INTRODUCTION — This topic will review general principles guiding intraoperative decisions to transfuse blood products, and the indications and risks for administration of specific components (eg, red blood cells, plasma, platelets, cryoprecipitate). Strategies employed to avoid or minimize perioperative transfusion are discussed separately. (See "Perioperative blood management: Strategies to minimize transfusions".)
Indications for and risks from transfusion of blood products in other settings are addressed in separate topics:
●Red blood cells (adults) (see "Indications and hemoglobin thresholds for red blood cell transfusion in the adult")
●Red blood cells (children) (see "Red blood cell transfusion in infants and children: Indications")
●Plasma (see "Clinical use of plasma components")
●Platelets (see "Platelet transfusion: Indications, ordering, and associated risks")
●Cryoprecipitate (see "Clinical use of Cryoprecipitate")
Management of massive blood transfusion (defined as the need for transfusion of more than three units of RBCs over one hour or more than 10 units in 24 hours) and resultant complications are reviewed in a separate topic. (See "Massive blood transfusion".)
PREPARATIONS FOR LARGE EXPECTED BLOOD LOSSES
Elective surgery with large expected blood loss — For elective surgical cases associated with clinically significant bleeding, the patient's total blood volume and the overall amount and rate of expected blood loss are estimated in the preoperative period in consultation with the surgeon. In some cases, management includes planning for blood conservation techniques such as preoperative autologous blood donation, intraoperative acute normovolemic hemodilution, and/or intraoperative blood salvage to avoid or minimize the need for allogeneic transfusions. Indications, candidate selection, and technical aspects of these surgical blood conservation techniques are discussed separately:
●(See "Surgical blood conservation: Preoperative autologous blood donation".)
●(See "Surgical blood conservation: Acute normovolemic hemodilution".)
●(See "Surgical blood conservation: Blood salvage".)
Preoperative pretransfusion testing (typing and crossmatching) for red blood cells (RBCs) is routinely performed for selected procedures. For cases with the potential for sudden significant blood loss, RBC units should be available in the operating room before the surgical incision (eg, cardiac surgical cases, open repair of abdominal aortic aneurysm, hepatic resection). If a large volume of blood loss is likely, the anesthesiologist should also communicate with the transfusion service to ensure that additional RBC units and other blood products will be readily available, and that there are no risk factors affecting access to additional cross-matched units (eg, unusual blood type or RBC alloantibodies). (See "Pretransfusion testing for red blood cell transfusion".)
Emergency surgery with massive blood transfusion — For patients with hemorrhage requiring massive transfusion and emergency surgery, we employ protocols for ordering appropriate amounts and types of blood components. Typically, RBCs, plasma products such as Fresh Frozen Plasma (FFP), and platelets are ordered and transfused in approximately equal (1:1:1) ratios as soon as these blood products are available, either before and/or during the intraoperative period. Early communication with the institutional blood bank is necessary to activate a massive transfusion protocol. (See "Massive blood transfusion" and "Initial management of moderate to severe hemorrhage in the adult trauma patient", section on 'Severe ongoing hemorrhage'.)
Examples of surgical cases that may require early activation of a massive transfusion protocol include:
●Trauma surgery (see "Massive blood transfusion", section on 'Trauma' and "Coagulopathy in trauma patients")
●Aortic rupture (see "Surgical and endovascular repair of ruptured abdominal aortic aneurysm", section on 'Preparation')
●Obstetrical catastrophes (see "Postpartum hemorrhage: Management approaches requiring laparotomy" and "Postpartum hemorrhage: Medical and minimally invasive management")
TECHNICAL ASPECTS OF BLOOD TRANSFUSION
Venous access — If significant blood loss is anticipated, planning for adequate intravascular access for possible transfusion is necessary. If rapid fluid and blood product administration may be required, large-bore catheters with short lumens should be employed for optimal flow [1,2]. If patient positioning for the planned procedure will create challenges for obtaining additional access, all intravascular catheters should be inserted prior to final positioning, with confirmation of patency after final patient positioning.
Either peripheral or central routes of access may be selected:
●Peripheral venous access – Large-bore (eg, 14 or 16 gauge) peripheral intravenous catheters (or a short 7 French rapid infusion catheter inserted using a modified Seldinger technique) may be selected [3,4]. Peripheral catheters are typically placed in the upper extremities. Compared with a central venous catheter (CVC), peripheral catheters are generally associated with fewer complications. However, large-bore peripheral venous access may not be possible in some patients due to body habitus, vein fragility, or prior use of multiple peripheral veins. (See "Peripheral venous access in adults".)
