• Global: Trauma is the leading cause of death in people < 40 years old ^[2][3]. Road traffic accidents (RTAs) account for ~50% of trauma deaths, followed by homicides (~20%), suicides (~15%), falls (~10%), and burns (~5%) ^[3].
• Hong Kong context: RTAs remain the predominant mechanism. Hong Kong's dense urban environment, heavy traffic, and high-rise buildings contribute to both vehicular trauma and falls from height. Interpersonal violence (gang fights with chopping/stabbing wounds) is also a significant mechanism, particularly in certain districts ^[1].
• Chest injuries occur in ~50% of multiply-injured patients.
• Blunt chest trauma accounts for > 80% of thoracic injuries in civilian settings (most commonly RTAs, falls). Penetrating chest trauma (stab wounds, gunshot wounds) is less common in Hong Kong compared to Western countries but still significant in the context of interpersonal violence ^[1].

• Ribs: 12 pairs. The 4th–10th ribs are most commonly fractured ^[3]. The upper ribs (1st–3rd) are protected by the scapula, clavicle, and thick muscles — fracture of these ribs implies high-energy trauma and should alert you to mediastinal/great vessel injury ^[3]. The lower ribs (10th–12th) overlie the spleen (left) and liver (right) — fractures here suggest intra-abdominal organ injury ^[3].
• Sternum: Sternal fractures suggest significant anterior force (e.g., steering wheel, seatbelt) and should prompt evaluation for myocardial contusion.
• Intercostal neurovascular bundle: Runs along the inferior border of each rib (vein-artery-nerve, from top to bottom). This is why chest drains are inserted just above the rib to avoid the bundle, and why rib fractures can cause significant bleeding.
• Muscles: Intercostals (external, internal, innermost), diaphragm. The diaphragm is the primary muscle of respiration — rupture causes herniation of abdominal contents into the thorax.

• A potential space between the visceral pleura (adherent to lung) and parietal pleura (lines chest wall). Normally contains only a thin film of serous fluid (~5-15 mL) for lubrication.
• Why does air in the pleural space collapse the lung? Because the lung has intrinsic elastic recoil pulling it inward, while the chest wall has elastic recoil pulling it outward. The negative intrapleural pressure (~-5 cmH₂O at rest) keeps the lung expanded. If air enters (pneumothorax), pressure equalises → lung collapses.
• Why does tension pneumothorax cause shock? A one-way valve mechanism allows air in but not out → progressive positive pressure → mediastinal shift → compression of the contralateral lung AND kinking of the great veins (SVC/IVC) → decreased venous return → obstructive shock ^[4][5].

• Right lung: 3 lobes; Left lung: 2 lobes (cardiac notch).
• Lung parenchyma is highly vascular — contusion causes bleeding into airways → appears as consolidation on CXR ^[3].
• The tracheobronchial tree can rupture with severe deceleration or crush injury → pneumomediastinum, persistent air leak.

• Anterior: thymus, internal mammary vessels.
• Middle: heart, pericardium, great vessels (aorta, SVC, IVC, pulmonary arteries/veins), trachea, main bronchi, oesophagus, phrenic/vagus nerves.
• Posterior: descending aorta, oesophagus, thoracic duct, azygos vein, thoracic vertebral bodies.
• The aortic isthmus (junction of the mobile aortic arch and the fixed descending aorta, just distal to the left subclavian artery) is the most vulnerable point for deceleration injury — this is where 80-85% of traumatic aortic injuries occur ^[3]. Think of it like holding a rope at one end and whipping it — the point of fixation takes the maximum shear force.

• The pericardium is a fibrous sac containing 15-50 mL of fluid ^[6]. It is relatively non-distensible in the acute setting.
• Why does a small pericardial effusion cause tamponade in trauma but not in chronic effusions? Because in chronic effusions (e.g., malignancy), the pericardium stretches gradually and can accommodate up to 1-2L. In acute trauma, even 100-200 mL of blood can dramatically increase intrapericardial pressure → compress the chambers (especially the thin-walled right atrium/ventricle) → impair diastolic filling → decreased cardiac output → obstructive shock (Beck's triad: hypotension, distended neck veins, muffled heart sounds) ^[1].

