Cardiac Arrest - Adult

Quick Answer

Critical: Adult cardiac arrest requires immediate high-quality CPR using DRSABCD approach, early defibrillation for shockable rhythms, and systematic identification of reversible causes (4Hs and 4Ts). Survival depends on minimising no-flow time and ensuring CPR quality metrics are met.

Cardiac arrest is the cessation of mechanical cardiac activity confirmed by the absence of a palpable central pulse, unresponsiveness, and absent or abnormal breathing [1]. In Australia, out-of-hospital cardiac arrest (OHCA) affects approximately 53 per 100,000 population annually, with survival to hospital discharge around 11.7% [2]. The Chain of Survival—early recognition, early CPR, early defibrillation, and post-resuscitation care—determines outcome [3]. Every minute without CPR reduces survival by 7-10%, making immediate intervention critical. The Australian Resuscitation Council (ARC) and ANZCOR guidelines form the basis of resuscitation practice in Australia and New Zealand [4].

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ACEM Exam Focus

Primary Exam Relevance

• Physiology: Cellular hypoxia cascade, myocardial oxygen consumption, coronary perfusion pressure (CPP = aortic diastolic pressure - RVEDP), cerebral autoregulation failure, ischaemia-reperfusion injury
• Pharmacology: Adrenaline pharmacokinetics (alpha-1 vasoconstriction for CPP, beta effects on chronotropy/inotropy), amiodarone mechanism (Class III antiarrhythmic, multiple ion channel blockade), calcium chloride membrane stabilisation
• Anatomy: Cardiac conduction system (SA node, AV node, bundle branches), coronary artery anatomy for STEMI recognition, chest wall anatomy for compressions (lower half of sternum, avoiding xiphisternum)

Fellowship Exam Relevance

• Written SAQ Topics: ALS algorithm application, drug timing and dosing, reversible causes identification and treatment, TTM controversies post-TTM2 trial, ECPR criteria and indications
• OSCE: Resuscitation leadership station is a CORE scenario—expect to lead a team through cardiac arrest with rhythm changes. Communication stations may involve breaking bad news after unsuccessful resuscitation or discussing prognosis with family
• Key domains tested: Medical Expert (algorithm knowledge, drug dosing), Leader (team management, role allocation), Communicator (closed-loop communication, family updates)

High-Yield Exam Points

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Key Points

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Epidemiology

Australian and New Zealand Data

Aus-ROC Epistry Data

The Aus-ROC (Australian Resuscitation Outcomes Consortium) Epistry is the largest Australasian cardiac arrest registry, capturing data from South Australia, Victoria, Western Australia, Queensland, and New Zealand [2]. Key findings:

• Regional variation: Metropolitan survival higher than rural/regional (13.1% vs 8.4%) [13]
• Seasonal variation: Higher OHCA rates in winter months (July-August in Southern Hemisphere) [14]
• Location: 70% occur at home (lower survival due to delayed EMS and variable bystander CPR), 30% in public places (higher survival) [2]
• Witnessed arrests: 43% witnessed by bystander, 8% witnessed by EMS [2]
• Time of day: Peak incidence 06:00-12:00 (circadian variation in sympathetic activity) [2]

Aetiology Distribution (OHCA)

Indigenous Health Disparities

Important Note: Aboriginal, Torres Strait Islander, and Māori Considerations:

Aboriginal and Torres Strait Islander Australians experience cardiac arrest at significantly younger ages than non-Indigenous Australians, with higher rates of underlying cardiovascular disease [15]:

• Earlier onset: Mean age of cardiac arrest 10-15 years younger
• Higher prevalence of risk factors: Smoking (41% vs 13%), diabetes (12% vs 5%), hypertension, chronic kidney disease
• Rheumatic heart disease: 8-fold higher prevalence in Indigenous Australians
• Geographic barriers: Remote communities have delayed EMS response (over 60 minutes in some areas)
• Lower bystander CPR rates: Due to geographic isolation, fewer trained bystanders
• Māori in NZ: Similar disparities with 2-3 times higher cardiovascular mortality

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Pathophysiology

Cardiac Arrest Physiology

Immediate Phase (0-5 minutes)

Cessation of circulation → Global tissue hypoxia → Anaerobic metabolism → Lactate accumulation
                                    ↓
              ATP depletion → Cell membrane dysfunction → Ion pump failure
                                    ↓
              Cellular swelling → Calcium influx → Mitochondrial dysfunction

