HEMOTHORAX

(Light's Pleural Diseases, 6th Edition - Chapter 25)

DEFINITION

Key diagnostic rule: Even if pleural fluid looks like pure blood, always measure the hematocrit - fluid with a hematocrit < 5% can appear bloody. If a hematocrit is unavailable, a rough estimate: divide pleural fluid RBC count by 100,000 (e.g., RBC count of 1,000,000 = hematocrit of ~10%).

PATHOPHYSIOLOGY

• Blood may enter the pleural space from injury to the chest wall, diaphragm, lung, or mediastinum
• Blood entering the pleural space coagulates rapidly
• Physical agitation from heart and lung movement may defibrinate the clot
• Loculation occurs early in the course, similar to empyema

CLASSIFICATION & CAUSES

1. Traumatic Hemothorax (Most Common)

• Penetrating trauma (stab wounds, gunshot wounds)
• Blunt trauma (e.g., road traffic accidents, rib fractures)
  • In a retrospective analysis of 515 blunt chest trauma cases, 193 patients (37%) had hemothoraces
  • With rib fractures, hemothorax is more common if the fracture is displaced
• Hemopneumothorax is common: 62% of blunt trauma hemothoraces also had pneumothorax; 83% of penetrating trauma hemothoraces had pneumothorax

2. Iatrogenic Hemothorax

• Most common causes:
  • Perforation of a central vein by a percutaneously inserted catheter (subclavian/internal jugular route)
  • Leakage from the aorta after translumbar aortography
• Other causes: thoracentesis, pleural biopsy, Swan-Ganz catheter rupture of pulmonary artery (requires immediate thoracotomy), percutaneous lung aspiration/biopsy, transbronchial biopsy, sclerotherapy for esophageal varices

3. Nontraumatic (Spontaneous) Hemothorax

• Least common category; causes include:
  1. Metastatic malignant pleural disease (most common non-pneumothorax cause) - especially schwannomas (von Recklinghausen disease), sarcomas, angiosarcomas, hepatocellular carcinoma
  2. Anticoagulant therapy for pulmonary embolism - appears 4-7 days after initiation; almost always on the ipsilateral side of the pulmonary embolus
  3. Catamenial hemothorax - associated with menstruation and endometriosis; almost always right-sided; treated with oral contraceptives, progesterone, danazol, or GnRH analogues; chemical pleurodesis or hysterectomy + bilateral oophorectomy if hormonal therapy fails
  4. Spontaneous hemopneumothorax - 3.8-6.6% of spontaneous pneumothoraces; 28% are hypotensive
  5. Others: hemophilia, thrombocytopenia, ruptured thoracic aorta, pancreatic pseudocyst, patent ductus arteriosus rupture, coarctation rupture, splenic artery aneurysm rupture, AV fistula rupture, hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber), intrathoracic extramedullary hematopoiesis, chickenpox pneumonia, osteochondroma of the rib, bronchopulmonary sequestration

DIAGNOSIS

Clinical

• Suspected in any patient with penetrating or nonpenetrating chest trauma

Imaging

• Occult hemothorax = seen on CT but not on supine CXR; most do NOT require tube thoracostomy
• Delayed hemothorax (up to 22 hours-16 days after injury) occurs in 4.2% of blunt trauma patients; all have multiple rib fractures (5/7 displaced)

TREATMENT

1. Traumatic Hemothorax

• Large-bore chest tubes (24-36 F) due to risk of blood clotting
• Inserted at 4th or 5th intercostal space in the midaxillary line (diaphragm may be elevated by trauma)
• Average drainage time: 27.1 hours; 82% discharged in < 48 hours
• Remove when: no air leak AND < 50 mL drainage in previous 6 hours

1. More complete evacuation of blood
2. Stops bleeding from pleural lacerations (by apposing pleural surfaces = tamponade effect)
3. Quantifies ongoing bleeding
4. Decreases risk of subsequent empyema (blood = good culture medium)
5. Autotransfusion of drained blood is possible
6. Rapid evacuation decreases risk of fibrothorax

• Suspected cardiac tamponade
• Vascular injury (initial chest tube output > 1,500 mL)
• Pleural contamination, devitalized tissue, sucking chest wounds, major bronchial air leaks
• Continued hemorrhage > 200 mL/hour with no signs of slowing
• Approximately 10-20% of patients require thoracotomy or VATS

• VATS is replacing thoracotomy in hemodynamically stable patients with persistent bleeding
• Thoracotomy preferred for exsanguinating hemorrhage through chest tubes
• VATS effective in 82% of persistent bleeding cases in one literature review

• Alternative for persistent bleeding: contrast-enhanced CT → embolization if contrast extravasation seen
• Successful in 5/5 patients with active extravasation in one study

• Role is unclear/controversial
• One RCT showed cefazolin significantly reduced empyema; another showed no significant benefit
• Risk factors for empyema: longer duration of chest tube, higher thoracic trauma score, shock on admission

• Prehospital autotransfusion has a role in life-threatening hemothorax
• System: 28-30 F chest tube + autotransfusion bag (750 mL with filters); no anticoagulation needed
• In one Paris study, 18 patients received 4.1 ± 0.6 L autotransfused; 72% survived

2. Nontraumatic Hemothorax

• Insert chest tube to evacuate blood and assess rate of bleeding
• Thoracotomy/VATS if brisk bleeding > 100 mL/hour persists
• If from intercostal artery: selective angiographic embolization

COMPLICATIONS (Four Main Pleural Complications)

1. Retained Clotted Blood

• Occurs in ~3% of patients treated with tube thoracostomy
• Chest X-ray is unreliable for predicting fluid vs. clot (correct in < 50% of cases); CT scan is required
• Indications for removal: Residual clot occupies ≥ 1/3 of the involved hemithorax at 48-72 hours post-tube thoracostomy
• Optimal timing: 48-96 hours after injury
• Method of choice: VATS - successful in 90% of cases
• After 7-9 days, clot adheres to lung/pleura - thoracoscopic removal becomes difficult and complication rate rises
• Second chest tube is less effective (42% eventually require thoracoscopy/thoracotomy; hospitalization longer: 8.1 vs. 5.4 days with VATS)
• Intrapleural fibrinolytics (streptokinase 250,000 IU; urokinase 100,000 IU): 62.5% complete response but not recommended (more expensive, longer hospitalization, risk of acute hypoxemic respiratory failure)

2. Posttraumatic Empyema

• Occurs in 3-4% of cases
• Risk factors: persistent bronchopleural fistula, pulmonary contusions, residual clotted hemothorax, shock on admission, gross pleural contamination, associated abdominal injuries, prolonged pleural drainage
• Prevention: meticulous sterile technique, good pleural apposition, prophylactic antibiotics
• Treatment: same as any bacterial pleural infection

3. Pleural Effusion After Tube Removal

• 13% (37/290) with no residual hemothorax develop pleural effusion after tube removal
• 34% (40/118) with residual hemothorax have pleural effusions at discharge
• Of these effusions: 26% have empyema; 74% resolve spontaneously
• Management: Diagnostic thoracentesis to rule out infection; if no infection, effusion usually resolves spontaneously

4. Fibrothorax

• Diffuse pleural thickening developing weeks to months after hemothorax
• Occurs in < 1% of patients even without blood removal
• More common with hemopneumothorax or concurrent pleural infection
• Treatment: Decortication of the lung (see Chapter 27); postpone for several months as pleural thickening frequently diminishes with time

SUMMARY TABLE