• A dome-shaped musculotendinous sheet separating the thorax from the abdomen.
• Rupture is more common on the left (because the liver provides a protective buttress on the right) ^[3].
• Rupture allows abdominal viscera (stomach, colon, spleen) to herniate into the thorax → compresses lung, may strangulate herniated viscera.

• Posterior mediastinal structure, has no serosa → inherently more susceptible to perforation and poor healing ^[7].
• Rupture → contamination of mediastinum with gastric contents and bacteria → mediastinitis (a surgical emergency with high mortality).

Classification of injuries ^[1]:

Blunt injury is the most common mechanism in Hong Kong ^[1][2].

1. Direct impact (compression): The chest wall is compressed between the impacting force and the spine/posterior chest wall. This directly fractures ribs, compresses the heart (cardiac contusion), and can rupture the lung parenchyma (contusion). Example: steering wheel impact, fall onto chest.

2. Deceleration (shearing): When the body rapidly decelerates (e.g., high-speed RTA, fall from height), structures of different densities or those tethered at different points experience shear forces at their points of attachment. This is the mechanism behind:

   • Aortic injury at the isthmus: The relatively mobile aortic arch shears against the fixed descending aorta ^[3].
   • Tracheobronchial injury at the carina.
   • Mesenteric tears (abdominal).

3. Blast/overpressure: A pressure wave travels through tissues. Air-containing organs (lungs, bowel, middle ear) are most susceptible because of the air-tissue interface. The pressure wave causes disruption at these interfaces → blast lung (haemorrhagic alveolitis, pulmonary contusion).

Penetrating injury ^[1]:

• Stab wounds: Low-velocity, localised damage along the tract of the weapon. The injury is predictable based on the weapon trajectory and depth of penetration. In gang fights, chopping and stabbing wounds are common ^[1].
• Gunshot wounds: Higher velocity → greater energy transfer → more tissue destruction. The injury zone extends beyond the wound tract (cavitation effect). The path may be unpredictable (bullet tumbling, fragmentation, ricocheting off bone).

• RTAs: The most common mechanism. A bus hit a train scenario represents a mass casualty incident (MCI) / disaster ^[2], requiring triage and disaster management protocols.
• Falls from height: Very common due to construction and high-rise buildings. Vertical deceleration → bilateral calcaneal fractures, spinal fractures, and thoracic/abdominal injuries.
• Gang fights: Chopped and stabbed wounds are a recognised pattern of interpersonal violence in Hong Kong ^[1]. These present with nerve and vascular injuries as well as chest/abdominal penetration.
• Burns/scalds: Scalds can affect the chest wall and airway ^[8]. Circumferential chest burns can cause a restrictive physiology requiring escharotomy.
• Industrial/construction injuries: Crush injuries, falls from scaffolding.

"Haemo" (Greek: haima = blood) + "thorax."

• Blood accumulates in the pleural space from injured intercostal vessels, internal mammary vessels, lung parenchyma, or great vessels.
• Why does haemothorax cause shock? Two mechanisms:
  1. Hypovolaemic shock: Each hemithorax can hold 2-3L of blood. Massive haemothorax is defined as > 1500 mL of blood immediately drained on chest tube insertion, or > 200 mL/hour for 2-4 consecutive hours → indication for thoracotomy ^[1].
  2. Compression of lung: Blood occupies space → atelectasis → V/Q mismatch → hypoxaemia.

