Point-of-Care Ultrasound (POCUS)

Quick Reference

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Quick Answer

Point-of-care ultrasound (POCUS) is bedside imaging performed by the treating clinician to answer focused clinical questions. In emergency medicine, POCUS provides real-time diagnostic information for trauma (eFAST), respiratory failure (BLUE protocol), shock states (RUSH exam), cardiac arrest (ACES protocol), and procedural guidance (central lines, paracentesis). Requires structured training and minimum scan numbers for competency.

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ACEM Exam Focus

Primary Exam

• Anatomy: Thoracic and abdominal anatomy for eFAST, cardiac chambers, IVC, vascular landmarks
• Physics: Ultrasound principles (piezoelectric effect, reflection, attenuation, resolution)
• Viva: Applied anatomy for POCUS applications, probe selection, ultrasound artifacts

Fellowship Written

• SAQ topics: eFAST interpretation, BLUE protocol differential, IVC volume assessment
• Clinical scenarios: Integrating POCUS into ATLS, acute dyspnoea workup, shock management

Fellowship OSCE

• Procedural stations: Performing eFAST, cardiac views, IVC assessment, DVT assessment
• Communication: Explaining POCUS findings to patients, family, consultants
• Interpretation: Image interpretation stations with video clips

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Key Points

Key Point: 1. eFAST protocol scans four abdominal views (RUQ, LUQ, suprapubic, subxiphoid) and two thoracic views (bilateral anterior chest) for free fluid and pneumothorax in trauma patients - sensitivity 79-85% for haemoperitoneum, specificity 95-100%

Key Point: 2. BLUE protocol achieves greater than 90% diagnostic accuracy for acute dyspnoea by systematically scanning three zones per hemithorax to differentiate pulmonary oedema, pneumonia, pneumothorax, COPD, PE, and asthma

Key Point: 3. Cardiac POCUS assesses global contractility (qualitative), pericardial effusion/tamponade, RV dilatation (PE), and volume status - NOT a substitute for formal echocardiography

Key Point: 4. IVC assessment measures diameter and respiratory variation to estimate volume status - IVC below 2.1 cm with greater than 50% collapse suggests hypovolaemia, greater than 2.1 cm with below 50% collapse suggests hypervolaemia (unreliable in mechanical ventilation, raised IAP, cardiac disease)

Key Point: 5. Procedural guidance with ultrasound reduces complications for central venous cannulation (NNT 20 to prevent arterial puncture), paracentesis, thoracentesis, and peripheral IV access - real-time guidance superior to landmark technique

Key Point: 6. ACEM credentialing requires minimum 25-50 supervised scans per application with competency assessment - logbook documentation essential for Fellowship training

Key Point: 7. Lung ultrasound is more sensitive than CXR for pneumothorax (88-98% vs 28-75%), pleural effusion (93% vs 47%), and pulmonary consolidation (90-98% vs 70-77%) - performed at bedside with immediate results

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Epidemiology

POCUS Adoption

• Emergency Medicine: 85-95% of Australian EDs have ultrasound capability
• Training: ACEM mandates POCUS training for all trainees since 2016
• Applications: eFAST most common (90%), followed by vascular access (75%), cardiac (60%)
• Credentialing: Variable across hospitals - range from informal to formal competency assessment

Evidence Base

• eFAST meta-analysis: 31 studies, 5,158 patients - sensitivity 79% (95% CI 72-85%), specificity 96% (95% CI 94-97%) for free fluid
• BLUE protocol: Original Lichtenstein study - 260 patients, 90.5% diagnostic accuracy for acute dyspnoea
• US-guided CVC: Cochrane review 13 trials, 2,341 patients - relative risk 0.14 (95% CI 0.06-0.33) for inadvertent arterial puncture

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Ultrasound Physics Principles

Piezoelectric Effect

• Crystal transducer converts electrical energy → mechanical sound waves (transmission) and sound waves → electrical signals (reception)
• Frequency range: 2-15 MHz in clinical use
• Higher frequency: Better resolution, less penetration (superficial structures)
• Lower frequency: Worse resolution, greater penetration (deep structures)

Image Generation

• A-mode (Amplitude): Signal strength vs time (not used in POCUS)
• B-mode (Brightness): 2D greyscale image - standard POCUS mode
• M-mode (Motion): Single line over time - cardiac wall motion, lung sliding
• Doppler: Detects moving structures (blood flow, cardiac valves)

Ultrasound Interactions

Resolution

• Axial resolution: Ability to distinguish objects along beam axis (0.1-1 mm)
• Lateral resolution: Ability to distinguish objects perpendicular to beam (1-3 mm)
• Temporal resolution: Frame rate (real-time imaging requires greater than 15 frames/sec)

Ultrasound Artifacts

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Equipment

Ultrasound Machines

Probe Selection

Curvilinear (Convex) Probe

• Frequency: 2-5 MHz
• Depth: 15-30 cm
• Field of view: Wide sector (convex footprint)
• POCUS applications: Abdominal eFAST, AAA, IVC, obstetric, deep structures
• Advantages: Penetrates deep structures, wide field
• Disadvantages: Poorer near-field resolution

Linear (High-Frequency) Probe

• Frequency: 5-15 MHz
• Depth: 4-8 cm
• Field of view: Rectangular (linear footprint)
• POCUS applications: Vascular access, DVT, soft tissue, lung, nerve blocks, MSK
• Advantages: Excellent near-field resolution, wide rectangular field
• Disadvantages: Limited depth penetration

Phased Array (Cardiac) Probe

• Frequency: 2-4 MHz
• Depth: 15-25 cm
• Field of view: Narrow sector from small footprint
• POCUS applications: Cardiac views, subxiphoid eFAST, difficult thoracic windows
• Advantages: Small footprint (intercostal imaging), good depth
• Disadvantages: Narrow near-field

Endocavitary Probe

• Frequency: 5-9 MHz
• Depth: 8-12 cm
• POCUS applications: First-trimester pregnancy, pelvic pathology
• ED use: Limited - curvilinear probe adequate for most applications

Essential Equipment

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Core POCUS Applications in Emergency Medicine

1. eFAST Protocol (Extended Focused Assessment with Sonography in Trauma)

Indications

• All major trauma patients (blunt or penetrating)
• Haemodynamically unstable trauma with potential torso injury
• Mechanism concerning for internal bleeding (high-speed MVA, falls greater than 3 metres, penetrating torso)
• Serial exams in observed trauma patients

Systematic Approach - 6 Views

View 1: Right Upper Quadrant (RUQ) - Morison's Pouch

• Probe: Curvilinear or phased array
• Position: Right mid-axillary line, 8th-11th intercostal space
• Orientation: Indicator cephalad (longitudinal/coronal plane)
• Structures visualised: Liver, right kidney, hepatorenal space (Morison's pouch), diaphragm, pleural space
• Looking for: Free fluid (anechoic stripe) in hepatorenal recess, right hemithorax effusion, subphrenic fluid

Clinical Pearl: Morison's pouch is the most dependent part of the peritoneal cavity in supine position - first place to accumulate free fluid. As little as 100-200 mL can be detected. Scan from anterior to posterior to assess entire hepatorenal space.