Circulatory Phase (5-15 minutes)

• CPR generates cardiac output approximately 25-30% of normal [16]
• Coronary perfusion pressure (CPP) = Aortic diastolic pressure - Right atrial pressure
• CPP over 15 mmHg associated with ROSC; CPP below 10 mmHg associated with failure [17]
• Chest compressions create oscillating intrathoracic pressure → cardiac output via "thoracic pump" and "cardiac pump" mechanisms

Metabolic Phase (greater than 15 minutes)

• Profound tissue ischaemia and reperfusion injury
• ECPR may be required as sole means of restoring circulation
• Neurological injury becomes increasingly severe and irreversible
• Myocardial ATP depletion leads to VF waveform degradation (coarse → fine → asystole)

Why CPR Works

• Chest compressions create forward blood flow through direct cardiac compression and thoracic pump mechanism
• Compression depth of 5-6cm achieves optimal stroke volume [5]
• Rate of 100-120/min optimises cardiac output; rates over 120/min reduce compression depth [18]
• Full chest recoil allows venous return; incomplete recoil (leaning) reduces coronary perfusion [19]

Why Defibrillation Works

• VF represents uncoordinated electrical activity with no effective mechanical output
• Defibrillation delivers synchronized electrical shock → simultaneous depolarisation of myocardium
• Creates "electrical silence" allowing native pacemakers (SA node) to resume [20]
• Success decreases ~10% per minute without CPR, ~3-4% per minute with CPR [21]
• Biphasic waveforms are more effective at lower energies than monophasic [22]

Post-Cardiac Arrest Syndrome

Following ROSC, patients develop a complex pathophysiological state termed "post-cardiac arrest syndrome" comprising four key components [23]:

1. Post-cardiac arrest brain injury: Ischaemia-reperfusion injury, excitotoxicity (glutamate release), calcium dysregulation, free radical formation, cerebral oedema
2. Post-cardiac arrest myocardial dysfunction: Stunned myocardium, reduced EF (typically reversible over 48-72 hours), arrhythmias
3. Systemic ischaemia-reperfusion response: SIRS-like picture, cytokine release, coagulopathy, adrenal dysfunction
4. Persistent precipitating pathology: Underlying cause (ACS, PE, sepsis) continues to cause harm

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Clinical Approach - DRSABCD

The ARC/ANZCOR Systematic Approach (ANZCOR Guideline 8)

D - Danger

• Scene safety assessment for rescuer and patient
• Remove patient from ongoing hazards if safe to do so
• In hospital: Consider electrical safety, infection control

R - Response

• Verbal: "Can you hear me? Open your eyes!"
• Tactile: Squeeze shoulders firmly
• Painful stimulus if no response (trapezius squeeze)
• No response → Call for help

S - Send for Help

• Activate emergency response: 000 (Australia), 111 (New Zealand)
• In-hospital: "MET call" or cardiac arrest team activation
• Request defibrillator/AED
• Assign someone to meet retrieval team and bring equipment

A - Airway

• Head tilt, chin lift (caution in trauma - use jaw thrust)
• Look for foreign bodies, remove if visible
• Suction if secretions present
• Do NOT delay CPR for advanced airway

B - Breathing

• Look: chest movement, respiratory effort
• Listen: breath sounds, stridor, gurgling
• Feel: air movement at mouth/nose
• Look for 10 seconds maximum
• Agonal gasps are NOT normal breathing → commence CPR

C - CPR

• Place patient supine on firm surface
• Expose chest
• Commence compressions immediately if not breathing normally and unresponsive
• Compression landmark: lower half of sternum (heel of hand, interlocking fingers)
• Rate: 100-120/min
• Depth: 5-6 cm
• Allow full chest recoil
• Ratio: 30 compressions : 2 ventilations

D - Defibrillation

• Apply AED/defibrillator pads as soon as available
• Analyse rhythm (minimise pause below 5 seconds)
• Shock if indicated (VF/pVT)
• Resume CPR immediately after shock - do not pause to check rhythm

Recognition of Cardiac Arrest

Agonal Gasping

• Present in approximately 40% of cardiac arrests [9]
• Irregular, infrequent (typically below 10/min), noisy respirations
• Often misinterpreted as "still breathing" by bystanders - major cause of delayed CPR
• Associated with better outcomes if CPR commenced (indicates shorter downtime, higher VF rate)
• Ceases when hypoxia worsens or with effective CPR