• Definition: ≥ 3 consecutive ribs fractured in ≥ 2 places (or ≥ 2 ribs fractured with bilateral costochondral separations) → a free-floating segment of chest wall.
• Paradoxical movement: During inspiration, the negative intrapleural pressure draws the flail segment INWARD (instead of outward with the rest of the chest wall). During expiration, the segment moves OUTWARD.
• Why does this cause respiratory failure?
  1. Underlying pulmonary contusion (the real killer) — direct lung parenchymal damage → haemorrhage and oedema into alveoli → intrapulmonary shunt → hypoxaemia.
  2. Pain → splinting → hypoventilation → atelectasis → infection.
  3. Mechanical disadvantage → reduced tidal volume.
• Treatment priority: analgesia (epidural/paravertebral block), oxygen, positive pressure ventilation if needed. Internal pneumatic splinting with positive pressure ventilation is the definitive management if mechanical ventilation is required ^[1].

• Mechanism: Blood accumulates in the pericardial sac (most commonly from penetrating injury to the heart, especially the right ventricle — the most anterior chamber).
• Pathophysiology: The fibrous pericardium is non-distensible in the acute setting → even small volumes (100-200 mL) → ↑intrapericardial pressure → compression of cardiac chambers (especially thin-walled RA and RV in diastole) → impaired diastolic filling → ↓stroke volume → ↓cardiac output → obstructive shock ^[1][5].
• Compensatory mechanisms: Initially, sympathetic activation → tachycardia + vasoconstriction to maintain BP. This is why the patient may look "stable" initially before sudden decompensation.
• Beck's triad: hypotension, distended neck veins, muffled heart sounds ^[1].
• Pulsus paradoxus: Exaggerated drop in systolic BP > 10 mmHg during inspiration. Mechanism: during inspiration, increased venous return to the right heart → RV distension → the interventricular septum bulges into the LV (because total cardiac volume is fixed by the non-distensible pericardium) → reduced LV filling → ↓stroke volume → ↓systolic BP.
• Kussmaul's sign: Paradoxical rise in JVP on inspiration (because the RV cannot accommodate the increased venous return).
• Electrical alternans on ECG: Alternating amplitude of QRS complexes due to the heart "swinging" in the pericardial fluid.

• Mechanism: high-speed deceleration (RTA, fall from height) ^[3].
• Site: aortic isthmus (80-85%) — where the mobile aortic arch meets the fixed descending aorta (tethered by the ligamentum arteriosum and intercostal arteries) ^[3].
• Lethality: 80-90% die at the scene. Of those reaching hospital, 30% die within 6h, 50% within 24h, 90% within 4 months if untreated ^[3].
• Pathophysiology: Shear force → intimal tear ± medial disruption → contained rupture (if the adventitia holds) → pseudoaneurysm. If the adventitia ruptures → free rupture → exsanguination.
• CXR clues: widened mediastinum ( > 8 cm), abnormal aortic contour/loss of aortic knuckle, thickened paratracheal stripe, deviation of trachea/NG tube to right, left apical pleural cap, depression of left main bronchus ^[3].
• CT aortogram is the definitive investigation (fast, high sensitivity) ^[3].

• Definition: Bruising of lung parenchyma → haemorrhage and oedema into the alveoli and interstitium.
• Pathophysiology: Direct impact → disruption of alveolocapillary membrane → blood and plasma leak into alveoli → consolidation + intrapulmonary shunt → hypoxaemia. Worsens over 24-48 hours as the inflammatory response peaks (similar to ARDS pathophysiology — diffuse alveolar damage) ^[3][9].
• CXR: consolidation that does NOT respect lobar boundaries (unlike pneumonia). Appears within 6 hours of injury ^[3].
• CT is more sensitive than CXR for detecting early/subtle contusion.
• Key difference from ARDS: pulmonary contusion is localised to the area of impact (though severe bilateral contusion can progress to ARDS).

• Left side > right side (liver protects the right hemidiaphragm) ^[3].
• Mechanism: Blunt abdominal/thoracic trauma → sudden increase in intra-abdominal pressure against a fixed diaphragm.
• Pathophysiology: Defect in diaphragm → pressure gradient between abdomen (positive) and thorax (negative) → progressive herniation of abdominal viscera (stomach, colon, spleen, omentum) into the thorax.
• Presentation is often insidious — the initial defect may be small, and organs herniate gradually over days to weeks ^[3].
• Risk: strangulation of herniated viscera (a surgical emergency) ^[3].
• CXR clues: Elevated hemidiaphragm, gas-filled viscus in thorax (gastric bubble), nasogastric tube coiled in thorax ^[3].

