ≥65 without vasopressors
• Decreasing arrhythmias

Weaning trial:

• Sweep gas OFF
• Ventilator settings to near-standard
• Monitor for 1-2 hours
• Assess stability

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Complications

Bleeding (40-60% of patients)

Types:

• Cannula site bleeding
• Gastrointestinal
• Pulmonary
• Intracranial hemorrhage (worst prognosis)

Risk factors:

• Prolonged ECMO run
• High anticoagulation
• Thrombocytopenia
• Recent surgery/trauma

Management:

• Reduce ECMO flow (if possible)
• Decrease anticoagulation
• Blood product support (platelets, FFP, cryoprecipitate)
• Antifibrinolytics (tranexamic acid) consideration

Thrombosis (10-30%)

Oxygenator thrombosis:

• Rising transmembrane pressure
• Decreased gas exchange
• Visible clots

Circuit clot:

• Spinning down
• Dark blood in circuit

Management:

• Evaluate replacement
• Review anticoagulation
• Consider thrombolytics (rare)

Limb Ischemia (13-21% with peripheral VA-ECMO)

Prevention:

• DPC placement (distal perfusion cannula)
• Limb monitoring (pulse oximetry, NIRS)
• Doppler checks every 2-4 hours

Management of limb ischemia:

• Increase distal perfusion flow
• Vascular surgery consultation
• Fasciotomy if compartment syndrome
• Cannula repositioning

Harlequin Syndrome (North-South Syndrome)

Pathophysiology:

• VA-ECMO returns oxygenated blood via femoral artery retrograde to aorta
• Native LV ejects deoxygenated blood to coronary and cerebral vessels
• Upper body becomes hypoxic while lower body hyperoxygenated

Risk factors:

• Recovery of LV function
• High ECMO flow relative to native CO

Management:

• Reduce distal aortic pressure (reduce ECMO flow)
• Increase LV ejection (inotropes, balloon pump)
• Consider Impella or IABP for LV unloading
• Switch to central VA-ECMO

Infection (15-30%)

• Cannula site infections
• Bloodstream infections (circuit-related)
• Pneumonia (ventilator-associated)

Renal Failure

• Acute kidney injury in 50-70%
• CRRT often integrated into circuit

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ECPR Specific Considerations

ECPR Pathway

1. Rapid Assessment:

• Witnessed arrest?
• Witness time to EMS arrival below 5 min?
• High-quality CPR initiated?
• No ROSC after ≥10 min ACLS?

2. Contact ECMO Centre:

• NSW ECLS or VECMOS
• Provide update on situation

3. Initiation:

• Emergency femoral cannulation
• ECMO primed on-site or during transport
• Target: ECMO flow established within 60 min

4. Post-ECPR:

• Targeted temperature management 36°C (based on TTM2)
• Identify/treat underlying cause
• Neurological monitoring (EEG if prolonged arrest)

ECPR Outcomes

• Survival to discharge: 20-40% in selected patients
• Good neurological outcome (CPC 1-2): 15-30%
• Factors associated with survival:
  • Short low-flow time (below 30 min)
  • Initial rhythm shockable (VF/VT)
  • Younger age (below 65)
  • Witnessed arrest

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Australian ECMO Services

NSW ECLS (NSW)

Centres:

• Royal Prince Alfred Hospital (RPA)
• St Vincent's Hospital (SVH)

Retrieval service:

• 24/7 coordinated service
• Alternating on-call roster (weekly)
• ECMO team deploys to referring hospitals
• Mobile ECMO trial (NSW Ambulance 2025)

Contact: NSW ECLS website shows on-call centre

Outcome: 68 patients in 2022, 2/3 VV-ECMO, 1/3 VA-ECMO

Victoria ECMO Service (VECMOS)

Centres:

• The Alfred Hospital (lead centre)
• Austin Health
• Box Hill Hospital

Retrieval:

• Adult Retrieval Victoria (ARV) coordinates
• 24/7 availability
• Complex ambulance capability for ECMO transport

Contact: 1300 368 661

Queensland

Centres:

• Prince Charles Hospital (Brisbane)
• Limited retrieval capability

EXCEL Registry

Purpose:

• National prospective ECMO registry
• Monitors outcomes
• Embedded clinical trials
• Quality improvement

Data collected:

• ECMO retrieval
• Patient selection
• Device and cannula details
• Daily data (first 7 days)
• Complications
• Long-term outcomes (6, 12 months)

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Indigenous Health Considerations

