Cardiac Tamponade

Quick Answer

One-liner: Cardiac tamponade is pericardial fluid accumulation causing external cardiac compression and obstructive shock requiring emergent pericardiocentesis.

Cardiac tamponade occurs when pericardial fluid accumulates faster than the parietal pericardium can stretch, causing intrapericardial pressure to exceed intracardiac diastolic pressures. This results in impaired ventricular filling, reduced cardiac output, and obstructive shock. Mortality approaches 80% if untreated, but drops to 5-15% with prompt drainage. The key immediate action is recognition via clinical signs (Beck's triad, pulsus paradoxus) and POCUS confirmation, followed by emergent pericardiocentesis while temporizing with cautious fluid resuscitation and avoiding positive pressure ventilation if possible.

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ACEM Exam Focus

Primary Exam Relevance

• Anatomy: Pericardial layers (fibrous parietal, serous visceral/epicardium), pericardial sinuses (transverse, oblique), subxiphoid approach anatomy, coronary arteries at risk
• Physiology: Pericardial pressure-volume relationship, ventricular interdependence, diastolic filling pressures, pulsus paradoxus mechanism (exaggerated interventricular septal shift during inspiration)
• Pharmacology: Avoid negative inotropes (β-blockers, calcium channel blockers), avoid vasodilators, cautious use of induction agents (ketamine preferred over propofol/thiopentone)

Fellowship Exam Relevance

• Written: Beck's triad sensitivity/specificity, pulsus paradoxus measurement, ECG findings (electrical alternans, low voltage, sinus tachycardia), POCUS signs (RA/RV collapse timing), pericardiocentesis technique and complications, post-cardiac arrest PEA with tamponade
• OSCE: Likely scenarios include POCUS-guided diagnosis, obtaining consent for emergent pericardiocentesis, managing post-procedural complications, leading resuscitation of PEA arrest with tamponade as reversible cause
• Key domains tested: Medical Expert (diagnosis, procedural skill), Communicator (consent, crisis communication), Collaborator (team coordination for emergent procedure)

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Key Points

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Epidemiology

Australian/NZ Specific

• Limited Australian-specific epidemiological data; incidence mirrors international data
• Post-cardiac surgery tamponade occurs in 0.5-2% of cases (higher in Australian cardiothoracic centres)
• Indigenous Australians have higher rates of rheumatic heart disease leading to pericardial complications (2-3× non-Indigenous rates)
• Remote/rural presentations often delayed due to access barriers - RFDS retrieval common for unstable tamponade requiring drainage

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Pathophysiology

Mechanism

Cardiac tamponade represents the extreme end of the pericardial pressure-volume relationship spectrum:

1. Normal pericardium: Contains 15-50 mL serous fluid, intrapericardial pressure 0-5 mmHg
2. Compensated effusion: Slow accumulation (weeks-months) allows parietal pericardium to stretch - up to 2 L can be tolerated without hemodynamic compromise
3. Decompensated tamponade: Rapid accumulation (hours-days) or exceeding pericardial compliance → intrapericardial pressure exceeds right-sided diastolic filling pressures → impaired ventricular filling

Critical concept: The rate of fluid accumulation matters more than absolute volume. As little as 100-200 mL of rapidly accumulated blood (trauma, aortic dissection, post-procedure) can cause tamponade, while 1-2 L of slowly accumulated fluid (malignancy, uremia) may be asymptomatic.

Pathological Progression

Pericardial fluid accumulation
    ↓
Intrapericardial pressure rises
    ↓
Exceeds right atrial pressure (first chamber affected - lowest pressure)
    ↓
RA diastolic collapse → impaired RV filling
    ↓
Exceeds RV diastolic pressure
    ↓
RV diastolic collapse → reduced RV stroke volume
    ↓
LV preload decreases → cardiac output falls
    ↓
Compensatory tachycardia + peripheral vasoconstriction
    ↓
Decompensation → obstructive shock → PEA arrest

Ventricular Interdependence

The mechanism of pulsus paradoxus:

• Inspiration: Negative intrathoracic pressure → increased venous return to right heart → RV volume increases
• Fixed pericardial volume: Expanded RV pushes interventricular septum leftward → LV volume decreases
• Result: LV stroke volume drops during inspiration → exaggerated fall in systolic BP (greater than 10 mmHg)

This interventricular dependence is exaggerated in tamponade because both ventricles compete for limited space within the rigid, fluid-filled pericardial sac.

Why It Matters Clinically

• Tachycardia is compensatory - maintain cardiac output (CO = HR × SV); bradycardia is pre-arrest sign
• Avoid positive pressure ventilation - eliminates negative intrathoracic pressure driving venous return; PPV can precipitate complete cardiovascular collapse
• Fluid boluses temporize - increase preload to partially overcome elevated intrapericardial pressure
• Small drainage = big effect - removing 50-100 mL can dramatically reduce intrapericardial pressure and restore filling

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Clinical Approach

Recognition

High-risk scenarios to trigger suspicion:

• Post-central line insertion (especially internal jugular, subclavian)
• Post-cardiac catheterization or ablation
• Post-pacemaker/ICD insertion
• Blunt/penetrating chest trauma
• Recent cardiac surgery
• Known malignancy (especially lung, breast, lymphoma)
• End-stage renal failure on dialysis
• Acute chest pain with syncope (aortic dissection)
• PEA arrest with narrow complex QRS

Initial Assessment

Primary Survey

• A (Airway): Usually patent, patient may be distressed/agitated due to hypoperfusion
• B (Breathing):
  • Tachypnea common (compensatory)
  • Respiratory distress if large effusion compressing lungs
  • "CRITICAL: Avoid intubation if possible - PPV can cause arrest"
• C (Circulation):
  • Hypotension (SBP below 90 mmHg)
  • Narrow pulse pressure
  • Tachycardia (HR greater than 100-120 bpm)
  • Elevated JVP (difficult to assess if patient supine)
  • Muffled heart sounds (insensitive)
  • Weak peripheral pulses
  • Cold, clammy peripheries (peripheral vasoconstriction)
• D (Disability):
  • Anxious, agitated (hypoperfusion)
  • Altered mental status if shock severe
• E (Exposure):
  • Pericardiocentesis site preparation (subxiphoid, apical)
  • Look for signs of trauma, recent procedures

Beck's Triad (Classical but INSENSITIVE)

Clinical Pearl: Absence of Beck's triad does NOT exclude tamponade. Low sensitivity means many cases present atypically, especially in early/subacute tamponade.

Pulsus Paradoxus (SENSITIVE)

Definition: Exaggerated drop in systolic BP during inspiration greater than 10 mmHg (normal below 10 mmHg).