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ARC/ANZCOR Adult Advanced Life Support Algorithm (Guideline 11)

Algorithm Flowchart

┌─────────────────────────────────────────────────────────────────────────┐
│                         CARDIAC ARREST                                   │
│              Unresponsive, not breathing normally                        │
│                        DRSABCD approach                                  │
└─────────────────────────────────────────────────────────────────────────┘
                                    ↓
┌─────────────────────────────────────────────────────────────────────────┐
│                          CALL FOR HELP                                   │
│           Request defibrillator (000/111 or MET call)                   │
│                     Activate arrest team                                 │
└─────────────────────────────────────────────────────────────────────────┘
                                    ↓
┌─────────────────────────────────────────────────────────────────────────┐
│                         START CPR 30:2                                   │
│              Attach defibrillator pads when available                   │
│      Rate 100-120/min | Depth 5-6cm | Full recoil | Minimise pauses    │
└─────────────────────────────────────────────────────────────────────────┘
                                    ↓
┌─────────────────────────────────────────────────────────────────────────┐
│                        ANALYSE RHYTHM                                    │
│                Minimise pause for analysis (below 5 sec)                      │
└─────────────────────────────────────────────────────────────────────────┘
              ↓                                            ↓
┌──────────────────────────────┐          ┌────────────────────────────────┐
│       SHOCKABLE              │          │       NON-SHOCKABLE            │
│       VF / pVT               │          │    Asystole / PEA              │
└──────────────────────────────┘          └────────────────────────────────┘
              ↓                                            ↓
┌──────────────────────────────┐          ┌────────────────────────────────┐
│  DEFIBRILLATE                │          │  Resume CPR immediately        │
│  150-200J biphasic           │          │  for 2 minutes                 │
│  Resume CPR immediately      │          │                                │
│  for 2 minutes               │          │  ADRENALINE 1mg IV/IO          │
│                              │          │  as soon as access obtained    │
│  Continue cycles             │          │  then every 3-5 min            │
└──────────────────────────────┘          └────────────────────────────────┘
              ↓
┌──────────────────────────────┐          ┌────────────────────────────────┐
│  AFTER 3RD SHOCK:            │          │  DURING CPR:                   │
│  • Adrenaline 1mg IV/IO      │          │  • Ensure quality CPR          │
│  • Amiodarone 300mg IV/IO    │          │  • Plan actions before pause   │
│                              │          │  • Vascular access (IV/IO)     │
│  Then adrenaline every       │          │  • Airway management           │
│  3-5 min                     │          │  • Waveform capnography        │
│                              │          │  • POCUS during rhythm check   │
│  AFTER 5TH SHOCK:            │          │  • Treat reversible causes     │
│  • Consider Amiodarone       │          │                                │
│    150mg IV/IO               │          │                                │
└──────────────────────────────┘          └────────────────────────────────┘
                                                        ↓
                        ┌─────────────────────────────────────────────────┐
                        │              REVERSIBLE CAUSES                   │
                        │  4Hs: Hypoxia, Hypovolaemia, Hypo/hyper-        │
                        │       kalaemia, Hypothermia                      │
                        │  4Ts: Tension pneumothorax, Tamponade,          │
                        │       Toxins, Thrombosis (PE/MI)                 │
                        └─────────────────────────────────────────────────┘
                                                        ↓
                        ┌─────────────────────────────────────────────────┐
                        │              ROSC ACHIEVED                       │
                        │  • Post-resuscitation care                       │
                        │  • 12-lead ECG                                   │
                        │  • Treat precipitating cause                     │
                        │  • TTM 32-36°C if comatose                       │
                        │  • Consider cath lab if STEMI                    │
                        │  • ICU admission                                 │
                        └─────────────────────────────────────────────────┘

CPR Quality Metrics (ANZCOR Guideline 8)

Defibrillation (ANZCOR Guideline 11.4)

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Medications in Cardiac Arrest (ANZCOR Guideline 11.3)

Adrenaline (Epinephrine)

Mechanism of Action:

• Alpha-1 agonist effect: Peripheral vasoconstriction → increases systemic vascular resistance → augments aortic diastolic pressure → improves coronary perfusion pressure [26]
• Beta-1 effect: Increases myocardial contractility and heart rate (less relevant during arrest)
• Beta-2 effect: Bronchodilation (useful in anaphylaxis)

Evidence - PARAMEDIC2 Trial (2018):

• Adrenaline vs placebo in OHCA: Improved ROSC (36.3% vs 11.7%) and survival to 30 days (3.2% vs 2.4%)
• BUT: No difference in survival with favourable neurological outcome (2.2% vs 1.9%)
• Remains standard of care per ARC guidelines despite this controversy [26]

Amiodarone

Indication: Refractory VF/pVT - VF/pVT persisting after 3 defibrillation attempts [6]

Mechanism: Class III antiarrhythmic - blocks multiple ion channels (K+, Na+, Ca2+), prolongs action potential duration and refractory period

Evidence - ALPS Trial (2016):

• Amiodarone vs lignocaine vs placebo in shock-refractory VF/pVT
• Amiodarone and lignocaine both improved survival to hospital admission compared to placebo
• No difference in survival to discharge with good neurological outcome [27]

Other Medications

Vascular Access

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Reversible Causes - 4Hs and 4Ts (ANZCOR Guideline 11.5)

The 4 Hs

The 4 Ts

Toxin-Specific Treatments

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Investigations

During Resuscitation

Point-of-Care Ultrasound (POCUS) in Cardiac Arrest

Immediate Post-ROSC Investigations

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Post-Resuscitation Care (ANZCOR Guideline 14)

Immediate Post-ROSC Management (First 60 Minutes)

1. CONFIRM ROSC
   • Palpable pulse
   • Rising ETCO2 (often dramatic rise from ~20 to greater than 40 mmHg)
   • Arterial waveform on invasive monitoring
   • Patient movement or breathing
           ↓
2. OPTIMISE OXYGENATION
   • Target SpO2 94-98%
   • AVOID hyperoxia (FiO2 100% only during arrest)
   • Titrate FiO2 down once SpO2 stable
           ↓
3. OPTIMISE VENTILATION
   • Confirm ETT position with waveform capnography
   • Target normocapnia: PaCO2 35-45 mmHg (4.5-6.0 kPa)
   • Avoid hyperventilation (causes cerebral vasoconstriction)
           ↓
4. HAEMODYNAMIC STABILISATION
   • Target MAP ≥65 mmHg (some evidence for higher ~80mmHg)
   • Place arterial line for continuous monitoring
   • Vasopressors: Noradrenaline 0.05-0.5 mcg/kg/min first-line
   • Fluid boluses if hypovolaemic
           ↓
5. 12-LEAD ECG
   • STEMI → Immediate cath lab activation
   • Arrhythmia management
   • Look for precipitating cause
           ↓
6. TARGETED TEMPERATURE MANAGEMENT (TTM)
   • If comatose (GCS motor below 6): Target 32-36°C for ≥24 hours
   • Initiate cooling: Surface devices, intravascular cooling, cold IV fluids
   • Prevent shivering: Sedation, paralysis if needed
           ↓
7. ICU ADMISSION
   • Ongoing monitoring and organ support
   • Neuroprotection
   • Cause identification and treatment

Post-ROSC Physiological Targets (ARC Recommendations)

Targeted Temperature Management (TTM)

Coronary Angiography Post-ROSC

Neuroprognostication

Multimodal Prognostic Assessment:

• Clinical examination: Absent pupillary reflexes, absent corneal reflexes, myoclonus status epilepticus
• EEG: Highly malignant patterns (suppressed background, burst-suppression without reactivity)
• Somatosensory evoked potentials (SSEPs): Bilateral absent N20 waves
• CT/MRI brain: Loss of grey-white differentiation, cerebral oedema, diffusion restriction
• Biomarkers: Neuron-specific enolase (NSE) over 60 µg/L at 48-72 hours

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Paediatric Modifications (ANZCOR Guideline 12)

Age Definitions (ARC)

Key Paediatric Differences

Paediatric Arrest Priorities

1. Ventilation and oxygenation are more important in children (respiratory aetiology common)
2. Give 5 rescue breaths initially if witnessed respiratory arrest
3. Vascular access: IO preferred in children if IV not rapidly available
4. Defibrillator pads: Anterior-posterior in small children; use paediatric pads if available (under 8 years)
5. Drug doses: Weight-based - use Broselow tape or age-based formulae