●Central venous access – In bleeding patients, a single-lumen, large-bore central venous introducer sheath or other CVC with large lumen(s) provides reliable access for blood and fluid administration, as well as central access for vasoactive drug infusions. In patients with poor peripheral venous access, a CVC may be the only durable large-bore intravascular option. Either a multilumen CVC or a large, single-lumen introducer sheath (typically, 8.5 French) may be used. Multilumen catheters have limited flow properties due to long length and smaller lumens, while an introducer sheath allows rapid flow through its single lumen (and may be used for later placement of a pulmonary artery catheter [PAC] if necessary) [5,6]. (See "Central venous access: General principles".)
Filters — All red blood cell (RBC) units, plasma products, and platelets must be transfused through a standard 170 to 260 micron filter (contained as an integral part of a standard infusion set), which is designed to remove clots and aggregates. An add-on filter for leukoreduction may be used for RBC units that were not leukocyte-reduced by the blood supplier. Most units released for transfusion in the United States have already been leukoreduced.
Warming before administration — Cold and previously thawed blood products (eg, RBC units and plasma products) are administered via a blood warmer to avoid hypothermia with resultant coagulopathy and other adverse effects [7-14]. Cryoprecipitate units are thawed to room temperature and should be administered within four to six hours of thawing; use of a blood warmer is unnecessary. Platelets are stored at room temperature and are typically infused via separate administration tubing that is not connected to a blood warmer. However, use of a blood warmer is not prohibited in hypothermic patients [15]. (See "Practical aspects of red blood cell transfusion in adults: Storage, processing, modifications, and infusion", section on 'Administering the transfusion'.)
GENERAL PRINCIPLES FOR TRANSFUSION DECISIONS — The decision to transfuse red blood cells (RBCs) and other blood components is generally based on estimates of the amount of current and expected ongoing blood loss, evidence of intractable microvascular bleeding indicating abnormal hemostasis, and clinical signs of anemia (eg, tachycardia, hypotension, dilute-appearing blood in the surgical field, pallor), ideally with confirmation by diagnostic test results. Further administration of blood products is generally avoided if the hemoglobin concentration has been raised to >9 g/dL and active microvascular and surgical bleeding has ceased.
We prefer a targeted approach to transfusion that is based on point-of-care (POC) laboratory tests and use of an institutional transfusion algorithm or guideline. Goals include minimizing unnecessary transfusion, as well as optimizing treatment of coagulopathy. Frozen products are not thawed unless it is likely that they will be needed. Refrigerated products such as RBCs should be kept cold until a decision has been made to transfuse. Unused blood products are returned to the blood bank for possible use in another patient or appropriate disposal. Blood products should not be transfused to avoid wastage if they are not needed; this would expose the patient to unnecessary risks. (See 'Intraoperative diagnostic testing' below and 'Use of a transfusion algorithm or guideline' below.)
For patients with obvious severe or ongoing hemorrhage due to trauma or other causes, RBCs and other appropriate blood products (ie, plasma and platelets) are transfused as soon as they are available. The target ratio for transfusion of these blood products is approximately 1:1:1 (RBC unit: plasma unit: apheresis platelet unit [one apheresis platelet unit is approximately equivalent to six pooled whole blood derived platelet units]). (See "Massive blood transfusion".)
ASSESSMENT OF BLEEDING — Notably, subjective estimates of blood loss as well as estimates based on formulas that include laboratory measurements may be inaccurate [16-22]. Hence, there is no clear consensus regarding optimal methods for assessment of blood loss or prediction of development of anemia or coagulopathy requiring transfusion of blood products.
Estimates of blood loss are typically based on periodic visual assessment of the surgical field and communication with the surgeon regarding perceived volume and persistence of blood loss, as well as standard quantitative methods (eg, monitoring blood suction canister volumes, number and degree of saturation of surgical sponges and drapes, and blood visualized on the floor of the operating room) and serial laboratory measurements.
Subjective assessment regarding excessive microvascular bleeding at surgical dissection or wound sites may prompt diagnostic testing to determine if administration of blood components or blood derivatives is indicated (eg, plasma, platelets, cryoprecipitate, coagulation factor concentrates). For example, if excessive microvascular bleeding is evident after loss of a large volume of blood, laboratory measurements are typically obtained to confirm quantitative and qualitative abnormalities in hemostatic function. (See 'Indications and risks for specific blood products' below.)