View 2: Left Upper Quadrant (LUQ) - Splenorenal Recess

• Probe: Curvilinear or phased array
• Position: Left posterior axillary line, 6th-9th intercostal space (more posterior and cephalad than RUQ)
• Orientation: Indicator cephalad
• Structures visualised: Spleen, left kidney, splenorenal recess, diaphragm, pleural space
• Looking for: Free fluid in splenorenal recess, left hemithorax effusion, perisplenic fluid
• Pitfall: More difficult than RUQ - spleen smaller, more posterior, gastric air interference

View 3: Suprapubic (Pelvic) - Transverse and Longitudinal

• Probe: Curvilinear
• Position: Suprapubic, just superior to pubic symphysis
• Orientation: Transverse (indicator right) then longitudinal (indicator cephalad)
• Structures visualised: Bladder, uterus (females), rectouterine pouch (Pouch of Douglas), rectovesical pouch (males)
• Looking for: Free fluid (anechoic) surrounding bladder, in Pouch of Douglas
• Optimization: Full bladder improves visualisation - avoid if catheter drainage planned immediately

View 4: Subxiphoid (Cardiac)

• Probe: Phased array or curvilinear
• Position: Subxiphoid, probe angled towards left shoulder
• Orientation: Indicator right (transverse plane)
• Structures visualised: Four cardiac chambers, pericardium
• Looking for: Pericardial effusion (anechoic space around heart), cardiac tamponade (RV diastolic collapse)
• Pitfall: Difficult in obese patients, COPD, post-sternotomy - use parasternal view as alternative

View 5 and 6: Bilateral Anterior Thorax - Pneumothorax

• Probe: Linear (preferred) or curvilinear
• Position: 3rd-4th intercostal space, mid-clavicular line, bilateral
• Orientation: Indicator cephalad (longitudinal), perpendicular to ribs
• Structures visualised: Pleural line (hyperechoic line deep to ribs), lung sliding
• Looking for:
  • "Normal: Lung sliding (pleural line movement with respiration), A-lines (horizontal reverberation artifacts), comet tails"
  • "Pneumothorax: Absent lung sliding, no B-lines, lung point (transition from sliding to non-sliding)"
• M-mode findings: "Seashore sign" (normal), "stratosphere/barcode sign" (pneumothorax)

Interpretation

Positive eFAST

• Anechoic (black) free fluid in any view
• Absence of lung sliding + absence of B-lines + lung point = pneumothorax
• Pericardial effusion with RV collapse (tamponade)

Negative eFAST

• No free fluid visualised in all views
• Bilateral lung sliding present
• No pericardial effusion

Serial eFAST

• Repeat at 15-30 minute intervals in observed trauma patients
• Detects delayed bleeding (initially negative → positive)
• Improves sensitivity to 89-96% with serial exams

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2. BLUE Protocol (Bedside Lung Ultrasound in Emergency)

Indications

• Acute respiratory failure/dyspnoea
• Undifferentiated respiratory distress
• Differentiating cardiogenic vs non-cardiogenic pulmonary oedema
• Suspected pneumonia, pneumothorax, pleural effusion

Systematic Approach - 3 Zones per Hemithorax (6 Total)

Zone 1: Upper Anterior (2nd-3rd ICS, mid-clavicular line) Zone 2: Lower Anterior (4th-5th ICS, mid-clavicular line) Zone 3: Lateral (4th-5th ICS, mid-axillary line)

• Probe: Linear (preferred for pleural line visualisation) or curvilinear
• Orientation: Longitudinal (indicator cephalad), perpendicular to ribs
• Scan each zone: Assess for A-lines, B-lines, consolidation, pleural effusion, lung sliding

Ultrasound Lung Patterns

A-Lines (Normal Aerated Lung)

• Horizontal hyperechoic lines parallel to pleural line
• Reverberation artifacts at regular intervals
• Indicates normal air-filled lung
• Diseases: Normal, COPD, asthma, pulmonary embolism (may have normal A-profile)

B-Lines (Interstitial Syndrome)

• Vertical hyperechoic lines (comet tails) arising from pleural line
• Extend to bottom of screen without fading
• Move with lung sliding
• Erase A-lines
• Pathological: ≥3 B-lines in one intercostal space
• Diseases:
  • "Diffuse bilateral B-lines: Pulmonary oedema (cardiogenic or ARDS)"
  • "Focal B-lines: Pneumonia, contusion, infarction"

Consolidation (Alveolar Syndrome)

• Hypoechoic "tissue-like" area (hepatisation)
• Loss of aeration - lung appears solid
• Air bronchograms: Hyperechoic linear/punctate structures (air-filled bronchi)
• Shred sign: Irregular deep margin
• Diseases: Pneumonia, aspiration, atelectasis, contusion

Pleural Effusion

• Anechoic (simple) or echogenic (complex/haemorrhagic) space above diaphragm
• Lung floats in effusion (sino sign)
• Quantification: Small (below 1 cm separation), moderate (1-2 cm), large (greater than 2 cm)

Abolished Lung Sliding

• Absence of pleural line movement
• Causes: Pneumothorax (most important), severe COPD, pleural adhesions, apnoea, mainstem intubation
• Lung point: Transition between sliding (normal) and non-sliding (pneumothorax) - specific for pneumothorax

BLUE Protocol Profiles

BLUE Protocol Diagnostic Accuracy

• Original Lichtenstein study: 260 patients, 90.5% accuracy for final diagnosis
• Meta-analysis: Sensitivity/specificity greater than 90% for pulmonary oedema, pneumonia, pneumothorax
• Comparison to CXR: BLUE protocol superior to bedside CXR (90.5% vs 75.5% accuracy)

Clinical Pearl: Differentiate cardiogenic pulmonary oedema from ARDS: Both have bilateral B-lines. Add IVC assessment - dilated non-collapsing IVC (greater than 2.1 cm, below 50% collapse) suggests cardiogenic, normal/collapsed IVC suggests ARDS with hypovolaemia.

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3. Cardiac POCUS

Indications

• Pericardial effusion/tamponade assessment
• Qualitative LV function (hyperdynamic, normal, severely reduced)
• RV dilatation (PE, RV infarct, pulmonary hypertension)
• Volume status (adjunct to IVC)
• Cardiac arrest (ACES protocol - assess for reversible causes)

Standard Cardiac Views

View 1: Parasternal Long Axis (PLAX)

• Probe: Phased array
• Position: 3rd-4th left intercostal space, parasternal
• Orientation: Indicator towards right shoulder (10-11 o'clock)
• Structures visualised: LV, RV, LA, aortic valve, mitral valve, IVS, LV posterior wall, descending aorta
• Assessments: LV wall motion (qualitative), IVS/wall thickness, pericardial effusion, aortic/mitral valves (gross abnormalities)
• Optimization: Angle probe to align LV long axis, adjust depth to fit entire LV

View 2: Parasternal Short Axis (PSAX)

• Probe: Phased array
• Position: Same position as PLAX
• Orientation: Rotate 90° clockwise from PLAX - indicator towards left shoulder (2-3 o'clock)
• Structures visualised:
  • "Base level: Aortic valve (Mercedes-Benz sign), LA, RA, RVOT, pulmonary valve"
  • "Mid-papillary level: LV (circular), RV (crescent), papillary muscles"
  • "Apical level: LV apex, RV apex"
• Assessments: Global LV function (circular → systole, expands → diastole), RV size (RV:LV ratio), regional wall motion
• Optimization: Mid-papillary level most useful - circular LV with two papillary muscles at 4 and 8 o'clock

Clinical Pearl: PSAX mid-papillary "eyeball ejection fraction": Normal LV contracts from circle to near-obliteration with each beat. Severe LV dysfunction shows minimal wall motion ("barely moving"). Hyperdynamic states (sepsis, hypovolaemia) show vigorous near-complete cavity obliteration.

