Practice Guidelines for Perioperative Blood Management: An Updated Report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

PRACTICE guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints, and are not intended to replace local institutional policies. In addition, practice guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data.

This document updates the “Practice Guidelines for Perioperative Blood Transfusion and Adjuvant Therapies: An Updated Report by the American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies,” adopted by the ASA in 2005 and published in 2006.^†

Perioperative blood management refers to perioperative blood transfusion and adjuvant therapies. Perioperative blood transfusion addresses the preoperative, intraoperative, and postoperative administration of blood and blood components (e.g., allogeneic or autologous blood, red blood cells, platelets, cryoprecipitate, and plasma products, fresh-frozen plasma [FFP], PF24, or Thawed Plasma).^‡ Adjuvant therapies refer to drugs and techniques to reduce or prevent blood loss and the need for transfusion of allogeneic blood.

The purposes of these updated Guidelines are to improve the perioperative management of blood transfusion and adjuvant therapies and to reduce the risk of adverse outcomes associated with transfusions, bleeding, or anemia.

These Guidelines focus on the perioperative management of patients undergoing surgery or other invasive procedures in which significant blood loss occurs or is expected. This includes but is not limited to (1) patients undergoing cardiopulmonary bypass or cardiac surgery, urgent or emergent procedures, obstetric procedures, organ transplantation, and noncardiac surgery; (2) patients with pre-existing blood disorders or acquired coagulation deficiency; (3) critically ill patients undergoing surgical or other interventional procedures; and (4) patients who elect not to undergo perioperative transfusion. Excluded from the focus of these Guidelines are neonates, infants, children weighing less than 35 kg, and patients who are not undergoing procedures.

The Task Force recognizes that the physiology of bleeding may be influenced by the vasodilatory effects of anesthetics; therefore, for some clinical presentations or surgical situations, the recommendations in these Guidelines may not apply. Practitioners will need to use their judgment of the clinical situation in applying the more generalized recommendations contained in these Guidelines.

These Guidelines apply to both inpatient and outpatient surgical settings, and to interventional procedures performed in operating rooms as well as in other locations (e.g., interventional radiology, critical care units) where blood transfusion or other adjuvant therapy is indicated. They are directly applicable to care administered by anesthesiologists and individuals who deliver care under the medical direction or supervision of an anesthesiologist. They are also intended to serve as a resource for other physicians and patient care personnel who are involved in the perioperative care of these patients.

In 2012, the ASA Committee on Standards and Practice Parameters requested that the updated Guidelines published in 2006 be re-evaluated. This current revision consists of a literature evaluation and an evaluation of new survey findings of expert consultants and ASA members. A summary of recommendations is found in appendix 1.

This revision was developed by an ASA appointed Task Force of 10 members, consisting of anesthesiologists in both private and academic practices from various geographic areas of the United States, a pathologist specializing in transfusion medicine, and two consulting methodologists from the ASA Committee on Standards and Practice Parameters.

The Task Force developed the Guidelines by means of a seven-step process. First, they reached consensus on the criteria for evidence of effective blood transfusion and adjuvant therapies. Second, original published research studies from peer-reviewed journals relevant to the perioperative management of patients undergoing blood transfusions were reviewed. Third, a panel of expert consultants was asked to (1) participate in opinion surveys on the effectiveness of various perioperative management strategies and (2) review and comment on a draft of the Guidelines developed by the Task Force. Fourth, survey opinions about the Guideline recommendations were solicited from a random sample of active members of the ASA. Fifth, the Task Force held open forums at two major national meetings to solicit input on its draft recommendations.^§ National organizations representing specialties whose members typically care for patients undergoing perioperative transfusion were invited to participate in the open forums. Sixth, the consultants were surveyed to assess their opinions on the feasibility of implementing the Guidelines. Seventh, all available information was used to build consensus within the Task Force to finalize the Guidelines.

Preparation of these updated Guidelines followed a rigorous methodological process. Evidence was obtained from two principal sources such as scientific evidence and opinion-based evidence (appendix 2).

Scientific evidence used in the development of these updated Guidelines is based on cumulative findings from literature published in peer-reviewed journals. Literature citations are obtained from PubMed and other healthcare databases, direct internet searches, Task Force members, liaisons with other organizations and from manual searches of references located in reviewed articles.

Findings from the aggregated literature are reported in the text of the Guidelines by evidence category, level, and direction. Evidence categories refer specifically to the strength and quality of the research design of the studies. Category A evidence represents results obtained from randomized-controlled trials (RCTs), and Category B evidence represents observational results obtained from nonrandomized study designs or RCTs without pertinent comparison groups. When available, Category A evidence is given precedence over Category B evidence in the reporting of results. These evidence categories are further divided into evidence levels. Evidence levels refer specifically to the strength and quality of the summarized study findings (i.e., statistical findings, type of data, and the number of studies reporting/replicating the findings) within the two evidence categories. For this document, only the highest level of evidence is included in the summary report for each intervention, including a directional designation of benefit, harm, or equivocality for each outcome.