Measurement technique:

1. Inflate BP cuff above systolic pressure
2. Deflate slowly (~2 mmHg/sec)
3. Note pressure at which Korotkoff sounds first heard during expiration only
4. Continue deflating until sounds heard throughout respiratory cycle
5. Pulsus paradoxus = difference between these two pressures

Interpretation:

• greater than 10 mmHg: Suggestive of tamponade (sensitivity 75-95%)
• greater than 20 mmHg: Highly suggestive
• greater than 30 mmHg: Severe tamponade

Limitations:

• Difficult to measure in shock (low BP)
• Difficult in atrial fibrillation (irregular rhythm)
• May be absent in:
  • Aortic regurgitation
  • ASD
  • Regional tamponade (post-cardiac surgery)
  • Severe LV dysfunction

History

Key Questions

Red Flag Symptoms

Examination

General Inspection

• Patient often sitting upright, leaning forward (reduces pericardial pressure)
• Anxious, restless (catecholamine surge)
• Tachypneic
• Diaphoretic, pale (sympathetic activation)

Specific Findings

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Investigations

Immediate (Resus Bay)

POCUS - Diagnostic Criteria

Four cardinal POCUS findings (sensitivity/specificity when combined ~90%/95%):

1. Pericardial effusion:

   • Anechoic (black) space between epicardium (visceral pericardium) and pericardium (parietal layer)
   • Circumferential distribution
   • Size: Small (below 1 cm), moderate (1-2 cm), large (greater than 2 cm)
   • Remember: Size does NOT predict tamponade - rate of accumulation matters more

2. Diastolic chamber collapse (MOST SPECIFIC SIGN):

   • RA collapse: Occurs in late diastole/early systole (RA pressure lowest); sensitive but less specific
   • RV collapse: Occurs in early diastole (RV pressure lowest); more specific for tamponade
   • Duration: Collapse greater than 1/3 of cardiac cycle strongly suggestive
   • Best seen in subcostal and apical 4-chamber views

3. IVC plethora (high negative predictive value if absent):

   • IVC diameter greater than 2 cm
   • Minimal respiratory collapse (below 50% with inspiration)
   • Indicates elevated central venous pressure
   • Pearl: If IVC collapses normally (greater than 50%), tamponade is unlikely

4. Swinging heart:

   • Heart swings anteroposteriorly within large pericardial effusion
   • Causes electrical alternans on ECG (beat-to-beat variation in QRS amplitude)
   • Indicates large volume effusion with high risk of hemodynamic compromise

POCUS views:

• Subcostal: Best for pericardial effusion, RA collapse, IVC assessment
• Parasternal long axis: Good for anterior/posterior effusion size
• Apical 4-chamber: Good for RV collapse, mitral inflow Doppler
• Parasternal short axis: Assess circumferential distribution

Standard ED Workup

ECG Findings

Electrical alternans mechanism: Heart swings anteroposteriorly within large effusion → variable distance from chest wall electrodes → varying QRS amplitude.

Advanced/Specialist

Point-of-Care Ultrasound

POCUS is the diagnostic test of choice in the ED for suspected tamponade.

Advantages:

• Immediate bedside diagnosis
• No ionizing radiation
• Identifies reversible cause of PEA arrest during resuscitation
• Guides pericardiocentesis (real-time needle visualization)
• High sensitivity/specificity when 4 signs present (~90%/95%)

Limitations:

• Operator-dependent
• Poor windows in obesity, emphysema, subcutaneous emphysema
• Cannot distinguish transudative vs exudative vs hemorrhagic effusion (requires fluid analysis)
• Regional tamponade (post-surgical) may have atypical findings

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Management

Immediate Management (First 10 minutes)

Parallel processes - do not delay pericardiocentesis for investigations

1. RECOGNITION + CALL FOR HELP (0-2 min)
   - Activate resuscitation team
   - Notify cardiology/cardiothoracics
   - Prepare for emergent pericardiocentesis

2. MONITORING + ACCESS (2-5 min)
   - Continuous cardiac monitoring, pulse oximetry, BP
   - Large-bore IV access × 2 (14-16G)
   - Arterial line if time permits (monitor pulsus paradoxus)

3. TEMPORIZING MEASURES (5-10 min)
   - IV fluid bolus: 500-1000 mL crystalloid STAT (↑ preload)
   - Keep patient SITTING UPRIGHT (↓ pericardial pressure)
   - Supplemental oxygen (avoid HFNP/NIV if possible)
   - AVOID INTUBATION unless absolutely unavoidable

4. PREPARE FOR PERICARDIOCENTESIS (5-10 min)
   - Obtain verbal consent if time permits
   - Ultrasound machine ready + sterile probe cover
   - Pericardiocentesis kit + spinal needle (18-20G) + syringe
   - Guidewire + pigtail catheter for drainage

Resuscitation

Airway

• Keep patient spontaneously breathing if at all possible
• If intubation unavoidable (e.g., cardiac arrest, severe hypoxia):
  • Prepare for immediate pericardiocentesis or thoracotomy (PPV may precipitate arrest)
  • Use ketamine (1-2 mg/kg) - preserves sympathetic tone and cardiac output
  • AVOID propofol, thiopentone - negative inotropes, vasodilation → arrest
  • Use lowest PEEP possible (below 5 cmH₂O)
  • Bag-mask ventilation may be preferable to PPV initially

Breathing

• Supplemental O₂ to maintain SpO₂ ≥94%
• Avoid high-flow nasal oxygen or NIV - positive pressure impairs venous return
• If mechanical ventilation required:
  • Low tidal volumes (6-8 mL/kg IBW)
  • Minimal PEEP (0-5 cmH₂O)
  • Avoid auto-PEEP (allow adequate expiratory time)

Circulation

Haemodynamic targets:

• SBP greater than 90 mmHg (or MAP greater than 65 mmHg)
• HR below 120 bpm (if higher, suspect decompensation)
• Urine output greater than 0.5 mL/kg/hr
• Lactate clearance

Temporizing strategies (bridge to pericardiocentesis):

1. IV fluids:

   • Crystalloid bolus: 500-1000 mL STAT, repeat to total 2-3 L
   • Goal: Increase RA pressure to partially overcome elevated intrapericardial pressure
   • Caution: Excessive fluids may worsen RV distension - monitor response

2. Inotropes/vasopressors (if fluid resuscitation insufficient):

   • Noradrenaline 0.05-0.3 mcg/kg/min (first-line): Vasoconstriction + inotropy
   • Adrenaline 0.05-0.5 mcg/kg/min (if arrest imminent): Vasoconstriction + chronotropy + inotropy
   • Avoid vasodilators (nitroglycerin, hydralazine) - worsen hypotension

3. Positioning:

   • Sitting upright - reduces pericardial pressure
   • If patient prefers supine, allow (positional preference may indicate degree of compensation)

DO NOT delay definitive treatment (pericardiocentesis) for temporizing measures.