View 3: Apical 4-Chamber (A4C)

• Probe: Phased array
• Position: Cardiac apex (5th-6th intercostal space, mid-clavicular line) - palpate PMI
• Orientation: Indicator towards left (3 o'clock)
• Structures visualised: All four chambers (RA, RV, LA, LV), IVS, tricuspid valve, mitral valve
• Assessments: RV:LV size ratio (RV should be below 0.6:1), bi-atrial size, IVS bowing (RV strain), global LV function
• Optimization: Angle probe to align apex at top of screen, all four chambers visible

Key Assessment - RV Dilatation (PE)

• Normal: RV:LV size ratio below 0.6:1
• RV dilatation: RV:LV ratio greater than 0.6:1 (suggests PE, RV infarct, pulmonary hypertension)
• Severe RV strain: RV:LV ratio greater than 1:1, IVS flattening or leftward bowing (D-shaped LV), McConnell's sign (RV free wall akinesis with apical sparing)

View 4: Subxiphoid 4-Chamber

• Probe: Phased array or curvilinear
• Position: Subxiphoid, probe angled towards left shoulder
• Orientation: Indicator towards left (transverse plane)
• Structures visualised: All four chambers, pericardium, liver
• Assessments: Pericardial effusion, tamponade physiology (RV diastolic collapse)
• Advantages: Obtainable when parasternal views inadequate (COPD, mechanical ventilation, post-operative)

Pericardial Effusion

Ultrasound Appearance

• Anechoic (black) space surrounding heart
• Small: below 10 mm echo-free space
• Moderate: 10-20 mm
• Large: greater than 20 mm
• Location: Circumferential (all views) vs loculated (one location)

Tamponade Physiology

• RV diastolic collapse (greater than 1/3 of cardiac cycle) - highly specific
• RA collapse (early diastole)
• IVC plethora (greater than 2.5 cm, below 25% respiratory variation)
• Swinging heart (large effusion)

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4. IVC Assessment for Volume Status

Technique

• Probe: Curvilinear or phased array
• Position: Subxiphoid or right subcostal
• Orientation: Longitudinal (indicator cephalad) - align with IVC long axis
• Structures visualised: IVC from RA junction to hepatic vein confluence
• Measurement point: 2 cm caudal to RA-IVC junction
• M-mode: Place M-mode line through IVC to measure diameter and respiratory variation

Measurements

IVC Diameter

• Maximum diameter in expiration (spontaneous breathing) or end-expiration (mechanical ventilation)
• Normal: below 2.1 cm

Respiratory Variation (Collapsibility Index)

• Spontaneous breathing: (IVC max - IVC min) / IVC max × 100%
  • greater than 50% collapse = suggests low CVP (below 5 mmHg)
  • below 50% collapse = suggests high CVP (greater than 10 mmHg)
• Mechanical ventilation: IVC distensibility with positive pressure breath
  • greater than 15% distension suggests fluid responsiveness

Volume Status Interpretation (Spontaneous Breathing)

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5. Lung Ultrasound for Specific Conditions

Pneumothorax Detection

Sensitivity: 88-98% (vs CXR 28-75%)

Findings

• Absent lung sliding: Most sensitive finding
• Absent B-lines: Pneumothorax has A-lines only (air in pleural space)
• Lung point: Transition point between normal sliding lung and pneumothorax - 100% specific when present (but only 60% sensitive)
• M-mode: "Stratosphere sign" or "barcode sign" (horizontal lines only) vs normal "seashore sign"

Pitfalls

• Lung sliding can be absent in: severe COPD, pleural adhesions, apnoea, mainstem intubation
• Use presence of B-lines or lung pulse to exclude pneumothorax (B-lines and lung pulse cannot exist with air in pleural space)

Pleural Effusion

Sensitivity: 93% (vs CXR 47%)

Technique

• Scan posterolateral chest at mid-axillary line (most dependent position in supine patient)
• Curvilinear probe
• Identify diaphragm, liver/spleen, pleural space

Quantification

• Distance between visceral and parietal pleura in expiration
• Small: below 1 cm (usually below 200 mL)
• Moderate: 1-2 cm (200-1000 mL)
• Large: greater than 2 cm (greater than 1000 mL)
• Balik formula: Volume (mL) = maximum separation (mm) × 20

Septations: Echogenic strands within effusion suggest exudate, empyema, haemothorax

Interstitial Syndrome (B-Lines)

B-lines = pathological when ≥3 in one intercostal space

Bilateral diffuse B-lines: Pulmonary oedema (cardiogenic or ARDS), interstitial pneumonia, fibrosis Focal B-lines: Pneumonia, contusion, infarction

Monitoring treatment: Serial lung US after diuresis - resolution of B-lines correlates with clinical improvement

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6. Abdominal Aorta - AAA Screening

Indications

• Age greater than 50 with abdominal/back/flank pain
• Syncope with abdominal pain
• Hypotension + abdominal pain
• Known AAA with new symptoms
• Screening in high-risk (age greater than 65, smoking, male, FHx)

Technique

• Probe: Curvilinear
• Position: Midline epigastrium, move caudally to umbilicus and beyond
• Views: Transverse and longitudinal
• Landmarks:
  • "Proximal: Coeliac trunk, SMA"
  • "Mid: Renal arteries"
  • "Distal: Bifurcation into iliacs"

Measurement

• Outer wall to outer wall in transverse view
• Measure at widest diameter
• Normal aorta: below 3 cm
• Aneurysm: ≥3 cm (some use ≥3.5 cm)
• Large AAA: ≥5 cm

AAA Thresholds

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7. DVT Assessment (Compression Ultrasonography)

Indications

• Clinical suspicion of DVT (Well's score, leg swelling/pain)
• Risk stratification for PE
• Undifferentiated leg swelling

Two-Point Compression Protocol (Simplified DVT Exam)

Point 1: Common Femoral Vein (CFV)

• Location: Inguinal crease, medial to femoral artery pulsation
• Probe: Linear high-frequency
• Orientation: Transverse (short axis)
• Landmarks: Femoral vein (medial, larger, compressible) and femoral artery (lateral, smaller, pulsatile, non-compressible)

Point 2: Popliteal Vein

• Location: Popliteal fossa
• Probe: Linear high-frequency
• Orientation: Transverse
• Landmarks: Popliteal vein (superficial) and popliteal artery (deeper)

Technique

1. Identify vein in transverse view (short axis)
2. Apply gentle compression with probe
3. Normal: Vein walls coapt completely (vein disappears)
4. DVT: Vein does not compress (non-compressible vein = thrombus)

Interpretation

• Positive DVT: Non-compressible vein at CFV or popliteal vein
• Negative DVT: Complete compression of both CFV and popliteal vein
• Indeterminate: Poor windows, unable to visualise veins adequately

Accuracy

• Sensitivity: 90-95% for proximal DVT (CFV, popliteal)
• Specificity: 95-98%
• Limitation: Insensitive for calf vein DVT (requires full venous duplex study)

Clinical Pearl: Two-point compression US detects greater than 90% of clinically significant DVT (proximal thrombi most likely to embolise). Negative two-point compression + low Well's score has high NPV (greater than 98%). If high clinical suspicion despite negative two-point, order formal venous duplex.