RCTs report comparative findings between clinical interventions for specified outcomes. Statistically significant (P < 0.01) outcomes are designated as either beneficial (B) or harmful (H) for the patient; statistically nonsignificant findings are designated as equivocal (E).

• Level 1: The literature contains a sufficient number of RCTs to conduct meta-analysis,^‖ and meta-analytic findings from these aggregated studies are reported as evidence.

• Level 2: The literature contains multiple RCTs, but the number of RCTs is not sufficient to conduct a viable meta-analysis for the purpose of these updated Guidelines. Findings from these RCTs are reported as evidence.

• Level 3: The literature contains a single RCT, and findings from this study are reported as evidence.

Observational studies or RCTs without pertinent comparison groups may permit inference of beneficial or harmful relationships among clinical interventions and outcomes. Inferred findings are given a directional designation of beneficial (B), harmful (H), or equivocal (E). For studies that report statistical findings, the threshold for significance is P < 0.01.

• Level 1: The literature contains observational comparisons (e.g., cohort, case-control research designs) between clinical interventions for a specified outcome.

• Level 2: The literature contains observational studies with associative statistics (e.g., relative risk, correlation, sensitivity/specificity).

• Level 3: The literature contains noncomparative observational studies with descriptive statistics (e.g., frequencies, percentages).

• Level 4: The literature contains case reports.

The lack of sufficient scientific evidence in the literature may occur when the evidence is either unavailable (i.e., no pertinent studies found) or inadequate. Inadequate literature cannot be used to assess relationships among clinical interventions and outcomes, as such literature does not permit a clear interpretation of findings due to methodological concerns (e.g., confounding in study design or implementation) or does not meet the criteria for content as defined in the “Focus” of the Guidelines.

All opinion-based evidence (e.g., survey data, open-forum testimony, internet-based comments, letters, and editorials) relevant to each topic was considered in the development of these updated Guidelines. However, only the findings obtained from formal surveys are reported.

Opinion surveys were developed for this update by the Task Force to address each clinical intervention identified in the document. Identical surveys were distributed to expert consultants and a random sample of ASA members.

Survey responses from Task Force-appointed expert consultants are reported in summary form in the text, with a complete listing of consultant survey responses reported in appendix 2.

Survey responses from active ASA members are reported in summary form in the text, with a complete listing of ASA member survey responses reported in appendix 2.

Survey responses from expert and membership sources are recorded using a 5-point scale and summarized based on median values.^#

• Strongly Agree: Median score of 5 (At least 50% of the responses are 5)

• Agree: Median score of 4 (At least 50% of the responses are 4 or 4 and 5)

• Equivocal: Median score of 3 (At least 50% of the responses are 3, or no other response category or combination of similar categories contain at least 50% of the responses)

• Disagree: Median score of 2 (At least 50% of responses are 2 or 1 and 2)

• Strongly Disagree: Median score of 1 (At least 50% of responses are 1)

Open-forum testimony obtained during development of these Guidelines, Internet-based comments, letters, and editorials are all informally evaluated and discussed during the formulation of Guideline recommendations. When warranted, the Task Force may add educational information or cautionary notes based on this information.

Preoperative evaluation of a patient to identify risk factors for requiring a blood transfusion or adjuvant therapy includes (1) reviewing previous medical records, (2) conducting a patient or family interview, (3) reviewing existing laboratory test results, and (4) ordering additional laboratory tests when indicated.

Although it is well accepted clinical practice to review medical records and conduct a patient interview, comparative studies are insufficient to evaluate the impact of these practices. Observational studies and case reports indicate that certain congenital or acquired conditions (e.g., sickle-cell anemia, clotting factor deficiency, hemophilia, and liver disease) may be associated with blood transfusion complications (Category B3/B4-H evidence)^5–24  In addition, observational studies indicate that findings from pertinent preoperative laboratory tests (e.g., hemoglobin, hematocrit, coagulation tests) may be predictive of perioperative blood loss, the risk of transfusion, or other adverse events (e.g., acute kidney injury) associated with transfusion (Category B2-B evidence).^25–45 

The consultants and ASA members both strongly agree to (1) a review of previous medical records and interview the patient or family to identify previous blood transfusion, history of drug-induced coagulopathy, presence of congenital coagulopathy, history of thrombotic events, and risk factors for organ ischemia and (2) a review of available laboratory test results including hemoglobin, hematocrit, and coagulation profiles and the ordering of additional laboratory tests depending on a patient’s medical condition (e.g., coagulopathy, anemia). The ASA members agree and the consultants strongly agree regarding (1) informing patients of the potential risks versus benefits of blood transfusion and elicit their preferences and (2) conducting a physical examination of the patient (e.g., ecchymoses, petechiae, pallor).