Access Barriers

• Geographic: Indigenous Australians more likely to reside in remote areas (rural/remote)
• Transport distance: ECMO centres are metropolitan; retrieval times impact ECPR eligibility
• Health literacy: Understanding of ECMO may be limited

Cultural Safety

Communication:

• Use plain language for ECMO explanation
• Avoid medical jargon ("heart-lung machine," "circulatory support")
• Allow family members/support persons during discussions

Decision-making:

• Respect family and community involvement
• Understand cultural protocols around end-of-life
• Involve Aboriginal Health Workers when available

Cultural Determinants

Holistic health:

• Consider physical, emotional, social, spiritual aspects
• Family and community wellbeing (not just patient)

Connection to Country:

• Retrieval disrupts connection; acknowledge loss

Mourning practices:

• If ECMO unsuccessful facilitate culturally appropriate processes

Outcome Disparities

• Indigenous patients have poorer outcomes across critical care
• Higher comorbidity burden (cardiovascular disease, diabetes)
• Later presentation may delay ECMO candidacy

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Remote and Rural Considerations

Retrieval Challenges

Transport times:

• Metropolitan to regional: 1-3 hours
• Remote communities: 3-6+ hours
• ECPR requires ≤60 minutes to ECMO initiation

Limitations:

• Fewer patients eligible for ECPR from remote areas
• VV-ECMO retrieval for respiratory failure more feasible

Resource Limitations

• Smaller hospitals lack ECMO expertise
• Limited blood product availability
• Difficulty maintaining circuit integrity during transport

Telemedicine

• Phone consultation with ECMO centre
• Video support for assessment
• Teleconferencing with family

Royal Flying Doctor Service (RFDS)

• Primary retrieval service for remote areas
• Limited ECMO capability
• Coordination with state ECMO services essential

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Viva Scenarios

Viva 1: ECPR Candidate Selection

Examiner: "A 45-year-old man collapses in the ED after running for a bus. Bystander CPR started. Paramedics arrive after 4 minutes with ongoing VF. ACLS provided for 15 minutes with no ROSC. Is he an ECPR candidate?"

Candidate response:

Yes, likely ECPR candidate. Key favorable factors:

1. Age 45 (within typical 18-75 range)
2. Witnessed arrest (bystander witnessed)
3. Short EMS response (4 minutes)
4. Shockable rhythm initiated (VF)
5. No ROSC after high-quality ACLS ≥15 minutes
6. Presumably reversible cause (likely MI in clinical context)

However, must assess:

1. Duration: Total arrest time must be below 90 minutes
2. Underlying cause: Likely primary cardiac (MI) - reversible with revascularization
3. Comorbidities: Screen for severe chronic disease, advanced directives
4. Neurological injury: No obvious signs of irreversible brain damage
5. ECMO access: Ensure ECMO centre available within 60 minutes total

Actions:

• Continue high-quality CPR
• Target temperature management
• Contact ECMO centre for ECPR activation
• Monitor rhythm, continue defibrillation
• Prepare for femoral cannulation

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Viva 2: Harlequin Syndrome

Examiner: "Day 5 of VA-ECMO post-myocardial infarction. Patient improving clinically but now saturations 70% on pulse oximetry. What's going on?"

Candidate response:

This is Harlequin syndrome (North-South syndrome).

Pathophysiology:

• VA-ECMO returns oxygenated blood retrograde via femoral artery to aorta
• Patient recovering LV function
• Native LV pumping deoxygenated blood to coronary and cerebral circulation
• Upper body becomes hypoxic while lower body hyperoxygenated

Confirmatory findings:

• Right radial SaO2 below 80% while femoral SaO2 above 95%
• Echocardiogram shows recovering LV function

Management:

1. Reduce VA-ECMO flow (improves distal aortic oxygenation)
2. Increase LV ejection (inhaled milrinone, low-dose adrenaline)
3. Consider LV unloading device:
   • Intra-aortic balloon pump (IABP)
   • Impella micro-axial pump
   • Consider switching to central cannulation
4. If refractory, transition to VV-ECMO (if respiratory failure remains)

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Viva 3: ECMO Anticoagulation with HIT

Examiner: "Patient on VA-ECMO developed HIT. What's your management?"

Candidate response:

Stop heparin immediately.

