HEMOTHORAX

Surgery Theory Exam - 20 Marks Answer

DEFINITION

ETIOLOGY / CAUSES

1. Traumatic Hemothorax (Most Common)

• Blunt trauma: Motor vehicle collisions, falls - injures intercostal vessels, lung parenchyma, diaphragm, great vessels, or mediastinal structures
• Penetrating trauma: Gunshot wounds, stab wounds - 83% of penetrating thoracic injuries are associated with hemopneumothorax
• Rib fractures: Strong correlation - patients with >5 rib fractures have ≥48% likelihood of concomitant hemothorax
• Sources of bleeding:
  • Chest wall: Intercostal arteries, internal mammary artery (arterial - more severe, requires intervention)
  • Lung parenchyma: Most common; low pulmonary arterial pressure + lung thromboplastin limit bleeding (usually stops with drainage alone)
  • Major vessels: Pulmonary artery/vein, aorta (life-threatening)
  • Mediastinum, diaphragm

2. Non-Traumatic (Spontaneous) Hemothorax

• Spontaneous pneumothorax: Most common non-traumatic cause; hemothorax develops in 2-7% of cases, from torn pleural adhesions or rupture of vascularized bullae
• Vascular pathology: Aortic dissection/rupture (usually left-sided), pulmonary arteriovenous malformations (associated with hereditary hemorrhagic telangiectasia)
• Neoplasms: Malignant pleural tumors, metastatic disease
• Coagulopathy / anticoagulant therapy
• Spontaneous: From pleural endometriosis (catamenial hemothorax)

3. Iatrogenic Hemothorax

• Central venous catheter insertion
• Thoracentesis, pleural biopsy
• Post-cardiac surgery
• Pacemaker placement

PATHOPHYSIOLOGY

1. Compressing effect of blood accumulation in the pleural space
2. High concentration of lung thromboplastin promoting clot formation
3. Low pulmonary arterial pressure (compared to systemic circulation)

• Respiratory compromise: Lung is compressed and collapsed, causing ventilation-perfusion mismatch and hypoxia
• Hemodynamic compromise: Significant blood loss leads to hypovolemic shock
• Massive hemothorax (>1500 mL) can cause tension physiology - mediastinal shift, decreased venous return, reduced cardiac output (similar to tension pneumothorax)

CLASSIFICATION

CLINICAL FEATURES

Symptoms

• Chest pain (pleuritic or dull)
• Dyspnea, breathlessness
• Signs of hemorrhagic shock (tachycardia, hypotension, pallor) depending on volume lost

Signs

• Asymmetric chest expansion on the affected side
• Decreased/absent breath sounds on the affected side
• Stony dullness to percussion on the affected side (distinguishes from pneumothorax)
• Tracheal deviation to the opposite side in massive hemothorax with tension component
• Hypotension, tachycardia - from both blood loss and tension physiology

Key clinical distinction: Hemothorax = dull percussion + absent breath sounds; Tension pneumothorax = hyper-resonant percussion + absent breath sounds + tracheal deviation

INVESTIGATIONS / DIAGNOSIS

1. Chest X-Ray (CXR) - First-Line Investigation

• Blunting of costophrenic angle - requires ~200 mL of fluid (upright PA view)
• Blunting of cardiophrenic angle
• Obliteration of hemidiaphragm - requires ~500-650 mL
• Homogeneous opacity of hemithorax (white-out)
• Mediastinal shift away from the effusion in large collections
• Supine CXR: May only show a diffuse haziness; >1000 mL of blood may be missed due to posterior layering
• Lateral decubitus CXR: Most sensitive plain film; can detect as little as 10 mL

2. Ultrasound (FAST / eFAST)

• Point-of-care ultrasound can rapidly detect pleural fluid in the trauma bay
• Extended FAST (eFAST): Sensitivity 77%, negative predictive value close to 100%
• Pleural fluid appears as anechoic collection superior to the diaphragm
• Can be used in the critically ill patient at bedside without radiation

3. CT Scan (Gold Standard)

• CT thorax is the gold standard for detection of hemothorax
• Detects exact location, volume, and associated injuries (pneumothorax, rib fractures, aortic injury)
• Shows "hematocrit effect" - fluid-fluid level between denser blood cells inferiorly and serum superiorly
• Identifies active contrast extravasation (active hemorrhage)
• Ideal for stable patients; NOT appropriate for hemodynamically unstable patients

4. Diagnostic Thoracocentesis / Pleural Fluid Analysis

• Confirms diagnosis: pleural fluid hematocrit >50% of peripheral blood hematocrit
• pH, LDH, cytology as needed
• Not usually required in trauma setting where diagnosis is clinical

MANAGEMENT

Initial Resuscitation (ATLS Protocol)

• Airway: Secure airway, supplemental oxygen
• Two large-bore IV access: Aggressive IV fluid resuscitation
• Blood transfusion as required (O-negative in emergencies)
• Monitoring: BP, pulse, SpO2, urine output

Definitive Treatment Algorithm

Step 1: Is the patient hemodynamically unstable?