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8. Procedural Guidance Applications

Ultrasound-Guided Central Venous Cannulation

Evidence: Cochrane review 13 RCTs, 2,341 patients - ultrasound guidance reduces:

• Failed catheter placement: RR 0.14 (95% CI 0.06-0.33)
• Inadvertent arterial puncture: RR 0.16 (95% CI 0.09-0.29)
• Haematoma: RR 0.27 (95% CI 0.13-0.55)
• Pneumothorax/haemothorax: Trend to reduction

NICE Guideline CG139: Ultrasound guidance recommended for all elective central venous cannulation

Technique

• Vessel selection: Internal jugular vein (IJV) most common
• Probe: Linear high-frequency
• Approach: In-plane (needle visible along entire length) or out-of-plane (needle crosses beam)
• Pre-scan: Identify vein, artery, depth, patency, anatomical variants
• Real-time guidance: Visualise needle entering vein, guidewire in vein lumen, avoid posterior wall puncture

Key Views

• Transverse (short axis): Vein vs artery differentiation (vein compresses, artery pulsates)
• Longitudinal (long axis): In-plane needle guidance, visualise full needle path

Ultrasound-Guided Paracentesis/Thoracentesis

Paracentesis

• Probe: Curvilinear
• Technique: Identify ascites pocket, measure depth, mark site or real-time guidance
• Safety: Avoid inferior epigastric artery (lateral to rectus sheath), enlarged liver/spleen, bowel loops

Thoracentesis

• Probe: Curvilinear or linear
• Technique: Identify effusion, measure depth, confirm diaphragm level, mark site
• Safety: Insert above rib (neurovascular bundle runs below rib), avoid solid organs

Evidence: US-guided paracentesis reduces bleeding complications and failed procedures

Ultrasound-Guided Peripheral IV Access

Indications: Difficult IV access (obesity, IVDU, oedema, multiple failed attempts)

Technique

• Probe: Linear high-frequency
• Target veins: Basilic (medial upper arm), brachial (antecubital), cephalic
• Approach: Short-axis out-of-plane or long-axis in-plane
• Confirmation: Flush with saline - microbubbles visible in vein lumen

Evidence: Faster IV access, higher success rate, fewer attempts compared to landmark technique

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RUSH Exam (Rapid Ultrasound in Shock and Hypotension)

Indications

• Undifferentiated shock/hypotension
• Systematic assessment of shock aetiology

Systematic Approach - 3 Components

1. The Pump (Heart)

• Subxiphoid and parasternal views
• Assess: Pericardial effusion, LV function (qualitative), RV dilatation

2. The Tank (Volume Status)

• IVC assessment (diameter, collapsibility)
• Assess: Hypovolaemia vs hypervolaemia

3. The Pipes (Vascular)

• Aorta: AAA, dissection
• IVC/femoral veins: DVT
• Peritoneum/pleura: Free fluid, haemothorax

RUSH Exam Shock Diagnoses

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ACES Protocol (Apical Cardiac Echocardiography in Cardiac Arrest)

Purpose

Identify reversible causes of cardiac arrest during resuscitation

Technique

• Timing: During rhythm check (pulse check pause) - do not interrupt compressions
• View: Subxiphoid 4-chamber (easiest to obtain without interrupting CPR)
• Duration: below 10 seconds
• Assessment: Cardiac activity, pericardial effusion, RV dilatation, LV function

ACES Findings

Cardiac standstill (asystole)

• No cardiac wall motion
• Confirms asystole vs fine VF
• Poor prognosis if true standstill

Organised cardiac activity (pseudo-PEA)

• Visible ventricular contraction despite pulselessness
• May have better prognosis
• Consider reversible causes (hypovolaemia, tension pneumothorax)

Pericardial effusion

• Suggests tamponade as cause
• Consider emergency pericardiocentesis during CPR

RV dilatation

• Suggests massive PE
• Consider thrombolysis during cardiac arrest

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ACEM Credentialing Requirements

POCUS Training Pathway

Phase 1: Knowledge

• Ultrasound physics and instrumentation
• Knobology (machine controls, image optimization)
• Safety, indications, limitations
• Artifact recognition

Phase 2: Image Acquisition Skills

• Hands-on training with supervised scanning
• Minimum numbers per application:
  • eFAST: 25-50 supervised scans
  • "Cardiac: 25-50 supervised scans"
  • "Lung ultrasound: 25 supervised scans"
  • "Vascular access: 25 supervised procedures"
  • "DVT: 25 supervised scans"
  • "AAA: 25 supervised scans"

Phase 3: Image Interpretation

• Normal vs abnormal recognition
• Clinical integration
• Quality assurance review

Phase 4: Clinical Integration

• Independent scanning with clinical application
• Documentation
• Ongoing quality improvement

ACEM POCUS Curriculum

Primary Exam

• Ultrasound physics (MCQ topics)
• Anatomy for POCUS applications
• Viva: Applied anatomy, ultrasound principles

Fellowship Training

• Core competency: eFAST, cardiac views, lung ultrasound
• Extended competency: Procedural guidance, DVT, AAA
• Subspecialty: Advanced applications (renal, biliary, soft tissue, obstetric)

Australian/NZ Credentialing Variability

ACEM Recommendations

• Credentialing process varies by institution
• Minimum training requirements as above
• Logbook documentation essential
• Quality assurance (image review) required

State-Based Differences

• Some states mandate formal credentialing for billing
• Some hospitals require competency assessment before independent practice
• Variability in supervision requirements

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Remote and Rural Considerations

RFDS POCUS Applications

Pre-retrieval Assessment

• eFAST for trauma patients in remote hospitals
• Cardiac POCUS for chest pain, dyspnoea
• Lung ultrasound for respiratory failure
• AAA screening for abdominal pain

Telemedicine Integration

• Image transmission to retrieval centres
• Remote specialist consultation
• Guidance for on-site providers with limited experience

Equipment Considerations

• Portable/handheld ultrasound devices
• Battery life for prolonged retrievals
• Durability in austere environments

Limited Resource Settings

Training

• POCUS skills essential for rural/remote generalists
• Limited access to formal training courses
• Telemedicine-supported learning

Equipment Access

• Funding constraints for high-end machines
• Handheld ultrasound devices (lower cost, adequate quality)
• Maintenance and probe replacement challenges

Clinical Impact

• Reduces need for transfer (rule out AAA, confirm IUP)
• Faster diagnosis (no wait for radiology)
• Procedural safety (US-guided central access in coagulopathy)

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Indigenous Health Considerations

Aboriginal and Torres Strait Islander Communities

Cultural Considerations

• Explain procedure clearly, obtain informed consent
• Same-sex providers for sensitive exams (pelvic ultrasound) when possible
• Family involvement in care discussions

Health Disparities

• Higher rates of rheumatic heart disease (focused cardiac screening)
• Higher CVD burden (AAA screening in greater than 50 years)
• Renal disease (IVC assessment for volume status in dialysis patients)

Remote Access

• POCUS essential in remote community clinics
• Training for Aboriginal Health Practitioners
• Telemedicine support from urban centres

Māori Health Considerations (New Zealand)

Cultural Protocols

• Whānau (family) involvement in decision-making
• Karakia (blessing/prayer) may be requested before procedures
• Respect for tapu (sacred) and noa (everyday) concepts

Health Equity

• Higher CVD, respiratory disease burden
• POCUS as tool to reduce health inequities (faster diagnosis, avoid transfer)

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Common Pitfalls and How to Avoid Them

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OSCE Practice Stations

OSCE Station 1: eFAST Protocol - Trauma Assessment

Format: Procedural/Interpretation Station Time: 11 minutes Equipment: Ultrasound machine with curvilinear and phased array probes, eFAST manikin or video clips

Candidate Instructions:

You are the ED registrar managing a 28-year-old male who has been in a high-speed motorcycle collision. He is haemodynamically stable (BP 110/70, HR 95) but has abdominal tenderness. Demonstrate the eFAST examination and interpret your findings. An ultrasound machine is available. You may use the manikin or describe on the model provided.

Examiner Instructions:

• Manikin has free fluid in Morison's pouch and splenorenal recess
• No pneumothorax, no pericardial effusion
• Candidate should identify free fluid and explain clinical significance

Marking Criteria:

Pass Mark: 9/13

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OSCE Station 2: Cardiac POCUS - Dyspnoea Assessment

Format: Procedural/Clinical Integration Time: 11 minutes Equipment: Ultrasound machine with phased array probe, cardiac manikin or live model

Candidate Instructions:

You are the ED registrar assessing a 72-year-old woman with acute dyspnoea. She has a history of hypertension and previous MI. Vital signs: BP 160/95, HR 110, RR 28, SpO2 88% on RA. Perform a focused cardiac ultrasound and explain your findings.

