INTRODUCTION — Surgical blood conservation techniques reduce patient exposure to allogeneic blood during and after surgery. Techniques include preoperative autologous donation, intraoperative hemodilution, and surgical blood salvage (ie, cell salvage).
This topic will review the indications, benefits, and potential complications of intraoperative blood salvage. The other perioperative blood conservation techniques are discussed separately. (See "Surgical blood conservation: Preoperative autologous blood donation" and "Surgical blood conservation: Acute normovolemic hemodilution".)
INDICATIONS — Blood salvage can be used throughout the surgical procedure to rapidly provide a large volume of washed autologous red blood cell (RBC) units. Indications include:
●Major surgical procedures with anticipated significant blood loss – There are no good data to define the estimated blood loss at which blood salvage is appropriate. The rationale is strong for an estimated blood loss of 1000 mL and reasonable for some patients with estimated blood loss of 500 to 750 mL. This discussion uses a threshold of >750 mL; however, the value is only an estimate, different thresholds may apply to different patients, and the exact threshold is individualized.
We recommend intraoperative blood salvage (also known as blood recovery) for most surgical procedures having a high likelihood of significant blood loss (eg, >750 mL), particularly if transfusion of allogeneic blood is likely (algorithm 1). This recommendation is based on evidence that allogeneic transfusion and associated complications can potentially be avoided or minimized when intraoperative blood salvage is used, with a low incidence of adverse events [1-4]. This technique is used effectively in various elective and emergency major surgical procedures, including cardiac, major vascular, major orthopedic, trauma, transplantation, and selected urologic, gynecologic, neurosurgical, and plastic surgical procedures. (See 'Benefits' below and 'Potential complications' below.)
Decisions regarding the use of intraoperative blood salvage in cases with moderate anticipated blood loss (eg, 500 to 750 mL) are individualized, considering factors such as known preoperative or intraoperative factors that influence the likelihood of transfusion, nature of any relative contraindications, and availability of crossmatch-compatible allogeneic blood. (See 'Relative contraindications' below.)
●Patients who decline allogeneic blood – Intraoperative blood salvage is also used for patients who will not accept allogeneic blood, provided there are no absolute contraindications. The technique is usually acceptable to Jehovah's Witnesses who decline allogeneic blood and is nearly always used after discussion with such patients if there are no absolute contraindications [5-7] (see 'Absolute contraindications' below). Although specific beliefs vary, requirements for acceptance may include assurance that the blood does not leave the operating room for processing and/or that the blood remains continuously connected to the patient via intravenous tubing. (See "Approach to the patient who declines blood transfusion", section on 'Jehovah's Witnesses'.)
●Situations when crossmatch-compatible blood cannot be obtained – Intraoperative blood salvage may be lifesaving in patients with a rare blood type or multiple RBC alloantibodies when crossmatch-compatible blood cannot readily be obtained. However, patients should never be denied potentially life-saving transfusion due to cross-matching difficulties, since emergency release blood is always available and is generally well-tolerated. (See "Pretransfusion testing for red blood cell transfusion", section on 'Emergency release blood for life-threatening anemia or bleeding'.)
BENEFITS — Intraoperative blood salvage can be effective in avoiding or reducing allogeneic red blood cell (RBC) transfusion, with its attendant costs and risks [1,2]. (See "Indications and hemoglobin thresholds for RBC transfusion in adults", section on 'Risks and complications of transfusion'.)