1. Observation (Small Hemothorax, <300 mL, Asymptomatic)

• Supportive: Supplemental oxygen, analgesia, incentive spirometry, early ambulation
• Serial CXR monitoring for progression
• No drainage required if asymptomatic and no ongoing bleeding

2. Tube Thoracostomy (Chest Drain) - MAINSTAY OF TREATMENT

• Position: Supine with ipsilateral arm extended overhead
• Site: 4th or 5th intercostal space, midaxillary line (triangle of safety)
• Under local anesthesia (lignocaine)
• Large-bore tube (28-32 Fr) is preferred for hemothorax to prevent clot blockage
• Connect to underwater seal drain / Pleur-Evac at -20 cmH2O suction
• Secure with sutures

• In ~85% of cases, bleeding stops as the lung re-expands (low pulmonary vascular pressure allows tamponade)
• Initial output >1500 mL OR ongoing output >200 mL/hour for 4 hours = indication for thoracotomy

3. Emergency/Urgent Thoracotomy

4. Video-Assisted Thoracoscopic Surgery (VATS)

• Retained hemothorax (most common indication)
• Empyema from infected retained hemothorax
• Fibrothorax / trapped lung
• Continuous air leak not resolving with chest drain
• Clotted hemothorax within 7-10 days (before fibrous peel organizes)

COMPLICATIONS

1. Retained Hemothorax (Most Common Complication)

• Occurs in approximately 10-15% of hemothoraces treated by tube thoracostomy
• Defined as persistent pleural opacity after adequate chest tube placement
• Clotted blood unable to drain through tube
• Risk: Empyema, fibrothorax
• Treatment: Early VATS evacuation (ideally within 3-5 days, before day 10)
• Intrapleural fibrinolytics (tPA/DNase) can be used for smaller retained collections

2. Empyema

• Infected retained hemothorax
• Organisms: S. aureus, gram-negative rods
• Presents with fever, leukocytosis, chest pain
• Treatment: Tube drainage + antibiotics ± VATS decortication

3. Fibrothorax

• Organized fibrous peel encasing the lung, preventing re-expansion
• Leads to restrictive lung disease
• Treatment: Surgical decortication

4. Hypovolemic Shock

• Due to massive blood loss
• Can be compounded by tension hemothorax physiology

5. Tension Hemothorax

• Massive hemothorax causing mediastinal shift, kinking of great veins, decreased cardiac output
• Presents with hypotension + absent breath sounds + tracheal deviation
• Immediate chest tube decompression

SPECIAL SITUATIONS

Hemopneumothorax

• Associated pneumothorax present in 2.4% of blunt trauma and 83% of penetrating thoracic injury cases
• Managed with same chest drain; tube positioned posteriorly for blood, superiorly for air

Delayed Hemothorax

• Can occur hours to days after apparently minor trauma
• Risk factors: Anticoagulant use, rib fractures
• Requires vigilance with serial imaging in high-risk patients

Non-Operative Management of Occult Hemothorax

• Small hemothorax incidentally found on CT in a stable patient without respiratory compromise
• Can be observed with serial imaging
• Failure rate under observation: ~6% (higher if on positive pressure ventilation)

KEY POINTS SUMMARY (for exam recall)

FLOWCHART: MANAGEMENT OF HEMOTHORAX

Suspected Hemothorax (chest trauma / hemodynamic instability)
              |
    ┌─────────┴──────────┐
Unstable                Stable
    |                    |
Immediate ICD       Imaging (CXR/eFAST/CT)
    |                    |
  ┌─┴──┐           ┌────┴────┐
Stop  Cont.      Small     Large
bleed  bleed    (<300 mL)  (>300 mL)
  |     |          |          |
Obs. Thoracotomy  Observe    ICD + drain
         |          |          |
      (>1500 mL  Serial    Stops (~85%)
       initial   CXR       |  Continues
       or >200            Obs.   |
       mL/hr x 4h)           Thoracotomy
                              (>1500 mL or
                               >200 mL/hr x4h)
              Retained? → VATS