• Mechanism: Severe deceleration, crush injury, penetrating trauma.
• 80% occur within 2.5 cm of the carina.
• Pathophysiology: Airway rupture → massive air leak → pneumomediastinum, subcutaneous emphysema, persistent pneumothorax despite chest drain (the air leak cannot be controlled because air is continuously escaping from the ruptured airway).
• CXR: pneumomediastinum signs — ring around artery sign, continuous diaphragm sign, Naclerio's V sign, subcutaneous emphysema ^[3].
• Fallen lung sign: The collapsed lung falls peripherally/dependently (away from the hilum) rather than toward the hilum, because the bronchus is disrupted → the lung is no longer tethered to the mediastinum.

• Penetrating trauma or Boerhaave's syndrome (spontaneous rupture from forceful vomiting) ^[7].
• The oesophagus has no serosa → poor healing, rapid contamination of mediastinum ^[7].
• Pathophysiology: Perforation → leakage of gastric contents and saliva into mediastinum → chemical mediastinitis → bacterial mediastinitis → sepsis (mortality 20-40% even with treatment; approaches 100% if untreated for > 24h).
• Mackler's triad: vomiting, excruciating chest pain, subcutaneous emphysema ^[7].
• Hamman's sign: mediastinal crunching/clicking sound synchronous with heartbeat (due to mediastinal emphysema) ^[7].

• Mechanism: Direct sternal impact (steering wheel, fall onto anterior chest).
• Pathophysiology: Bruising of myocardium → myocardial oedema + haemorrhage → cellular dysfunction → arrhythmias (most dangerous consequence) and reduced contractility.
• The right ventricle is most commonly affected (most anterior chamber).
• Clinical features: May be asymptomatic. Chest pain (similar to pericarditis). Arrhythmias (sinus tachycardia, atrial fibrillation, premature ventricular contractions, ventricular tachycardia). Rarely → cardiogenic shock if severe contusion.
• ECG: ST-T changes, new RBBB, arrhythmias.
• Troponin: May be elevated (but non-specific in polytrauma).
• Echo: Wall motion abnormalities, pericardial effusion.

• Reduced physiological reserve: Pre-existing cardiopulmonary disease, medications (beta-blockers may mask tachycardia, anticoagulants increase bleeding risk).
• Osteoporotic ribs: Fracture with lower energy → higher morbidity per rib fractured.
• Each additional rib fracture in elderly patients increases pneumonia risk by ~27% and mortality by ~19% [literature].
• Blunted sympathetic response: Tachycardia may be absent → "look-well" patient who is actually in compensated shock.

• Compliant chest wall: Children have very flexible ribs → significant internal organ injury can occur WITHOUT rib fractures. If a child has rib fractures, suspect very high-energy mechanism (or NAI — non-accidental injury).
• Higher metabolic rate: Decompensate more quickly.
• Small blood volume: Relatively smaller absolute volume → smaller blood loss is proportionally more significant.

• Physiological changes: ↑blood volume (by ~40%), ↑heart rate, ↓BP (physiological) → may mask haemorrhage.
• Elevated diaphragm: Chest drain insertion should be 1-2 intercostal spaces higher than usual.
• Supine hypotension: Gravid uterus compresses IVC → always tilt to left lateral position (or manual left uterine displacement) in supine patients.

• Full head-to-toe examination including log roll ^[2].
• Trauma series: AP CXR, AP pelvis XR. (Lateral C-spine XR largely replaced by CT in modern practice but still relevant in resource-limited settings.) ^[2][3]
• FAST scan: To detect pericardial effusion and intra-abdominal free fluid ^[2][3][10].