INTRAOPERATIVE DIAGNOSTIC TESTING — Information rapidly derived from intraoperative laboratory tests for anemia and/or coagulopathy allows rational decision-making regarding transfusion of red blood cells (RBCs) and other blood components.
Standard tests — All laboratory tests are considered in the context of the intraoperative clinical situation, and transfusion is generally avoided if the patient is not actively bleeding. Standard laboratory tests include:
●Hemoglobin concentration for transfusion of red blood cells – (See 'Red blood cells' below.)
●Standard coagulation tests – (See 'Plasma' below and "Perioperative management of patients receiving anticoagulants", section on 'Urgent/emergency invasive procedure'.)
●Platelet count – (See 'Platelets' below.)
●Fibrinogen concentration – (See 'Cryoprecipitate' below and "Perioperative blood management: Strategies to minimize transfusions", section on 'Fibrinogen concentrate (versus cryoprecipitate)'.)
The time required for processing and reporting standard coagulation tests, platelet count, and fibrinogen concentration is typically 45 to 90 minutes and may be longer, limiting the utility of this testing in assessment of immediate cause(s) of bleeding and coagulopathy in rapidly changing intraoperative situations.
Point-of-care tests — When available, point-of-care (POC) testing of hemostatic function provides more timely information compared with standard tests, allowing more rapid decision-making regarding the need for targeted transfusion of blood products. In general, POC testing reduces the number of transfused blood products, particularly when used in conjunction with a transfusion algorithm or guideline to standardize blood product management [23-29]. (See 'Use of a transfusion algorithm or guideline' below.)
Hemoglobin or hematocrit measurements — In many institutions, rapid estimates of Hgb or hematocrit are possible using arterial blood gas machines located in or near the operating room. We also use an automated analyzer for POC analysis of complete blood counts. POC instruments to measure hemoglobin are available, but are not as accurate as standard laboratory measurements [30-34].
Overall hemostatic function — POC tests of hemostatic function allow rapid assessment of coagulopathy and responses to interventions (eg, blood product transfusion). We agree with recommendations from the International Society on Thrombosis and Hemostasis regarding use of viscoelastic POC methods such as thromboelastography (TEG), or an adaptation of TEG known as rotational thromboelastometry (ROTEM), to test overall hemostatic function in selected surgical procedures (eg, cardiac and liver transplant surgery) when these tests are available [27,28,35-38]. Meta-analyses of randomized trials in cardiac surgical patients have noted that use of transfusion algorithms guided by viscoelastic testing reduces RBC and platelet transfusions compared with standard care (eg, standard laboratory coagulation tests and/or clinical judgment) [27,39-42]. Also, observational studies suggest that TEG-based algorithms can effectively guide use of blood products and hemostatic support in patients undergoing liver transplant surgery [27,36-38]. However, scant data exist for use of these POC tests during other types of elective surgical procedures [35]. (See "Clinical use of coagulation tests", section on 'Point-of-care testing'.)
TEG-based transfusion of blood products is commonly used to manage the acute coagulopathy associated with trauma, as discussed separately. (See "Coagulopathy in trauma patients", section on 'Thromboelastography' and "Coagulopathy in trauma patients", section on 'Thromboelastography-based transfusion'.)
With TEG or ROTEM tests, a tracing result provides information regarding clot initiation, kinetics of clot formation, clot strength, and fibrinolysis (figure 1 and figure 2 and table 1):
●Primary fibrinolysis (figure 3A-B)
●Secondary hyperfibrinolysis (figure 3A, 3C)
●Thrombocytopenia (figure 3A, 3D)
●Clotting factor consumption (figure 3A, 3E)
●Hypercoagulability (figure 3A, 3F)
Use of a transfusion algorithm or guideline — For stable patients, we prefer use of goal-directed protocols or algorithms to guide transfusion decisions, based on measurement of Hgb or hematocrit as well as assessment of specific abnormalities of hemostasis. Similar recommendations for algorithmic approaches are published in the practice guidelines of several professional societies [43-46]. However, actively bleeding patients cannot be transfused based on hemoglobin values and may require more aggressive transfusion to compensate for ongoing blood loss.