Pericardiocentesis - Definitive Treatment

Indications

Absolute indications:

• Cardiac tamponade with hemodynamic instability (hypotension, shock)
• Cardiac tamponade with impending arrest
• PEA arrest with POCUS showing pericardial effusion (resuscitative pericardiocentesis)

Relative indications (can defer to elective drainage):

• Large pericardial effusion (greater than 2 cm) without hemodynamic compromise
• Diagnostic aspiration for suspected purulent/malignant effusion

Contraindications

Absolute:

• Aortic dissection with hemopericardium (requires surgery, not drainage)
• Traumatic hemopericardium requiring surgical repair
• Myocardial free wall rupture post-MI (requires surgery)

Relative (risk vs benefit):

• Coagulopathy (INR greater than 1.5, platelets below 50,000) - correct if time permits
• Small loculated effusion (below 1 cm) - high complication risk

Techniques

1. Ultrasound-guided subxiphoid approach (PREFERRED in ED):

Landmarks:

• Entry point: 1-2 cm below xiphoid process, 1 cm left of midline
• Angle: 30-45° to skin, directed toward left shoulder

Procedure:

1. Preparation:

   • Informed consent (verbal if emergent)
   • Supine or 30° head-up
   • Sterile field (chlorhexidine, drape)
   • Local anaesthetic: 1% lidocaine 5-10 mL (if patient conscious)

2. POCUS identification:

   • Subcostal view - identify effusion, heart chambers, liver
   • Mark entry point and needle trajectory on screen
   • Measure depth to effusion

3. Needle insertion:

   • 18-20G spinal needle or pericardiocentesis needle
   • Attach 20-60 mL syringe
   • Advance at 30-45° toward left shoulder
   • Constant gentle aspiration while advancing
   • ECG monitoring (some recommend alligator clip on needle to detect ST elevation if touching myocardium - not evidence-based)

4. Real-time ultrasound guidance:

   • Visualize needle as hyperechoic line approaching effusion
   • Agitated saline test: Inject 1-2 mL agitated saline - microbubbles appear in pericardial space (NOT cardiac chambers)
   • Once in pericardial space, advance guidewire (Seldinger technique)

5. Catheter placement:

   • Dilate tract (8-10 Fr dilator)
   • Insert pigtail catheter over guidewire
   • Remove guidewire
   • Aspirate fluid - send for analysis

6. Confirmation:

   • POCUS: Reduced/absent effusion, improved RV filling
   • Hemodynamics: Improved BP, HR, pulsus paradoxus

Expected findings:

• Hemodynamic improvement with aspiration of even 50-100 mL - dramatic drop in intrapericardial pressure
• Total drainage: Variable (100 mL to greater than 1 L depending on cause)

Complications (3-7% with ultrasound guidance):

• Cardiac perforation/laceration (most common) - stop procedure, surgical consultation
• Coronary artery laceration - life-threatening, requires immediate surgery
• Pneumothorax - if needle too lateral
• Liver laceration - if needle too caudal or right of midline
• Arrhythmias - usually benign (PVCs), resolve with needle withdrawal
• Infection - rare with sterile technique
• Hemothorax - if enters pleural space

2. Apical approach (alternative if subxiphoid unsuccessful):

Landmarks:

• Entry point: Point of maximal impulse (PMI), usually 5th intercostal space, mid-clavicular line
• Angle: Perpendicular to chest wall

Advantages: More direct route to apex Disadvantages: Higher risk of coronary artery injury, pneumothorax

3. Emergent resuscitative thoracotomy (if pericardiocentesis fails in extremis):

Indications:

• Traumatic cardiac arrest with suspected tamponade
• Failed pericardiocentesis in PEA arrest
• Penetrating chest trauma with witnessed arrest

Procedure: Left anterolateral thoracotomy (4th-5th intercostal space), open pericardium anterior to phrenic nerve, evacuate blood/clot, repair cardiac injury if possible

Pericardial Fluid Analysis

Always send pericardial fluid for:

• Appearance: Bloody, serous, purulent, chylous
• Cell count + differential: WCC, RBC
• Gram stain + culture: Bacterial, mycobacterial (TB), fungal
• Biochemistry: Protein, glucose, LDH (differentiate transudate vs exudate)
• Cytology: Malignant cells

Interpretation:

Medications

Temporizing Pharmacotherapy

For Intubation (if unavoidable)

Paediatric Dosing

Ongoing Management

After pericardiocentesis:

1. Leave pigtail catheter in situ - continue drainage over 24-48 hours (reduces recurrence)
2. Serial POCUS - q4-8h to monitor for re-accumulation
3. Hemodynamic monitoring - arterial line, CVP monitoring if ICU
4. Pericardial fluid analysis - guide further management (treat cause)
5. Treat underlying cause:
   • Uremic: Intensive hemodialysis
   • Bacterial: IV antibiotics (vancomycin + 3rd gen cephalosporin)
   • Malignant: Oncology consultation, consider pericardial window
   • Autoimmune: Immunosuppression (corticosteroids, colchicine)
   • Idiopathic viral: NSAIDs, colchicine

Definitive Care

Indications for cardiothoracic surgery consultation:

• Recurrent tamponade (greater than 2 episodes)
• Purulent pericarditis requiring washout
• Traumatic hemopericardium requiring repair
• Malignant effusion requiring pericardial window (pleuropericardial or peritoneopericardial)
• Constrictive pericarditis (chronic sequelae)

Surgical options:

• Pericardial window (subxiphoid or thoracoscopic): Creates communication between pericardial and pleural/peritoneal space - reduces recurrence
• Pericardiectomy: Complete removal of pericardium - for recurrent/constrictive pericarditis
• Cardiac repair: For traumatic injuries, myocardial rupture

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Disposition

Admission Criteria

ALL patients with cardiac tamponade require admission.

ICU/HDU admission:

• All patients post-pericardiocentesis (monitor for re-accumulation, hemodynamic stability)
• Hemodynamic instability requiring inotropes/vasopressors
• Post-cardiac arrest
• Ongoing drainage greater than 50-100 mL/hour (suggests active bleeding)

Ward admission (monitored bed):

• Stable post-drainage with small residual effusion
• Definitive cause identified and being treated (e.g., uremic on dialysis)

ICU/HDU Criteria

• SBP below 90 mmHg despite drainage
• Requiring inotropes/vasopressors
• Post-intubation
• Post-cardiac arrest (resuscitative pericardiocentesis)
• Purulent pericarditis requiring antibiotics + serial drainage
• High-risk of re-accumulation (malignant, traumatic)

Discharge Criteria

No patient with acute tamponade is discharged from ED.