Potential benefits include:
●Reduced need for transfusion of allogeneic RBCs – Evidence supporting intraoperative blood salvage comes from randomized trials and observational studies demonstrating that blood salvage reduces the need for allogenic RBC transfusion with certain high blood loss procedures [1,2,8-34]. A 2023 meta-analysis of 106 randomized trials (14,528 patients) identified a benefit of blood salvage in reducing allogeneic RBC transfusion in the following [1]:
•Cardiovascular surgery without cardiopulmonary bypass (CPB) (Relative risk [RR] 0.82, 95% CI 0.69-0.97; 3 trials with 169 patients)
•Cardiovascular surgery with CPB (RR 0.81, 95% CI 0.73-0.89; 29 trials with 2936 patients)
•Major orthopedic (hip only) surgery (RR 0.52, 95% CI 0.38-0.72; 14 trials with 1641 patients)
•Major orthopedic (knee only) surgery (RR 0.49, 95% CI 0.37-0.66; 21 trials with 2214 patients)
•Orthopedic spine surgery (RR 0.44, 95% CI 0.31-0.63; 3 trials with 194 patients)
•Mixed orthopedic surgical procedures (RR 0.64, 95% CI 0.45-0.90; 11 trials with 4011 patients)
However, certainty regarding evidence of efficacy ranged from low to moderate because of marked heterogeneity among studies due to differences in methodology, type of surgery, blood loss, and transfusion behavior. Also, efficacy of blood salvage was inconclusive in vascular, cancer, and obstetrical surgical procedures in this meta-analysis [1]. An earlier 2010 meta-analysis in patients undergoing orthopedic and cardiovascular procedures noted similar results for use of blood salvage compared with controls (risk of transfusion, 30 versus 51 percent; absolute risk reduction 21 percent, 95% CI 15-26 percent; RR 0.62, 95% 0.55-0.70; 67 trials with 6025 patients) [2]. Adverse effects were not increased by the use of blood salvage in either meta-analysis [1,2].
●Provision of more RBC units than other blood conservation techniques – Intraoperative blood salvage complements other methods for autologous blood conservation. It can potentially deliver many more units of RBCs than intraoperative acute normovolemic hemodilution, which generally only provides 1 to 3 units of autologous blood [35,36]. (See "Surgical blood conservation: Acute normovolemic hemodilution".)
●Possible time and cost savings – Intraoperative blood salvage is usually done in the operating room without direct involvement of the transfusion service and also eliminates the need for the patient to provide autologous donations. Thus, intraoperative salvage may save the patient and the blood collection facility time. Cost savings may apply in cardiac cases, where the perfusionist handles the cell saver. In other procedures, cost may be greater due to the need for cell saver equipment and additional personnel in the operating room.
CONTRAINDICATIONS — There are both absolute and relative contraindications to the use of intraoperative blood salvage [37].
Absolute contraindications
●Presence of contraindicated fluids – Salvaged blood must never be used when solutions that would be toxic with intravascular administration could come into contact with the salvaged blood. Examples include antibiotic irrigation or hydrogen peroxide, alcohol, or povidone-iodine solutions. Also, salvaged blood must never be mixed with hypotonic fluids such as sterile water because this will cause hemolysis [21,37].
●Admixture with hemostatic products or bone cement – Suctioned blood from the surgical field cannot be used when there is any potential for simultaneous collection of biologic hemostatic products such as topical thrombin, fibrin glue, or microfibrillar bovine collagen-based products. Examples are Avitene, Actifoam Collagen Sponge, Ultrafoam Sponge, Instat, and Helitene. Although not specifically studied, topical (or intravenous) tranexamic acid is commonly used during surgical cases employing cell salvage and is not contraindicated. (See "Overview of topical hemostatic agents and tissue adhesives".)
Similarly, blood salvage cannot be used if there is any chance of admixture with the bone cement methyl methacrylate [21,37].
Relative contraindications — The following relative contraindications are controversial because there is no compelling evidence to suggest an association with adverse outcomes. Use of intraoperative blood salvage for patients with these diagnoses has been expanded without clear-cut negative consequences [37].
●Bacterial infections – Decisions about using intraoperative blood salvage in patients with bacterial infections are made on a case-by-case basis, with consideration of relative risks and benefits for the individual patient, and with informed consent [4]. These include the potential infection risk of this technique compared with the known risk of postoperative infection after transfusion of allogeneic blood [38]. (See "Indications and hemoglobin thresholds for RBC transfusion in adults", section on 'Risks and complications of transfusion' and "Transfusion-transmitted bacterial infection".)