FAST scan assesses 4 windows: subxiphoid (pericardial), right upper quadrant/Morison's pouch (hepatorenal), left upper quadrant (splenorenal), pelvis (pouch of Douglas). ± Extended FAST (eFAST) includes bilateral thoracic views for pneumothorax and haemothorax ^[3][10].

• CT whole body ("trauma CT"): Gold standard for stable patients to fully evaluate all injuries ^[2][3].
  • Arterial phase: for bleeding points and pseudoaneurysms
  • Portovenous phase (most important): visceral injury
  • Delayed phase: urinary extravasation
  • Lung and bone windows ^[10]

This is where your history of the mechanism becomes the most powerful diagnostic tool. Each mechanism predicts a pattern.

The standard acute chest pain differential applies and must be considered even in trauma ^[11][12][13]:

This table is taken directly from the standard clinical approach to acute chest pain ^[11][12].

This combination should raise suspicion for:

• Oesophageal rupture (Boerhaave's or penetrating) — because the left posterolateral distal oesophagus is the most common rupture site → contamination of left pleural space ^[7]
• Diaphragmatic rupture with herniation of abdominal contents ^[3]
• Thoracic duct injury → chylothorax (rare, usually with penetrating left supraclavicular/mediastinal trauma)

DDx beyond ATAI ^[3]:

• Aortic dissection (non-traumatic — consider if risk factors present: hypertension, Marfan's, cocaine)
• Mediastinal haematoma from vertebral fracture
• Thymic/mediastinal mass (incidental finding)
• Technical factors: AP projection (magnifies mediastinum vs. PA), supine positioning, patient rotation
  • In trauma, CXR is often AP supine — this artefactually widens the mediastinum. Always consider this before panicking, but err on the side of further imaging (CT aortogram) if concerned.

Penetrating injury to the neck is closely related to chest injury because structures traversing the thoracic inlet can be injured. The lecture slides specifically highlight ^[1]:

• Exsanguinating external bleeding (may be from external jugular vein)
• Expanding haematoma → requires endotracheal intubation to protect airway then operative exploration
• If unsure of diagnosis or wound deeper than platysma → operative exploration or CT angiography

The neck is traditionally divided into three zones for penetrating injuries:

Lower rib fractures (10th-12th) should trigger consideration of abdominal organ injury ^[3][10]:

• Left lower ribs → Splenic injury (delayed rupture possible — patient may be stable initially then deteriorate hours/days later) ^[10]
• Right lower ribs → Hepatic injury
• Bilateral lower ribs → Renal injury

This is why a FAST scan is essential even in patients presenting primarily with chest trauma — the diaphragm is not a boundary for injury patterns.

Thoracic spinal fractures are part of the chest trauma DDx because:

• They coexist with other thoracic injuries (especially in high-energy mechanisms)
• They can cause spinal cord injury → paraplegia ^[15]
• Vertebral fractures can cause mediastinal haematoma → widening on CXR (mimicking ATAI)
• They contribute to neurogenic shock (loss of sympathetic tone below the level of injury → vasodilation + bradycardia → hypotension with paradoxical bradycardia — unlike hypovolaemic shock which has tachycardia)

This is a CLINICAL diagnosis. Do NOT wait for CXR or any imaging ^[4][5].

Diagnostic criteria (all clinical):

• Severe respiratory distress
• Obstructive shock: hypotension + elevated JVP
• Ipsilateral absent breath sounds + hyperresonance
• Tracheal deviation to contralateral side (may be absent in splinted mediastinum, e.g., malignancy/fibrosis)
• Immediate improvement after needle decompression confirms the diagnosis (therapeutic and diagnostic simultaneously)

Diagnostic criteria:

• > 1500 mL of blood drained immediately on chest tube insertion, OR
• > 200 mL/hour of ongoing drainage for 2-4 consecutive hours ^[1]
• These are the indications for thoracotomy — they define the injury as "massive" and imply a source (usually intercostal artery, internal mammary artery, or great vessel) that will not stop without surgical intervention.

