POCUS LEARNING HUB

Indications

• Blunt or penetrating torso trauma
• Haemodynamic instability with unknown source
• Trauma primary survey adjunct (ATLS/RCEM guidance)
• Repeat scanning for evolving haemoperitoneum

Probe & Views

• Curvilinear 3.5–5 MHz probe
• Right upper quadrant (Morison’s pouch & right hemidiaphragm)
• Left upper quadrant (splenorenal recess & left hemidiaphragm)
• Suprapubic (pelvic free fluid, transverse and longitudinal)
• Subxiphoid (pericardial effusion/tamponade)
• Bilateral anterior chest (pneumothorax — lung sliding, barcode sign)

Key Findings & Pitfalls

• Free fluid appears as anechoic (black) stripe between organs
• Minimum detectable volume ~200 mL in Morison’s pouch
• False negative: retroperitoneal bleeding, early solid organ injury, bowel injury
• False positive: pre-existing ascites, physiological pelvic fluid
• Absent lung sliding — consider pneumothorax (confirm with M-mode barcode sign)
• Always correlate with clinical picture; eFAST is a screening tool, not definitive

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Indications

• Acute dyspnoea — differentiate cardiac vs pulmonary cause
• Suspected pneumothorax (trauma or spontaneous)
• Pleural effusion assessment and volume estimation
• Suspected pulmonary oedema (B-lines)
• Consolidation / pneumonia (hepatisation pattern)

Probe & Technique

• Linear high-frequency probe (pneumothorax, lung sliding)
• Curvilinear probe (effusion, consolidation, deeper structures)
• BLUE protocol zones: upper/lower anterior, lateral, PLAPS point
• M-mode for lung sliding confirmation (seashore vs barcode sign)

Key Findings

• A-lines — normal horizontal artefacts (also seen in pneumothorax and COPD)
• B-lines — vertical laser-like artefacts; 3+ per zone suggests interstitial oedema
• Lung sliding — shimmering at pleural line; absent in pneumothorax
• Lung point — transition between sliding and non-sliding; specific for pneumothorax
• Consolidation — tissue-like (hepatised) lung, dynamic air bronchograms
• Effusion — anechoic collection above diaphragm, quad/sinusoid sign

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Indications

• Cardiac arrest — assess for cardiac activity (Resuscitation Council UK guidance)
• Undifferentiated shock (tamponade, RV dilatation, hypovolaemia)
• Suspected pericardial effusion / tamponade
• Gross LV systolic function assessment (“eyeball” squeeze)
• Acute PE — RV dilatation and interventricular septum bowing

Views

• Subxiphoid 4-chamber — best first view; pericardial effusion, cardiac activity
• Parasternal long axis (PLAX) — LV/RV size, mitral/aortic valves, effusion
• Parasternal short axis (PSAX) — D-sign (RV pressure overload), LV function
• Apical 4-chamber — RV:LV ratio, global function, valve regurgitation
• IVC assessment — subcostal longitudinal; diameter and collapsibility for volume status

Key Findings & Pitfalls

• Pericardial fat pad can mimic small effusion (usually anterior, echogenic)
• RV:LV ratio >1:1 in apical view suggests significant RV strain
• IVC >2.1 cm with <50% collapse suggests raised CVP
• Tamponade: diastolic RA/RV collapse with clinical context
• During cardiac arrest: use pulse checks to minimise CPR interruption (<10 seconds)

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Indications

• Suspected abdominal aortic aneurysm (pulsatile abdominal mass, shock)
• Undifferentiated hypotension in elderly patient
• Abdominal/back/flank pain with haemodynamic compromise
• Screening in high-risk populations (NICE AAA screening guidance)

Probe & Technique

• Curvilinear 3.5–5 MHz probe
• Measure outer wall to outer wall in transverse (AP diameter)
• Scan from xiphoid to bifurcation (at umbilicus)
• Three levels: proximal (coeliac trunk), mid (renal arteries), distal (bifurcation)

Key Findings & Pitfalls

• Normal aortic diameter <3 cm; AAA defined as ≥3 cm
• Surgical emergency if >5.5 cm or symptomatic at any size
• Intraluminal thrombus may make lumen appear normal — always measure outer-to-outer
• Bowel gas can obscure views — use graded compression, reposition patient
• Ruptured AAA: free fluid + large aorta + clinical shock = do not delay for CT

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Indications

• Unilateral lower limb swelling with raised Wells score
• Suspected DVT when formal imaging delayed or unavailable
• Risk stratification in suspected PE pathway (NICE CG144)

Probe & Technique

• Linear high-frequency probe (7.5–12 MHz)
• 2-point compression: common femoral vein (CFV) and popliteal vein
• 3-point compression: add superficial femoral vein at mid-thigh
• Complete compressibility of vein walls = no DVT at that point
• Augmentation with distal calf squeeze if needed