Diagnosis:

• 50% platelet fall from baseline
• Thrombosis or new thrombosis
• HIT antibody confirmed (positive serotonin release assay or ELISA with high probability)

Alternative anticoagulation agents:

Bivalirudin (preferred):

• Direct thrombin inhibitor
• No HIT risk
• Short half-life (25 min)
• Start 0.15 mg/kg/hr
• Target aPTT 60-80 seconds
• Monitor renal function

Alternative (if bivalirudin unavailable):

Argatroban:

• Alternative DTI
• Metabolised hepatobiliary (use in renal failure)
• Start 0.2 mcg/kg/min
• Target aPTT 60-80

Danaparoid:

• Heparinoid (less availability)
• Anti-Xa monitoring

Management:

• Switch immediately
• Reduce heparin flushes
• Ensure circuit remains anticoagulated
• Follow HIT treatment duration (4-6 weeks minimum)
• Maintain platelet monitoring

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Viva 4: Indigenous Patient Retrieval

Examiner: "A 55-year-old Indigenous man from remote NSW presents to local hospital with severe ARDS (PCO2 50, PO2 55, PaO2/FiO2 60). 5 hours from nearest ECMO centre. Discuss approach to ECMO retrieval."

Candidate response:

Approach:

1. Immediate management at referring hospital:

• Optimise conventional ventilation (volume 6 mL/kg, PEEP 10)
• Prone positioning (if equipment and staff trained)
• Muscle paralysis (cis-atracurium)
• Recruitment manoeuvres if appropriate
• Consider neuromuscular blockade

2. ECMO decision-making:

• VV-ECMO indication met (failed optimal ventilation, P/F Ratio 60)
• ECPR not an option (not cardiac arrest)
• VV-ECMO retrieval feasible despite 5-hour transport time

3. Cultural considerations:

• Use plain language: "external support for lungs" rather than "extracorporeal..."
• Include family in discussions
• If possible, involve Aboriginal Hospital Liaison Officer
• Respect connection to Country: acknowledge disruption from removal

4. Practical retrieval:

• Contact NSW ECLS early
• Consider early retrieval team deployment
• Ensure blood products available at referring hospital
• Clear communication goals: ECMO as bridge to lung recovery

5. Barriers:

• Remote location limited blood product availability
• Need to ensure staff trained in circuit maintenance during transport
• Consider complex ambulance ECMO transport (VECMOS capability)

6. Decision:

• Early VV-ECMO if criteria met and transport team available
• If not possible, optimize conventional management and transfer for consideration

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OSCE Stations

OSCE 1: ECMO Decision Assessment

Station type: Clinical reasoning / Communication (11 minutes)

Scenario: 56-year-old woman, severe ARDS post-influenza. pH 7.18, PaCO2 65, PaO2 55 on FiO2 1.0, PEEP 15, tidal volume 6 mL/kg. Plateau 32. 45 minutes drive to ECMO centre.

Task:

1. Assess if she meets ECMO criteria
2. Discuss with patient's husband (actor)
3. Explain ECMO, risks, benefits, alternatives

Marking criteria:

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OSCE 2: ECPR Cannulation

Station type: Procedure (11 minutes)

Scenario: 38-year-old male refractory VF cardiac arrest, 20 minutes of high-quality CPR, no ROSC. ECMO team present. Equipment available.

Task:

1. State cannulation steps for femoral VA-ECMO
2. Demonstrate ultrasound guidance approach
3. State circuit priming considerations

Marking criteria:

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OSCE 3: Harlequin Syndrome Recognition and Management

Station type: Critical problem solving (11 minutes)

Scenario: Day 6 VA-ECMO post-MI with LV failure. Patient improving: EF recovering to 30%. Now saturations 68% on pulse ox (upper limb). Pulse strong. No bleeding. Circuit functioning. You suspect Harlequin syndrome.

Task:

1. Outline diagnosis and confirmation
2. State management options
3. Prevent recurrence

Marking criteria:

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SAQ Practice

SAQ 1: ECMO Indications and Contraindications

Question (8 marks):

A 62-year-old man presents to your ED with refractory hypoxic respiratory failure 3 days after severe COVID-19 pneumonia. pH 7.18, PaCO2 68, PaO2 55 on FiO2 1.0, PEEP 15, tidal volume 6 mL/kg, plateau 32. Blood pressure 115/70, lactate 2.1.

a) Does he meet criteria for VV-ECMO? List key criteria. (4 marks)

b) List three ABSOLUTE contraindications to ECMO. (3 marks)

c) What is the FIRST action to arrange ECMO retrieval? (1 mark)

Model Answer:

a) Yes meets VV-ECMO criteria (4 marks):

• PaO2/FiO2 below 80 (55/1.0 = 55) (1 mark)
• pH below 7.20 (7.18) (1 mark)
• PaCO2 ≥60 mmHg (68) (1 mark)
• Optimal ventilation still elevated plateau greater than 30 cmH2O (32) (1 mark)

b) Absolute contraindications (3 marks):