Diagnostic criteria:

• ≥ 3 consecutive ribs fractured in ≥ 2 places each (creating a free-floating segment), OR
• ≥ 2 ribs fractured bilaterally with sternal separation
• Paradoxical chest wall movement on inspection
• Underlying pulmonary contusion (the cause of significant morbidity) typically confirmed on CXR/CT

Diagnostic criteria (clinical + bedside):

• Beck's triad: hypotension + distended neck veins + muffled heart sounds ^[1]
• Pulsus paradoxus > 10 mmHg (exaggerated SBP drop on inspiration)
• FAST/echocardiography: pericardial fluid collection with RA/RV diastolic collapse ^[3][10]
• Electrical alternans on ECG (alternating QRS amplitude)

Diagnostic criteria (radiological):

• CXR screening: widened mediastinum ( > 8 cm on AP), loss of aortic knuckle, thickened paratracheal stripe, tracheal/NG deviation to right, left apical cap, depression of left main bronchus ^[3]
• CT aortogram (definitive): intimal flap, pseudoaneurysm, mediastinal haematoma, extravasated contrast, periaortic haematoma ^[3]
• 80-85% occur at the aortic isthmus ^[3]

Diagnostic criteria (radiological):

• Erect CXR: visible visceral pleural edge with radiolucency and no lung markings peripheral to it ^[3][4]
• Supine CXR (common in trauma — patient cannot sit up): deep sulcus sign, double diaphragm sign, increased sharpness of mediastinal/cardiac borders, depression of ipsilateral hemidiaphragm ^[3]
• Size classification ^[4]:
  • Small: < 2 cm between lung edge and chest wall at level of hilum
  • Large: ≥ 2 cm (≈ ↓50% lung volume)
  • Formula: % pneumothorax = (1 - average lung diameter³ / average hemithorax diameter³) × 100%
  • 1 cm on PA CXR ≈ 27% hemithorax

Diagnostic criteria:

• CXR: non-lobar consolidation at site of impact, appearing within 6 hours ^[3]
• CT is more sensitive: ground-glass opacification and consolidation not respecting lobar boundaries
• Clinical correlation: worsening hypoxaemia over 24-48 hours despite treatment
• Key distinguishing feature from pneumonia: contusion follows the anatomical distribution of impact, not lobar anatomy; appears early; no infectious prodrome

Diagnostic criteria:

• CXR: elevated hemidiaphragm, gas-filled viscus above diaphragm, NG tube coiled in thorax ^[3]
• CT with coronal/sagittal reconstruction: direct visualisation of diaphragmatic discontinuity with herniated viscera
• Contrast studies (barium meal/water-soluble contrast): confirm bowel in thorax ^[3]
• Often diagnosed late — presentation can be insidious with a small defect that enlarges over time ^[3]

Diagnostic criteria:

• Clinical: Mackler's triad (vomiting + excruciating chest pain + subcutaneous emphysema) ^[7]
• CXR: pneumomediastinum, surgical emphysema, left pleural effusion ^[7]
• CT with oral water-soluble contrast: localises the site of perforation (contrast extravasation) ^[7]
• Hamman's sign: mediastinal crunching synchronous with heartbeat ^[7]

After addressing all immediately life-threatening injuries:

1. Complete secondary survey: head-to-toe examination including log roll ^[2]
2. Adjunct investigations: CXR, eFAST, ECG, bloods, ± CT whole body ^[10]
3. Continuous monitoring: BP/P, SpO₂, cardiac monitor, urine output, temperature
4. Reassess and repeat primary survey — the patient's condition can change rapidly

Indications ^[4]:

• Pneumothorax: haemodynamically unstable, bilateral PTX, PSP ≥ 2 cm or symptomatic, SSP ≥ 1 cm or symptomatic
• Haemothorax / chylothorax
• Pleural effusion: bilateral effusion failing medical treatment, malignancy, complicated parapneumonic effusion / empyema
• Post-operative: thoracic/cardiac surgery, thoracoscopy
• Instillation of agents (e.g., talc, tPA)

Technique ^[4]:

Three-bottle chest drain system ^[4]:

Removal criteria ^[4]:

• No air leak (no bubbling) for > 24 hours
• Fluid output < 150-200 mL/day
• Lung fully re-expanded on CXR
• Remove during expiration or Valsalva (to prevent air entry)

This is a last-resort, heroic procedure performed in the emergency department or operating theatre.