Discharge from hospital (after 3-7 days):

• No re-accumulation on serial POCUS
• Hemodynamically stable off inotropes greater than 24 hours
• Underlying cause treated or plan in place
• Pigtail catheter removed (once drainage below 25-50 mL/24h)
• Follow-up arranged with cardiology

Follow-up

• Cardiology outpatient in 1-2 weeks - repeat echocardiography to confirm resolution
• Repeat POCUS at 1, 3, 6 months (recurrence risk 10-40% depending on cause)
• Treat underlying cause:
  • "Malignancy: Oncology referral"
  • "Autoimmune: Rheumatology referral"
  • "Uremic: Nephrology optimization of dialysis"
  • "Post-procedure: Device clinic review"
• Red flags to return: Dyspnea, chest pain, syncope, lightheadedness

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Special Populations

Paediatric Considerations

Differences from adults:

• More commonly post-cardiac surgery or congenital heart disease
• Viral pericarditis (coxsackie, adenovirus) more common
• Smaller pericardial volumes - as little as 30-50 mL can cause tamponade
• Tachycardia more pronounced (HR greater than 150-180 bpm)

Paediatric-specific management:

• Fluid bolus: 20 mL/kg (repeat up to 60 mL/kg)
• Pericardiocentesis needle: 20-22G (smaller gauge)
• Pigtail catheter: 5-8 Fr (smaller size)
• Sedation: Ketamine 1-2 mg/kg IV preferred
• Early cardiothoracic surgery consultation (higher surgical intervention rate)

Pregnancy

Physiological changes:

• Increased blood volume → compensated tamponade may present later
• Tachycardia baseline higher (HR 80-100 bpm) → subtle sign
• Supine hypotension from IVC compression by gravid uterus → confounds diagnosis

Pregnancy-specific causes:

• Peripartum cardiomyopathy with effusion
• Pre-eclampsia/HELLP syndrome
• Aortic dissection (rare)

Management modifications:

• Left lateral tilt (30°) - relieves IVC compression
• Fetal monitoring if viable (greater than 24 weeks)
• Avoid teratogenic drugs: Most resuscitation drugs safe in emergency
• Caesarean section if maternal arrest (perimortem C-section at 4 minutes if no ROSC)

Elderly

Considerations:

• More likely to have pericardial effusion from malignancy, uremia, post-MI
• Atypical presentation common (confusion, falls, weakness)
• Comorbidities (AF, CKD, anticoagulation) complicate diagnosis
• Higher procedural complication risk
• Poorer outcomes (mortality 15-25% vs 5-10% in younger patients)

Management:

• Careful fluid resuscitation - risk of pulmonary edema in heart failure
• Anticoagulation reversal if time permits (vitamin K, PCC, platelets)
• Early goals-of-care discussion - procedural risks, prognosis

Indigenous Health

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

Health disparities:

• Aboriginal and Torres Strait Islander Australians have 2-3× higher rates of rheumatic heart disease → increased risk of pericarditis/effusion
• Māori in New Zealand have higher rates of cardiovascular disease, post-MI complications
• Higher prevalence of chronic kidney disease → uremic pericarditis risk
• Delayed presentations due to geographic isolation (remote/rural communities)

Cultural safety:

• Family involvement: Consult whānau (Māori), family/community elders (Aboriginal/Torres Strait Islander) in decision-making
• Interpreter services: Arrange Aboriginal/Torres Strait Islander interpreter if language barrier
• Cultural liaison: Involve Aboriginal Liaison Officer or Māori Health Worker
• Explain procedures clearly: Pericardiocentesis may be culturally sensitive (body invasion) - ensure informed consent with family present if possible

Remote/rural access:

• Many Indigenous Australians live in remote communities with limited healthcare access
• RFDS retrieval often required for definitive management
• Delayed presentations → higher acuity on arrival
• Telehealth consultation with retrieval physician/cardiologist for guidance

Post-discharge:

• Arrange local follow-up (Aboriginal Medical Service, Māori Health Provider)
• Medication access may be limited in remote areas (PBS restrictions)
• Close-the-Gap programs for chronic disease management

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Pitfalls & Pearls

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Viva Practice

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OSCE Scenarios

Station 1: POCUS Diagnosis of Cardiac Tamponade

Format: Examination/Technical Skills Time: 11 minutes Setting: ED resuscitation bay

Candidate Instructions:

You are the ED registrar. A 55-year-old male presents with acute dyspnea and hypotension 4 hours after a cardiac catheterization. The nursing staff are concerned about his deterioration. Perform a focused cardiac POCUS examination to assess for the cause of his shock and present your findings to the examiner.

The examiner will provide you with POCUS images. You have an ultrasound machine and a high-fidelity mannequin available.

Examiner Instructions: This station assesses the candidate's ability to systematically perform cardiac POCUS to diagnose tamponade and interpret findings. Provide the candidate with pre-recorded POCUS clips showing:

• Subcostal view: Large circumferential pericardial effusion (2.5 cm), diastolic RV collapse
• Parasternal long axis: Pericardial effusion, swinging heart
• IVC view: Dilated IVC (2.8 cm) with minimal respiratory variation (below 20% collapse)
• Apical 4-chamber: Pericardial effusion, diastolic RA collapse

The candidate should perform a systematic examination and correctly identify the four cardinal signs of tamponade.

Actor/Patient Brief: N/A (mannequin)

Marking Criteria:

Expected Standard:

• Pass: ≥6/11
• Key discriminators:
  • Obtaining adequate views (subcostal is essential)
  • Correctly identifying RV diastolic collapse (NOT systolic) - timing is critical
  • Distinguishing RA vs RV collapse and stating RV is more specific
  • Synthesizing 4 findings into diagnosis of tamponade
  • Stating definitive management (pericardiocentesis) rather than just temporizing

Common mistakes:

• Confusing RV collapse (diastole) with normal RV free wall motion (systole)
• Not assessing IVC (high negative predictive value if normal)
• Missing swinging heart (causes electrical alternans)
• Stating "large effusion = tamponade" (size does NOT predict tamponade - physiology does)

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Station 2: Obtaining Consent for Emergent Pericardiocentesis

Format: Communication Time: 11 minutes Setting: ED resuscitation bay

Candidate Instructions:

You are the ED registrar. You have just diagnosed cardiac tamponade in a 68-year-old male patient using POCUS. He is hypotensive (BP 85/60) but conscious and able to communicate. You need to perform emergent pericardiocentesis to save his life. Obtain informed consent for the procedure, explaining the risks, benefits, and alternatives.

Examiner Instructions: The actor will play a conscious but anxious patient with tamponade. He is dyspneic and uncomfortable but able to understand and provide consent. He will ask appropriate questions about the procedure, risks, and alternatives. Assess the candidate's ability to obtain informed consent in an emergency situation while balancing thoroughness with urgency.

Actor/Patient Brief: You are a 68-year-old retired accountant who has been feeling increasingly short of breath and unwell. You had a heart procedure (cardiac catheterization) earlier today. You are frightened and don't fully understand what is happening. You are willing to consent to life-saving treatment but need clear explanations. Ask the following questions if not addressed:

• "What exactly is wrong with me?"
• "Is this procedure dangerous?"
• "What happens if I don't have it?"
• "Will I be asleep for this?"

You should ultimately consent to the procedure if the doctor communicates clearly and empathetically.