Coagulation test-based transfusion algorithms (eg, TEG-based or ROTEM-based parameters) have been used to guide rapid decision-making, thereby reducing practice variability and unnecessary transfusions of hemostatic blood products such as plasma products, platelets, and cryoprecipitate in several intraoperative settings (eg, cardiac surgery, noncardiac surgery with expected large blood losses, trauma surgery) (table 2) [23,26,46-69]. (See "Clinical use of coagulation tests", section on 'Point-of-care testing' and "Coagulopathy in trauma patients", section on 'Thromboelastography-based transfusion'.)
In a 2016 systematic review that included 1493 patients with significant bleeding and/or coagulopathy during surgery (mostly cardiac), use of TEG- or ROTEM-guided transfusion reduced the proportion of patients transfused with RBCs (risk ratio [RR] 0.86, 95% CI 0.79-0.94), FFP (RR 0.57, 95% CI 0.0.33-0.96), or platelets (RR 0.73, 95% CI 0.60-0.88), compared with transfusion guided by any other method [70]. Overall mortality was also reduced (7.4% versus 3.9%; RR 0.52, 95% CI 0.28-0.95). However, the 15 studies included in this meta-analysis were limited by high risk of bias, large heterogeneity, imprecision, and/or indirectness, and the TEG or ROTEM parameters used in the transfusion algorithm or protocol was institution-specific for each study. A 2017 systematic review with similar limitations involved 8737 patients at risk for coagulopathic bleeding during cardiac surgery (15 trials) [39]. Transfusion based on TEG- or ROTEM-guided algorithms resulted in similar reductions in the frequency of transfusion of RBCs (RR 0.88, 95% CI 0.79-0.97) and platelets (RR 0.78, 95% CI 0.66-0.93) compared with standard care, but mortality was not reduced. No trials have prospectively compared different algorithms.
INDICATIONS AND RISKS FOR SPECIFIC BLOOD PRODUCTS
Red blood cells — We transfuse autologous, salvaged, or allogeneic red blood cells (RBCs) when hemoglobin (Hgb) is <7 to 8 g/dL (approximately equivalent to a hematocrit ≤21 to 24 percent) in most cardiac and noncardiac surgical patients without significant ongoing bleeding. These threshold values are similar to the guidelines of several professional societies [43,44,71,72]. Accurate assessment of a post-transfusion Hgb level can be performed as early as 15 minutes following RBC administration (in the absence of ongoing active bleeding) [73,74]. (See "Indications and hemoglobin thresholds for red blood cell transfusion in the adult", section on 'Orthopedic surgery' and "Indications and hemoglobin thresholds for red blood cell transfusion in the adult".)
We typically use a higher Hgb threshold of <9 g/dL (approximately equivalent to a hematocrit ≤27 percent) in patients who have significant ongoing bleeding, a known acute coronary syndrome, or signs of myocardial or other organ ischemia, particularly during high-risk noncardiac surgery [43,75-78].
Decisions to transfuse should be individualized and broad guidelines should not supersede clinical judgment in decisions regarding transfusion. For example, if a patient is known to tolerate a hemoglobin concentration lower than 8 g/dL, then it may be possible to avoid transfusion. However, there is general consensus that transfusion of packed RBCs is indicated if Hgb <6 g/dL, and that transfusion is rarely indicated if Hgb >10 g/dL [43,72,79,80].
When blood loss is rapid and extensive, immediate life-saving transfusion may be necessary before quantitative laboratory assessment of Hgb can be obtained, based on the rate of bleeding, expected volume of ongoing bleeding, and, if known, the preoperative red cell mass [44,45]. Although Hgb measurements are obtained in such situations, it is recognized that these values will not accurately reflect the degree of reduced red cell mass until a stable euvolemic state has been achieved [81]. If RBC units have not been made available and the need is emergent, the transfusion service can provide "immediate release" blood without pretransfusion testing. (See "Massive blood transfusion", section on 'Approach to volume and blood replacement'.)
Risks of severe anemia versus risks of RBC transfusion — Decisions to transfuse RBCs weigh risks of anemia against the risks associated with transfusion such as infection or transfusion reactions. The balance depends on underlying patient factors.