Bacterial contamination of the surgical wound has traditionally been a contraindication to intraoperative blood salvage. However, there are no reports of bacteremia and sepsis in otherwise healthy people who were transfused in the intraoperative period with salvaged blood containing bacteria. Small studies support the appropriateness of more liberal use of intraoperative blood salvage in this setting. In a case series that included 11 hemorrhaging trauma patients with enterically contaminated wounds, rapid access to a large volume of autologous blood for reinfusion was potentially lifesaving; no patient developed intra-abdominal sepsis, and no deaths were reported [39]. A 2015 systematic review in emergency abdominal or thoracic trauma surgery noted no difference in sepsis (measured by blood cultures) or mortality in the blood salvage group compared with the control group receiving allogeneic blood (one trial; n = 44) [8]. A retrospective study of clinical outcomes in 36 patients who received salvaged blood during cardiac surgery noted no clinical sequelae in the third of patients transfused with blood containing bacteria or endotoxin [40]. In another retrospective study, cell salvage was used during cardiac surgery in patients with endocarditis without clinically important adverse consequences [41].
Reasons for the absence of adverse consequences of blood salvage include use of broad-spectrum antibiotics in surgical patients, the practice of irrigating surgical wounds before resuming salvage procedures when contamination occurs, and the thorough washing and filtration used to process salvaged intraoperative blood [21]. Although processing blood via a blood salvage system and then filtering it using a leukocyte reduction filter does not completely sterilize it, a 98 to 100 percent reduction in a variety of bacterial organisms has been demonstrated [42,43]. (See 'Technology and procedural steps' below.)
●Active malignancy – Decisions about using intraoperative blood salvage in patients with active malignancy are made on a case-by-case basis, with consideration of factors such as the risk of major intraoperative bleeding, the need for transfusion, the availability of allogeneic blood, and informed patient consent [4]. In a 2012 systematic review that included 10 observational studies, patients who received salvaged autologous blood during oncology surgery did not have a higher incidence of cancer recurrence or metastasis development than those receiving allogeneic blood [44].
The successful use of intraoperative blood salvage in cancer surgery supports more liberal use of the technique in patients with active malignancy [44-47].
Malignant cells have been observed in shed blood collected intraoperatively, and extensive cell washing does not remove these cells [48]. However, leukocyte reduction filters have been shown to remove tumor cells from salvaged blood, similar to their ability to remove white blood cells [46,48-53]. (See 'Reinfusion' below.)
Areas of uncertainty — Intraoperative blood salvage has been used successfully in the following settings, with continuing research to clarify its risks and benefits [4,21,37,54,55]:
●Obstetrics – Blood salvage, if available, can be helpful in managing patients at risk for postpartum hemorrhage (PPH) during cesarean birth, when patients decline allogeneic blood, or when autologous or crossmatched allogeneic blood is not available [54-60]. Preoperative planning for its use is prudent in obstetric patients at high risk for significant PPH (eg, placenta accreta) [4,61]. Blood salvage in this setting is discussed separately. (See "Postpartum hemorrhage: Management approaches requiring laparotomy", section on 'Role of intraoperative cell salvage'.)
In some centers, blood salvage is used routinely for patients undergoing cesarean birth, or in patients who develop abnormal bleeding during the procedure [61,62]. In this setting, unique hazards include the possibility of aspiration of amniotic fluid or hemostatic agents together with blood in the surgical field, although the washing process minimizes these risks. (See 'Washing' below.)
●Hemoglobinopathies – There is uncertainty regarding the safety of intraoperative blood salvage for patients with sickle cell disease (eg, theoretical risk of increased sickling) or thalassemia (eg, theoretical risk of increased hemolysis) [21,37,63]. (See "Perioperative management of adults with sickle cell disease or thalassemia".)
●Cold agglutinin disease – There is uncertainty regarding the safety of intraoperative blood salvage for patients with cold agglutinin disease, depending on the thermal amplitude of the autoantibody and the temperature of the operating room. If intraoperative blood salvage is used in a patient with known cold agglutinin disease, the reinfused blood should be passed through a blood warmer. (See "Cold agglutinin disease", section on 'Cold avoidance'.)
POTENTIAL COMPLICATIONS — In one multicenter retrospective review of the records for 33,351 patients receiving intraoperative salvaged blood, only two adverse events were identified (one patient with acute tachycardia, hypertension, dyspnea, and rigors; a second patient with acute hypotension and dyspnea) [3]. There were no deaths.