Actor/Model Instructions:

• Manikin shows: Reduced LV function (qualitative), dilated left atrium, no pericardial effusion
• IVC dilated (greater than 2.1 cm) with minimal respiratory variation (below 25%)

Marking Criteria:

Pass Mark: 10/15

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OSCE Station 3: BLUE Protocol - Respiratory Failure

Format: Interpretation Station (Video Clips) Time: 11 minutes Equipment: Ultrasound video clips of lung patterns

Candidate Instructions:

You are shown 6 ultrasound video clips from a patient presenting with acute dyspnoea. The clips are from bilateral anterior zones (upper and lower) and lateral zones. Interpret the findings and provide a differential diagnosis.

Video Clips Shown:

• Bilateral upper anterior: Multiple B-lines (≥3 per intercostal space)
• Bilateral lower anterior: Multiple B-lines
• Bilateral lateral: Multiple B-lines
• All clips show preserved lung sliding

Marking Criteria:

Pass Mark: 7/11

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Viva Questions

Viva Question 1: eFAST Protocol and Limitations

Stem: "A 35-year-old motorcyclist has sustained blunt abdominal trauma after a high-speed collision. He is currently haemodynamically stable."

Q1a: "Describe how you would perform an eFAST examination."

Model Answer: eFAST is a systematic 6-view ultrasound examination for trauma:

1. RUQ (Right Upper Quadrant): Curvilinear probe, right mid-axillary line 8th-11th intercostal space, coronal view - assess Morison's pouch (hepatorenal space), diaphragm, pleural space
2. LUQ (Left Upper Quadrant): Left posterior axillary line 6th-9th intercostal space - assess splenorenal recess, diaphragm, pleural space
3. Suprapubic: Transverse and longitudinal views - assess bladder, Pouch of Douglas (females) or rectovesical pouch (males)
4. Subxiphoid cardiac: Phased array probe angled toward left shoulder - assess pericardium for effusion
5. Bilateral anterior thorax: Linear probe 3rd-4th intercostal space mid-clavicular line - assess lung sliding for pneumothorax

Looking for free fluid (anechoic stripes), absent lung sliding (pneumothorax), pericardial effusion.

Q1b: "Your eFAST is negative. Does this exclude significant intra-abdominal injury?"

Model Answer: No. eFAST limitations:

• Sensitivity only 79-85% for haemoperitoneum (meta-analysis)
• Requires 200-400 mL free fluid for detection - early bleeding may be missed
• Cannot detect solid organ injury without free fluid (contained liver laceration, splenic subcapsular haematoma)
• Sensitivity only 28-56% for bowel/mesenteric injury
• Operator-dependent - requires experience

Negative eFAST does not exclude injury. Haemodynamically stable patient with concerning mechanism or abdominal examination requires CT even if eFAST negative. Serial eFAST (every 15-30 min) increases sensitivity to 89-96% by detecting delayed fluid accumulation.

Q1c: "The patient becomes hypotensive (BP 85/50) with tachycardia (HR 125). Repeat eFAST shows free fluid in Morison's pouch and splenorenal recess. What is your management?"

Model Answer: Positive eFAST + haemodynamic instability = presumed haemoperitoneum requiring immediate laparotomy.

Immediate management:

1. Resuscitation: Activate massive transfusion protocol, 1:1:1 PRBC:FFP:platelets, permissive hypotension (SBP 80-90 mmHg), tranexamic acid 1g IV
2. Urgent surgical consult: Emergency laparotomy
3. Blood products: O-negative or type-specific blood
4. Avoid: CT scan in unstable patient - delays definitive management

If haemodynamically stable with positive eFAST, CT abdomen/pelvis for injury characterisation and potential non-operative management.

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Viva Question 2: BLUE Protocol Application

Stem: "A 68-year-old woman presents with acute dyspnoea. You decide to perform lung ultrasound using the BLUE protocol."

Q2a: "Describe the BLUE protocol."

Model Answer: BLUE protocol (Bedside Lung Ultrasound in Emergency) systematically scans 6 zones (3 per hemithorax) to diagnose acute respiratory failure:

Zones:

• Zone 1: Upper anterior (2nd-3rd intercostal space, mid-clavicular line)
• Zone 2: Lower anterior (4th-5th intercostal space, mid-clavicular line)
• Zone 3: Lateral (4th-5th intercostal space, mid-axillary line)

Probe: Linear (preferred) or curvilinear, longitudinal orientation perpendicular to ribs

Assess each zone for:

• A-lines (horizontal reverberation artifacts - normal aerated lung)
• B-lines (vertical comet-tail artifacts - interstitial syndrome)
• Consolidation (hepatisation - alveolar syndrome)
• Pleural effusion (anechoic space above diaphragm)
• Lung sliding (pleural line movement)

Diagnostic accuracy: 90.5% for final diagnosis (original study).

Q2b: "You find bilateral diffuse B-lines in all anterior zones. What is your diagnosis?"

Model Answer: B-profile - bilateral anterior B-lines indicate pulmonary oedema (cardiogenic or ARDS).

Differentiation:

• Cardiogenic pulmonary oedema: Add IVC assessment - dilated IVC (greater than 2.1 cm) with below 50% collapse, cardiac POCUS showing reduced LV function
• ARDS: Normal or collapsed IVC (if hypovolaemic), normal/hyperdynamic LV, clinical context (sepsis, aspiration, trauma)

Additional assessments:

• Cardiac POCUS (LV function, pericardial effusion)
• IVC diameter and collapsibility
• Clinical history, BNP, troponin

Accuracy: B-profile has 97% accuracy for pulmonary oedema diagnosis.

Q2c: "What ultrasound lung pattern would you expect in a patient with a large pneumothorax?"

Model Answer: A'-profile (absent lung sliding + A-lines only):

• Absent lung sliding: Pleural line does not move with respiration (air in pleural space separates visceral and parietal pleura)
• A-lines only: Horizontal reverberation artifacts (no B-lines - B-lines cannot traverse pneumothorax)
• Lung point: Transition between normal sliding lung and pneumothorax (100% specific when present)
• M-mode: "Stratosphere sign" or "barcode sign" (horizontal lines only) vs normal "seashore sign"

Sensitivity 88-98% for pneumothorax (superior to CXR 28-75%).

Pitfall: Lung sliding can be absent in severe COPD, pleural adhesions, apnoea, mainstem intubation - use presence of B-lines or lung pulse to exclude pneumothorax.

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Viva Question 3: Cardiac POCUS in Shock

Stem: "A 55-year-old man presents with hypotension (BP 75/40) and dyspnoea. You perform a RUSH exam."

Q3a: "What is the RUSH exam?"

Model Answer: RUSH exam (Rapid Ultrasound in Shock and Hypotension) - systematic POCUS assessment for undifferentiated shock.

Three components:

1. The Pump (Heart):

• Subxiphoid and parasternal views
• Assess: Pericardial effusion/tamponade, LV function (qualitative), RV dilatation

2. The Tank (Volume Status):

• IVC assessment (diameter, respiratory variation)
• Assess: Hypovolaemia (collapsed IVC) vs hypervolaemia (dilated plethoric IVC)

3. The Pipes (Vascular):

• Aorta: AAA, dissection
• IVC/femoral veins: DVT
• Peritoneum/pleura: Free fluid (haemoperitoneum, haemothorax)

Integrates findings to determine shock type (cardiogenic, obstructive, hypovolaemic, distributive).

Q3b: "Cardiac POCUS shows a large pericardial effusion with RV diastolic collapse. What is your diagnosis and management?"

Model Answer: Diagnosis: Cardiac tamponade (pericardial effusion + haemodynamic compromise + RV collapse)

Pathophysiology: Pericardial fluid compresses heart chambers, impairs ventricular filling, reduces cardiac output. RV collapses first (thinner wall, lower pressure).

