• Transfusion of the patient's own blood or blood components back to them has the theoretical advantages of:
  • No risk of transmission of infection
  • No blood transfusion reaction
  • No graft versus host disease
  • No storage of blood required (except with preoperative autologous blood donation [PABD])
• There are 4 types of autologous blood transfusion:
  • Preoperative autologous blood donation
  • Intraoperative hemodilution
  • Cell salvage or saver
  • Postoperative blood collection and re-transfusion
• Allogeneic transfusions are the "opposite" of autologous transfusions and involve giving a patient blood collected from another person and has been stored in the blood bank.
• "You know what you’ve got inside you and therefore what you’re getting."

• Oxygen-carrying capacity: In a normal person breathing room air, arterial blood carries approximately 20 mL O₂/100 mL; 19.7 mL combined with hemoglobin (Hb) and only 0.3 mL dissolved in plasma. Hemoglobin molecules within red blood cells contain iron that can bind reversibly to oxygen molecules to form oxyhemoglobin. Normal Hb is 13–16 g/dL in men and 12–16 g/dL in women.
• Viscosity is the tendency of fluids to resist flow. Blood viscosity depends largely on hematocrit (increasing exponentially as hematocrit increases), red cell characteristics, and blood protein concentration. Increasing viscosity (from blood transfusion) leads to reduced flow, especially in vessels <0.3 mm in diameter. This causes an increase in resistance with a resultant increase in blood pressure (blood pressure is equal to cardiac output multiplied by resistance: BP = CO × R).
• Transfusion, even of autologous blood, should be reserved for when it is needed, and local protocols should be followed. The ACC/AHA Guidelines recommend that blood is given when the Hb <6 g/dL; as this is described as lifesaving. They also state that transfusion in most postoperative patients with a Hb <7 g/dL is reasonable and that in select patients with critical end-organ ischemia, it may be necessary to transfuse at a Hb of 10 g/dL.
• Preoperative autologous blood donation (PABD): 1–2 units of blood are collected from the patient 2–4 weeks before surgery.
  • The goal is to remove red blood cells and plasma, process it, and store it until the day of surgery. The blood is not separated into components and is re-administered as whole blood. Thus, it contains some or all of the blood components needed by the patient.
  • Preoperative donation allows the patient time to recover and begin red cell regeneration, provided that iron stores are adequate. Thus, levels should be checked and iron supplementation administered if necessary.
  • Guidelines state that patients should be in good health to tolerate phlebotomy of around 450 mL and autologous blood collection should only be offered to those patients in whom there is a reasonable expectation that blood will be required.
  • Patients who would not normally require cross-matched blood (e.g., Group and Save only) should not be considered, unless there is a specific clinical reason. Direct patient requests should be discouraged after adequate explanation.
  • Contraindications include anemia (Hb <11 g/dL), current infection, no definite surgical date, severe cardiac, respiratory, or cerebrovascular disease, and pregnancy.
  • Autologous blood should be stored in a refrigerator at a controlled temperature between 2 and 8°C, with alarms set at 3–7°C, and physically separated from homologous blood stocks and cross-matched blood. This refrigerator should be equipped with a recorder and an alarm similar to those on other fridges used for blood storage.
  • The autologous label for each unit should include all necessary information for correct identification of the patient and should have a suitable adhesive for refrigerated storage.
• Intraoperative hemodilution consists of blood collection immediately before surgery (usually after induction of anesthesia), followed by IV fluid replacement to prevent hypovolemia. Blood is then re-infused at the end of, or after, surgery. Blood is kept warm in the operating theatre (can be stored for up to 8 hours in blood collection [containing citrate] bags without refrigeration).
  • Popular in cardiac surgery before or immediately after commencing cardiopulmonary bypass
  • Usually acceptable to Jehovah's Witnesses if blood is kept in continuous contact with the patient
  • Less metabolic derangements due to the shorter storage time; hyperkalemia does not develop in <24 hours but hemolysis can occur during blood removal if too small a line is used.
  • Hematocrit before blood removal should be >30%, and generally >36%. After blood removal, hematocrit should be >24%.
• Cell salvage is the most common method of autologous blood transfusion. Blood lost during or immediately after surgery is suctioned and collected into a designated reservoir. Heparin is added to prevent clotting and is processed and transfused back to the patient.
  • May commonly be utilized in cardiac, vascular, and orthopedic surgery
• Postoperative blood collection (most often after orthopedic surgery) and re-transfusion of unprocessed blood back to the patient. It has been used in cardiac and orthopedic surgery, as well as traumatic hemothorax. During total knee replacement, the surgery is most commonly performed with a tourniquet in place, and this is then deflated at the end of the procedure after a drain has been placed in the joint. This drain is then opened after 30–60 minutes, and the blood collects into a specifically designed collection reservoir (bellows) using vacuum suction (as opposed to wall suction). The collected blood is filtered before being immediately transfused back to the patient; this is performed on an hourly basis. This system is low-cost, easy to perform, and with minimal side effects. Blood is defibrinogenated and thus does not require anticoagulation prior to transfusion; additionally, it is sterile.
• Autologous platelet-rich plasma is collected from the patient intraoperatively via apheresis equipment. When used for cardiac surgery patients, it is removed prior to heparin administration and the onset of cardiopulmonary bypass. It is returned after heparin reversal. Studies have not shown improved benefit in regard to hemostasis and/or decreased need for transfusion.