Although transfusion of autologous salvaged red blood cell (RBC) units avoids the risk of allergic reactions or alloimmunization, other potential complications are the same as those associated with transfusion of allogeneic blood including:
●Coagulopathy – Since intraoperative blood salvage replaces only RBCs, dilution of clotting factors can result in clinical coagulopathy and may be a challenging problem accompanying significant blood loss (eg, >1000 mL) after replacement solely by reinfusion of salvaged RBCs without plasma or platelets [64,65].
Using viscoelastic testing with rotational thromboelastometry (ROTEM) measurements, one study noted that salvaged blood transfusion exceeding 18.5 percent of a patient's whole blood volume decreased the maximum clot firmness of fibrinogen assay (FIBTEM-MCF), with potentially impaired coagulation function [66]. However, decisions to administer other blood components (plasma, platelets, Cryoprecipitate) are based on testing for hemostatic function and the specific intraoperative context. (See "Intraoperative transfusion and administration of clotting factors", section on 'Intraoperative diagnostic testing'.)
●Transfusion-associated circulatory overload – Pulmonary edema due to transfusion-associated circulatory overload (TACO) may occur, especially in patients with compromised cardiac function. TACO may occur more frequently in surgical settings where large volumes of fluid and blood are administered. (See "Transfusion-associated circulatory overload (TACO)".)
●Infection – As with transfusion of any blood component, the risk of transfusion-transmitted bacterial infection is a possibility [65]. (See "Transfusion-transmitted bacterial infection".)
●Air embolism – Blood salvage machines have the ability to pump massive amounts of air into the reinfusion bag [67,68]. Safety measures and air detection have been added to most cell recovery equipment. If these are not present in older equipment, safeguards to avoid air embolism include [68,69]:
•Transferring the blood into a separate bag.
•Disconnecting the bag from the blood salvage equipment before giving it back to the patient.
Other standard safety precautions to avoid air embolism are also employed, including removing residual air from the bag, avoiding use of "pressure bags" to increase the reinfusion rate, and using inline air detectors when an infusion pump is used. (See "Air embolism".)
●Embolism of microaggregates or fat – Embolism of microaggregates consisting of white blood cell and platelet debris in salvaged blood is preventable by use of a 40-micron microaggregate filter for reinfusion. This is standard practice in blood salvage programs, in addition to RBC washing. Although fat embolism is also possible, this is preventable by extra washing and/or use of a leukocyte-reducing filter [70]. (See "Fat embolism syndrome".)
TECHNOLOGY AND PROCEDURAL STEPS — The intraoperative blood salvage machine (commonly referred to as a "cell saver" or "cell recovery device") separates, concentrates, and washes salvaged red blood cells (RBCs). Several steps are involved (figure 1) [4,21]:
●Suctioning of shed blood from the surgical field and addition of an anticoagulant
●Centrifugation to separate the RBCs from platelets and plasma, concentrate the RBC product, and remove some of the anticoagulant
●Washing of RBCs (to remove the remaining anticoagulant, free hemoglobin, activated thrombogenic substances, and cellular stroma)
●Eventual reinfusion to the patient
Aspiration of blood from the surgical field — Intraoperative cell salvage starts with aspiration of shed blood through a suction wand as it collects in the surgical field or is squeezed out from blood-soaked surgical gauze pads [71].
As it is aspirated, the blood is mixed with an anticoagulant (typically heparin) to prevent clotting of the blood before reinfusion [21]. Typically, heparin in saline with a concentration of approximately 30,000 units/L is used. This solution is slowly and automatically added to the aspirated blood at a rate of 15 mL per 100 mL of collected blood [21]. During subsequent washing of the collected blood, all but a trace of heparin is removed [21,72].
Citrate is another anticoagulant that may be used. If there is concern about heparin-induced thrombocytopenia (HIT), a citrate-based anticoagulant/preservative solution (eg, citrate-phosphate-dextrose [CPD] or citrate-phosphate-dextrose-adenine [CPD-A]) should be used instead of heparin. Citrate-containing solutions are administered at a rate of 15 mL per 100 mL of collected blood [21].
