Autotransfusion of hemothorax blood in trauma patients: is it the same as fresh whole blood?

BACKGROUND Autotransfusable shed blood has been poorly characterized in trauma and may have similarities to whole blood with additional benefits. METHODS This was a prospective descriptive study of adult patients from whom ≥50 mL of blood was drained within the first 4 hours after chest tube placement. Pleural and venous blood samples were analyzed for coagulation, hematology, and electrolytes. RESULTS Twenty-two subjects were enrolled in 9 months. The following measured coagulation factors of hemothorax were significantly depleted compared with venous blood: international normalized ratio (>9 in contrast to 1.1, P < .001), activated partial thromboplastin time (>180 in contrast to 28.5 seconds, P < .001), and fibrinogen (<50 in contrast to 288 mg/dL, P < .001). The mean hematocrit (26.4 in contrast to 33.9), (P = .003), hemoglobin (9.3 in contrast to 11.8 g/dL, P = .004), and platelet count (53 in contrast to 174 K/μL, P < .001) of hemothorax were significantly lower than venous blood. A hemothorax volume of 726 mL was calculated to be equivalent to 1 U of red blood cells. CONCLUSIONS Hemothorax blood contains significantly decreased coagulation factors and has lower hemoglobin when compared with venous blood.