• Review previous medical records and interview the patient or family to identify:

  • Previous blood transfusion

  • History of drug-induced coagulopathy (e.g., warfarin, clopidogrel, aspirin and other anticoagulants, as well as vitamins or herbal supplements that may affect coagulation [appendix 3])

  • Presence of congenital coagulopathy

  • History of thrombotic events (e.g., deep vein thrombosis, pulmonary embolism)

  • Risk factors for organ ischemia (e.g., cardiorespiratory disease) which may influence the ultimate transfusion trigger for red blood cells (e.g., hemoglobin level)

• Inform patients of the potential risks versus benefits of blood transfusion and elicit their preferences.

• Review available laboratory test results including hemoglobin, hematocrit, and coagulation profiles.

• Order additional laboratory tests depending on a patient’s medical condition (e.g., coagulopathy, anemia).

• Conduct a physical examination of the patient (e.g., ecchymosis, petechiae, pallor).

• If possible, perform the preoperative evaluation well enough in advance (e.g., several days to weeks) to allow for proper patient preparation.

Preadmission patient preparation includes (1) treatment of anemia, (2) discontinuation of anticoagulants and antiplatelet agents, and (3) preadmission autologous blood collection.

The World Health Organization identifies anemia as hemoglobin thresholds of 11.0 g/dl for children 0.50–4.99 yr,^** 11.5 g/dl for children 5.0–11.99 yr, 12.0 g/dl for children 12.0–14.99 yr, and nonpregnant women ≥15.0 yr, 11.0 g/dl for pregnant women and 13.0 g/dl for men ≥15.0 yr.^46,47  Preadmission treatment of anemia includes the administration of erythropoietin and/or iron to improve preoperative hemoglobin levels.

Meta-analyses of placebo-controlled RCTs indicate that erythropoietin with or without iron is effective in reducing the number of patients requiring allogeneic transfusions as well as reducing the volume of allogeneic blood transfused (Category A1-B evidence).^48–62  The literature is insufficient to evaluate the efficacy of erythropoietin with iron compared with erythropoietin without iron. RCTs report equivocal findings when preadmission oral iron is compared with either placebo or no iron regarding preoperative hemoglobin levels or perioperative allogeneic blood transfused (Category A2-E evidence).^63–65 

Both the consultants and ASA members agree that erythropoietin with or without iron may be administered when possible to reduce the need for allogeneic blood in select patient populations (e.g., renal insufficiency, anemia of chronic disease, refusal of transfusion); and both the consultants and ASA members strongly agree regarding the administration of iron to patients with iron deficiency anemia if time permits.

One nonrandomized comparative observational study is equivocal regarding the effect of discontinuing warfarin and replacing it with low-molecular-weight heparin on blood transfusion requirements when compared with patients not on warfarin(Category B1-E evidence).⁶⁶  Observational studies report blood loss volumes ranging from 265 to 756 ml, and blood transfusion requirements ranging from a mean of 0.08 to 0.5 units when clopidogrel is discontinued preoperatively (Category B3 evidence).^67–69  The literature is insufficient to evaluate the effects of discontinuing aspirin before surgery, although two RCTs comparing the administration of aspirin with placebo before surgery report equivocal findings (P > 0.01) for perioperative blood loss, transfusion requirements, or postoperative adverse events (e.g., myocardial infarction, major bleeding, or death) (Category A2-E evidence).^70,71 

Both the consultants and ASA members strongly agree regarding (1) discontinuing anticoagulation therapy (e.g., warafin, anti-Xa drugs, antithrombin agents) for elective surgery, in consultation with an appropriate specialist; (2) if clinically possible, discontinuing nonaspirin antiplatelet agents (e.g., thienopyridines such as clopidogrel, ticagrelor, or prasugrel) for a sufficient time in advance of surgery, except for patients with a history of percutaneous coronary interventions; and (3) that the risk of thrombosis versus the risk of increased bleeding should be considered when altering anticoagulation status.

RCTs indicate that the preadmission donation of autologous blood reduces the number of patients requiring allogeneic transfusions and the volume of allogeneic blood transfused per patient (Category A2-B evidence).^{72–77 ††}

The consultants and ASA members both strongly agree regarding assuring that blood and blood components are available for patients when significant blood loss or transfusion is expected; they both agree that when autologous blood is preferred, the patient should be offered the opportunity to donate blood before admission only if there is adequate time for erythropoietic reconstitution.

• Erythropoietin with or without iron may be administered when possible to reduce the need for allogeneic blood in selected patient populations (e.g., renal insufficiency, anemia of chronic disease, refusal of transfusion).^‡‡

• Administer iron to patients with iron deficiency anemia if time permits.

• In consultation with an appropriate specialist, discontinue anticoagulation therapy (e.g., warfarin, anti-Xa drugs, antithrombin agents) for elective surgery.

  • Transition to a shorter acting drug (e.g., heparin, low-molecular-weight heparin) may be appropriate in selected patients.