Key Findings & Pitfalls

• Non-compressible vein = DVT until proven otherwise
• Sensitivity of 2-point CUS: ~95% for proximal DVT
• May miss isolated calf vein DVT — correlate with clinical probability
• Chronic DVT may show thickened, echogenic walls — compare with contralateral side
• Lymphadenopathy or Baker’s cyst can mimic DVT — assess compressibility

Tutorial Resources

Indications

• Renal colic — assess for hydronephrosis
• Acute urinary retention — bladder volume estimation
• AKI — exclude obstructive uropathy
• Haematuria assessment (alongside formal imaging)

Probe & Technique

• Curvilinear 3.5–5 MHz probe
• Kidneys: coronal view from posterior axillary line (right: use liver as window)
• Bladder: suprapubic transverse and longitudinal; calculate volume (L × W × H × 0.52)
• Compare bilateral renal pelvis to identify unilateral dilatation

Key Findings & Pitfalls

• Grade 1 hydronephrosis: mild pelvic dilatation; Grade 4: cortical thinning
• Sensitivity for hydronephrosis ~90% but may be absent early in acute obstruction
• Extrarenal pelvis (anatomical variant) can mimic mild hydronephrosis
• Full bladder can cause bilateral mild pyelectasis — rescan post-void
• Bladder >300 mL in acute retention; consider catheterisation >500 mL

Tutorial Resources

Indications

• Differentiate abscess from cellulitis (drainable vs non-drainable)
• Foreign body localisation (wood, glass, metal)
• Joint effusion assessment (knee, hip in paediatrics)
• Tendon injury evaluation (Achilles, patellar)

Probe & Technique

• Linear high-frequency probe (7.5–15 MHz)
• Scan in two planes (transverse and longitudinal) over area of concern
• Compare with contralateral side when appropriate
• Use colour Doppler to identify surrounding hyperaemia (abscess wall)

Key Findings & Pitfalls

• Abscess: hypoechoic collection, posterior acoustic enhancement, compressible, may have internal debris
• Cellulitis: thickened subcutaneous tissue with cobblestoning but no drainable collection
• Foreign body: hyperechoic linear structure with posterior shadow or reverberation artefact
• Small abscess (<2 cm) may respond to antibiotics alone — clinical correlation required

Tutorial Resources

Indications

• Acute vision loss — retinal detachment, vitreous haemorrhage
• Suspected raised ICP — optic nerve sheath diameter (ONSD) measurement
• Periorbital swelling preventing direct fundoscopy
• Intraocular foreign body localisation (penetrating eye injury)

Probe & Technique

• Linear high-frequency probe (7.5–12 MHz) with generous gel
• Apply over closed eyelid with minimal pressure
• ONSD: measure 3 mm behind the globe, perpendicular to the optic nerve
• Contraindicated with suspected globe rupture (open globe injury)

Key Findings

• Retinal detachment: bright, tethered membrane floating within vitreous
• Vitreous haemorrhage: swirling echogenic debris in vitreous cavity
• ONSD >5.0 mm in adults correlates with raised intracranial pressure
• Lens dislocation: displaced hyperechoic lens within vitreous

Tutorial Resources

Indications

• Neck of femur fracture (NICE CG124 recommends early nerve block)
• Femoral shaft fracture
• Anterior thigh laceration repair
• Quadriceps tendon injury

Anatomy & Technique

• Linear high-frequency probe placed at inguinal crease
• Identify: femoral artery, femoral vein (medial), femoral nerve (lateral to artery, under fascia iliaca)
• In-plane approach from lateral to medial
• Deposit local anaesthetic around nerve, deep to fascia iliaca
• Typical dose: 15–20 mL 0.25% levobupivacaine (max 2 mg/kg)

Key Points & Safety

• Aspirate before injection to exclude intravascular placement
• Watch for LAST (local anaesthetic systemic toxicity) — have Intralipid available
• Motor block expected — warn patient about weight-bearing
• Document block, dose, time, and motor/sensory assessment
• Contraindicated if local infection, allergy, or patient refusal

Tutorial Resources

Indications

• Hip fracture analgesia (NICE CG124 — first-line if available)
• Proximal femoral fracture, acetabular fracture
• Broader coverage than femoral nerve block (femoral + lateral cutaneous nerves)
• Burn care to anterior/lateral thigh

Anatomy & Technique

• Linear probe placed at inguinal crease, lateral to femoral artery
• Identify fascia lata (superficial) and fascia iliaca (deeper) — two fascial “pops”
• In-plane needle approach from lateral
• Deposit 30–40 mL 0.25% levobupivacaine beneath fascia iliaca (max 2 mg/kg)
• Look for fascial lifting and spread on ultrasound

Key Points

• Higher volume block — dose calculation critical, especially in elderly/frail patients
• Onset 15–30 minutes; duration 6–12 hours
• May partially block obturator nerve — improved hip fracture pain relief
• LAST risk: have 20% lipid emulsion (Intralipid) drawn up and resuscitation equipment available