Marking Criteria:

Expected Standard:

• Pass: ≥6/11
• Key discriminators:
  • Balancing thoroughness with urgency (explain clearly but don't delay)
  • Framing procedure as life-saving (not optional)
  • Clear communication in lay terms (avoiding medical jargon like "tamponade," "hemodynamic compromise")
  • Empathy and reassurance despite urgency

Common mistakes:

• Over-emphasizing risks without emphasizing life-saving benefit (frightens patient unnecessarily)
• Using medical jargon ("pericardial effusion," "hemodynamic instability") without lay explanations
• Not explicitly obtaining consent (assumes patient agrees)
• Taking too long (this is emergent - consent should be obtained efficiently within 3-5 minutes)

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Station 3: Managing Post-Pericardiocentesis Complication

Format: Resuscitation/Crisis Management Time: 11 minutes Setting: ED resuscitation bay

Candidate Instructions:

You are the ED registrar. You have just performed pericardiocentesis on a patient with cardiac tamponade. During the procedure, the patient suddenly becomes hypotensive (BP 60/40 mmHg) and tachycardic (HR 140 bpm). The nurse calls you urgently to the bedside. Manage this situation.

The examiner will provide clinical information as you request it. You have a full resuscitation team available (state what you need and the examiner will confirm actions are completed).

Examiner Instructions: This station assesses crisis management and recognition of iatrogenic cardiac perforation during pericardiocentesis. The patient has developed acute hemopericardium from RV perforation by the pericardiocentesis needle.

Scenario progression:

• Initial: BP 60/40, HR 140, SpO₂ 90% on room air, GCS 13 (confused)
• POCUS (if requested): Worsening pericardial effusion, new clot in pericardium
• After fluid resuscitation + adrenaline: BP improves to 75/50, HR 130
• After stopping needle advancement + draining pericardium: BP improves to 90/60, HR 110
• If candidate calls cardiothoracics: Available within 20 minutes for emergent thoracotomy

Provide information only when requested. Assess systematic approach, recognition of complication, and appropriate escalation.

Actor/Patient Brief: N/A (mannequin - patient is unable to communicate due to altered mental status)

Marking Criteria:

Expected Standard:

• Pass: ≥6/11
• Key discriminators:
  • Immediate recognition of iatrogenic complication (NOT just "worsening tamponade")
  • Stopping further needle advancement
  • Calling cardiothoracic surgery early (may require emergent operative repair)
  • Continuing pericardial drainage (draining new hemopericardium may temporize)
  • Avoiding intubation unless absolutely necessary (PPV worsens hemodynamics)

Common mistakes:

• Assuming worsening is due to "not draining fast enough" (rather than iatrogenic injury)
• Not calling cardiothoracic surgery (delays definitive management if repair needed)
• Removing needle AND pigtail catheter completely (loses ability to drain accumulating hemopericardium)
• Intubating patient without preparing for arrest (PPV can precipitate arrest in tamponade)

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SAQ Practice

Question 1 (6 marks)

Stem: A 45-year-old man presents to ED with sudden onset chest pain and dyspnea. He was involved in a bar fight and sustained a single stab wound to the left chest 2 hours ago. Observations: HR 125 bpm, BP 80/60 mmHg, RR 28/min, SpO₂ 92% on room air. JVP is elevated. Heart sounds are difficult to auscultate.

Question: List SIX POCUS findings that would support a diagnosis of cardiac tamponade in this patient.

Model Answer:

1. Pericardial effusion - circumferential anechoic (black) space between epicardium and pericardium (1 mark)
2. Right atrial (RA) collapse - inward bowing of RA free wall during late diastole/early systole (1 mark)
3. Right ventricular (RV) collapse - inward bowing of RV free wall during early diastole, lasting greater than 1/3 cardiac cycle (more specific than RA collapse) (1 mark)
4. IVC plethora - dilated inferior vena cava (greater than 2 cm diameter) with minimal respiratory collapse (below 50% decrease in diameter with inspiration) (1 mark)
5. Swinging heart - heart swings anteroposteriorly within large pericardial effusion (causes electrical alternans on ECG) (1 mark)
6. Interventricular septal shift - exaggerated leftward shift of interventricular septum during inspiration (mechanism of pulsus paradoxus on Doppler) (1 mark)

Examiner Notes:

• Also accept:
  • Collapse of left atrium/ventricle (less common, seen in loculated effusions)
  • Mitral inflow variation greater than 25% on Doppler (pulsus paradoxus equivalent)
  • Tricuspid inflow variation greater than 40% on Doppler
  • Absence of respiratory IVC collapse (same as IVC plethora)
• Do not accept:
  • "Fluid around heart" (too vague - must specify pericardial effusion)
  • "Heart not beating well" (not a POCUS finding)
  • "Collapsed right ventricle" without specifying timing (RV collapses in DIASTOLE, not systole)

Common mistakes:

• Not specifying timing of chamber collapse (RA = late diastole, RV = early diastole)
• Confusing IVC findings (in tamponade, IVC does NOT collapse - it's dilated and plethoric)
• Listing only 3-4 findings (need 6 for full marks)

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Question 2 (8 marks)

Stem: You are performing ultrasound-guided pericardiocentesis on a patient with cardiac tamponade using the subxiphoid approach.

Question: Describe the subxiphoid pericardiocentesis technique, including anatomical landmarks, needle trajectory, and ultrasound guidance. (8 marks)

Model Answer:

Anatomical landmarks and positioning:

• Entry point: 1-2 cm inferior to xiphoid process, 1 cm left of midline (1 mark)
• Patient position: Supine or 30° head-up (1 mark)

Needle trajectory:

• Angle: 30-45° to skin, directed toward left shoulder (or left scapular tip) (1 mark)

Pre-procedure POCUS planning:

• Obtain subcostal view to identify pericardial effusion, heart chambers, liver (1 mark)
• Measure depth to effusion on screen, plan needle trajectory (1 mark)

Needle insertion technique:

• Use 18-20G spinal needle (or pericardiocentesis needle) attached to 20-60 mL syringe (0.5 mark)
• Advance with constant gentle aspiration while advancing (identifies entry into pericardial space when fluid aspirated) (0.5 mark)

Ultrasound guidance:

• Real-time visualization of needle (hyperechoic line) approaching pericardial space (1 mark)
• Agitated saline test: Inject 1-2 mL agitated saline; microbubbles appearing in pericardial space (NOT cardiac chambers) confirms correct position (1 mark)

Catheter placement (Seldinger technique):

• Advance guidewire through needle once in pericardial space, remove needle, dilate tract, insert pigtail catheter (8-10 Fr), remove guidewire, aspirate fluid (1 mark)

Examiner Notes:

• Accept: Alternative entry point landmarks (e.g., "left xiphocostal angle")
• Do not accept:
  • Apical approach landmarks (this question specifically asks for subxiphoid)
  • "Insert needle into chest" (too vague - need specific landmarks and trajectory)

Common mistakes:

• Not mentioning constant aspiration while advancing (critical for identifying pericardial space)
• Stating needle is directed toward "heart" (too vague - should be left shoulder)
• Not mentioning ultrasound guidance (question specifically asks for this)
• Forgetting Seldinger technique for catheter placement

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Question 3 (8 marks)

Stem: A 70-year-old woman presents in PEA cardiac arrest. POCUS during a brief pause in CPR reveals a moderate pericardial effusion with diastolic RV collapse.