Risks of severe anemia are well-known [82-84]. For example, in one study of patients who refused postoperative transfusion, mortality was 21 percent in those with an Hgb nadir of 6.1 to 7 g/dL, but increased to 41 percent in those with a lower Hgb nadir of 5.1 to 6 g/dL [82]. Blood loss impacts oxygen delivery to vital organs because of both reduced cardiac output (CO) due to hypovolemia as well as reduced oxygen carrying capacity due to anemia. Physiologic compensatory responses include augmentation of CO and increased oxygen extraction from available RBCs due to a shift in the oxyhemoglobin dissociation curve. The ability of an individual patient to adequately compensate for hypovolemia and anemia depends on the presence and severity of cardiopulmonary disease and other comorbid conditions. (See "Indications and hemoglobin thresholds for red blood cell transfusion in the adult", section on 'Rationale for transfusion'.)
Most trials in surgical patients comparing a restrictive transfusion threshold (typically defined as Hgb <7 or <8 g/dL) with a liberal transfusion threshold (typically defined as Hgb <9 or <10 g/dL) have found that use of a restrictive threshold reduced the number of RBC transfusions without increasing the incidence of adverse events [85-97]. In addition, a large retrospective study noted that perioperative transfusion of at least one RBC unit in approximately 41,000 of 1.5 million patients more than doubled the risk for stroke or myocardial infarction (odds ratio [OR] 2.33, 95% CI 1.90-2.86); this study excluded surgical patients undergoing procedures with high risk of blood transfusion and morbidity (ie, cardiac, vascular, and intracranial procedures) [98]. These trials are summarized in more detail separately. (See "Indications and hemoglobin thresholds for red blood cell transfusion in the adult", section on 'Overview of our approach'.)
However, in surgical patients with severe ischemic heart disease or limited cardiopulmonary reserve, data regarding transfusion thresholds are equivocal. In a 2016 systematic review of patients undergoing cardiac or vascular procedures, a restrictive transfusion strategy showed a trend toward increased risk for mortality (risk ratio [RR] 1.39, 95% CI 0.95-2.04) and inadequate tissue oxygen supply (defined as myocardial, cerebral, renal, mesenteric, or peripheral ischemic injury; RR 1.09, 95% CI 0.97-1.22), compared with a liberal transfusion strategy [99].
Although we employ a restrictive transfusion strategy in both cardiac and noncardiac surgical patients using the thresholds noted above, we minimize anemia-induced risks by employing intraoperative monitoring for signs of myocardial ischemia (eg, ischemic changes noted on the electrocardiogram [ECG], pulmonary artery catheter [PAC], or with transesophageal echocardiography [TEE]), or evidence of other organ ischemia such as decreased urine output, decreased mixed venous oxygen saturation, or increased lactate levels in an anemic patient with coronary artery disease or limited cardiopulmonary reserve, or a decrease in regional cerebral oxygen saturation (rSO2) in a neurocritically ill patient [43,75,76,85,100]. (See "Anesthesia for noncardiac surgery in patients with ischemic heart disease", section on 'Monitoring for myocardial ischemia' and "Intraoperative management for noncardiac surgery in patients with heart failure", section on 'Monitoring'.)
Risks of RBC transfusion are noted below (see 'Risks of blood product transfusion' below). In addition, hypokalemia may occur rarely.
Platelets
●Indications – Platelet transfusions are a component of massive transfusion protocols. (See "Massive blood transfusion", section on 'Dilutional coagulopathy'.)
We administer platelet transfusions as a component of massive transfusion protocols. In surgical patients, we typically maintain platelet count >50,000/microL, or >100,000/microL when central nervous system bleeding is present or likely [101]. We typically avoid prophylactic platelet transfusions in patients with counts below these thresholds (unless they are excessively low) who are not bleeding [102], unless the risk of even minor bleeding is significant (eg, ophthalmic or neurosurgery) or the planned surgical procedure is likely to result in significant bleeding (eg, major surgery). (See "Platelet transfusion: Indications, ordering, and associated risks", section on 'Actively bleeding patient'.)
Importantly, abnormalities of platelet function affect hemostasis even if platelet count is adequate. Thus, the platelet transfusion threshold may be higher (typically >100,000/microL) in a surgical patient with microvascular bleeding when qualitative platelet defects are strongly suspected or noted on platelet function tests [101]. Qualitative platelet defects may be caused by use of antiplatelet agents that inhibit cyclooxygenase, glycoprotein IIb/IIIa, and/or adenosine diphosphate (ADP), as well as by uremia, hypothermia, acidosis, or hyperfibrinolysis due to disseminated intravascular coagulation (DIC), trauma, malignancy, liver transplantation or failure, or cardiopulmonary bypass (CPB). (See "Platelet transfusion: Indications, ordering, and associated risks", section on 'Specific clinical scenarios'.)