Citrate is rapidly metabolized by the liver after transfusion, unless there is severe liver disease or hypoperfusion/shock. Therefore, iatrogenic anticoagulation is unlikely with intraoperative blood salvage. In patients with advanced liver disease who receive a large volume of salvaged blood, it is helpful to monitor calcium levels to detect hypocalcemia if citrate is used as the anticoagulant [34,73]. If there is concern about citrate-induced hypocalcemia (eg, due to impaired liver function, changes consistent with hypocalcemia on the electrocardiogram, or a low measured ionized calcium level), intravenous calcium chloride or calcium gluconate can be administered. (See "Practical aspects of red blood cell transfusion in adults: Storage, processing, modifications, and infusion", section on 'Anticoagulant-preservative (A-P) solutions'.)
Centrifugation to concentrate RBCs — The aspirated blood is collected in a sterile, filtered collection reservoir until the amount is sufficient for processing (typically 375 to 750 mL). The blood is then pumped into the centrifuge bowl where the RBCs are separated and concentrated to a hemoglobin concentration as high as 18 g/dL, while plasma, platelets, and waste components are sent to a waste bag (figure 1). This reduces the total fluid volume administered to the patient.
Blood salvage devices can process a full reservoir of blood in approximately three minutes, resulting in 55 to 250 mL of RBCs with hemoglobin concentration as high as 18 g/dL [21,74]. A "partial bowl" that is at least one-half filled with RBCs (eg, insufficient blood to process a full bowl) can be processed if necessary, but the resulting hemoglobin concentration will be <18 g/dL.
Washing
●Standard washing process – Since salvaged blood has a high concentration of free hemoglobin (due to hemolysis), inflammatory mediators, and other cellular debris, standard procedure is to wash the blood with an isotonic solution (usually normal [0.9 percent] saline) [21]. In one study, use of a balanced bicarbonate buffered solution (Balsol) resulted in fewer acid-base and electrolyte derangements than normal saline [75]. Some centers change to a balanced electrolyte solution (eg, PlasmaLyte-A) only after administration of a large volume of normal saline (eg, after approximately 1500 mL of saline is reinfused with 3000 mL of salvaged blood) [21,76].
Washing removes plasma and platelets; as a result, all clotting factors are decreased [77]. Thus, patients who receive ≥1000 mL of washed autologous RBCs may develop a dilutional coagulopathy that requires treatment with plasma and/or platelet transfusions. (See "Massive blood transfusion", section on 'Approach to volume and blood replacement'.)
Overall, the quality of salvaged, washed, autologous RBCs, as measured by posttransfusion RBC survival and enzymatic indices of RBC function, is equivalent, if not superior, to RBCs in allogeneic transfusions [76,78-80].
Separation and washing of RBCs with the blood salvage machine removes added anticoagulant and virtually eliminates free hemoglobin, platelets, white blood cells, and cellular stroma products that are potentially thrombogenic. In addition, washing markedly decreases biologic response modifiers such as cell-derived microvesicles and CD40 ligand, with no effect on neutral lipids [81].
●Double washing process for partial bowls – Double washing is used to process a partial bowl in the reservoir that is at least one-half full of RBCs and is also used in selected orthopedic surgical cases or to process any amount of blood in a patient who declines allogeneic blood.
●Rare use of salvaged unwashed whole blood – In rare intraoperative settings with extremely rapid sustained blood loss (eg, >500 mL/min), it may be beneficial to use the emergency mode of the blood salvage machine in order to rapidly return the salvaged blood without centrifuging or washing, until control of bleeding can be achieved.
Returning whole blood in this setting allows the blood to be almost immediately available for reinfusion and may preserve some clotting factors and platelets. However, the risks and disadvantages of infusing unwashed whole blood are significant [82,83]:
•The anticoagulant that was added to the blood is not removed and may increase bleeding risk.
•The reinfused platelets may be dysfunctional after being suctioned from the surgical field [84].
•Thrombogenic substances (eg, inflammatory mediators and microaggregates consisting of white blood cell and platelet debris) may be introduced.
•The hemoglobin concentration of whole blood is lower (range: 7 to 9 g/dL or lower, depending on the hemoglobin level in the aspirated blood) compared with a typical concentration of 16 to 18 g/dL in centrifuged, washed blood.