  • If clinically possible, discontinue nonaspirin antiplatelet agents (e.g., thienopyridines such as clopidogrel, ticagrelor, or prasugrel) for a sufficient time in advance of surgery, except for patients with a history of percutaneous coronary interventions.^§§

  • Aspirin may be continued on a case-by-case basis.

• The risk of thrombosis versus the risk of increased bleeding should be considered when altering anticoagulation status.

• Assure that blood and blood components are available for patients when significant blood loss or transfusion is expected.

• When autologous blood is preferred, the patient may be offered the opportunity to donate blood before admission only if there is adequate time for erythropoietic reconstitution.^‖‖

Preprocedure patient preparation includes the following strategies for reducing intraoperative allogeneic transfusion: (1) blood management protocols, (2) reversal of anticoagulants, (3) antifibrinolytics for prophylaxis of excessive blood loss,^## and (4) acute normovolemic hemodilution (ANH).

Protocols for perioperative blood management include (1) multimodal protocols or algorithms, (2) restrictive versus liberal transfusion criteria, (3) avoidance of transfusion, (4) a massive(i.e., hemorrhage) transfusion protocol, and (5) maximal surgical blood order schedules.

Multimodal protocols are strategies that typically consist of a predetermined “bundle” of interventions intended to reduce blood loss and transfusion requirements. The bundle components may include consultation with multiple medical specialties, institutional support, using transfusion algorithms, and point-of-care testing in addition to other perioperative blood conservation interventions. Algorithms are intended to identify decision points or “pathways” during a procedure whereby certain interventions should be employed.

RCTs comparing multimodal protocols or algorithms using coagulation tests or hemoglobin concentrations with routine blood management practices report variable findings regarding blood and blood product transfusions when such protocols are implemented (Category A2-E evidence).^78–80  RCTs demonstrate reduced blood transfusions and percentage of patients transfused when thromboelastrography (TEG)-guided protocols or algorithms are compared with standard laboratory coagulation testing in cardiac surgery patients. (Category A2-B evidence).^81–83  An RCT reports reductions in allogeneic blood product requirements when comparing a rotational thromboelastometry (ROTEM)-guided algorithm with no algorithm for bleeding burn patients (Category A1-B evidence).⁸⁴  The above studies report protocols or algorithms that contain a large variety of interventional components and the impact of any single component on outcome is not reported.

The consultants and ASA members both strongly agree regarding employment of multimodal protocols or algorithms as strategies to reduce the usage of blood products.

Definitions for a restrictive versus liberal strategy for blood transfusion vary in the literature, although hemoglobin criteria for transfusion less than 8 g/dl and hematocrit values less than 25% are typically reported as restrictive.

Meta-analysis of RCTs comparing restrictive with liberal transfusion criteria report fewer red blood cell transfusions when restrictive transfusion strategies are employed (Category A1-B evidence).^85–89  RCT findings for mortality, cardiac, neurologic or pulmonary complications, and length of hospital stay were equivocal (Category A2-E evidence).^85–93 

The ASA members agree and the consultants strongly agree that a restrictive red blood cell transfusion strategy may be used to reduce transfusion requirements.

A protocol to avoid transfusion or to reduce the volume of blood lost may be preferred in certain selected cases.

Studies with observational findings report low blood loss volumes for certain cardiac or other major procedures when these protocols are implemented (Category B3-B evidence).^94–99 

Both the consultants and ASA members strongly agree that a protocol for avoidance of transfusion may be used as a strategy to reduce blood loss for patients in whom transfusion is refused or is not possible.

Massive transfusion protocols are implemented in cases of life-threatening hemorrhage after trauma and/or during a procedure, and are intended to minimize the adverse effects of hypovolemia and dilutional coagulopathy. These protocols require the availability of large amounts of allogeneic blood and blood products. They often prescribe the transfusion FFP and platelets in a higher (e.g., 1:1) ratio with the transfusion of red blood cells.

An observational study indicates that the ratio of FFP to red blood cells (RBCs) is higher after the implementation of a massive transfusion protocol (Category B3-E evidence).¹⁰⁰ 

The consultants and ASA members both strongly agree regarding use of a massive transfusion protocol when available as a strategy to optimize the delivery of blood products to massively bleeding patients.

Observational studies indicate that implementing a maximal surgical blood order schedule or surgical blood order equation may improve the efficiency of blood ordering practices (Category B2-B evidence).^101–110  An RCT comparing a surgical blood order equation (SBOE) with a maximal surgical blood order schedule showed an improved crossmatch-to-transfusion ratio for SBOE (Category A3 evidence).¹¹¹ 

The consultants and ASA members both agree regarding the use of a maximal surgical blood order schedule, when available and in accordance with institutional policy, as a strategy to improve the efficiency of blood ordering practices.

Reversal of anticoagulants includes the topics of (1) preprocedure administration of prothrombin complex concentrates (PCCs), (2) administration of FFP, and (3) preprocedure administration of vitamin K.

