Protocol: Blood Utilization in Cardiac Surgery

Supportive Data

Perioperative bleeding, while universal after cardiac surgery, remains complex and is poorly defined. Current literature supports general strategies to maintain hemostasis and avoid transfusion, with sparse evidence to guide specific management in this population. While there is general agreement that blood transfusion poses adverse risks, severe anemia/hemorrhage may be fatal and the timely use of blood products, possibly in combination with hemostatic factors, can be life-saving. Additionally, a variety of clinicians including surgeons, anesthesiologists, perfusionists, intensivists, and nurses can impact these decisions. The multidisciplinary approach to perioperative blood management for cardiac surgical patients at CPMC is outlined below.

Policy Statement

1. Patient risk for bleeding and transfusion varies significantly. Patients at highest risk for transfusion include those who are elderly, have reduced red cell volume (low hematocrit and/or small BSA), or are undergoing emergent/complex procedures. Patients receiving anticoagulant or anti-platelet medications preoperatively are also at high risk for bleeding, and surgery may be delayed in such patients based on a risk-benefit analysis by the surgeon.
2. Standardization of practices to avoid intraoperative hemodilution and conserve red cell volume will be employed including conservative perioperative crystalloid administration, avoidance of cardiac catheterization during the same admission as surgery, perioperative administration of tranexemic acid, and use of topical hemostatic agents, as appropriate.
3. Additional perfusion strategies will be used, as appropriate, to facilitate hemoconcentration via the cardiopulmonary bypass circuit and optimize heparin management.
4. Patients who refuse blood transfusion merit special attention to conserve red cell volume; strategies may include preoperative use of EPO, autotransfusion of chest tube drainage, and conservative blood withdrawal for laboratory assessments in these patients.
5. An appropriate RBC transfusion “trigger” will vary by patient. It is generally appropriate to forgo a transfusion for a Hgb > 8 gm/dl in stable, non-bleeding patients. For patients who are actively bleeding or display symptoms of anemia, a higher threshold will be used, as appropriate.
6. For patients with clinically significant bleeding in the OR or ICU, use of blood products and/or hemostatic factors should be administered per surgeon request based on appropriate use criteria below.

Procedures

For patients with active hemorrhage, a step-wise approach will be used to proactively manage bleeding. Intraoperatively, the surgeon will determine the appropriate management approach and coordinate decisions regarding the administration of blood products and/or hemostatic factors. Upon arrival in the ICU, the surgeon will direct the intensivist and nurse practitioner team regarding goals of care and blood management strategies to be utilized. The surgeon should be notified immediately of the presence of significant bleeding (>200 mL/hr or > 100 mL/hr x 3 consecutive hours).

1. Regardless of patient location, the onset of clinically significant bleeding, defined as hemorrhage > 150 mL/min, warrants activation of CPMC’s Massive Blood Transfusion order set and notification of the blood bank to ensure the timely, ongoing release of needed blood products until this order is canceled.
2. The early administration of plasma, in adequate amounts to counteract hemodilution, consumption, and fibrinolysis, has been shown to improve outcomes. Suggested regimens include an initial cycle of blood products in ratios of 4 PRBC/4 FFP/1 platelet pheresis units, followed by reassessment of clinical bleeding and coagulation parameters, as time allows. This regimen achieves replacement of approximately 70% of RBC volume and 60% of circulating plasma volume for a 70-kg patient. Although laboratory-guided component therapy is optimal, time delays in obtaining these results may limit the utility of this tool for clinical decision making.
3. For continued hemorrhage, a second cycle of blood products in the same ratio should be considered without delay, with the addition of cryoprecipitate (10 units) and/or hemostatic factors as indicated below.
4. The off-label use of prothrombin complex concentrates (PCC) or recombinant factor VIIa (rVIIa) may be used for severe bleeding that is refractory to an initial cycle of blood product replacement. This decision is made by the surgeon or intensivist after weighing the potential thrombotic risks vs benefits in the presence of profound bleeding. Although expensive, these factors offer the advantage of more rapid administration and onset with significantly less fluid volume than blood products, while avoiding additional blood exposures and their well-documented risks. 4 Factor PCC (KCentra) contains factors II, IX, X and inactivated VII and is indicated for moderately severe, refractory bleeding. One vial of KCentra = 500 or 1000 units; recommended dosage is 1000 u administered via dedicated IV line at a rate < 210 u/min. Redosing is not recommended.
5. rVIIa (Novoseven RT) is indicated for severe, refractory, life-threatening bleeding. One vial of rVIIa = 1 mg; recommended dosage is 3-4 mg. Re-dosing may be considered if significant bleeding persists.
6. In the presence of significant bleeding with normal coagulation parameters, surgical causes for bleeding should be investigated and return to the operating room should occur without delay. Distribution: Operating room, intensive care, anesthesia, cardiology

References

1. Alfirevic A, Duncan A, Jing Y, et al. Recombinant factor VII is associated with worse survival in complex cardiac surgical patients. Ann Thorac Surg 2014;98:618-624.
2. Carson JL, Noveck H, Berline JA, Gould SA. Mortality and morbidity in patients with very low postoperative Hb levels who decline blood transfusion. Transfusion 2002;42:812-818.
3. Carson JL, Brooks MM, Abbott JD, et al. Liberal versus restrictive transfusion thresholds for patients with symptomatic coronary artery disease. Am Heart J 2013;164\5:964-971.
4. Clark KB, Kon ND, Hammon JW, et al. Factor IX complex for the treatment of severe bleeding after cardiac surgery. J Cardiovasc Pharmacol 2013;62(1):67-71.
5. Dyke C, Aronson S, Dietrick W, et al. Universal definition of perioperative bleeding in adult cardiac surgery. J Thorac Cardiovasc Surg 2013;1-6.
6. Goodnough LT, Levy JH. Off-label use of recombinant human factor VIIa (editorial). Ann Thorac Surg 2014;98:393-395.
7. Logan AC, Goodnough LT. Recombinant factor VIIa: an assessment of evidence regarding its efficacy and safety in the off-label setting. Hematology 2010;153-159.
8. Sorensen B, Spahn DR, Innerhofer P, et al. Clinical review: prothrombin complex concentrates – evaluation of safety and thrombogenicity. Critical Care 2011;15:201-210.
9. Young PP, Cotton BA, Goodnough LT. Massive transfusion protocols for patients with substantial hemorrhage. Transfus Med Rev 2011;25(4):293-303.

This protocol is provided by Jill Ley and the California Pacific Medical Center (CPMC).