• Severe irreversible neurological injury (1 mark)
• Advanced directives prohibiting invasive life support (1 mark)
• Uncontrolled active bleeding (1 mark)

c) First action (1 mark):

• Contact state ECMO retrieval service (NSW ECLS or VECMOS) to initiate retrieval and assessment (1 mark)

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SAQ 2: ECPR Candidate Assessment

Question (10 marks):

A 52-year-old woman collapses in gym. Bystander CPR commenced. Paramedics arrive after 3 minutes, initiate ACLS. Rhythm VF throughout. No ROSC after 20 minutes. You are at tertiary hospital with ECMO capability.

a) List FOUR factors supporting ECPR candidacy. (4 marks)

b) List THREE factors that would exclude ECPR. (3 marks)

c) What is the target time from arrest to ECMO flow for optimal outcomes? (1 mark)

d) List TWO complications of femoral VA-ECMO. (2 marks)

Model Answer:

a) Factors supporting ECPR (4 marks):

• Witnessed cardiac arrest (1 mark)
• Shockable initial rhythm (VF) (1 mark)
• Short elapsed time to EMS arrival (3 minutes) (1 mark)
• Age 52 (within 18-75 range) (1 mark)

b) Exclusion factors (3 marks):

• Total arrest duration greater than 90 minutes (1 mark)
• Severe pre-morbid neurological condition (1 mark)
• Advanced directives limiting invasive support (1 mark)

c) Target time (1 mark):

• ECMO flow established within 60 minutes of arrest for optimal outcomes (1 mark)

d) VA-ECMO complications (2 marks):

• Limb ischemia (1 mark)
• Bleeding/hemorrhage (1 mark)

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SAQ 3: ECMO Retrieval for Remote Patient

Question (8 marks):

You are at a regional hospital 4 hours from the nearest ECMO centre. A 40-year-old Aboriginal man (from remote community) has severe ARDS post-pneumonia (P/F 58, pH 7.15, PaCO2 70, plateau 36). Optimised conventional ventilation for 12 hours.

a) Is VV-ECMO retrieval appropriate? Justify. (3 marks)

b) List TWO cultural considerations in discussing ECMO with the family. (2 marks)

c) State TWO barriers to ECMO retrieval in remote/rural areas. (2 marks)

d) What retrieval service coordinates ECMO transfer in Victoria? (1 mark)

Model Answer:

a) Yes VV-ECMO retrieval appropriate (3 marks):

• Meets VV-ECMO criteria: P/F below 80, pH below 7.2, PaCO2 ≥60 (2 marks)
• Patient not in cardiac arrest, VV-ECMO (not ECPR); 4-hour transport time feasible (1 mark)

b) Cultural considerations (2 marks):

• Use plain language; avoid medical jargon explaining ECMO (1 mark)
• Involve family and community support members; respect cultural protocols (1 mark)

c) Barriers in remote/rural areas (2 marks):

• Longer transport time impacts ECPR candidacy (1 mark)
• Limited local resources: blood products, staff training for circuit maintenance (1 mark)

d) Victoria ECMO retrieval (1 mark):

• VECMOS / Adult Retrieval Victoria (ARV) (1 mark)

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SAQ 4: VA-ECMO Complications - Limb Ischemia

Question (8 marks):

Day 3 VA-ECMO post-MI with cardiogenic shock. Nurse notes left leg 2+ darker colour, reduced pulse oximetry signal. Doppler shows absent flow.

a) What is the likely diagnosis and cause? (2 marks)

b) What TWO measures reduce this complication? (2 marks)

c) State THREE management options for established limb ischemia. (3 marks)

d) How would you monitor for this complication? (1 mark)

Model Answer:

a) Diagnosis and cause (2 marks):

• Limb ischemia (1 mark)
• Femoral arterial cannulation occludes distal flow (1 mark)

b) Preventive measures (2 marks):

• Distal perfusion cannula (DPC) placement (1 mark)
• Regular limb monitoring (pulse ox, NIRS, Doppler) every 2-4 hours (1 mark)

c) Management options (3 marks):

• Increase distal perfusion flow through DPC (1 mark)
• Consult vascular surgery: emergent intervention/fasciotomy (1 mark)
• Consider cannula repositioning or removal (1 mark)

d) Monitoring (1 mark):

• Serial limb assessment: pulse oximetry, NIRS, Doppler, visual inspection (1 mark)

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