•There may be significant amounts of free hemoglobin due to hemolysis.
•Fat may be present in the unwashed product, with increased risk of fat embolism.
In these rare emergency circumstances, it is particularly important to use a 40-micron microaggregate filter for reinfusion. Also, the anticoagulant drip rate is increased due to the larger blood volume being processed. In such cases, protamine may be administered to neutralize the heparin in the reinfused unwashed blood to avoid coagulopathy. Ideally, the protamine dose is determined using a point-of-care heparin-protamine titration assay. If this is not available, an empiric dosing strategy may be used basing a calculated protamine dose on the amount of heparin that had been administered. Also, activated clotting time (ACT) values are typically obtained to determine adequacy of anticoagulation reversal. (See "Protamine: Administration and management of adverse reactions during cardiovascular procedures".)
Reinfusion — The processed RBC units are pumped from the centrifuge bowl into a blood salvage bag for reinfusion. Reinfusion is typically instituted as soon as the washed RBCs are available, but it may be delayed for up to six hours if not clinically indicated at the moment of preparation (eg, in a clinically hypervolemic patient) [21]. A filter is used during reinfusion:
●Microaggregate filter – A 40-micron microaggregate filter is installed between the blood salvage bag and the patient to filter the final blood product as it is reinfused into the patient [85].
●Leukocyte reduction filter – Although not routinely used because of cost and poor flow due to clogging, a leukocyte reduction filter is an alternative to a microaggregate filter when it is desirable to achieve optimal removal of bacteria, cancer cells, fat particles, or amniotic fluid [4,56,70] (see 'Relative contraindications' above and 'Areas of uncertainty' above). This type of filter must be changed after infusion of each 500 mL of blood [21]. Typically, leukocyte-reduced products have <1x106 leukocytes/mL, corresponding to approximately 99 percent leukocyte reduction [86,87]. Other components such as platelets can also adhere to these filters, but at least 85 percent of RBCs pass through the filter and into the patient. Polyester or polyamide filters commonly used in blood salvage have a 40-micron pore size and promote relatively selective adhesion of negatively charged leukocytes via three passive mechanisms (blocking, bridging, and interception) and one active mechanism (adhesion). Adhesion-based filters are the most efficient, allowing >99.9 percent leukocyte reduction [88,89]. Technical specifications of leukoreduction filters are discussed separately. (See "Practical aspects of red blood cell transfusion in adults: Storage, processing, modifications, and infusion", section on 'Pre-storage leukoreduction'.)
Storage and handling — Blood collected by intraoperative blood salvage may be stored either at room temperature for up to six hours or at 1 to 6°C for up to 24 hours if it is collected under aseptic conditions with a device that provides washing, provided that cold storage starts within six hours of initiating collection. Such stored blood must be properly labeled. Minimum labeling requirements include the patient's name and identifying number, the component name, the statement "For Autologous Use Only," and the expiration date and time.
Blood collected by cell salvage is generally reinfused rather than discarded.
Blood collected by intraoperative salvage should never be transfused to any patient other than the one from whom it was collected [90].
ESTABLISHING A BLOOD SALVAGE PROGRAM — The Association for the Advancement of Blood & Biotherapies (AABB) Standards for Perioperative Autologous Blood Collection and Administration recommend that hospitals with intraoperative blood salvage programs and blood centers providing the service should establish written policies and procedures for proper collection, labeling, and storage of the collected blood [69]. The clinician responsible for the program should regularly review all policies and procedures. Periodic quality control testing of collected blood is recommended to ensure that collection equipment and techniques result in an aseptic blood product.
Guidelines and training are essential for the quality assurance of intraoperative blood salvage [4]; this has been described in an editorial as a "largely unregulated cottage industry" [91]. The technique can be performed by a perfusionist who may be available if cardiopulmonary bypass is also necessary for the surgical case, or by a cross-trained operating room employee (eg, anesthesia technician). Cross-training employees as blood salvage technicians might be more economical than using an outsourced specialist service when the caseload exceeds 55 cases per year [92].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Transfusion and patient blood management".)