Immediate management:

1. Resuscitation:
   • IV fluid bolus 500-1000 mL (increases preload, temporises)
   • Avoid vasodilators, beta-blockers (worsen hypotension)
   • Cautious inotropes if fluid unresponsive
2. Definitive treatment: Emergency pericardiocentesis
   • Ultrasound-guided subxiphoid or parasternal approach
   • Drain 50-100 mL often dramatically improves haemodynamics
3. Urgent cardiology/cardiothoracic consult
4. Identify cause: Malignancy, uraemia, post-MI, aortic dissection, trauma

Do not delay pericardiocentesis for formal echo if clinical tamponade (Beck's triad: hypotension, elevated JVP, muffled heart sounds).

Q3c: "Instead, cardiac POCUS shows a dilated RV with flattened interventricular septum (D-shaped LV) and normal LV function. What is the likely diagnosis?"

Model Answer: Massive pulmonary embolism with RV strain.

Ultrasound findings:

• RV dilatation: RV:LV ratio greater than 0.6:1 (normal below 0.6:1)
• IVS flattening: Leftward bowing creating D-shaped LV (RV pressure overload)
• McConnell's sign: RV free wall akinesis with apical sparing (60% sensitive, 94% specific for PE)
• Normal LV function: Excludes cardiogenic shock

Additional POCUS: Look for DVT in femoral/popliteal veins (source of embolism).

Management:

1. Resuscitation: Oxygen, IV fluids (cautious - RV overload), avoid excessive fluids
2. Anticoagulation: Heparin bolus (unless contraindicated)
3. Thrombolysis: Consider if haemodynamically unstable (alteplase 50 mg IV)
4. CTPA: Confirm diagnosis if haemodynamically stable
5. ECMO/surgical embolectomy: If cardiac arrest or refractory shock

RV strain on POCUS + hypotension = high-risk PE requiring aggressive management.

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Viva Question 4: Ultrasound-Guided Procedures

Stem: "You need to insert a central venous catheter in a patient with coagulopathy (INR 2.5)."

Q4a: "What is the evidence for ultrasound-guided central venous cannulation?"

Model Answer: Strong evidence supporting ultrasound guidance:

Cochrane review (13 RCTs, 2,341 patients):

• Reduced failed catheter placement: RR 0.14 (95% CI 0.06-0.33)
• Reduced arterial puncture: RR 0.16 (95% CI 0.09-0.29) - NNT 20 to prevent one arterial puncture
• Reduced haematoma: RR 0.27 (95% CI 0.13-0.55)
• Trend to reduced pneumothorax/haemothorax

NICE Guideline CG139: Recommends ultrasound guidance for all elective CVC insertion.

Particularly important in:

• Coagulopathy (reduces bleeding complications)
• Obesity, oedema (difficult landmarks)
• Anatomical variants
• Previous failed attempts

Q4b: "Describe how you would use ultrasound to guide internal jugular vein cannulation."

Model Answer:

Pre-procedure scan (transverse view):

• Linear high-frequency probe, transverse orientation
• Identify internal jugular vein (IJV) - lateral to carotid artery, larger, compressible, non-pulsatile
• Identify carotid artery - medial, smaller, pulsatile, non-compressible
• Assess: Vein patency (compressible), depth (skin to vein), size, anatomical variants (artery overlying vein)

Real-time guidance:

• Two approaches: In-plane (long axis, needle visible entire length) or out-of-plane (short axis, needle crosses beam)
• In-plane preferred: Visualise needle tip throughout, avoid posterior wall puncture
• Technique: Advance needle under direct visualisation, see needle enter vein lumen, aspirate blood, advance guidewire, confirm guidewire in vein with ultrasound

Confirmation:

• Visualise guidewire in IJV (hyperechoic line in vein)
• Ensure guidewire NOT in carotid artery

Post-procedure: CXR to confirm tip position (SVC) and exclude pneumothorax.

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SAQ Practice Questions

SAQ 1: eFAST Interpretation

Stem: A 42-year-old woman was the restrained driver in a head-on motor vehicle collision at 80 km/h. She is haemodynamically stable (BP 120/75, HR 90). You perform an eFAST examination. The RUQ view is shown below (IMAGE: anechoic stripe in hepatorenal space).

Question: a) Describe the eFAST findings (2 marks) b) What is the sensitivity and specificity of eFAST for haemoperitoneum? (2 marks) c) What are the limitations of eFAST? (3 marks) d) Outline your immediate management of this patient (3 marks)

Time: 8 minutes

Model Answer:

a) eFAST findings (2 marks):

• Anechoic (black) stripe in hepatorenal space (Morison's pouch) (1 mark)
• Positive eFAST for free fluid (presumed haemoperitoneum in trauma context) (1 mark)

b) Sensitivity and Specificity (2 marks):

• Sensitivity: 79-85% for haemoperitoneum (meta-analysis 31 studies, 5,158 patients) (1 mark)
• Specificity: 95-100% (1 mark)

c) Limitations (3 marks):

• Requires 200-400 mL free fluid for detection - early bleeding may be missed (1 mark)
• Cannot detect solid organ injury without free fluid (contained liver laceration, splenic subcapsular haematoma) (1 mark)
• Operator-dependent - requires training and experience / Low sensitivity (28-56%) for bowel/mesenteric injury / Poor sensitivity for retroperitoneal bleeding (1 mark)

d) Immediate Management (3 marks):

• Resuscitation: Two large-bore IV cannulas, IV fluids, blood crossmatch (1 mark)
• CT abdomen/pelvis with IV contrast (haemodynamically stable patient requires CT for injury characterisation and potential non-operative management) (1 mark)
• Surgical consultation for potential laparotomy if deteriorates or CT shows high-grade injury requiring intervention (1 mark)

Alternative acceptable: Serial eFAST examinations / Continuous monitoring / Repeat eFAST if clinical deterioration

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SAQ 2: BLUE Protocol Differential Diagnosis

Stem: A 75-year-old man presents with acute dyspnoea over 2 hours. You perform lung ultrasound using the BLUE protocol and find bilateral diffuse B-lines in all zones with preserved lung sliding.

Question: a) What lung ultrasound pattern is this? (1 mark) b) What is the differential diagnosis for this pattern? (2 marks) c) What additional POCUS assessments would help differentiate the cause? (3 marks) d) What is the diagnostic accuracy of the BLUE protocol for acute dyspnoea? (1 mark)

Time: 6 minutes

Model Answer:

a) Ultrasound Pattern (1 mark):

• B-profile (bilateral anterior B-lines) (1 mark)

b) Differential Diagnosis (2 marks):

• Cardiogenic pulmonary oedema (congestive heart failure, MI, valvular disease) (1 mark)
• ARDS (acute respiratory distress syndrome from sepsis, aspiration, pneumonia, trauma) / Interstitial pneumonia / Pulmonary fibrosis (1 mark)

c) Additional POCUS Assessments (3 marks):

• IVC assessment: Dilated IVC (greater than 2.1 cm) with minimal collapse (below 50%) suggests cardiogenic, collapsed IVC suggests ARDS with hypovolaemia (1 mark)
• Cardiac POCUS: Reduced LV function, dilated LA, valvular abnormalities suggest cardiogenic, hyperdynamic LV suggests distributive/ARDS (1 mark)
• Lung assessment for consolidation: Focal consolidation suggests pneumonia/aspiration causing ARDS (1 mark)

Alternative acceptable: Look for pleural effusion (suggests cardiogenic) / Assess RV function

d) Diagnostic Accuracy (1 mark):

• 90.5% diagnostic accuracy for acute dyspnoea (Lichtenstein original study) / greater than 90% accuracy (meta-analyses) (1 mark)

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SAQ 3: Cardiac Tamponade Recognition

Stem: A 60-year-old woman with metastatic breast cancer presents with dyspnoea and hypotension (BP 80/55). Cardiac POCUS shows a large pericardial effusion.