●Preparations – Platelets are administered as an apheresis platelet pack harvested from a single donor or as pooled units of whole blood derived platelets (typically manufactured from whole blood donations from four to six different donors). One apheresis unit is equivalent to four to six pooled platelet units. Although exact platelet quantities vary, each platelet dose (ie, one apheresis unit or a pool of whole blood derived platelets) contains approximately 3 to 4 x 1011 platelets suspended in 200 to 300 mL of plasma and will increase the platelet count by approximately 30,000/microL to 50,000/microL in a non-bleeding adult (table 3). (See "Platelet transfusion: Indications, ordering, and associated risks", section on 'Whole blood derived (WBD) versus apheresis platelets'.)
●Risks – Risks of platelet transfusion are noted below (see 'Risks of blood product transfusion' below). Notably, the incidence of bacterial infection is higher with platelet transfusion compared with other blood products due to storage at room temperature. Rarely, post-transfusion purpura may occur.
Plasma
●Indications – Plasma products such as Fresh Frozen Plasma (FFP) or Plasma Frozen within 24 Hours of Collection (PF24) are a component of massive transfusion protocols. (See "Massive blood transfusion", section on 'Definitions and jargon' and "Massive blood transfusion", section on 'Dilutional coagulopathy'.)
Other intraoperative uses include emergency surgery in patients with severe bleeding or anticipated severe bleeding, particularly if intracranial hemorrhage is present (table 3 and table 4), and/or if there are suspected or documented severe abnormalities on standard coagulation tests (eg, international normalized ratio [INR] >2.0) with evidence of reduced clotting factor activity (which may be due to consumption or other causes of deficiency) on point-of-care (POC) tests (figure 3A, 3E). (See 'Standard tests' above and 'Overall hemostatic function' above.)
Specific examples of emergency intraoperative situations in which plasma products may be necessary are discussed in other topics:
•Replacement of deficient coagulation factors – (See "Clinical use of plasma components", section on 'Overview of indications'.)
•Reversal of warfarin, if a prothrombin complex concentrate (PCC) is not available or cannot be given – (See "Perioperative management of patients receiving anticoagulants", section on 'Urgent/emergency invasive procedure' and "Management of warfarin-associated bleeding or supratherapeutic INR", section on 'Urgent surgery/procedure'.)
In patients requiring immediate reversal of anticoagulation due to warfarin in preparation for urgent surgery, a four-factor prothrombin complex concentrate (PCC) should be used (see "Perioperative blood management: Strategies to minimize transfusions", section on 'Prothrombin complex concentrate'). However, FFP may be used if neither four-factor nor three-factor PCC products are available (eg, in a resource-limited setting).
In contrast to these indications, plasma products are not administered to stable nonbleeding patients solely to "correct" a mildly elevated INR (eg, INR up to 2) [103]. The rationale is discussed separately. (See "Clinical use of plasma components", section on 'Settings in which plasma is not appropriate'.)
Notably, FFP contains approximately 2 to 3 mg/mL of fibrinogen. (See "Perioperative blood management: Strategies to minimize transfusions", section on 'Fibrinogen concentrate (versus cryoprecipitate)'.)
●Risks – Risks of FFP transfusion are noted below (see 'Risks of blood product transfusion' below). Plasma remains the most commonly ordered and transfused hemostatic agent in the world, despite these risks and the lack of evidence of efficacy to support its use in most situations, as well as several published professional society guidelines that recommend only the limited indications noted above [43,104-109]. Risk of transfusion-related acute lung injury (TRALI) has decreased due to implementation of mitigation practices (ie, preferential or exclusive use of male plasma for transfusion).
Cryoprecipitate
●Indications – Cryoprecipitate is used to treat hypofibrinogenemia during massive transfusion, especially in a bleeding surgical patient who has known low fibrinogen concentrations <50 to 100 mg/dL or when fibrinogen cannot be measured in a timely fashion (table 3) [43,110-112]. Abnormally low concentrations of fibrinogen can result in impaired clot formation and increased bleeding. (See "Clinical use of Cryoprecipitate", section on 'Clinical uses'.)
