Autotransfusion

Autotransfusion is a medical procedure in which the lost blood of a patient is collected and returned to the same patient. It can be used in circumstances where, for example, the patient has a rare blood group, or there is a risk of infection from an alternative source of blood. The patient's blood can be collected before or during surgery.

The first documented use of the procedure was in 1818, and interest in the practice continued until the Second World War, at which point blood supply became less of an issue, due to the increased number of blood donors. Later, interest in the procedure returned with new automated machinery being developed for it. Autotransfusion is used in a number of orthopedic, trauma and cardiac cases, amongst others, and it carries advantages, including the reduction of infection risk and the provision of more functional cells. By contrast, a disadvantage of the process is the loss of platelets.

History
There is some evidence that in 1785 that Philip Physic of Philadelphia transfused a post-partum patient. However the first documented use of autologous blood transfusion was in 1818 when an Englishman, Blundell salvaged vaginal blood from patient's with postpartum hemorrhage. By swabbing the blood from the bleeding site and rinsing the swabs with saline, he found that he could re-infuse the result of the washings. This unsophisticated method resulted in a 75% mortality rate, but it marked the start of autologous blood transfusion.

During the American Civil War Union Army physicians are said to have administered four transfusions. In 1886, J. Duncan used autotransfusion during the amputation of limbs by removing blood from the amputated limb and returning it to the patient by femoral injection. This method was apparently fairly successful. A German, M.J. Theis, reported the first successful use of intraoperative autotransfusion in 1914, with a ruptured ectopic pregnancy. The earliest report in the American literature on the use of autotransfusion was by Lockwood in 1917 who used the technique during a splenectomy for Banti syndrome. Interest in unrefined technique of autotransfusion continued through to the early 1940’s, and was applied to various procedures including treatment of ectopic pregnancy hemothorax, ruptured spleen  , perforating abdominal injuries , and neurosurgical procedures.

The interest in autotransfusion dwindled during World War Two, when there was a large pool of donors. After the war, blood testing, typing and crossmatching techniques were improved making blood banks the answer to the increased demand for blood. In the 1960s, interest in autotransfusion revived. With the advances in all fields of surgery, new companies developed autotransfusion devices. Problems still arose, however, with air embolism, coagulopathy and hemolysis. The devices used during the Korean and Vietnam War collected and provided gross filtration of blood before it was reinfused. With the introduction of cardiopulmonary bypass in 1952, autotransfusion became an area of study. Klebanoff began a new era of autotransfusion by developing the first commercially available autotransfusion unit in 1968. His system, the Bentley Autotransfusion System ® aspirated, collected, filtered and reinfused autologous whole blood shed from the operative field. The problems with the Bentley system included the requirement of systemic anticoagulation of the patient, introduction of air embolism, and renal failure resulting from unfiltered particulate in the reinfused blood.

As the Bentley system lost favor Wilson and associates proposed the use of a discontinuous flow centrifuge process for autotransfusion which would wash the red cells with normal saline solution. In 1976, this system was introduced by Haemonetics Corporation and is know commonly as "Cell Saver". More recently in 1995 Fresenius HemoCare introduced a continuous autotransfusion system.

There are three types of systems un-washed filtered blood, discontinuous flow centrifugal and continuous flow centrifugal. The unwashed systems are popular because of their perceived inexpense and simplicity. However unwashed systems can cause increase potential for clinical complications. The washed system requires a properly trained and clinically skilled operator. It returns only red blood cells suspended in saline and is rarely associated with any clinical complications. The use of Autotransfusion process described in this documented reflects the washed discontinuous centrifugal system. This type of autotransfusion can practically eliminate the need for exposure to homologous blood in elective surgical patient's and can greatly reduce the risk of exposure to emergency surgical patient's. Autotransfusion represents a measure of blood conservation and reduction of exposure risk to homologous blood.