Observational studies and case reports indicate that four-factor PCCs administered preoperatively are followed by a reduction in International Normalized Ratio (INR) values (Category B3/4-B evidence), with thromboembolic events reported in 0.003% of patients following infusions (Category B3 evidence).^112–114  The literature is insufficient to evaluate the impact of the use of FFP with reversal of anticoagulants. One retrospective study comparing vitamin K administered immediately before surgery with no vitamin K administered reports equivocal findings for transfusion requirements (Category B3-E evidence).¹¹¹ 

Both the consultants and ASA members strongly agree that for urgent reversal of warafin, administer PCCs in consultation with the appropriate specialist, or administer FFP. The ASA members agree and the consultants strongly agree regarding administration of vitamin K for nonurgent reversal of warfarin, except when rapid restoration of anticoagulation after surgery is required.

Meta-analysis of placebo-controlled RCTs indicate that the use of ε-aminocaproic acid administered before and/or during a procedure is effective in reducing total perioperative blood loss and the number of patients transfused in major cardiac, orthopedic, or liver surgery (Category A1-B evidence); equivocal findings are reported for the volume of blood transfused (Category A1-E evidence).^116–125  An RCT comparing ε-aminocaproic acid with placebo reports less blood loss and lower RBC transfusion requirements when ε-aminocaproic acid is administered for prophylaxis of excessive bleeding after total knee replacement surgery and before tourniquet deflation (Category A3-B evidence).¹²⁶ 

Meta-analysis of placebo-controlled RCTs indicate that tranexamic acid for prophylaxis of excessive bleeding administered before and/or during a procedure is effective in reducing perioperative blood loss, the number of patients transfused, and the volume of blood products transfused (CategoryA1-B evidence).^127–150  Randomized trials comparing tranexamic acid with placebo or no tranexamic acid controls report no differences for stroke, myocardial infarction, renal failure, reoperation for bleeding, or mortality (Category A2-B evidence).^151–157 

Meta-analysis of placebo-controlled RCTs indicate that tranexamic acid for prophylaxis of excessive bleeding initiated after a knee and hip arthroplasty and before tourniquet deflation compared with placebo also reported lower blood loss volumes (Category A1-B evidence).^{126,158–163}  One RCT did not show efficacy when tranexamic acid was administered after cardiac surgery and continued for 12 h (Category A3-E evidence).¹⁶⁴ 

The consultants and ASA members both agree regarding use of prophylactic antifibrinolytic therapy to reduce bleeding and the risk of transfusion for patients at risk of excessive bleeding. The consultants and ASA members both agree regarding use of antifibrinolytic therapy to reduce allogeneic blood transfusion in patients undergoing cardiopulmonary bypass. They also both agree regarding the consideration of using antifibrinolytic therapy in other clinical circumstances at high risk for excessive bleeding.

Meta-analyses of RCTs indicate that ANH is effective in reducing the volume of allogeneic blood transfused and the number of patients transfused with allogeneic blood for major cardiac, orthopedic, thoracic, or liver surgery (Category A1-B evidence).^165–178  Additional meta-analyses of RCTs indicate that ANH combined with intraoperative red blood cell recovery compared with intraoperative red blood cell recovery alone is effective in reducing the volume of allogeneic blood transfused (Category A1-B evidence) and is equivocal regarding the number of patients transfused with allogeneic blood (Category A1-E evidence).^179–188 

Both the consultants and ASA members agree regarding use of ANH to reduce allogeneic blood transfusion in patients at high risk for excessive bleeding (e.g., major cardiac, orthopedic, thoracic, or liver surgery), if possible.

• Multimodal protocols or algorithms may be employed as strategies to reduce the usage of blood products. However, no single algorithm or protocol can be recommended at this time.

• A restrictive red blood cell transfusion strategy may be safely used to reduce transfusion administration.^***

  • The determination of whether hemoglobin concentrations between 6 and 10 g/dl justify or require red blood cell transfusion should be based on potential or actual ongoing bleeding (rate and magnitude), intravascular volume status, signs of organ ischemia, and adequacy of cardiopulmonary reserve.

  • Red blood cells should be administered unit-by-unit, when possible, with interval reevaluation.

• A protocol for avoidance of transfusion may be used as a strategy to reduce blood loss for patients in whom transfusion is refused or is not possible.

• A massive (i.e., hemorrhagic) transfusion protocol may be used when available as a strategy to optimize the delivery of blood products to massively bleeding patients.

• Use a maximal surgical blood order schedule, when available and in accordance with your institutional policy, as a strategy to improve the efficiency of blood ordering practices.

• For urgent reversal of warfarin, administer PCCs in consultation with the appropriate specialist, or administer FFP.

• Administer vitamin K for selected patients for nonurgent reversal of warfarin, except when rapid restoration of anticoagulation after surgery is required.