Paediatric Drug Doses

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Special Circumstances (ANZCOR Guideline 13)

Pregnancy (ANZCOR 13.1)

Drowning (ANZCOR 13.3)

Electrocution

• Ensure power source disconnected before approaching
• Higher incidence of VF (may respond well to defibrillation)
• May have associated trauma (falls, tetanic muscle contraction)
• Burns may indicate current pathway
• Standard ALS otherwise

Anaphylaxis-Related Arrest

• Adrenaline 1mg IV (1:10,000) in arrest - standard dosing
• Pre-arrest: Adrenaline 0.5mg IM (1:1,000) is first-line
• Large volume fluid resuscitation (intravascular depletion from capillary leak)
• Prolonged CPR may be needed
• Consider adrenaline infusion post-ROSC

Severe Asthma

• High airway pressures expected
• Consider permissive hypercapnia
• Disconnect from ventilator during compressions to allow expiration (auto-PEEP)
• Adrenaline, magnesium 2g IV, salbutamol nebulisers
• Consider tension pneumothorax

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Team Leadership and Communication

Resuscitation Team Roles

Closed-Loop Communication (Essential for OSCE)

Team Leader: "Give adrenaline 1mg IV"
Nurse: "Adrenaline 1mg IV - preparing now"
[Administers drug]
Nurse: "Adrenaline 1mg IV given"
Team Leader: "Thank you, adrenaline 1mg given at [time]"

10-Second Rhythm Check Protocol

1. Team Leader: "Pause for rhythm check"
2. Stop compressions
3. "Rhythm check"

• all eyes on monitor

4. Identify rhythm: "Rhythm is VF/asystole/PEA/organised"
5. If organised rhythm: "Check pulse" (central pulse, below 10 seconds)
6. If shockable: "Charging, all stand clear. Shocking on three... one, two, three"
7. Shock delivered
8. "Resume compressions immediately"
9. Total pause below 10 seconds

Debriefing

• Hot debrief: Immediately after event (5-10 minutes)
  • Focus on systems, not individuals
  • What went well, what could improve
  • Address immediate emotional impact on team
• Cold debrief: Scheduled for detailed analysis (24-48 hours later)
  • Formal morbidity and mortality review
  • Education opportunities
  • System improvements

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Indigenous Health Considerations

Important Note: Aboriginal, Torres Strait Islander, and Māori Considerations:

Health Disparities

Aboriginal and Torres Strait Islander Australians:

• Higher rates of cardiovascular disease at younger ages (10-15 years earlier) [15]
• Increased prevalence of risk factors: smoking (41% vs 13%), diabetes (12% vs 5%), hypertension, chronic kidney disease
• Higher prevalence of rheumatic heart disease (8-fold higher)
• Lower rates of bystander CPR in some remote communities
• Delayed EMS response in remote communities (over 60 minutes in some areas)
• Later presentation to healthcare services

Māori (New Zealand):

• 2-3 times higher cardiovascular mortality
• Similar disparities in risk factor prevalence
• Whānau (family) involvement crucial in decision-making

Cultural Safety in Resuscitation

Communication Principles:

• Involve Aboriginal Health Workers/Liaison Officers early
• Use interpreters for language barriers (over 100 Aboriginal languages in Australia)
• Allow time for family discussions and community consultation
• Respect extended family structures and kinship systems
• Understand that community elders may need to be involved in major decisions
• Be aware of cultural protocols around death and dying

Specific Considerations:

• "Sorry Business": Cultural protocols around death - may affect family's wishes for resuscitation and organ donation
• "Men's Business" and "Women's Business": Same-gender staff may be preferred for some discussions
• Eye contact: May be culturally inappropriate in some communities
• Silence: Silence may indicate respect and consideration, not lack of understanding
• Organ donation: Discuss sensitively; beliefs about body integrity vary between communities and individuals

Practical Considerations:

• Remote communities: Delayed EMS response, limited AED access
• Telemedicine may facilitate specialist input for post-ROSC care
• RFDS retrieval for post-ROSC patients requiring ICU care
• Consider cultural needs in post-resuscitation care (family visiting, traditional healers)
• Social work and pastoral care involvement for family support

Māori Considerations (New Zealand)