Question: a) State the relevant ANZCOR guideline that addresses this scenario. (1 mark) b) List the "4Hs and 4Ts" reversible causes of cardiac arrest. (4 marks) c) Outline your management of this patient's cardiac arrest. (3 marks)

Model Answer:

a) ANZCOR Guideline:

• ANZCOR Guideline 11.7 - Reversible Causes of Cardiac Arrest (1 mark)
  • Accept: "ANZCOR Guideline 11.7," "Guideline 11.7," "ANZCOR reversible causes guideline"

b) Reversible Causes (4Hs and 4Ts):

4 Hs:

1. Hypoxia (0.5 mark)
2. Hypovolemia (0.5 mark)
3. Hypo/Hyperkalaemia (and other electrolyte abnormalities) (0.5 mark)
4. Hypothermia (0.5 mark)

4 Ts:

1. Tamponade (cardiac) (0.5 mark)
2. Tension pneumothorax (0.5 mark)
3. Thrombosis - coronary (acute MI) (0.5 mark)
4. Thrombosis - pulmonary (massive PE) (0.5 mark)

c) Management of cardiac arrest with tamponade (3 marks):

1. Continue high-quality CPR per ANZCOR guidelines (depth 5-6 cm, rate 100-120/min, minimal interruptions) + airway management (LMA/ETT) + adrenaline 1 mg IV q3-5 min (1 mark)

2. Resuscitative pericardiocentesis during CPR: Insert pericardiocentesis needle (subxiphoid approach) and aspirate pericardial fluid during CPR; even small volume (50-100 mL) may restore cardiac output and achieve ROSC (1 mark)

3. If pericardiocentesis fails or not possible: Consider emergent resuscitative thoracotomy (left anterolateral, 4th-5th intercostal space, open pericardium, evacuate fluid/blood, internal cardiac massage) (1 mark)

Examiner Notes:

• Accept:
  • For 4Hs: "Hydrogen ions" (acidosis) instead of "Hypo/Hyperkalaemia" (some versions of ANZCOR)
  • For management: "Place pigtail catheter" (Seldinger technique after initial aspiration)
• Do not accept:
  • "Heart attack" for thrombosis-coronary (must use "acute MI" or "coronary thrombosis")
  • For management: "Wait for ROSC then drain" (pericardiocentesis must be performed DURING CPR for tamponade-related arrest)

Common mistakes:

• Confusing 4Hs and 4Ts (e.g., listing "toxins" or "trauma"
• these are NOT in the classic list)
• Not specifying that pericardiocentesis is performed DURING CPR (not after ROSC)
• Stating "stop CPR to perform pericardiocentesis" (CPR continues, pericardiocentesis is done during brief pauses or with modified hand position)

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Question 4 (6 marks)

Stem: You aspirate pericardial fluid during pericardiocentesis. The fluid is heavily blood-stained.

Question: List THREE features that would distinguish hemopericardium (true blood in the pericardial space) from a bloody tap (iatrogenic cardiac chamber puncture). (6 marks - 2 marks per feature)

Model Answer:

1. Clotting:

   • Hemopericardium: Fluid does NOT clot (blood in pericardium is defibrinated by constant cardiac motion) (2 marks)
   • Bloody tap: Fluid clots (fresh blood from cardiac chamber contains active clotting factors)
   • Accept: "Hemopericardium is non-clotting, bloody tap clots"

2. Hematocrit:

   • Hemopericardium: Hematocrit of pericardial fluid is 50-70% of peripheral blood hematocrit (blood has been in pericardium for some time, RBCs settle/lyse) (2 marks)
   • Bloody tap: Hematocrit of aspirated fluid is equal to peripheral blood hematocrit (fresh whole blood)
   • Accept: "Hemopericardium has lower hematocrit than bloody tap"

3. Ultrasound appearance during aspiration:

   • Hemopericardium: Fluid appears uniformly bloody on POCUS before and during aspiration; effusion size decreases with drainage (2 marks)
   • Bloody tap: May see swirling or layering of blood on real-time POCUS during aspiration (injection of fresh blood into pericardial space); effusion may not decrease in size (blood entering = blood being aspirated)
   • Accept: "Hemopericardium is uniform on ultrasound, bloody tap shows real-time swirling"

Examiner Notes:

• Also accept (2 marks each):
  • "Hemopericardium: Patient has clinical history consistent with hemorrhage (trauma, dissection, rupture, anticoagulation); Bloody tap: No clear cause for hemopericardium"
  • "Hemopericardium: Hemodynamic improvement with aspiration; Bloody tap: No hemodynamic improvement or worsening (if ongoing perforation)"
• Do not accept:
  • "Color" alone (both are bloody - too vague)
  • "Amount" (both can yield large volumes)

Common mistakes:

• Not providing BOTH sides of the comparison (must distinguish hemopericardium vs bloody tap for each feature)
• Listing only 1-2 features (need 3 for full marks)
• Confusing clotting (hemopericardium does NOT clot, bloody tap does - opposite is incorrect)

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Australian Guidelines

ARC/ANZCOR

ANZCOR Guideline 11.7 - Reversible Causes of Cardiac Arrest:

Key Points:

• Cardiac tamponade is one of the "4 Ts" (Tamponade, Tension pneumothorax, Thrombosis-coronary, Thrombosis-pulmonary)
• Diagnosis: POCUS during brief pauses in CPR (identify pericardial effusion + chamber collapse)
• Treatment: Resuscitative pericardiocentesis during CPR (aspiration of even small volume may achieve ROSC)
• Alternative: Emergent resuscitative thoracotomy if pericardiocentesis fails or not feasible

Key differences from AHA/ERC:

• ANZCOR places greater emphasis on POCUS integration during CPR (pause compressions briefly to obtain subcostal view)
• AHA focuses more on pre-hospital recognition (less ultrasound availability)

ANZCOR Guideline 11.8 - Post-Resuscitation Care:

• Patients achieving ROSC after tamponade require ICU admission, hemodynamic monitoring, pigtail catheter for ongoing drainage, serial POCUS

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Therapeutic Guidelines

Therapeutic Guidelines: Cardiovascular (Version 7, 2022):

Pericardial Effusion and Tamponade:

• First-line treatment for tamponade: Emergent pericardiocentesis (ultrasound-guided preferred)
• Underlying cause management:
  • "Uremic pericarditis: Intensive hemodialysis (daily for 1-2 weeks)"
  • "Bacterial pericarditis: IV antibiotics - empiric: vancomycin 25-30 mg/kg loading + ceftriaxone 2 g daily (adjust based on cultures)"
  • "Tuberculous pericarditis: Anti-TB therapy (rifampicin, isoniazid, pyrazinamide, ethambutol) + corticosteroids (prednisolone 1 mg/kg for 4-6 weeks, taper over 3 months)"
  • "Malignant effusion: Systemic chemotherapy + pericardial window if recurrent"
  • "Autoimmune (SLE, RA): NSAIDs (ibuprofen 400-600 mg TDS) + colchicine (0.5 mg BD) +/- corticosteroids"

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State-Specific

NSW Health:

• NSW ECLS (Extracorporeal Life Support) Service: Available for refractory tamponade with cardiac arrest; contact via NSW Ambulance Medical Director
• NSW Ambulance Protocols: Pre-hospital POCUS for trauma patients - identify pericardial effusion, activate trauma team

Victoria:

• Adult Retrieval Victoria (ARV): Provides retrieval for patients with tamponade requiring transfer to cardiothoracic centres (1300 368 661)
• Alfred Hospital Major Trauma Service: Tertiary referral for traumatic hemopericardium requiring surgical repair

Queensland:

• Retrieval Services Queensland (RSQ): Coordinates retrieval for regional/rural patients with tamponade
• Queensland Ambulance Service: Clinical Practice Procedures - authorize paramedics to perform needle decompression for tension pneumothorax (but NOT pericardiocentesis - medical officer only)

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Remote/Rural Considerations

Pre-Hospital

Recognition:

• Pre-hospital POCUS (if available in RFDS aircraft or advanced paramedic vehicles)
• Clinical diagnosis: Beck's triad (insensitive), pulsus paradoxus (difficult to measure in moving vehicle)
• High index of suspicion in post-trauma, post-MI, known malignancy

Temporizing measures:

• IV access, fluid resuscitation (500-1000 mL crystalloid)
• Avoid intubation unless airway compromise or arrest (PPV worsens hemodynamics)
• Supplemental oxygen
• Rapid transport to definitive care

Resource-Limited Setting

Challenges:

• Limited ultrasound availability (rely on clinical diagnosis)
• No cardiology/cardiothoracic surgery on-site
• Pericardiocentesis may be performed by ED physician or rural generalist (training required)

Modified approach:

• If ultrasound unavailable: Use ECG guidance (attach alligator clip to pericardiocentesis needle, monitor for ST elevation if needle touches myocardium - NOT evidence-based but historical technique)
• If pericardiocentesis expertise unavailable: Temporize with fluids + inotropes, arrange urgent retrieval
• Blind pericardiocentesis (without ultrasound): Higher complication rate (10-20%), only in extremis if no alternative

Retrieval

Indications for retrieval:

• Hemodynamically unstable tamponade requiring pericardiocentesis but no local expertise
• Post-pericardiocentesis requiring cardiology/cardiothoracic follow-up
• Recurrent tamponade requiring pericardial window (surgical intervention)
• Purulent pericarditis requiring surgical washout
• Traumatic hemopericardium requiring cardiac repair

Retrieval considerations:

• RFDS (Royal Flying Doctor Service): Primary retrieval service for remote Australia
  • "Contact: 1800 625 800 (24/7)"
  • Can bring ultrasound, pericardiocentesis equipment
  • Retrieval physician may perform pericardiocentesis en route if patient deteriorates
• Stabilization pre-retrieval:
  • IV access, fluid resuscitation
  • "If trained: Perform pericardiocentesis, leave pigtail catheter in situ for transfer"
  • Avoid intubation if possible (if required, use ketamine, low PEEP)
• In-flight management:
  • "Altitude effects: Reduced barometric pressure may worsen effusion (rare)"
  • Pressurized cabin (RFDS aircraft are pressurized - equivalent to 8,000 feet / 2,400 m)
  • Monitor hemodynamics, drain pigtail catheter PRN

Retrieval destinations:

• NSW: Royal Prince Alfred, St Vincent's, Westmead (cardiothoracic centres)
• Victoria: Alfred, Austin, Box Hill (cardiothoracic centres)
• Queensland: Prince Charles, Royal Brisbane (cardiothoracic centres)
• South Australia: Royal Adelaide
• Western Australia: Fiona Stanley, Royal Perth
• Northern Territory: Royal Darwin (limited cardiothoracic - may retrieve to Adelaide)

Telemedicine

Remote consultation:

• Contact retrieval physician or cardiologist via telemedicine (video consultation available in many rural EDs)
• Send POCUS clips via secure network (e.g., Coviu, Zoom Healthcare) for expert interpretation
• Discuss procedural guidance for pericardiocentesis (real-time telemedicine-guided procedure feasible in experienced hands)

Example:

• Rural ED physician contacts ARV retrieval consultant
• Transmits POCUS clips showing tamponade
• Consultant confirms diagnosis, advises immediate pericardiocentesis
• Rural physician performs procedure with telemedicine guidance (consultant watches via video, provides step-by-step advice)
• Post-procedure: Arrange retrieval for definitive cardiology care

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References

Guidelines

1. Adler Y, Charron P, Imazio M, et al. 2015 ESC Guidelines for the diagnosis and management of pericardial diseases. Eur Heart J. 2015;36(42):2921-2964. PMID: 26320112
2. Australian Resuscitation Council. ANZCOR Guideline 11.7: Reversible Causes of Cardiac Arrest. 2023. Available from: https://resus.org.au
3. Klein AL, Abbara S, Agler DA, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular imaging of patients with pericardial disease. J Am Soc Echocardiogr. 2013;26(9):965-1012. PMID: 23998693
4. Imazio M, Adler Y. Management of pericardial effusion. Eur Heart J. 2013;34(16):1186-1197. PMID: 23125278
5. Therapeutic Guidelines: Cardiovascular. Version 7. Melbourne: Therapeutic Guidelines Limited; 2022.

Key Evidence - Epidemiology

6. Mercé J, Sagristà-Sauleda J, Permanyer-Miralda G, Soler-Soler J. Should pericardial drainage be performed routinely in patients who have a large pericardial effusion without tamponade? Am J Med. 1998;105(2):106-109. PMID: 9727815
7. Imazio M, Spodick DH, Brucato A, Trinchero R, Adler Y. Controversial issues in the management of pericardial diseases. Circulation. 2010;121(7):916-928. PMID: 20177006
8. Spodick DH. Acute cardiac tamponade. N Engl J Med. 2003;349(7):684-690. PMID: 12917306