• Use antifibrinolytic therapy for prophylaxis of the use of allogeneic blood transfusion in patients undergoing cardiopulmonary bypass.

  • Consider using antifibrinolytic therapy for prophylaxis in certain orthopedic procedures such as knee replacement surgery.

  • Consider using antifibrinolytic therapy for prophylaxis in liver surgery and other clinical circumstances at high risk for excessive bleeding.^†††

• Consider ANH to reduce allogeneic blood transfusion in patients at high risk for excessive bleeding (e.g., major cardiac, orthopedic, thoracic, or liver surgery), if possible.^‡‡‡

Intraoperative and postoperative interventions include (1) allogeneic red blood cell transfusion, (2) reinfusion of recovered red blood cells, (3) intraoperative and postoperative patient monitoring, and (4) treatment of excessive bleeding.

Transfusion of allogeneic blood includes the topics of (1) the age of stored blood and (2) leukocyte reduction.

Nonrandomized comparative studies are equivocal regarding the effects of newer versus older stored blood on in-hospital mortality, 30-days postdischarge mortality, infectious complications, and length of stay in the intensive care unit or hospital (Category B1-E evidence).^189–198 

The consultants are equivocal and ASA members disagree regarding the administration of blood without consideration of duration of storage.

RCTs are equivocal regarding postoperative infections and infectious complications when leukocyte RBC depletion is compared with nonleukocyte depletion (Category A2-B evidence).^199–205 

The ASA members agree and the consultants strongly agree that leukocyte-reduced blood may be used for transfusion for the purpose of reducing complications associated with allogeneic blood transfusion.

Meta-analyses of RCTs indicate that intraoperative red blood cell recovery compared with conventional transfusion (i.e., nonblood cell recovery) is effective in reducing the volume of allogeneic blood transfused (Category A1-B evidence).^206–217 

RCTs indicate that postoperative blood recovery and reinfusion with recovered red blood cells reduces the frequency of allogeneic blood transfusions (Category A2-B evidence) in patients undergoing major orthopedic surgery.^218–220 

The consultants and ASA members both strongly agree regarding the reinfusion of recovered red blood cells as a blood-sparing intervention in the intraoperative and/or postoperative period.

Intraoperative and postoperative monitoring consists of monitoring for: (1) blood loss, (2) perfusion of vital organs, (3) anemia, (4) coagulopathy, and (5) adverse effects of transfusion.

Blood loss monitoring consists of visual assessment of the surgical field, including the extent of blood present, presence of microvascular bleeding, surgical sponges, clot size and shape, and volume in suction canister.

The literature is insufficient to evaluate the impact of periodically assessing the surgical field for the extent of blood present, the presence of excessive microvascular bleeding (i.e., coagulopathy) or observing surgical sponges, clot size and shape, or the volume of blood in the suction canister to measure blood loss.^§§§

Both the consultants and ASA members strongly agree regarding: (1) periodically conducting a visual assessment of the surgical field jointly with the surgeon to assess the presence of surgical or excessive microvascular (i.e., coagulopathy) bleeding and (2) use of standard methods for quantitative measurement of blood loss including checking suction canisters, surgical sponges, and surgical drains.

Monitoring for perfusion of vital organs includes standard ASA monitoring. Additional monitoring may include echocardiography, renal monitoring (urine output), cerebral monitoring (i.e., cerebral oximetry and near infrared spectroscopy [NIRS]), analysis of arterial blood gasses, and mixed venous oxygen saturation.

The literature is insufficient to evaluate the efficacy of the above monitoring techniques on clinical outcomes associated with blood transfusion.

Both the consultants and ASA members strongly agree regarding: (1) monitoring for perfusion of vital organs using standard ASA monitors (i.e., blood pressure, heart rate, oxygen saturation, electrocardiography) in addition to observing clinical symptoms and physical examination features and (2) that additional monitoring may include echocardiography, renal monitoring (urine output), cerebral monitoring (i.e., cerebral oximetry and NIRS), analysis of arterial blood gasses, and mixed venous oxygen saturation.

Monitoring for anemia includes hemoglobin/hematocrit monitoring.

The literature is insufficient to evaluate the efficacy of perioperative monitoring for anemia.

The consultants and ASA members both strongly agree that if anemia is suspected, monitor hemoglobin/hematocrit values based on estimated blood loss and clinical signs.

Monitoring for coagulopathy includes standard coagulation tests (e.g., INR, activated partial thromboplastin time [aPTT], fibrinogen concentration), as well as platelet count. Additional monitoring for coagulopathy may include tests of platelet function, and viscoelastic assays (e.g., TEG, ROTEM).

