295.3 🏥 內科專科考前版

295.3.1 Mechanistic Deep Dive

295.3.1.1 Aortic Deceleration Injury

  • Aorta fixed at ligamentum arteriosum (isthmus)
  • During deceleration: aorta swings, isthmus is “anchor point” → tear
  • 50% fatal at scene
  • Survivors often have a contained hematoma
  • Intimal tear → false lumen → aneurysm or rupture

295.3.1.2 Cardiac Tamponade Physiology Refresher (Ch283)

  • Acute pericardial fluid → ↑ pressure → impaired filling
  • Even small volumes (< 100 mL) cause tamponade if acute
  • Beck triad: hypotension + JVD + muffled heart sounds
  • Pulsus paradoxus

295.3.1.3 RV Anatomic Position

  • Most anterior chamber
  • Closest to chest wall
  • Most commonly injured in blunt trauma

295.3.2 Recent Trials & Updates

295.3.2.1 TEVAR vs Open Repair Aortic Transection

  • Multiple studies + meta-analyses 2010s-2020s
  • TEVAR: lower mortality + morbidity
  • Now standard of care for most

295.3.2.2 Damage Control Resuscitation

  • Avoid crystalloids; use blood products 1:1:1 (RBC:plasma:platelets)
  • Permissive hypotension during initial resuscitation
  • Tranexamic acid (TXA) for major trauma (CRASH-2)

295.3.2.3 REBOA (Resuscitative Endovascular Balloon Occlusion of Aorta)

  • For non-compressible torso hemorrhage
  • Limited role; trials ongoing
  • May save selected patients

295.3.2.4 ECPR (ECMO-CPR) for Traumatic Arrest

  • Limited role
  • Highly selected centers

295.3.3 High-Yield Specialist Points

295.3.3.1 Trauma + Anticoagulant Reversal

  • Warfarin: 4-factor PCC + vitamin K
  • DOAC: andexanet alfa (Xa inhibitor); idarucizumab (dabigatran)
  • Aspirin: platelet transfusion (debated, NSAID-induced trauma)

295.3.3.2 Multidisciplinary Approach

  • Trauma surgery
  • Cardiothoracic surgery
  • Anesthesia
  • Critical care
  • Cardiology
  • Interventional radiology
  • Vascular surgery

295.3.3.3 Pediatric Trauma Pearls

  • Different mechanism (bike handlebars)
  • Greater chest compliance → may have severe internal without external injury
  • AED + CPR same as adults

295.3.3.4 Late Complications of Cardiac Trauma

  • Pericarditis / pericardial effusion (post-traumatic, weeks-months)
  • Constrictive pericarditis (chronic)
  • Pseudoaneurysm
  • AV block
  • Late valvular dysfunction

295.3.3.5 Cardiac Imaging Post-Trauma

  • Echo within 24 hours
  • Repeat echo 1-3 months if injury suspected
  • CMR for late complications
  • CT for vascular injury

295.3.3.6 Iatrogenic Coronary Dissection

  • During PCI ~ 0.1-0.5%
  • Treatment: stenting at proximal end, observation if minor
  • Re-do PCI if extending

295.3.3.7 Pacemaker / Lead Perforation

  • ~ 1% with active fixation leads
  • Late perforation: weeks-months
  • Echo + lead repositioning surgery
  • Pericardial drainage if tamponade

295.3.3.8 Endomyocardial Biopsy Risk

  • Perforation < 1% with experienced operator
  • TR + coronary artery injury rare

295.3.3.9 Trauma + Aortic Dissection (Different from Spontaneous)

  • Type B usually
  • Younger patient
  • Surgical / TEVAR considered
  • Similar mortality if untreated

295.3.4 Pearls

  • Blunt cardiac contusion: troponin (best NPV at 4-6 hr), ECG, echo
  • Cardiac rupture: FAST → emergent surgery; RA most common
  • Aortic transection: CXR signs (widened mediastinum) → CT angio → TEVAR + esmolol
  • Valvular blunt injury: TV most common
  • Penetrating: ED thoracotomy for peri-arrest stab; OR repair for stable
  • Iatrogenic: cath, lead, biopsy perforation; reverse AC + pericardiocentesis if tamponade
  • Damage control + TXA + permissive hypotension in major trauma
  • TEVAR > open for aortic injury