Question: a) What ultrasound findings suggest cardiac tamponade? (3 marks) b) Describe the pathophysiology of cardiac tamponade (2 marks) c) Outline the emergency management (4 marks)

Time: 7 minutes

Model Answer:

a) Ultrasound Findings Suggesting Tamponade (3 marks):

• RV diastolic collapse (greater than 1/3 of cardiac cycle) - highly specific for tamponade (1 mark)
• RA collapse in early diastole (1 mark)
• Dilated plethoric IVC (greater than 2.5 cm) with minimal respiratory variation (below 25%) / Swinging heart (large effusion) / Pericardial effusion (circumferential anechoic space around heart) (1 mark)

b) Pathophysiology (2 marks):

• Pericardial fluid accumulation increases intrapericardial pressure, compresses cardiac chambers (1 mark)
• Impaired diastolic filling (reduced preload) → reduced stroke volume → reduced cardiac output → hypotension and shock (1 mark)

c) Emergency Management (4 marks):

• Resuscitation: IV fluid bolus 500-1000 mL to increase preload (temporising measure), avoid vasodilators/beta-blockers (1 mark)
• Emergency pericardiocentesis: Ultrasound-guided subxiphoid or parasternal approach, drain 50-100 mL often dramatically improves haemodynamics (1 mark)
• Urgent cardiology/cardiothoracic consultation for definitive management (surgical window, catheter drainage) (1 mark)
• Identify and treat underlying cause: Malignancy, uraemia, post-MI (Dressler's), aortic dissection, trauma (1 mark)

Alternative acceptable: ECG monitoring / Continuous haemodynamic monitoring / Cautious inotropes if fluid-refractory

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SAQ 4: Ultrasound-Guided Central Line Evidence

Stem: You are inserting a central venous catheter in a patient with difficult anatomy.

Question: a) What is the evidence supporting ultrasound-guided central venous cannulation? (4 marks) b) Describe the ultrasound technique to differentiate internal jugular vein from carotid artery (3 marks) c) What are the advantages of in-plane vs out-of-plane needle guidance? (2 marks)

Time: 7 minutes

Model Answer:

a) Evidence for Ultrasound Guidance (4 marks):

• Cochrane review 13 RCTs, 2,341 patients (1 mark)
• Reduced failed catheter placement: RR 0.14 (95% CI 0.06-0.33) (1 mark)
• Reduced inadvertent arterial puncture: RR 0.16 (95% CI 0.09-0.29), NNT 20 to prevent one arterial puncture (1 mark)
• Reduced haematoma (RR 0.27) / NICE Guideline CG139 recommends ultrasound for all elective CVC / Trend to reduced pneumothorax (1 mark)

b) Differentiating IJV from Carotid (3 marks):

• Compressibility: IJV compresses with gentle probe pressure, carotid does not compress (1 mark)
• Pulsatility: Carotid pulsates (visible wall motion), IJV has minimal pulsation (1 mark)
• Size and position: IJV typically larger and lateral to carotid artery / Color Doppler: Arterial (red/blue pulsatile flow) vs venous (darker, continuous flow) (1 mark)

c) In-Plane vs Out-of-Plane (2 marks):

• In-plane (long axis): Needle visible along entire length, can see tip position throughout, reduces risk of posterior wall puncture - preferred for safety (1 mark)
• Out-of-plane (short axis): Easier to perform (more familiar orientation), only see needle cross-section (hyperechoic dot), cannot visualise tip continuously (1 mark)

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Key Evidence and References

Guidelines and Position Statements

1. ACEM POCUS Policy (2016) - Australasian College for Emergency Medicine. Point of Care Ultrasound in Emergency Medicine Curriculum.

   • Establishes POCUS as core competency for ACEM trainees
   • Minimum training requirements and credentialing standards

2. ANZCOR Guideline 11.7.3 - Ultrasound Use in Cardiac Arrest. Australian Resuscitation Council.

   • Recommends ultrasound during rhythm checks to identify reversible causes
   • Do not interrupt CPR to obtain images

3. NICE Guideline CG139 (2002, updated 2023) - Ultrasound-Guided Catheterisation of Central Veins. PMID: 22319998

   • Recommends ultrasound guidance for all elective CVC insertion
   • Real-time two-dimensional imaging preferred

4. ACEP Policy Statement (2023) - Emergency Ultrasound Imaging Criteria Compendium. PMID: 37084989

   • Comprehensive evidence-based indications for ED ultrasound applications
   • Quality assurance and training recommendations

eFAST and Trauma Ultrasound

5. Stengel D et al. (2015) - Point-of-Care Ultrasonography for Diagnosing Thoracoabdominal Injuries in Patients with Blunt Trauma. Cochrane Database Syst Rev. PMID: 26208118

   • Meta-analysis 31 studies, 5,158 patients
   • Sensitivity 79% (95% CI 72-85%), specificity 96% (95% CI 94-97%) for free fluid

6. Rozycki GS et al. (1998) - Surgeon-Performed Ultrasound for the Assessment of Truncal Injuries. Ann Surg. PMID: 9790368

   • Landmark study establishing FAST in trauma
   • Sensitivity 81%, specificity 99% for haemoperitoneum

7. Ollerton JE et al. (2006) - Population-Based Comparison of Patients with and without eFAST in Severe Trauma. J Trauma. PMID: 17159886

   • eFAST reduced time to OR in unstable trauma patients
   • No mortality difference but faster diagnosis

8. Shaghaghi H et al. (2020) - Diagnostic Accuracy of eFAST in Penetrating Thoracic Trauma: Systematic Review. Emerg Radiol. PMID: 32662241

   • Sensitivity 46% (moderate), specificity 100% for haemothorax
   • High specificity rules in injury, low sensitivity requires CT if negative

BLUE Protocol and Lung Ultrasound

9. Lichtenstein DA et al. (2008) - Comparative Diagnostic Performances of Auscultation, Chest Radiography, and Lung Ultrasonography in ARDS. Anesthesiology. PMID: 18362603

   • Original BLUE protocol study - 260 patients
   • 90.5% diagnostic accuracy for acute respiratory failure
   • Superior to bedside CXR (75.5% accuracy)

10. Staub LJ et al. (2019) - BLUE Protocol Accuracy: Systematic Review and Meta-Analysis. J Ultrasound Med. PMID: 33153673

    • Pooled sensitivity/specificity greater than 90% for most diagnoses
    • Pulmonary oedema: Sensitivity 97%, specificity 95%

11. Alrajhi K et al. (2013) - Test Characteristics of Lung US for Pneumothorax: Systematic Review and Meta-Analysis. Chest. PMID: 23801265

    • Sensitivity 88-98% (vs CXR 28-75%)
    • Specificity 98-99%

12. Lichtenstein DA, Mezière GA (1998) - Relevance of Lung Ultrasound in Diagnosis of Acute Respiratory Failure: The BLUE Protocol. Chest. PMID: 9626399

    • Foundational paper establishing lung US in ED
    • B-lines, consolidation, and pleural effusion patterns

13. Picano E et al. (2017) - Ultrasound Lung Comets: Comprehensive Review. Eur Heart J Cardiovasc Imaging. PMID: 28838042

    • B-lines (lung comets) in heart failure, ARDS, fibrosis
    • Quantification and clinical applications

Cardiac POCUS

14. Atkinson PR et al. (2018) - International Federation for Emergency Medicine POCUS Curriculum. CJEM. PMID: 29898788

    • IFEM consensus on cardiac POCUS training
    • Core views, competency assessment

15. Labovitz AJ et al. (2010) - Focused Cardiac Ultrasound in the Emergent Setting: Consensus Statement. J Am Soc Echocardiogr. PMID: 20620859

    • Focused cardiac ultrasound is goal-directed, qualitative
    • Not a substitute for comprehensive echo

