Massive Haemothorax

Massive haemothorax is the accumulation of over 1500 mL of blood in the pleural space, or more than one third of circulating blood volume, or an initial chest drain output of over 1500 mL or over 200 mL/h for 2 to 4 hours. It causes hypovolaemic shock and respiratory compromise.

Epidemiology. It complicates a minority of chest trauma, both penetrating and blunt. Penetrating wounds, rib fractures and great vessel injuries carry the highest risk.

Causes and associations. Intercostal and internal mammary artery laceration, lung parenchymal laceration, great vessel or cardiac injury, diaphragmatic injury, vertebral fracture and iatrogenic injury (central line, biopsy, anticoagulated patient). Non-traumatic causes include aortic rupture, malignancy and ruptured pulmonary arteriovenous malformation.

Pathophysiology. Each hemithorax holds 2 to 3 litres or more of blood. Blood in the pleural cavity compresses the lung, shifts the mediastinum, reduces venous return and causes shock. Clotting and later fibrosis lead to retained haemothorax and empyema.

Presentation is shock with a dull hemithorax, reduced air entry, distended neck veins in severe cases (or flat in hypovolaemia), tachypnoea and hypoxia. Look for entry wounds, bruising and instability of the chest wall.

Red flags.

• Systolic pressure under 90 mmHg or ongoing need for blood.
• Initial drain output over 1500 mL, or over 200 mL/h for 2 to 4 hours.
• Penetrating wound over the cardiac box or mediastinal injury.

Diagnosis is clinical in the unstable patient. Extended ultrasound examination shows fluid in the pleural space. Chest radiograph (supine films may show only a hazy hemithorax) and CT when stable. Send blood for group and crossmatch, full blood count, coagulation tests, fibrinogen, lactate and gas.

Differential diagnosis. Tension pneumothorax, pulmonary contusion, pleural effusion, cardiac tamponade and diaphragmatic rupture.

Resuscitation. Two large bore IV or intraosseous lines, early blood products in a ratio near 1 red cell unit to 1 plasma to 1 platelet pool, or whole blood where available. Permissive hypotension (systolic 80 to 90 mmHg) until bleeding is controlled, except in head injury. Warm products and give calcium (calcium gluconate 10% 20 mL IV for each 4 units).

Tranexamic acid. 1 g IV over 10 minutes within 3 hours of injury, then 1 g over 8 hours.

Chest drain. Insert a 28 to 32 Fr drain through the fourth or fifth intercostal space in the anterior to mid axillary line, using open finger thoracostomy first. Connect to an underwater seal at suction minus 20 cmH2O. Do not clamp the drain.

Autotransfusion. Collect and return blood from the drain with a suitable collection system when allowed.

Thoracotomy indications. Initial drainage over 1500 mL, or over 200 mL/h for 2 to 4 hours, or continued transfusion requirement, or haemodynamic instability. Emergency resuscitative thoracotomy for arrest after penetrating chest injury.

Antibiotic. Cefazolin 2 g IV once (3 g if weight is over 120 kg) at drain insertion.

Retained haemothorax. Image at 24 to 72 hours. Treat residual clot of over 300 to 500 mL by video assisted thoracoscopic surgery within 3 to 7 days, since delay increases the risk of empyema and trapped lung.

Monitoring. Hourly drain output, vital signs, haemoglobin every 4 to 6 hours, coagulation, calcium and lactate.

Referral and escalation. Trauma surgeon and thoracic surgeon at once, and activate a massive transfusion plan.

Special groups. In anticoagulated patients, reverse the anticoagulant. In pregnancy, tilt left, maintain foetal and maternal perfusion and involve obstetrics.