Cryoprecipitate is used by some clinicians to treat life-threatening intraoperative bleeding in patients with:
•Uremic bleeding (see "Uremic platelet dysfunction")
•Hepatic insufficiency with active bleeding, particularly with a low fibrinogen concentration (see "Hemostatic abnormalities in patients with liver disease", section on 'Bleeding')
A single unit of Cryoprecipitate contains most of the fibrinogen (factor I), factor VIII, factor XIII, von Willebrand factor (VWF), and fibronectin derived from one unit of FFP (table 5). Each unit has a small volume of 5 to 20 mL and contains the following protein quantities:
•Fibrinogen – >150 mg (range is 150 to 250 mg); half-life is 100 to 150 hours
•Factor VIII – >80 international units (range is 80 to 150 units); half-life is 12 hours
•Factor XIII – 50 to 75 units; half-life is 150 to 300 hours
•von Willebrand factor – 100 to 150 units; half-life is 24 hours
The typical Cryoprecipitate transfusion dose, as received from the blood bank, is a pooled product that has been prepared by combining individual Cryoprecipitate units derived from 5 to 10 blood donors in a volume of 50 to 200 mL.
●Risks — Risks of Cryoprecipitate transfusion are noted below (see 'Risks of blood product transfusion' below). These risks are similar to those for FFP, although transfusion-related circulatory overload (TACO) is less likely with Cryoprecipitate. In some settings, clinical use of Cryoprecipitate has declined or become obsolete due to the availability of products with lower risk (eg, specific coagulation factor concentrates, fibrinogen concentrates, recombinant factor products).
RISKS OF BLOOD PRODUCT TRANSFUSION — Potential complications of transfusion of blood products such as red blood cells (RBCs), platelets, Fresh Frozen Plasma (FFP), and less commonly Cryoprecipitate include hemolytic transfusion reactions, febrile non-hemolytic transfusion reactions (FNHTRs), transfusion-related acute lung injury (TRALI) [113], transfusion-related circulatory overload (TACO), transfusion-transmissible infections (bacterial, viral, or parasitic (table 6)), transfusion-associated graft-versus-host disease (ta-GVHD), and transfusion-related immunomodulation that may lead to postoperative infection [114]. These complications are discussed elsewhere:
●(See "Platelet transfusion: Indications, ordering, and associated risks", section on 'Complications'.)
●(See "Clinical use of plasma components", section on 'Risks'.)
●(See "Clinical use of Cryoprecipitate", section on 'Risks and adverse events'.)
The approach to a patient with an acute transfusion reaction is discussed separately. Cognitive aids are available for perioperative management of transfusion reactions, including rare life-threatening events such as transfusion-associated respiratory distress [115,116]. (See "Approach to the patient with a suspected acute transfusion reaction".)
Additional details are available in separate topics discussing specific complications of transfusion therapy:
●(See "Immunologic transfusion reactions".)
●(See "Transfusion-related acute lung injury (TRALI)".)
●(See "Transfusion-associated circulatory overload (TACO)".)
●(See "Transfusion-transmitted bacterial infection".)
●(See "Blood donor screening: Laboratory testing", section on 'Viruses'.)
●(See "Transfusion-associated graft-versus-host disease".)
Massive transfusion may result in additional complications (eg, citrate toxicity with hypocalcemia, hyperkalemia, acidosis, hypothermia), which are discussed separately. (See "Massive blood transfusion".)
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
Preparations for surgical blood losses - Preparations for anticipated large intraoperative blood losses include (see 'Preparations for large expected blood losses' above):
•Elective surgery – For elective surgery with large expected blood loss, we determine whether preoperative typing and crossmatching is necessary, and whether blood products should be available in the operating room before incision. (See 'Elective surgery with large expected blood loss' above.)
•Emergency surgery – For emergency surgery requiring massive transfusion, we order and begin transfusion of red blood cell (RBC) units, fresh frozen plasma (FFP), and platelets in approximately equal (1:1:1) ratios. (See 'Emergency surgery with massive blood transfusion' above.)
●Technical aspects of intraoperative blood transfusion
•Establish adequate venous access – Planning for adequate peripheral or central intravascular access for possible transfusion is necessary if significant blood loss is anticipated. (See 'Venous access' above.)
•Use filters – Administration through a standard 170 to 260 micron filter to remove clots and aggregates. An add-on filter for leukoreduction may be used for RBC units that were not leukocyte-reduced by the blood supplier. (See 'Filters' above.)