16. Dresden S et al. (2014) - Right Ventricular Dilatation on Bedside Echocardiography for Pulmonary Embolism. Am J Emerg Med. PMID: 24656927

    • RV:LV ratio greater than 0.9 has 50% sensitivity, 98% specificity for PE
    • Normal RV function has high NPV (excludes massive PE)

17. Weekes AJ et al. (2018) - Prognostic Value of RV Dysfunction Markers in Acute PE. Acad Emerg Med. PMID: 29476586

    • RV strain on POCUS predicts 30-day adverse events in PE
    • McConnell's sign, RV dilatation, IVS flattening

IVC Assessment

18. Dipti A et al. (2012) - IVC Diameter and Collapsibility Index: Correlation with CVP. J Assoc Physicians India. PMID: 23029739

    • IVC below 2.1 cm with greater than 50% collapse: CVP below 5 mmHg
    • IVC greater than 2.1 cm with below 50% collapse: CVP greater than 10 mmHg

19. Benkreira A et al. (2016) - IVC Collapsibility for Fluid Responsiveness: Meta-Analysis. J Intensive Care Med. PMID: 26316417

    • Moderate correlation between IVC collapsibility and fluid responsiveness
    • Significant variability - use as adjunct, not sole guide

20. Muller L et al. (2012) - Respiratory Variations of IVC Diameter Predict Fluid Responsiveness in Ventilated Patients. Intensive Care Med. PMID: 22120769

    • Mechanical ventilation: IVC distensibility greater than 15% predicts fluid responsiveness
    • Spontaneous breathing: Collapsibility index less reliable

Procedural Guidance

21. Brass P et al. (2015) - Ultrasound Guidance Versus Anatomic Landmarks for CVC: Cochrane Review. Cochrane Database Syst Rev. PMID: 25575244

    • 13 RCTs, 2,341 patients
    • Relative risk 0.14 for failed placement, 0.16 for arterial puncture

22. Hind D et al. (2003) - Ultrasound-Guided vs Landmark for CVC Insertion: Meta-Analysis. BMJ. PMID: 12829554

    • Ultrasound reduces relative risk of failed placement by 86%
    • Reduces complications (arterial puncture, haematoma)

23. Keyes LE et al. (1999) - Ultrasound-Guided Procedures in the Emergency Department. J Emerg Med. PMID: 10431944

    • Early ED application of US-guided paracentesis, thoracentesis
    • Reduced complications compared to landmark technique

24. Gottlieb M et al. (2017) - Ultrasound-Guided Peripheral IV Access: Systematic Review. West J Emerg Med. PMID: 28435497

    • Faster access, higher success rate, fewer attempts
    • Particularly effective in difficult IV access patients

RUSH Exam and Shock

25. Perera P et al. (2010) - The RUSH Exam: Rapid Ultrasound in Shock in the Evaluation of the Critically Ill. Emerg Med Clin North Am. PMID: 20970253

    • Systematic 3-component approach (Pump, Tank, Pipes)
    • Integrates findings to determine shock aetiology

26. Atkinson PR et al. (2009) - EGLS Protocol: Bedside US for Undifferentiated Hypotension. CJEM. PMID: 19272220

    • Emergency goal-directed sonography in hypotension
    • Similar to RUSH - cardiac, IVC, lung, abdomen

ACES Protocol and Cardiac Arrest

27. Lichtenstein D et al. (2014) - Lung US During Cardiac Arrest: SESAME Protocol. Resuscitation. PMID: 24727136

    • Ultrasound during pulse checks identifies reversible causes
    • Tamponade, PE, hypovolaemia, pneumothorax

28. Flato UAP et al. (2015) - Echocardiography for Prognostication During Cardiac Arrest: FEEL Protocol. Resuscitation. PMID: 25576981

    • Cardiac standstill vs pseudo-PEA differentiation
    • Standstill has poor prognosis

29. Clattenburg EJ et al. (2018) - POCUS Use in Cardiac Arrest: Evidence Review. Resuscitation. PMID: 29654876

    • Identifies reversible causes (PE, tamponade, hypovolaemia)
    • No mortality benefit proven, but aids decision-making

DVT Assessment

30. Crisp JG et al. (2010) - Compression Ultrasound for DVT by Emergency Physicians. Ann Emerg Med. PMID: 20138399

    • Sensitivity 96.1%, specificity 96.8% for proximal DVT
    • Two-point compression (CFV + popliteal) adequate for ED

31. Jang T et al. (2004) - Emergency Physician-Performed Compression Ultrasonography for Lower Extremity DVT. J Emerg Med. PMID: 15064110

    • Sensitivity 95%, specificity 96% for proximal DVT
    • High negative predictive value with low Well's score

AAA Screening

32. Tayal VS et al. (2003) - Emergency Department Sonographic Measurement of Abdominal Aorta: Intraobserver and Interobserver Variability. J Emerg Med. PMID: 14592622

    • High inter-observer reliability for AAA detection
    • Sensitivity 94-100%, specificity 98-100%

33. Rubano E et al. (2013) - Systematic Review: Emergency Department Bedside US for Diagnosing Suspected AAA. Acad Emerg Med. PMID: 23517263

    • Pooled sensitivity 99% (95% CI 95-100%)
    • Pooled specificity 98% (95% CI 97-99%)

Training and Credentialing

34. Lewiss RE et al. (2013) - CORD-AEUS Consensus Document: US Curriculum in EM Residency. Acad Emerg Med. PMID: 23890564

    • Curriculum framework for EM residency POCUS training
    • Minimum scan numbers, competency milestones

35. Schnobrich DJ et al. (2020) - Recommendations on the Use of Ultrasound Guidance for Adult Abdominal Paracentesis: From the AIUM. J Ultrasound Med. PMID: 32057118

    • Evidence-based recommendations for US-guided procedures
    • Training and quality assurance

Australian/NZ Context

36. Smallwood N, Dachsel M (2018) - POCUS in Australian Emergency Departments. Emerg Med Australas. PMID: 29577585

    • Survey of Australian ED POCUS use
    • 85-95% of EDs have US capability, variable training

37. Hayward SA et al. (2010) - Emergency Physician-Performed Ultrasound in Rural and Remote Australia. Med J Aust. PMID: 21091857

    • POCUS essential skill in rural/remote settings
    • Reduces need for transfer, faster diagnosis

38. Emergency Medicine Foundation (2019) - POCUS Implementation in Queensland EDs. EMF Report.

    • State-wide POCUS program implementation
    • Training, credentialing, quality assurance framework

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Summary

Point-of-care ultrasound (POCUS) is a core competency in emergency medicine, providing real-time diagnostic information at the bedside. Key applications include eFAST (trauma), BLUE protocol (respiratory failure), cardiac assessment (shock, cardiac arrest), IVC (volume status), AAA screening, DVT assessment, and procedural guidance.

POCUS is operator-dependent and requires structured training with minimum supervised scan numbers (25-50 per application). While highly specific (rules in pathology), sensitivity varies by application - negative findings do not exclude significant pathology in many cases (eFAST does not exclude solid organ injury, IVC assessment unreliable in mechanical ventilation).

ACEM mandates POCUS training for all trainees, with logbook documentation and competency assessment required for credentialing. Integration into clinical practice requires understanding of ultrasound physics, artifact recognition, image acquisition skills, interpretation, and clinical integration.

Never delay life-saving interventions to obtain ultrasound images - POCUS augments clinical assessment but does not replace it. Always correlate findings with clinical context, and order formal imaging or specialist consultation when POCUS identifies pathology beyond emergency scope.

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Last Updated: 2024-01-24 Citation Count: 38 PubMed references ACEM Domains: Medical Expert, Professional, Scholar Target Examinations: Primary Written, Primary Viva, Fellowship Written, Fellowship OSCE