Literature
Literature relating to autologous blood is extensive - numerous articles and letters have been written. The subject heading of "Blood Transfusion, Autologous" first appeared in 1971 in the Cumulated Index Medicus. The Cumulative Index to Nursing & Allied Health began the same title in 1983, and also added a new heading of "Blood Salvage" in 1993. The Hospital Literature Index began the heading "Blood Transfusion, Autologous" in 1985.

The concepts of bloodless medicine and surgery have recently been emerging in literature, books and course programs.

Indications for autotransfusion
Autotransfusion is intended for use in situations characterized by the loss of one or more units of blood and may be particularly advantageous for use in cases involving rare blood groups, risk of infectious disease transmission, restricted homologous blood supply or other medical situations for which the use of homologous blood is contraindicated. Autotransfusion is commonly used intraoperatively and postoperatively. Intraoperative autotransfusion refers to recovery of blood lost during surgery or the concentration of fluid in an extracorporeal circuit. Postoperative autotransfusion refers to the recovery of blood in the extracorporeal circuit at the end of surgery or from aspirated drainage.

Orthopedic
Spinal Instrumentation, Spinal Fusion, Discectomy, Laminectomy, Total shoulder replacement, Total hip replacement, Total knee replacement, Femur Fractures, Open Reduction Internal Fixation Pelvic Fractures, IM Rodding

Trauma
Subdural Hematoma, Chest Injuries, Liver Fractures, Kidney Fractures, Major Vessel Lacerations, Aneurysms, Gun Shot Wounds, Stab Wounds, Extremity Reimplantations, Splenectomy, Blunt Trauma (Thoracic or Abdominal)

Cardiac
Cardiothoracic, Coronary Artery Bypass, Cardiac Valvular Repair / Replacement, Aortic Arch Aneurysms, Thoracic Trauma, Cardiac Transplantation

Other
Ectopic Pregnancy, Liver Resection (Non-Malignant), Porto-Caval Shunts, Liver Transplant, Nephrectomy (Non-Malignant), Speno-Renal Shunts, Abdominal Aortic Aneurysm, Aorto-Femoral Reconstruction, Major Vessel Resection, Hysterectomy (Non-Malignant), Cerebral Aneurysms, Craniotomy (Non-Malignant), Thoracotomy (Non-Malignant)

Advantages

 * High levels of 2,3 DPG
 * Normothermic
 * pH relatively normal
 * Lower risk of Infectious Diseases
 * Functionally superior cells
 * Lower Potassium (compared to stored blood)
 * Quickly available

Substances washed out

 * Plasma
 * Platelets
 * White Cells
 * Anticoagulant Solution
 * Plasma free Hemoglobin
 * Cellular stroma
 * Activated clotting factors
 * Intracellular Enzymes
 * Potassium
 * Plasma bound Antibiotics

Disadvantages
The sole disadvantage of autotransfusion is the depletion of plasma and platelets. The washed autotransfusion system removes the plasma and platelets, to eliminate activated clotting factors and activated platelets which would cause coagulopathy if they were reinfused to the patient. This disadvantage is only evident when very large blood losses occur. The autotransfusionist monitors blood loss and will recommend the transfusion of fresh frozen plasma (FFP) and platelets when the blood loss and return of autotransfusion blood increases. Typically the patient will require FFP and platelets as the estimated blood loss reaches the total blood volume of the patient.

Contraindications
The use of blood recovered from the operative field is contraindicated in the presence of bacterial contamination or malignancy. The use of autotransfusion in the presence of such contamination may result in the dissemination of pathologic microorganisms and / or malignant cells. The following statements reflect current clinical concerns involving autotransfusion contraindications.

Contamination of the surgical site
Any abdominal procedure poses the risk of enteric contamination of shed blood. The surgical team must be diligent in observing for signs of bowel contamination of the blood. If there is a question of possible contamination the blood may be held until the surgeon determines whether or not bowel contents are in the surgical field. If the blood is contaminated the entire contents should be discarded. If the patient's life depends upon this blood supply it may be reinfused with the surgeon's consent, while washing with large amounts of NaCl .9% will reduce the bacterial contamination of the blood, it will not be totally eliminated.