• PABD can have disadvantages, problems, and/or challenges including:
  • Wastage of blood due to cancellation of surgery
  • Inability to utilize the blood for another patient, in the event that it is not given to the donor patient. A small number of autologous units are administered to other patients; however, due to the donor's comorbidities, autologous units are often unsuitable for allogeneic donation.
  • The need for storage
  • Metabolic derangements still exist, such as hyperkalemia and loss of 2,3 DPG (related to length of storage)
  • Potential for administrative error
  • Blood must still be warmed during infusion to prevent hypothermia.
  • Donation may predispose to deterioration in medical condition (e.g., severe ischemic heart disease).
  • Contraindicated in patients with anemia
  • Unacceptable to Jehovah's Witnesses
  • Not often practiced due to logistical reasons, particularly scheduling of surgery, collecting, and storing blood (different locations)
  • Does not guarantee that allogeneic blood will not be transfused
  • Vasovagal reactions during collection from hypotension and bradycardia
  • Increased cost compared to allogeneic blood units
• Intraoperative hemodilution can have disadvantages including:
  • Hemodynamic instability: Removal of up to 500 mL of blood is possible; however, loss of volume may cause hypotension unless fluid is replaced immediately.
  • Precipitation of myocardial ischemia or worsening tissue oxygenation from acute anemia
  • Need for wide-bore vascular access; central venous may be necessary if the arm IV is insufficient or unreliable.
  • Blood storage time is limited to a few hours. It should not be stored in the blood fridge, but kept in the patient's immediate vicinity and transfused within 8 hours.
• Cell salvage can have disadvantages including:
  • Loss of plasma containing clotting factors and platelets leading to coagulopathy and bleeding. This is only relevant after at least 50% of a patient's blood volume has been processed.
  • Requires "enough" blood loss in order to prepare a unit
• Postoperative blood collection can have disadvantages including:
  • Risks of fluid overload with rapid re-infusion
  • Clotting of blood in re-transfusion bag if not administered to patient immediately after filtration
• Direct re-infusion of shed mediastinal blood from postoperative chest tube drainage is not recommended as a means of blood conservation and may cause harm (Level B evidence).

• Autologous transfusion can optimize or increase Hb while reducing the risk and amount of allogeneic blood transfusion.
• Allogeneic blood is strongly associated with increased risk of death (1) [B] and complications, including postoperative infection (2) [A], cancer recurrence, acute lung injury (TRALI) (3) [B], and increased length of stay in the intensive care unit and hospital. Risk correlates with the number of units of allogeneic blood transfused and length of time that the blood is stored (4) [B]. These risks are NOT associated with autologous transfusion.
• Needs advance planning and preparation before surgery
• Discuss with the surgeon and patient

• Cell Salvage
• Blood Transfusions
• Transfusion-Related Infections
• Blood Substitutes

andrew A. Klein , MD