• Whānau: Family involvement in all decision-making
• Tikanga Māori: Cultural protocols around death and dying
• Karakia: Prayers may be requested by family
• Tangi: Traditional funeral practices may affect timing of decisions
• Cultural liaison officers available in major NZ hospitals

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Remote and Rural Considerations

Pre-Hospital Challenges in Rural/Remote Australia

RFDS (Royal Flying Doctor Service) Considerations

• Provides aeromedical retrieval for post-ROSC patients to tertiary centres
• Telemedicine consultation during resuscitation available
• Limited ability to manage ongoing cardiac arrest during flight (space, vibration, safety)
• Transport decisions: ROSC must be achieved and stable before retrieval in most cases
• Early discussion with retrieval coordination for complex cases

Resource-Limited Resuscitation

Telemedicine Support

• Specialist consultation for complex resuscitation decisions
• Guidance on drug dosing and algorithm adherence
• Support for termination of resuscitation decisions
• Debrief and psychological support for remote teams
• Video-assisted CPR guidance for bystanders (emerging)

Termination of Resuscitation in Remote Areas

Consider cessation when:

• Asystole throughout resuscitation with no reversible cause identified
• No ROSC after 30-40 minutes of optimal CPR
• No access to ECPR
• Futility evident (prolonged unwitnessed downtime, no bystander CPR, non-shockable rhythm throughout)
• Consult with retrieval service or emergency physician if uncertain

Exceptions - Continue longer:

• Hypothermia (until core temp over 32°C)
• Drowning (especially cold water)
• Drug overdose/toxins
• Young patient with reversible cause

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Disposition

Post-ROSC Disposition

Termination of Resuscitation Criteria

Organ Donation Considerations

• Consider early referral to organ donation specialist for all cardiac arrest deaths
• OHCA patients can be DCD (donation after circulatory death) donors
• Contact local organ donation service (DonateLife in Australia)
• Sensitive discussion with family about donation wishes
• Cultural considerations particularly for Indigenous patients

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Pitfalls and Pearls

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Viva Practice

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OSCE Scenarios

Station 1: Cardiac Arrest Team Leadership (Resuscitation Station)

Format: Resuscitation leadership Time: 11 minutes Setting: ED resuscitation bay with high-fidelity manikin

Candidate Instructions:

You are the emergency registrar called to the resuscitation bay. A 58-year-old man has been brought in by ambulance in cardiac arrest. Paramedics have been performing CPR for 10 minutes. IV access has been established and one dose of adrenaline has been given 4 minutes ago. The defibrillator shows ventricular fibrillation. Lead the resuscitation. Team members will follow your instructions.

Examiner Instructions:

• Initial rhythm: VF
• 1st shock: Remains VF
• 2nd shock: Remains VF
• 3rd shock: Remains VF (candidate should now give adrenaline + amiodarone)
• 4th shock: Changes to PEA (rate 40)
• 5th shock: Not indicated (PEA)
• After 2 more cycles of PEA with adrenaline: ROSC
• Provide history when asked: Found collapsed at work, clutching chest, known HTN, no other history available

Available Resources:

• 1 nurse for airway/ventilation
• 1 nurse for compressions (rotatable)
• 1 nurse for drugs/defibrillator
• Full resuscitation trolley including IO equipment
• Defibrillator with pads attached
• Airway equipment including ETT and iGel

Expected Actions:

1. Confirm team leader role, brief assessment of situation
2. Confirm cardiac arrest status (unresponsive, not breathing, VF on monitor)
3. Allocate roles clearly with names
4. Ensure high-quality CPR continues (verbalise metrics)
5. Order defibrillation at correct energy (150-200J biphasic)
6. Direct rhythm checks every 2 minutes with minimal pause
7. Give correct drugs at correct times:
   • Adrenaline 1mg after 3rd shock (note: 1 dose given 4 min ago)
   • Amiodarone 300mg after 3rd shock
   • Adrenaline every 3-5 minutes thereafter
8. Recognise rhythm change to PEA, change strategy appropriately
9. Verbalise consideration of reversible causes (4Hs/4Ts)
10. Demonstrate closed-loop communication throughout
11. Manage ROSC appropriately when it occurs

Marking Criteria:

Expected Standard:

• Pass: ≥6/11
• Key discriminators: Correct drug timing (adrenaline after 3rd shock), ability to adapt when rhythm changes to non-shockable, maintaining calm leadership, closed-loop communication

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Station 2: Breaking Bad News - Unsuccessful Resuscitation

Format: Communication (OSCE) Time: 11 minutes Setting: Relatives room, ED

Candidate Instructions:

A 72-year-old man had a cardiac arrest at home. His wife called 000 and performed CPR with telephone guidance until paramedics arrived. Despite 35 minutes of resuscitation in the ED, he has not achieved return of spontaneous circulation. You and your consultant have made the decision to cease resuscitation. His wife is in the relatives' room. She knows he collapsed and that CPR was being performed, but has not been updated since arriving at the hospital. Speak with her.