An observational study examining point-of-care measurement of aPTT and prothrombin time by a portable laser photometer reports shorter times for obtaining test results with point-of-care monitoring (Category B2-B evidence).²²¹  Significant correlations were reported between photometer and traditional laboratory test findings. An observational study examining platelet count during cardiopulmonary bypass to predict excessive blood loss reports a sensitivity value of 83% and a specificity value of 58% (Category B2 evidence).²²²  An RCT reported equivocal findings for blood loss and transfusion requirements when TEG is compared with standard laboratory coagulation tests (Category A3-E evidence).²²³  An RCT reported equivocal findings with ROTEM versus no fibrinolysis monitoring for RBC, FFP, and platelet transfusion requirements (Category A3-E evidence).²²⁴  Note that TEG and ROTEM-guided algorithms are shown to be effective in reducing blood transfusion requirements (see multimodal protocols or algorithms above). For ROTEM, a sensitivity finding for blood loss was reported to be 13%, specificity values ranged from 52% to 80%, and a positive predictive value of 45% (Category B2 evidence).^225,226  Nonrandomized correlational studies reported significant correlations (P < 0.01) with standard coagulation tests for fibrinogen level and platelet count, whereas correlations between ROTEM and prothrombin time (PT) and aPTT measures were not statistically significant (Category B2 evidence).^227–232 

Both the consultants and ASA members agree that if coagulopathy is suspected, obtain viscoelastic assays (e.g., TEG and ROTEM), when available, as well as platelet count. They both strongly agree that if viscoelastic assays are not available, obtain standard coagulation tests (e.g., INR, aPTT, fibrinogen concentration), as well as platelet count for monitoring.

Monitoring for adverse effects of transfusions includes periodic checking for signs of ABO incompatibility such as hyperthermia, hemoglobinuria, or microvascular bleeding; signs of transfusion-related acute lung injury or transfusion-associated circulatory overload such as hypoxemia, respiratory distress and increased peak airway pressure; signs of bacterial contamination such as hyperthermia and hypotension; signs of allergic reaction such as urticaria; and signs of citrate toxicity such as hypocalcemia (appendix 4).

Nonrandomized comparative studies report higher risk of infection after RBC transfusion (Category B1-H evidence),^233–236  and case reports indicate that adverse outcomes including transfusion-related acute lung injury and delayed hemolytic transfusion reaction may occur after transfusion (Category B4-H evidence).^237–239  The literature is insufficient to recommend specific monitoring practices to identify these adverse transfusion effects.

Both the consultants and ASA members strongly agree that (1) during and after transfusion, periodically check for hyperthermia, hemoglobinuria, microvascular bleeding, hypoxemia, respiratory distress, increased peak airway pressure, urticaria, hypotension, and signs of hypocalcemia and (2) before instituting therapy for transfusion reactions, stop the blood transfusion and order appropriate diagnostic testing.

Intraoperative and postoperative treatment of excessive bleeding includes (1) transfusion of platelets, (2) transfusion of FFP, (3) transfusion of cryoprecipitate, and (4) pharmacologic treatment of excessive bleeding.

Recent literature is insufficient to evaluate the impact of platelet transfusion on resolution of coagulopathy.

The consultants and ASA members both agree regarding obtaining a platelet count before transfusion of platelets, if possible; however, the ASA members agree and the consultants are equivocal regarding obtaining a test of platelet function, if available, in patients with suspected or drug-induced (e.g., clopidogrel) platelet dysfunction.

RCTs report inconsistent findings regarding blood loss and RBC transfusion requirements when FFP transfusion is compared with non-FFP transfusion, (Category A2-E evidence).^240,241 

The consultants and ASA members both agree that, in patients with excessive bleeding, obtain coagulation tests (i.e., PT or INR and aPTT) before transfusion of FFP, if possible.

The literature is insufficient to evaluate the intraoperative or postoperative transfusion of cryoprecipitate to manage actual or potential coagulopathy.

The ASA members agree and the consultants strongly agree that, in patients with excessive bleeding, assess fibrinogen levels before the administration of cryoprecipitate, if possible.

Pharmacologic treatments for excessive bleeding include: (1) desmopressin, (2) antifibrinolytics (i.e., ε-aminocaproic acid, tranexamic acid), (3) topical hemostatics (i.e., fibrin glue, thrombin gel), (4) PCCs, (5) coagulation factor concentrates (recombinant factor VIIa), and (6) treatments for hypofibrinogenemia (cryoprecipitate, fibrinogen concentrate).

Meta-analysis of placebo-controlled RCTs indicate that desmopressin is effective in reducing the volume of postoperative blood loss (Category A1-B evidence).^242–248 

Both the consultants and ASA members agree that, in patients with excessive bleeding and platelet dysfunction, consider the use of desmopressin.

An RCT is equivocal regarding blood loss and RBC transfusion requirements when ε-aminocaproic acid is compared with placebo to treat postoperative blood loss in patients with chest drainage of 100 ml/h or more (Category A3-E evidence).²⁴⁹  The literature is insufficient to evaluate the postoperative administration of tranexamic acid for treatment of excessive blood loss.