Indications:

• Penetrating chest trauma with witnessed cardiac arrest or agonal rhythms (best outcomes — survival up to 35% for isolated stab wound to heart)
• Blunt trauma with cardiac arrest (very poor outcomes — survival < 2%)
• Massive haemothorax not responding to chest drain and resuscitation
• Cardiac tamponade not responding to pericardiocentesis

Approach: Left anterolateral thoracotomy (5th intercostal space) — allows:

• Opening the pericardium to relieve tamponade
• Direct cardiac massage (open CPR is more effective than closed chest compressions)
• Cross-clamping the descending aorta (redirects blood to heart and brain)
• Clamping the pulmonary hilum (stops massive pulmonary haemorrhage)
• Identification and repair of cardiac/great vessel injuries

Contraindications:

• Blunt trauma with no signs of life and prolonged CPR (futile)
• Patients with multiple severe injuries and no chance of meaningful survival

Technique (subxiphoid approach):

1. Patient semi-recumbent at 45° (pools blood inferiorly)
2. 18G spinal needle attached to syringe, inserted 1-2 cm below and to the left of the xiphoid process
3. Directed at 45° toward the left shoulder tip
4. Advance slowly while aspirating — ECG monitoring (ST elevation or ectopics suggest needle touching myocardium → withdraw slightly)
5. Aspirate as much blood as possible — even 20 mL can be dramatically effective
6. Can leave a catheter in situ for continued drainage (Seldinger technique)

Limitations: Blood in tamponade often clots → difficult to aspirate. Pericardiocentesis is a bridge to definitive surgery, not definitive treatment.

• Why? Retained haemothorax → excellent culture medium for bacteria → secondary infection → empyema (infected pleural collection). Also from direct contamination (penetrating wound, oesophageal perforation).
• Timeline: Typically develops 3-7 days after the initial injury if blood is not adequately drained.
• Prevention: Early and complete drainage of haemothorax. Early VATS for retained/clotted haemothorax (ideally within 3-5 days).
• Management: Chest drain (large bore, 28-32Fr) + IV antibiotics. If loculated → intrapleural fibrinolytics (tPA + DNase) or VATS decortication.

• Why? Inadequately drained haemothorax → blood organises → fibrous peel forms on the visceral pleura → the lung cannot re-expand ("trapped lung") ^[4].
• Lung entrapment: Active disease (e.g., malignancy, ongoing infection) prevents lung expansion; pleural fluid is exudative.
• Trapped lung: Remote inflammatory condition (e.g., organised haemothorax) has resolved but left behind a fibrous peel; pleural fluid is transudative ^[4].
• Consequence: Restrictive lung physiology → chronic dyspnoea, recurrent pleural effusion.
• Management: Decortication (surgical removal of the fibrous peel via VATS or thoracotomy) to free the lung.

• Splenic delayed rupture: Can occur days to weeks after initial trauma. The initial injury creates a subcapsular haematoma → the capsule eventually ruptures → sudden intra-abdominal haemorrhage. This is why patients with lower left rib fractures need serial monitoring even if initially stable ^[10].
• Hepatic delayed rupture: Similar mechanism but less common.

• If oesophageal perforation is missed or treatment is delayed → progressive contamination of the mediastinum with saliva, gastric contents, and bacteria → fulminant mediastinitis → septic shock → multi-organ failure.
• Mortality approaches 100% if untreated for > 24 hours ^[7].
• Clinical features: Septic shock, chest pain, subcutaneous emphysema, Hamman's sign ^[7].

• If ATAI is initially contained but missed or incompletely treated → the weakened aortic wall gradually dilates → pseudoaneurysm (false aneurysm — contained by adventitia only, not all three vessel wall layers).
• Develops in 2-5% of patients who survive the initial ATAI ^[3].
• Risk: Rupture at any time (potentially fatal). Requires surveillance and elective repair (TEVAR or open).