Actor Brief (Wife - Margaret):

• Name: Margaret, 69 years old
• Married to Brian for 48 years
• Brian had chest pain at breakfast, collapsed at the table
• She called 000 and did CPR with phone guidance - first time she has ever done CPR
• Anxious, tearful, hands shaking
• Initial responses: "Is he going to be okay? Can I see him?"
• Will ask: "Did I do the CPR right? Did I kill him?"
• Religious (Christian) - may ask about chaplain
• Eventually asks about what happens next (viewing, practical matters)

Expected Actions:

1. Enter room, introduce yourself, confirm identity ("Are you Brian's wife?")
2. Sit down at same level, appropriate body language, express concern
3. Establish what she knows/understands ("Can you tell me what you understand about what happened?")
4. Give a "warning shot" ("I'm afraid I have some very sad news...")
5. Deliver news clearly and unambiguously: Use the word "died" or "death"
6. Allow silence, do not rush to fill it
7. Acknowledge her emotions, express condolences ("I'm so sorry for your loss")
8. Briefly explain what happened (he had a cardiac arrest, we tried everything)
9. Strongly affirm her CPR efforts ("You did exactly the right thing. The CPR you did gave him the best possible chance")
10. Offer to see him (viewing the body)
11. Offer support services: chaplain, social worker, family contact
12. Mention practical matters sensitively (belongings, paperwork, coroner if applicable)
13. Offer opportunity for questions
14. Ensure she is not alone, offer to contact family

Marking Criteria:

Expected Standard:

• Pass: ≥6/11
• Key discriminators: Using the word "died" clearly (not euphemisms like "passed away" or "didn't make it"), allowing silence after delivering news, genuine empathy, affirming her CPR efforts

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SAQ Practice

Question 1 (6 marks)

Stem: A 60-year-old woman is found collapsed in a shopping centre. Bystanders commence CPR and apply an AED which delivers a shock. Paramedics arrive and continue resuscitation.

Question: List 6 features of high-quality CPR according to ARC/ANZCOR guidelines. (6 marks)

Model Answer:

• Rate of 100-120 compressions per minute (1)
• Depth of 5-6 cm in adults (at least 5cm, no more than 6cm) (1)
• Allow full chest recoil between compressions (avoid leaning) (1)
• Minimise interruptions to compressions (below 10 seconds for rhythm checks) (1)
• Chest compression fraction over 80% of arrest time (1)
• Rotate compressors every 2 minutes to prevent fatigue and maintain quality (1)

Alternative acceptable answers (any 6 for full marks):

• Hand position: Lower half of sternum / heel of hand
• Avoid excessive ventilation (10 breaths/min with advanced airway)
• 30:2 compression to ventilation ratio without advanced airway
• Pre-charge defibrillator during CPR to minimise peri-shock pause

Examiner Notes:

• Accept: Any 6 of the above points with reasonable wording
• Accept: "Allow chest to return to resting position" for recoil
• Do not accept: "30:2 ratio" alone (this is technique, not quality metric)
• Do not accept: Vague answers like "good compressions"

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Question 2 (8 marks)

Stem: A 55-year-old man with a history of chronic kidney disease is brought to the Emergency Department in cardiac arrest. The rhythm is pulseless electrical activity (PEA) with wide QRS complexes.

Question: a) List the 4Hs and 4Ts that are reversible causes of cardiac arrest. (4 marks) b) Given the clinical scenario, which reversible cause is most likely and describe its emergency treatment during cardiac arrest. (4 marks)

Model Answer:

Part a) 4Hs and 4Ts (4 marks - ½ mark each):

4 Hs:

• Hypoxia
• Hypovolaemia
• Hyperkalaemia / Hypokalaemia (accept hypo/hyperkalaemia or metabolic)
• Hypothermia

4 Ts:

• Tension pneumothorax
• Tamponade (cardiac)
• Toxins
• Thrombosis (coronary or pulmonary / PE or MI)

Part b) Most likely cause and treatment (4 marks):

Most likely cause (1 mark): Hyperkalaemia - Given the history of CKD and the wide QRS complexes on the rhythm strip, which is a classic ECG finding of severe hyperkalaemia.