The consultants and ASA members both agree that, in patients with excessive bleeding, consider the use of antifibrinolytics (i.e., ε-aminocaproic acid, tranexamic acid), if not already being used.

Meta-analysis of RCTs indicates that fibrin glue is effective in reducing the volume of perioperative blood loss and the number of patients transfused when compared with no fibrin glue (Category A1-B evidence).^250–261  RCTs indicate that thrombin gel is effective in reducing perioperative blood loss and time to hemostasis (Category A2-B evidence).^262–264 

The consultants and ASA members both agree that, in patients with excessive bleeding, consider topical hemostatics such as fibrin glue or thrombin gel.

Observational studies and case reports indicate that intraoperative administration of four-factor PCCs are followed by a reduction in blood loss and normalization of INR values (Category B3/4-B evidence).^265–268 

The consultants and ASA members both agree that, in patients with excessive bleeding and increased INR, consider the use of PCCs.

Meta-analysis of placebo-controlled RCTs of recombinant activated factor VII reports equivocal findings regarding the volume of blood loss, the volume of blood transfused, and the number of patients transfused (Category A1-E evidence).^269–275 

Both the consultants and ASA members agree that, when traditional options for treating excessive bleeding due to coagulopathy have been exhausted, consider administering recombinant activated factor VII.

The literature is insufficient to evaluate the intraoperative or postoperative transfusion of cryoprecipitate to manage hypofibrinogenemia. RCTs comparing fibrinogen concentrate with placebo report a lower volume of RBC transfusion and a reduced frequency of patients transfused when fibrinogen concentrate is administered intraoperatively (Category A2-B evidence).^276,277 

The consultants and ASA members both agree that, in patients with excessive bleeding, consider the use of fibrinogen concentrate.

• Administer blood without consideration of duration of storage.

• Leukocyte-reduced blood may be used for transfusion for the purpose of reducing complications associated with allogeneic blood transfusion.

• Reinfuse recovered red blood cells as a blood-sparing intervention in the intraoperative period, when appropriate.

• Periodically conduct a visual assessment of the surgical field jointly with the surgeon to assess the presence of excessive microvascular (i.e., coagulopathy) or surgical bleeding.

• Use standard methods for quantitative measurement of blood loss, including checking suction canisters, surgical sponges, and surgical drains.

• Monitor for perfusion of vital organs using standard ASA monitors (i.e., blood pressure, heart rate, oxygen saturation, electrocardiography) in addition to observing clinical symptoms and physical exam features.^‖‖‖

  • Additional monitoring may include echocardiography, renal monitoring (urine output), cerebral monitoring (i.e., cerebral oximetry and NIRS), analysis of arterial blood gasses, and mixed venous oxygen saturation.

• If anemia is suspected, monitor hemoglobin/hematocrit values based on estimated blood loss and clinical signs.

• If coagulopathy is suspected, obtain standard coagulation tests (e.g., INR, aPTT, fibrinogen concentration) or viscoelastic assays (e.g., TEG and ROTEM), if available, as well as platelet count.

• During and after transfusion, periodically check for signs of a transfusion reaction including hyperthermia, hemoglobinuria, microvascular bleeding, hypoxemia, respiratory distress, increased peak airway pressure, urticaria, hypotension, and signs of hypocalcemia.

  • If signs of a transfusion reaction are apparent, immediately stop the transfusion, give supportive therapy, and initiate supportive care.

  • Notify the blood bank of the transfusion reaction case.

• In patients with excessive bleeding, the following recommendations are made based upon the evidence for each of these interventions when studied singly or when compared with placebo. The impact of combinations of these interventions is not addressed in these Guidelines.

  • Obtain a platelet count before transfusion of platelets, if possible (see table 1 for suggested transfusion criteria for platelets).^### In addition, obtain a test of platelet function, if available, in patients with suspected or drug-induced (e.g., clopidogrel) platelet dysfunction.

  • Obtain coagulation tests (i.e., PT or INR and aPTT) before transfusion of FFP, if possible (see table 1 for suggested transfusion criteria for FFP).^****

  • Assess fibrinogen levels before the administration of cryoprecipitate, if possible (see table 1 for suggested transfusion criteria for cryoprecipitate).

  • Desmopressin may be used in patients with excessive bleeding and platelet dysfunction.

  • Consider topical hemostatics such as fibrin glue or thrombin gel.

  • Consider the use of antifibrinolytics (i.e., ε-aminocaproic acid, tranexamic acid) if fibrinolysis is documented or suspected and if these agents are not already being used.

  • PCCs may be used in patients with excessive bleeding and increased INR.

  • Consider recombinant activated factor VII when traditional options for treating excessive bleeding due to coagulopathy have been exhausted.^††††

  • Fibrinogen concentrate may be used.

Supported by the American Society of Anesthesiologists and developed under the direction of Jeffrey L. Apfelbaum, M.D., Chair, Committee on Standards and Practice Parameters.

The authors declare no competing interests.