SUMMARY AND RECOMMENDATIONS
●Indications – For most patients undergoing a surgical procedure anticipated to have a high likelihood of significant blood loss (eg, >750 mL), we recommend intraoperative blood salvage (Grade 1B), particularly if transfusion of allogeneic blood is likely. This is based on clinical trial evidence demonstrating that blood salvage reduces the need for allogeneic red blood cell (RBC) transfusion with a low incidence of adverse events. (See 'Indications' above.)
The technique is also used for patients who will not accept allogeneic blood, provided no absolute contraindications exist. (See "Approach to the patient who declines blood transfusion".)
For patients undergoing surgery with moderate anticipated blood loss (500 to 750 mL), decisions regarding use of intraoperative blood salvage are individualized considering factors such as known preoperative or intraoperative factors that influence the likelihood of transfusion, nature of any relative contraindications, and availability of crossmatch-compatible allogeneic blood (algorithm 1). (See 'Indications' above and 'Contraindications' above.)
●Benefits – In addition to reduced need for transfusion of allogeneic blood, potential benefits include provision of more RBC units than other blood conservation techniques and, in some settings, time and cost savings. (See 'Benefits' above.)
●Contraindications
•Absolute – Absolute contraindications include the presence of hypotonic solutions (eg, sterile water) or toxic substances (eg, alcohol, hydrogen peroxide, or povidone-iodine solution), or when there is a possibility of simultaneous collection of biologic hemostatic agents (microfibrillar collagen-based products, topical thrombin, fibrin glue) or methyl methacrylate (bone cement). Use of topical (or intravenous) tranexamic acid is not a contraindication for cell salvage. (See 'Absolute contraindications' above.)
•Relative – Relative contraindications include systemic bacterial infection, contamination of the surgical wound, or active malignancy. Decisions for use are individualized. (See 'Relative contraindications' above.)
•Areas of uncertainty – Although used in selected patients with the following conditions, investigation of benefits versus risks is ongoing for those with (see 'Areas of uncertainty' above):
-Risk for postpartum hemorrhage during cesarean birth
-Hemoglobinopathies
-Cold agglutinin disease
●Potential complications – Potential complications of blood salvage include some of the same transfusion complications as those associated with allogeneic blood transfusion (eg, dilutional coagulopathy, transfusion-related volume overload, bacterial infection, and embolism of air, cellular microaggregates, or fat), but without the risk of allergic reactions or alloimmunization. (See 'Potential complications' above.)
●Technology and processing – Processing of intraoperative salvaged blood involves (figure 1) (see 'Technology and procedural steps' above):
•Aspiration of blood – Shed blood from the surgical field is suctioned and mixed with an anticoagulant (typically heparin). (See 'Aspiration of blood from the surgical field' above.)
•Centrifugation and washing – The cell recovery device filters, centrifuges, and washes the aspirated blood to separate and concentrate the RBCs and remove the anticoagulant, free heme, and thrombogenic substances such as cell stroma. Salvaged washed RBCs have the same posttransfusion RBC survival as traditional washed RBC products but lack platelets, white blood cells, and clotting factors. (See 'Centrifugation to concentrate RBCs' above and 'Washing' above.)
•Unwashed whole blood – In rare situations (eg, extremely rapid sustained blood loss >500 mL/min), salvaged blood may be reinfused without processing. Risks include infusion of residual anticoagulant, dysfunctional platelets, thrombogenic substances, free hemoglobin, and possibly fat that might lead to coagulation abnormalities and/or fat emboli.
•Reinfusion – A 40-micron microaggregate filter is used during reinfusion. A leukocyte reduction filter is an alternative if optimal removal of bacteria, cancer cells, fat particles, or amniotic fluid is necessary. (See 'Reinfusion' above.)
●Storage – Blood collected by intraoperative blood salvage should only be given to the patient from whom it was collected; it should never be transfused to any other patient. Salvaged blood may be labeled and stored either at room temperature for up to six hours or at 1 to 6°C for up to 24 hours if collected under aseptic conditions with a device that provides washing and if cold storage begins within six hours of collection. (See 'Storage and handling' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Michael Avidan, MD, who contributed to an earlier version of this topic review.
The UpToDate editorial staff also acknowledges extensive contributions of Arthur J Silvergleid, MD to earlier versions of this and many other topic reviews.
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