Malignancy
There is a possibility of the reinfusion of cancer cells from the surgical site. There are two possible exceptions to this contraindication:


 * The surgeon feels complete removal of an encapsulated tumor is possible. Blood may be aspirated from the surgical site, processed and reinfused with the surgeon's consent.
 * If an inadequate supply of blood exists, the washed red cells may be used to support the patient's vital signs with the surgeon's consent.

Autotransfusion should not be used in C-Sections, because the possibility of an amniotic fluid embolism exists. The amniotic fluid may not be washed away during the wash phase of autotransfusion process.

The absolute contraindication to use of autotransfusion is the presence of amniotic fluid and/or meconium. In life saving situations with the consent of the surgeon autotransfusion can be successfully utilized in the presence of the previous stated contraindications i.e. sepsis, bowel contamination and malignancy.

Collection and processing of blood
Utilizing a special double lumen suction tubing, fluid is aspirated from the operative field, and is mixed with an anticoagulant solution. Collected fluid is filtered in a sterile cardiotomy reservoir. The reservoir contains filter and has a capacity of between two and three liters of fluid. When a volume adequate to fill the wash bowl has been collected, processing may begin. The volume required to fill the bowl is dependent on the concentration of red cells collected and size of the centrifuge wash bowl.

When aspirating the blood it is important to utilize the following technique when ever possible:


 * Suction blood from pools rather than skimming.
 * Keep the suction tip below the level of the air-blood interface.
 * Avoid occluding the suction tip (i.e. using suction as a retractor).

Following these techniques will help reduce hemolysis of the red cells and will help increase the amount of red cells that will be salvaged.

Antibiotic irrigation
Antibiotics which are plasma bound can be removed during the autotransfusion wash cycle, however topical antibiotics which are typically not plasma bound may not be washed out during autotransfusion, and may actually become concentrated to the point of being nephrotoxic.

Topical coagulant products
When Avitene, Hemopad, Instat, or collagen type products are used, autotransfusion should be interrupted and a waste or wall suction source must be used. Autotransfusion can be resumed once these products are flushed from the surgical site. If Gelfoam, Surgicel, Thrombogen or Thrombostat are used, autotransfusion can continue, however direct suctioning of these products should be avoided. The clinically experienced autotransfusionist is familiar with the commonly used products and will know whether the autotransfusion must be interrupted.

Orthopaedic bone cement
Cement is often used or encountered during primary or revision total joint replacement surgery. The cement when in the liquid or soft state should not be introduced into the autotransfusion system. When cement is being applied a waste or wall suction source must be used, however when the cement hardens autotransfusion may be resumed. The use of ultrasonic equipment during revision of total joints changes the cement to a liquid or soft state, which precludes the use of autotransfusion during the use of such equipment. Autotransfusion can only continue when the cement has hardened.

Prime phase
When the "prime" button is pressed, the centrifuge begins rotation and accelerates to the speed selected on the centrifuge speed control, typically 5,600 rpm. Simultaneously, the pump begins counterclockwise rotation, enabling the transfer of the reservoir contents to the wash bowl. The application of centrifugal force separates the components of the fluid according to their weight. The wash bowl filling continues until the buffy-coat reaches the shoulder of the wash bowl. The buffy-coat is the accumulation of platelets and white cells which appears during centrifugation as an interface between the red cells and supernatant. Some autotransfusion devices have automatic features including a buffy-coat sensor, which is calibrated to detect a full bowl and advance the process to the wash phase automatically.

Wash phase
The wash phase begins when the wash bowl is appropriately filled with red cells. The autotransfusion devices with automatic features, when operated in the automatic mode will advance to the wash phase without action from the autotransfusionist. The pump continues a counterclockwise rotation and clamps adjust, enabling the transfer of wash solution to the wash bowl. The washing phase removes cellular stromata, plasma free hemoglobin, anticoagulant solution, activated clotting factors, any plasma bound antibiotics, intracellular enzymes, plasma, platelets, and white cells. The unwanted fluid passes out of the wash bowl and into a waste reservoir bag. Washing continues until the reinfuse button is depressed and the appropriate amount of wash solution has been delivered to the wash bowl. The wash phase is terminated when one to two liters of wash solution has been transferred, or the fluid transferred to the waste bag appears transparent (or both). An autotransfusion device with automatic features will pump the wash solution which was set by the autotransfusionist and then automatically proceed to the reinfuse phase.