• Rarely, extensive chest wall bleeding (e.g., from multiple rib fractures with associated intercostal vessel injury) can cause increased pressure within the chest wall musculature → ischaemia.
• More relevant in circumferential burns of the chest → eschar acts as a constricting band → cannot expand → restrictive physiology → respiratory failure. Management: escharotomy ^[8].

• Why? Rib fractures heal but the intercostal nerves may be damaged or entrapped in callus → chronic neuropathic pain.
• Especially common after thoracotomy — the surgical approach involves rib spreading, which stretches/crushes the intercostal nerves.
• Management: Neuropathic pain agents (gabapentin, pregabalin), nerve blocks, physiotherapy. Prevention: VATS approaches where possible (less nerve damage than open thoracotomy).

• Risk of recurrence: 10-30% at 1-5 years (first PSP), 50% at 3 years (SSP) ^[5].
• Why? The underlying predisposition (subpleural blebs, emphysematous bullae) persists. The healed pleural breach may re-open.
• Indications for definitive surgery (pleurodesis) ^[4][5]:
  • SSP (all cases)
  • PSP: recurrent (2nd ipsilateral, 1st contralateral), synchronous bilateral PTX, persistent air leak, high-risk professions (pilots, divers, drivers), pregnancy
• Modalities: Surgical pleurodesis (VATS with bleb resection + mechanical abrasion ± pleurectomy — recurrence ~1-5%) ^[4][5]. Chemical pleurodesis (talc, minocycline, autologous blood) if surgically unfit ^[4].

• Why? Ribs are subject to constant movement with breathing → difficult to immobilise → some fractures heal with malposition (malunion) or fail to heal (non-union).
• Consequence: Chronic pain, chest wall deformity, rarely restrictive lung physiology.
• Management: Usually conservative. Surgical fixation only if symptomatic and refractory.

• Why? Traumatic haemopericardium → inflammation → organisation of blood into fibrous tissue → pericardial fibrosis and calcification → the pericardium becomes a rigid, non-compliant shell → restricts diastolic filling → diastolic heart failure.
• Timeline: Months to years after the initial injury.
• Clinical features: Signs of right heart failure (JVD, hepatomegaly, ascites, peripheral oedema) with Kussmaul's sign (JVP rises on inspiration) and pericardial knock (early diastolic sound).
• Management: Pericardiectomy (surgical stripping of the fibrosed pericardium).

• Missed or untreated ATAI → chronic pseudoaneurysm → risk of delayed rupture. Post-traumatic pseudoaneurysm develops in 2-5% of ATAI survivors ^[3].
• Requires lifelong surveillance and elective TEVAR/open repair.

• Initially missed diaphragmatic ruptures may present weeks to years later with progressive herniation of abdominal viscera ^[3].
• Risk: Strangulating intestinal obstruction (a surgical emergency) ^[3].
• Presentation: Insidious dyspnoea, bowel obstruction symptoms, bowel sounds heard in the chest.
• Management: Surgical repair (thoracic approach usually preferred for delayed presentations due to adhesions).

• Complication of oesophageal perforation repair or mediastinitis → healing by fibrosis → stricture (progressive dysphagia).
• Tracheo-oesophageal fistula may develop if the oesophageal perforation erodes into the adjacent trachea/bronchus → recurrent aspiration, pneumonia, cough with eating ^[27].
• Management: Endoscopic dilatation for strictures. Surgical repair for fistulae.

• Often overlooked but extremely common — up to 20-40% of major trauma survivors develop PTSD.
• Features: Re-experiencing (flashbacks, nightmares), avoidance (of reminders of trauma), hyperarousal (insomnia, exaggerated startle, irritability), emotional numbing.
• Management: Psychological support, trauma-focused CBT, EMDR (Eye Movement Desensitisation and Reprocessing). Consider SSRI if pharmacotherapy needed.