Key Evidence - Diagnosis

9. Roy CL, Minor MA, Brookhart MA, Choudhry NK. Does this patient with a pericardial effusion have cardiac tamponade? JAMA. 2007;297(16):1810-1818. PMID: 17456823
10. Shabetai R. Pericardial effusion: haemodynamic spectrum. Heart. 2004;90(3):255-256. PMID: 14966036
11. Armstrong WF, Feigenbaum H, Dillon JC. Acute right ventricular diastolic collapse in cardiac tamponade. Circulation. 1982;65(7):1491-1496. PMID: 7074809
12. Gillam LD, Guyer DE, Gibson TC, et al. Hydrodynamic compression of the right atrium: a new echocardiographic sign of cardiac tamponade. Circulation. 1983;68(2):294-301. PMID: 6861308
13. Leimgruber PP, Klopfenstein HS, Wann LS, Brooks HL. The hemodynamic derangement associated with right ventricular diastolic collapse in cardiac tamponade: an experimental echocardiographic study. Circulation. 1983;68(3):612-620. PMID: 6872174
14. Himelman RB, Kircher B, Rockey DC, Schiller NB. Inferior vena cava plethora with blunted respiratory response: a sensitive echocardiographic sign of cardiac tamponade. J Am Coll Cardiol. 1988;12(6):1470-1477. PMID: 3192848

Key Evidence - POCUS

15. Mandavia DP, Hoffner RJ, Mahaney K, Henderson SO. Bedside echocardiography by emergency physicians. Ann Emerg Med. 2001;38(4):377-382. PMID: 11574793
16. Goodman A, Perera P, Mailhot T, Mandavia D. The role of bedside ultrasound in the diagnosis of pericardial effusion and cardiac tamponade. J Emerg Trauma Shock. 2012;5(1):72-75. PMID: 22416159
17. Tayal VS, Kline JA. Emergency echocardiography to detect pericardial effusion in patients in PEA and near-PEA states. Resuscitation. 2003;59(3):315-318. PMID: 14659600

Key Evidence - Pericardiocentesis

18. Tsang TS, Enriquez-Sarano M, Freeman WK, et al. Consecutive 1127 therapeutic echocardiographically guided pericardiocenteses: clinical profile, practice patterns, and outcomes spanning 21 years. Mayo Clin Proc. 2002;77(5):429-436. PMID: 12004992
19. Tsang TS, Freeman WK, Sinak LJ, Seward JB. Echocardiographically guided pericardiocentesis: evolution and state-of-the-art technique. Mayo Clin Proc. 1998;73(7):647-652. PMID: 9663194
20. Maggiolini S, Bozzano A, Russo P, et al. Echocardiography-guided pericardiocentesis with probe-mounted needle: report of 53 cases. J Am Soc Echocardiogr. 2001;14(8):821-824. PMID: 11490333
21. Krikorian JG, Hancock EW. Pericardiocentesis. Am J Med. 1978;65(5):808-814. PMID: 707519
22. Salem K, Mulji A, Lonn E. Echocardiographically guided pericardiocentesis - the gold standard for the management of pericardial effusion and cardiac tamponade. Can J Cardiol. 1999;15(11):1251-1255. PMID: 10579742

Key Evidence - Complications

23. Vayre F, Lardoux H, Pezzano M, et al. Subxiphoid pericardiocentesis guided by contrast two-dimensional echocardiography in cardiac tamponade: experience of 110 consecutive patients. Eur J Echocardiogr. 2000;1(1):66-71. PMID: 12668699
24. Callahan JA, Seward JB, Tajik AJ. Cardiac tamponade: pericardiocentesis directed by two-dimensional echocardiography. Mayo Clin Proc. 1985;60(6):344-347. PMID: 3990372

Key Evidence - Etiology-Specific

25. Imazio M, Brucato A, Maestroni S, et al. Risk of constrictive pericarditis after acute pericarditis. Circulation. 2011;124(11):1270-1275. PMID: 21844077
26. Sagristà-Sauleda J, Mercé AS, Soler-Soler J. Diagnosis and management of pericardial effusion. World J Cardiol. 2011;3(5):135-143. PMID: 21666814
27. Imazio M, Mayosi BM, Brucato A, Markel G, Trinchero R, Spodick DH, Adler Y. Triage and management of pericardial effusion. J Cardiovasc Med (Hagerstown). 2010;11(12):928-935. PMID: 20736787
28. Bastian A, Meissner A, Lins M, Satter P. Pericardiocentesis: differential aspects of a common procedure. Intensive Care Med. 2000;26(5):572-576. PMID: 10923732

Key Evidence - Malignant Effusion

29. Vaitkus PT, Herrmann HC, LeWinter MM. Treatment of malignant pericardial effusion. JAMA. 1994;272(1):59-64. PMID: 7912285
30. Martinoni A, Cipolla CM, Cardinale D, et al. Long-term results of intrapericardial chemotherapeutic treatment of malignant pericardial effusions with thiotepa. Chest. 2004;126(5):1412-1416. PMID: 15539707

Key Evidence - Uremic Pericarditis

31. Rutsky EA, Rostand SG. Treatment of uremic pericarditis and pericardial effusion. Am J Kidney Dis. 1987;10(1):2-8. PMID: 3300293
32. Gunukula SR, Spodick DH. Pericardial disease in renal patients. Semin Nephrol. 2001;21(1):52-56. PMID: 11245779

Key Evidence - Traumatic

33. Asensio JA, Stewart BM, Murray J, et al. Penetrating cardiac injuries. Surg Clin North Am. 1996;76(4):685-724. PMID: 8782508
34. Rozycki GS, Feliciano DV, Ochsner MG, et al. The role of ultrasound in patients with possible penetrating cardiac wounds: a prospective multicenter study. J Trauma. 1999;46(4):543-551. PMID: 10217212

Systematic Reviews

35. Imazio M, Adler Y. Pericardial effusion: diagnosis and management. Curr Cardiol Rep. 2017;19(7):57. PMID: 28497351
36. Maisch B, Seferović PM, Ristić AD, et al. Guidelines on the diagnosis and management of pericardial diseases executive summary; The Task force on the diagnosis and management of pericardial diseases of the European society of cardiology. Eur Heart J. 2004;25(7):587-610. PMID: 15120056
37. Little WC, Freeman GL. Pericardial disease. Circulation. 2006;113(12):1622-1632. PMID: 16567581

Australian-Specific Evidence

38. Orde S, Slama M, Hilton A, Yastrebov K, McLean A. Pearls and pitfalls in comprehensive critical care echocardiography. Crit Care. 2017;21(1):279. PMID: 29162134
39. Royse CF, Royse AG. Ultrasound-guided pericardiocentesis: a safe and effective technique in the critical care environment. Crit Care Resusc. 2005;7(2):100-104. PMID: 16566764

Indigenous Health

40. Katzenellenbogen JM, Ralph AP, Wyber R, Carapetis JR. Rheumatic heart disease in Aboriginal and Torres Strait Islander people. Med J Aust. 2015;203(5):221-222. PMID: 26465693
41. Howden-Chapman P, Tobias M. Social Inequalities in Health: New Zealand 1999. Wellington: Ministry of Health; 2000.

Landmark Studies

42. Beck CS. Two cardiac compression triads. JAMA. 1935;104(9):714-716. [Historical reference - no PMID]