Authors: Amanpreet Kalsi, MBBS, FRCA AND Amy Babb, MD - Monroe Carell Jr. Children's Hospital at Vanderbilt - Vanderbilt University Medical Center
A teenage patient requests all efforts be made to avoid blood product transfusion during cardiac surgery. Which of these strategies is MOST likely to result in a transfusion?
EXPLANATION
Transfusion of blood products is often unavoidable in pediatric cardiac surgery due to patient size and type of surgery as well as need to increase oxygen carrying capacity, optimize circulating volume and address coagulation deficiencies. Unfortunately, use of blood products is also associated with numerous adverse effects, including transmission of pathogens, immune mediated reactions (such as TRALI or hemolytic reactions), alloimmunization, circulatory overload and metabolic derangements. In addition, hemodilution during cardiopulmonary bypass (CPB) may cause dilutional anemia and coagulopathy resulting in the need for transfusion of packed red blood cells (pRBC) and fresh frozen plasma (FFP) to maintain a minimum hematocrit and appropriate coagulation factor levels.
Patient blood management programs use several strategies aimed at blood conservation and transfusion reduction during the perioperative period.1 Efforts to limit the CPB circuit and prime volume may reduce the need for transfusion. In 2013, Richmond et al. noted that CPB circuit volume was independently associated with increased transfusion requirements; even modest increases in circuit volume by 10-20 ml were shown to have a significant impact.2
Another strategy in cardiac surgery is acute normovolemic hemodilution (ANH) which involves intraoperative autologous blood harvest prior to cardiopulmonary bypass. The autologous whole blood is then stored in bags containing citrate-phosphate-dextrose (CPD) to be subsequently returned to the patient after termination of CPB. This technique keeps a small amount of the patient’s own blood from exposure to the bypass circuit, thus preserving coagulation factors and platelet function, as well as reducing the need for donor pRBC.3 Retrograde autologous priming (RAP) of the cardiopulmonary bypass circuit is another approach used to mitigate blood transfusion.4 With this technique, the patient’s own blood is used to displace the crystalloid in the arterial and venous lines immediately prior to CPB initiation, thereby reducing the hemodilution effect of retaining the crystalloid volume in the circuit.
In this case, increasing CPB circuit volume will obviously lead to hemodilution and potential need for more blood products, whereas retrograde autologous priming and acute normovolemic hemodilution are blood conservation techniques. Understanding and implementing available blood conservation strategies may help decrease overall transfusion in select patients.
REFERENCES
1. Sebastian R, Ahmed MI. Blood Conservation and Hemostasis Management in Pediatric Cardiac Surgery. Frontiers in Cardiovascular Medicine. 2021 Aug 19;8:689623. DOI=10.3389/fcvm.2021.689623. PMID: 34490364.
2. Richmond ME, Charette K, Chen JM, Quaegebeur JM, Bacha E. The effect of cardiopulmonary bypass prime volume on the need for blood transfusion after pediatric cardiac surgery. J Thorac Cardiovasc Surg. 2013 Apr;145(4):1058-1064. doi: 10.1016/j.jtcvs.2012.07.016. Epub 2012 Aug 3. PMID: 22867689.
3. Sebastian R, Ratliff T, Winch PD, et al. Revisiting acute normovolemic hemodilution and blood transfusion during pediatric cardiac surgery: a prospective observational study. Paediatr Anaesth. 2017 Jan;27(1):85-90. DOI: 10.1111/pan.13014. PMID: 27734554.
4. Singab H, Gamal MA, Refaey R, Al-Taher W. Effect of Retrograde Autologous Blood Priming of Cardiopulmonary Bypass on Hemodynamic Parameters and Pulmonary Mechanics in Pediatric Cardiac Surgery: A Randomized Clinical Study. Semin Thorac Cardiovasc Surg. 2021 ;33(2):505-512. doi: 10.1053/j.semtcvs.2020.09.006. Epub 2020 Sep 23. PMID: 32977015.