Emergency treatment (3 marks):

1. Calcium chloride 10% 10mL IV (or calcium gluconate 30mL IV) - Immediate cardioprotection by stabilising the myocardial membrane. Can be repeated if no improvement in QRS width. (1)

2. Sodium bicarbonate 50 mmol (50mL of 8.4%) IV - Shifts potassium intracellularly and addresses metabolic acidosis. (1)

3. Insulin 10 units with 50mL of 50% dextrose IV - Shifts potassium intracellularly. Effect takes 15-30 minutes. (1)

Additional treatments (for additional marks if required):

• Salbutamol 10-20mg nebulised - Shifts potassium intracellularly
• Dialysis - Definitive treatment; consider emergency CVVHDF if ROSC achieved or ECMO circuit if available

Examiner Notes:

• Part a: Accept "hyperkalaemia" alone OR "hypo/hyperkalaemia"
• both acceptable
• Part a: Accept "thrombosis" OR "thrombosis (PE and MI)" OR just "PE" or "MI"
• Part b: Must identify hyperkalaemia as most likely cause for the mark
• Part b: Calcium is the most important immediate treatment - must be mentioned for full marks
• Do not accept: Calcium resonium during cardiac arrest (too slow)
• Do not accept: Kayexalate or sodium polystyrene sulfonate (not used in arrest)

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Question 3 (8 marks)

Stem: A 50-year-old man achieves return of spontaneous circulation after 15 minutes of cardiac arrest from ventricular fibrillation. He is intubated and sedated with a GCS of 3T. His blood pressure is 90/60 mmHg and heart rate is 105/min.

Question: a) List 4 immediate physiological targets for post-resuscitation care according to ANZCOR guidelines. (4 marks) b) Describe your approach to targeted temperature management (TTM) in this patient, including target temperature, duration, and cooling method. (4 marks)

Model Answer:

Part a) Physiological targets (4 marks - 1 mark each, any 4):

• Oxygenation: SpO2 94-98% (avoid hyperoxia and hypoxia) (1)
• Ventilation: Normocapnia, PaCO2 35-45 mmHg (4.5-6.0 kPa) (1)
• Blood pressure: MAP ≥65 mmHg (consider ≥80 mmHg in some patients) (1)
• Blood glucose: 6-10 mmol/L (avoid hypoglycaemia and marked hyperglycaemia) (1)

Additional acceptable answers:

• Temperature: 32-36°C if comatose (TTM)
• Avoid fever (≥37.5°C)
• Treat seizures aggressively

Part b) Targeted temperature management (4 marks):

Indication (1 mark): This patient is comatose (GCS motor score below 6) following ROSC from cardiac arrest, so he is a candidate for TTM.

Target temperature (1 mark): Target 32-36°C. Current evidence (TTM2 trial) suggests no benefit of 33°C over 36°C with strict fever prevention, so either end of this range is acceptable.

Duration (1 mark): Maintain target temperature for at least 24 hours. Rewarming should be slow at 0.25-0.5°C per hour.

Cooling method (1 mark):

• Surface cooling devices (cooling blankets, Arctic Sun pads)
• Intravascular cooling catheters (Thermogard, Coolguard)
• Cold IV fluids (4°C crystalloid boluses - limited effect for induction)
• Avoid shivering with adequate sedation and consider neuromuscular blockade if needed

Examiner Notes:

• Part a: Accept reasonable variations in wording for physiological targets
• Part a: Must include at least oxygenation AND blood pressure for full marks
• Part b: Accept 32-36°C as target (current ANZCOR recommendation)
• Part b: Accept 33°C OR 36°C specifically if candidate mentions TTM2 trial
• Part b: Must mention duration of at least 24 hours
• Do not accept: Ice packs to groin/axilla alone (insufficient for sustained TTM)

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Australian Guidelines Summary

Key ANZCOR Guidelines Referenced

Key Differences: ARC/ANZCOR vs AHA vs ERC

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References

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