Contraindications

• Patient refusal or inability to consent without an appropriate best-interests process
• Infection at the injection site
• Known allergy to local anaesthetic
• Previous femoral bypass graft in the groin (relative)
• Caution with significant coagulopathy — weigh benefit against bleeding risk

Complications

• Local anaesthetic systemic toxicity (LAST)
• Vascular puncture or haematoma
• Intravascular injection
• Block failure or incomplete analgesia
• Transient femoral nerve motor block — counsel re falls risk

Safety considerations

• Calculate the maximum weight-based local anaesthetic dose and document drug, concentration, and volume.
• Aspirate intermittently and inject under direct ultrasound vision, keeping the needle tip in view.
• Monitor the patient with resuscitation facilities available; assess neurovascular status before and after.

Escalation triggers

• Signs of LAST (perioral tingling, agitation, seizures, arrhythmia) — start LAST management and call for senior/anaesthetic help.
• Expanding groin haematoma or signs of limb ischaemia.
• Inadequate analgesia despite a correctly placed block — discuss alternative strategies with seniors.

Anticoagulation considerations

• A fascia iliaca block is a relatively superficial, compressible field block; it can often proceed in anticoagulated hip-fracture patients when clinically indicated.
• Weigh bleeding risk against analgesic benefit and follow local and regional anaesthesia guidance; seek senior advice if uncertain.

Tutorial Resources

Indications

• Hand lacerations requiring repair (distribution-specific block)
• Distal radius/ulna fracture reduction
• Finger/hand abscess drainage
• Foreign body removal from hand

Anatomy & Technique

• Linear high-frequency probe at wrist crease level
• Median nerve: between palmaris longus and FCR tendons; deep to flexor retinaculum
• Ulnar nerve: medial to ulnar artery, beneath FCU tendon
• Radial nerve: lateral to radial artery at anatomical snuffbox level (superficial branch)
• 1–3 mL 1% lidocaine or 0.25% levobupivacaine per nerve

Key Points

• USS guidance improves success rate and reduces vascular injection risk
• Avoid epinephrine in digital/end-artery distributions (historical concern, though increasingly debated)
• Document pre- and post-block neurological assessment
• Combination blocks provide near-complete hand anaesthesia

Tutorial Resources

Indications

• Finger laceration repair
• Nail bed repair or nail removal
• Finger dislocation reduction
• Paronychia/felon drainage
• Foreign body removal from digit

Technique

• Traditional: landmark-based ring block at base of finger (web space approach or dorsal approach)
• USS-guided: linear probe to visualise digital nerves; needle guided perineurally
• 1–2 mL 1% lidocaine per injection point (total 3–4 mL per digit)
• Block both palmar digital nerves (medial and lateral)
• Wait 5–10 minutes for full effect; test before procedure

Key Points

• Traditionally taught without epinephrine (end-artery concern), though WALANT technique increasingly accepted
• USS guidance most useful for difficult anatomy or failed landmark block
• Duration: 1–2 hours with lidocaine; 4–8 hours with levobupivacaine

Tutorial Resources

Indications

• Multiple rib fractures — opioid-sparing analgesia
• Chest drain insertion analgesia
• Lateral chest wall injuries
• Alternative to thoracic epidural or paravertebral block in ED

Anatomy & Technique

• Linear probe placed at mid-axillary line, 4th–5th rib level
• Identify latissimus dorsi (superficial), serratus anterior, rib, intercostal muscles
• In-plane approach; deposit 20–30 mL 0.25% levobupivacaine deep to serratus anterior
• Covers lateral cutaneous branches of intercostal nerves (T2–T9)

Key Points

• Growing evidence base in emergency medicine for rib fracture pain management
• Simpler than paravertebral or erector spinae blocks
• Minimal haemodynamic effects compared to thoracic epidural
• Document competency and consent; have LAST rescue available

Tutorial Resources

Indications

• Unilateral rib fractures (posterior/lateral)
• Thoracotomy or chest wall procedure pain
• Abdominal wall analgesia (renal colic, flank procedures)
• Emerging role in ED for multimodal opioid-sparing analgesia

Anatomy & Technique

• Linear or curvilinear probe placed longitudinally over transverse process
• Identify trapezius, rhomboid, erector spinae muscles and the transverse process
• In-plane approach; deposit 20–30 mL 0.25% levobupivacaine deep to erector spinae, superficial to transverse process
• Local anaesthetic spreads across multiple dermatomes (typically 3–4 levels)

Key Points

• Relatively superficial block with lower risk of pneumothorax than paravertebral
• Mechanism: local anaesthetic diffuses anteriorly to reach dorsal rami and ventral rami
• Can be performed seated or lateral — practical in ED setting
• Emerging evidence; not yet universally adopted in UK emergency medicine

Tutorial Resources