Autotransfusion

Introduction

Autologous blood transfusion, or autotransfusion, is the collection and reinfusion of a patient's own blood for volume replacement. Preoperative blood banking and intraoperative cell salvage techniques have increased in a multitude of surgical specialties. Autotransfusion in the emergency department (ED) is usually limited to patients with severe, traumatic hemothorax and clinically significant blood loss.

Autotransfusion is usually performed in trauma centers or in EDs with high trauma volume. Though not a uniform standard of care for emergency clinicians, it is applicable to any ED. As the procedure requires familiarity with the equipment, continuing education, and quality control, it would be counterproductive to institute the procedure in a hospital that has a low trauma census or in a setting in which it will be used infrequently enough that staff education issues are problematic. Clinicians practicing in more austere environments with a paucity of clinical resources, such as combat and disaster zones, may find that the procedure's benefits outweigh its risks.

Background

Reports of autotransfusion can be found as early as 1818 when Blundell, an English practitioner, reinfused shed blood after witnessing a woman exsanguinate from uterine hemorrhage. In 1886, Duncan published the first known human account of autotransfusion in which he reinfused shed blood in a patient with a traumatic amputation without any notable ill effects. In 1917, Elmendorf published a description of the first case of autotransfusion in a patient with traumatic hemothorax.

The discovery of ABO blood typing at the turn of the century and the institution of blood banks in the 1930s led to the almost exclusive use of allogeneic (homologous) blood up to and following World War II. During the 1960s and 1970s, cardiopulmonary bypass surgery and combat trauma experience during the Vietnam War generated extensive data regarding intraoperative retrieval of large quantities of blood for reinfusion. This revitalized interest, coupled with increased experience in surgical, trauma, and combat situations, has thus initiated a new era in autotransfusion.

Anatomy

Hemothorax refers to a collection of blood within the pleural space. Severe hemorrhage is more often associated with laceration of vessels on the inside of the chest wall, such as the internal mammary and intercostal arteries. Blunt trauma and penetrating trauma are by far the most common causes of hemothorax. Spontaneous hemothorax can occur secondary to intrathoracic malignancy, pulmonary infarction, bullous emphysema, virulent pulmonary or mediastinal infection, vascular malformation, and endometriosis of the pleura (catamenial).

Pathophysiology

The pathophysiologic sequelae of hemothorax include both hemodynamic instability and respiratory compromise. The pleural cavity can accommodate more than 50% of the total blood volume, so clinically significant intrathoracic blood loss can occur with minimal external signs of bleeding. The clinician should suspect hemothorax in the setting of chest trauma with clinical signs of hypovolemia. Physical examination may demonstrate decreased breath sounds and reduced tactile fremitus. Imaging during the initial resuscitation period is usually limited to supine chest radiographs, which may show haziness in the affected lung field as blood layers in the posterior pleural space ( Fig. 27.1 ). Ultrasound is also useful in the initial evaluation of hemothorax ( Fig. 27.2 ). Tube thoracostomy is the treatment of choice for acute hemothorax, with thoracotomy and video-assisted thoracic surgery performed as indicated for severe or ongoing hemorrhage.

Advantages

Shed blood from traumatic hemothorax is immediately available for rapid transfusion. The blood is normothermic and compatible, which avoids the risk of allergic reaction or infection from transfusion transmissible diseases. There are numerous transfusion transmissible diseases, including viruses such as human immunodeficiency virus (HIV) and hepatitis, bacteria, parasites, and most recently reported, variant Creutzfeldt-Jakob disease. Although the risk for transfusion transmissible diseases has decreased dramatically in developed countries, it is still very problematic worldwide. Immunologic transfusion reactions and posttransfusion sepsis continue to be risks as well. In trauma patients, allogeneic transfusions have been shown to be an independent risk factor for infection, which may be dose dependent and independently associated with increased morbidity and mortality. In patients whose religious convictions (e.g., Jehovah's Witness) prohibit transfusions with homologous blood, reinfusion of autologous blood that does not involve blood storage may be an acceptable alternative.

A recent multicenter study by Rhee and colleagues compared outcomes in 136 patients receiving autotransfused blood from a traumatic hemothorax to an equal number receiving only allogeneic transfusions. There was no difference between the groups in mortality or in-hospital complications (sepsis, disseminated intravascular coagulation [DIC], acute lung injury, or renal insufficiency). Despite its retrospective design, this study offers support for the practice of autotransfusion based on patient-oriented outcomes.

Autologous blood provides societal benefits by preserving the limited stores of banked blood and reducing the cost of medical care. Adias and colleagues compared the direct cost of banked blood with the cost of autologous blood transfusion and found substantial savings with autotransfusion.

Box 27.1 summarizes the advantages of autotransfusion.

Indications

In general, all victims of severe trauma, whether blunt or penetrating, should be considered potential candidates for autotransfusion. Several categories of patients for whom emergency autotransfusion is suitable have been described and are summarized in Review Box 27.1 . Reul and associates described the ideal autotransfusion candidate as a blunt or penetrating trauma victim with hemothorax consisting of 1500 mL or more of blood. Other patients who may benefit include those with an immediate need for transfusion for whom insufficient homologous blood is available (because of a shortage or a difficult crossmatch) and those whose religious convictions prohibit homologous transfusion.