•Use a blood warmer – Cold and previously thawed blood products (eg, RBC units, plasma products) are administered via a blood warmer to avoid hypothermia with resultant coagulopathy and other adverse effects. (See 'Warming before administration' above.)
●Assessment of blood losses – Estimates of blood loss are typically based on periodic visual assessment of the surgical field, communication with the surgeon regarding perceived volume and persistence of blood loss, quantitative methods (eg, monitoring blood suction canister volumes, number and degree of saturation of surgical sponges and drapes, and blood visualized on the floor of the operating room), and serial laboratory measurements. (See 'Assessment of bleeding' above.)
●Intraoperative laboratory testing – Testing for anemia and/or coagulopathy allows rational decision-making regarding transfusion of RBCs and other blood components. This includes (see 'Intraoperative diagnostic testing' above):
•Standard tests- Hemoglobin (Hgb) measurements and standard tests of hemostatic function (eg, prothrombin time [PT] with international normalized ratio [INR], activated partial thromboplastin time [aPTT], platelet count, fibrinogen concentration). (See 'Standard tests' above.)
•Point-of-care (POC) tests – POC tests of overall hemostatic function (eg, thromboelastography [TEG] or rotational thromboelastometry [ROTEM]) for rapid assessment of causes of coagulopathy and responses to interventions (figure 1 and figure 2 and table 1 and table 2). (See 'Overall hemostatic function' above.)
●Transfusion decisions – Decisions to transfuse RBCs and other blood components (table 3) are generally based on estimates of the amount of current and expected ongoing blood loss and clinical signs of anemia or intractable microvascular bleeding indicating abnormal hemostasis, ideally with confirmation by with diagnostic test results. We prefer use of protocols or algorithms to guide transfusion decisions based on measurement of Hgb and hemostatic function. For patients with significant coagulopathic bleeding, we suggest use of TEG- or ROTEM-based POC tests (if available) to guide algorithm-based decision-making and reduce transfusions, rather than standard coagulation assays (Grade 2B). (See 'General principles for transfusion decisions' above and 'Use of a transfusion algorithm or guideline' above.)
●Restrictive strategy for RBC transfusion – We suggest using a restrictive transfusion strategy to transfuse autologous, salvaged, or allogeneic RBCs for Hgb <7 to 8 g/dL in most surgical patients who do not have significant ongoing bleeding (Grade 2B). However, we typically use a higher Hgb threshold (eg, <9 g/dL) in patients with evidence of myocardial or other organ ischemia to avoid end-organ injury, as well as those with significant ongoing bleeding to avoid rapid development of severe anemia. (See 'Red blood cells' above.)
●Platelet transfusion – We administer platelet transfusions as a component of massive transfusion protocols. In surgical patients, we typically maintain platelet count >50,000/microL, or >100,000/microL when central nervous system bleeding is present or likely. Although exact platelet quantities vary, each platelet dose (ie, one apheresis unit or a pool of whole blood derived platelets) contains approximately 3 to 4 x 1011 platelets suspended in 200 to 300 mL of plasma and will increase the platelet count by approximately 30,000/microL to 50,000/microL in a non-bleeding adult (table 3). Risk of bacterial infection is higher compared with other blood components since platelets are stored at room temperature. (See 'Platelets' above.)
●Plasma transfusion – We administer plasma products such as Fresh Frozen Plasma (FFP) as a component of massive transfusion protocols. Other indications include emergency surgery in patients with severe bleeding or anticipated severe bleeding if there are deficiencies of multiple coagulation factors, particularly if intracranial hemorrhage is present (table 3 and table 4). (See 'Plasma' above.)
●Cryoprecipitate transfusion – We transfuse Cryoprecipitate to treat hypofibrinogenemia in massive transfusion protocols when fibrinogen cannot be measured in a timely fashion, and in bleeding surgical patients with known fibrinogen concentrations <50 to 100 mg/dL, or an inherited disorder of fibrinogen (table 3). Cryoprecipitate has also been used to treat life-threatening intraoperative bleeding in patients with disseminated intravascular coagulation (DIC), hepatic insufficiency, or uremia (table 5). (See 'Cryoprecipitate' above.)
●Risks of transfusion – Complications of transfusion (eg, infection (table 6)) and the approach to the patient with a suspected acute transfusion reaction are discussed in separate topic reviews. (See 'Risks of blood product transfusion' above and "Approach to the patient with a suspected acute transfusion reaction".)