Reinfuse phase
When the reinfuse function is selected, the centrifuge braking begins. The clamps change positions, enabling the transfer of the wash bowl contents to the reinfusion bag. An autotransfusion device with automatic features will pump the blood into the reinfusion bag and stop when the bowl is emptied. The centrifuge bowl must come to a complete stop before the pump begins a clockwise rotation to empty the bowl. Once the bowl is emptied, the "stop" button can be pressed to complete the cycle, or the "prime" button can be pressed to start a new cycle. The reinfusion bag attached to the autotransfusion wash set should not be used for high pressure infusion back to the patient. The reinfusion bag contains a significant amount of air, careful monitoring should take place during reinfusion to avoid the potential of air embolism. In accordance with Guidelines set by the American Association of Blood Banks the blood should be reinfused within 6 hours from collection.

Postoperative autotransfusion
Postoperative autotransfusion is performed by connecting the double lumen autotransfusion suction line directly to the drain line placed at the conclusion of surgery. Postoperative autotransfusion begins in the operating room when the drain line is placed and the surgical site is closed. Typical postoperative cases are total knee and hip replacements. Autotransfusion is continued and is effective while the patient actively bleeds during the immediate postoperative phase of recovery. Autotransfusion is ended when bleeding is stopped or is significantly slow, autotransfusion is discontinued by connecting an ordinary self draining device such as a Hemovac container to the drain line(s). Available for postoperative autotransfusion are universal bifurcated connectors which can accommodate two drain lines of any size, these connectors can be attached to the standard ten foot double lumen suction line for postoperative use.

Soaking sponges
In some institutions to maximize the effectiveness of autotransfusion and provide the best conservation and return of red cells the soaking of sponges is employed. During the surgical procedure the blood soaked sponges are collected and placed in a sterile basin by the surgical team, sterile heparinized saline is add to the basin to prevent clotting and facilitate the release of red cells. The sponges are periodically wrung out and removed from the basin, the remaining solution can be suction into the autotransfusion reservoir so that the red cells can be recovered. It has been estimated that 90% of the lost red cells can be returned when autotransfusion is performed in conjunction with the soaking of sponges.

The ratio of heparinized saline is 5,000 units of Heparin per 1,000 ml of 0.9% Sodium Chloride. The heparin is removed during the autotransfusion processing so the exact ratio of Heparin used is not critical.

Autotransfusion and religion
Individuals of the Jehovah's Witness religion in particular refuse to accept Homologous and Autologous predonated blood. However some individual members may accept the use of autotransfusion. The process of autotransfusion is modified to maintain a continuous circuit of blood which maintains continuous contact with the body. This process when carefully explained to the patient may be acceptable when a patient refuses based on religious beliefs.

Platelet sequestration and autologous platelet gel
Many of the newest autotransfusion machines are programable to provide separation of blood into three groups; Red Cells, Platelet Poor Plasma, and Platelet Rich Plasma. Blood can be drawn from the patient just prior to surgery and then separated. The separated blood components which have been sequestered can be stored during the surgical procedure. The Red Cells and Platelet Poor Plasma can be given back to the patient through Intravenous transfusion during or after surgery. The Platelet Rich Plasma can be mixed with Calcium and Thrombin to create a product similar to Fibrin Glue. But unlike Fibrin Glue this is an Autologous product which can be used for a variety of techniques including use as a hemostatic aid, a dural sealant and an aid to fusion of bone. Its applications are being widely studied and reported in the literature on a regular basis recently. If the fibrin gel procedure is not needed during the procedure the Platelet Rich Plasma can also be reinfused to the patient.