Chapter 21 Blood Therapy
Blood therapy procedures
1. What is the recipient’s blood tested for during the routine typing of blood? What is the risk of transfusing blood to patients without typing the recipient’s blood?
2. How is the crossmatching of blood accomplished?
3. How does the transfusion of O-negative packed red blood cells in an emergency situation affect the patient’s subsequent transfusions?
4. What does type-specific blood refer to? What is the chance of a significant hemolytic reaction with the transfusion of type-specific blood to a patient?
5. What does a type and screen refer to? When is a type and screen typically ordered? What is the chance of a significant hemolytic reaction with the transfusion of typed and screened blood to a patient?
6. What is contained in preservative solutions for the storage of blood? What is the benefit of adding adenine to the preservative solution?
Blood components
11. Name the components that can be derived from whole blood. What is the advantage of using components for blood therapy instead of whole blood?
12. What is the hematocrit and total volume in a unit of packed red blood cells?
13. How much will hemoglobin concentration increase with the transfusion of a single unit of packed red blood cells?
14. What is the indication for the administration of packed red blood cells?
15. What solutions may be used to reconstitute packed red blood cells for administration?
16. What potential complication associated with the administration of whole blood is less likely to occur with the administration of packed red blood cells?
17. What is the advantage of using whole blood for massive blood loss replacement?
18. What is the recommended ratio of packed red blood cells to fresh frozen plasma and platelets when transfusing for massive blood loss replacement?
19. When is the administration of platelets indicated during surgery?
20. How much will the platelet count increase after the administration of 1 unit of platelets?
21. What are some of the risks associated with the administration of platelets?
22. What is fresh frozen plasma? What is contained in fresh frozen plasma?
23. When is the administration of fresh frozen plasma indicated during surgery?
24. What is cryoprecipitate? What is contained in cryoprecipitate?
Complications of blood therapy
26. Name some potential complications of blood therapy.
27. What is the risk of the transmission of infectious diseases with the transfusion of blood?
28. What are the various types of transfusion reactions that may occur with blood therapy?
29. Why are febrile transfusion reactions thought to occur? How do febrile transfusion reactions manifest?
30. How are febrile transfusion reactions treated?
31. Why are allergic transfusion reactions thought to occur? How do allergic transfusion reactions manifest?
32. How are allergic transfusion reactions treated? How are allergic transfusion reactions distinguished from hemolytic transfusion reactions?
33. Why are hemolytic transfusion reactions thought to occur?
34. What are the clinical signs that a hemolytic transfusion reaction has occurred? Which of these are masked by anesthesia?
35. What diagnostic tool provides evidence that a hemolytic transfusion reaction has occurred?
36. What are some consequences that can follow a hemolytic transfusion reaction?
37. What is the treatment for a hemolytic transfusion reaction?
38. What is transfusion-related acute lung injury (TRALI)?
39. Describe the immunosuppression that may accompany blood transfusions.
40. What are some metabolic abnormalities that may accompany blood transfusions?
41. How much does the serum potassium level increase in patients after the transfusion of blood?
42. How do concentrations of 2,3-diphosphoglycerate change with the prolonged storage of blood? How does this affect oxygen delivery to the tissues?
43. How does the administration of citrate in blood products affect the recipient’s serum calcium concentration?
44. What is the potential risk of hypothermia with the administration of blood products?
45. What are some ways in which massive blood transfusions can result in coagulation disorders?
46. What is dilutional thrombocytopenia? What is the treatment of dilutional thrombocytopenia?
47. Which clotting factors may decrease in concentration in the patient’s blood with massive transfusions? What percent of each of these clotting factors is necessary to maintain hemostasis during surgery? How can this clotting factor deficiency be treated?
Autologous blood transfusions
48. What is the advantage of the administration of autologous blood over homologous blood for necessary blood transfusions?
49. What is an acceptable schedule for the collection of predeposited blood for autologous blood transfusion? How can anemia secondary to the donation of autologous blood be minimized?
50. What are some complications that can occur with autologous blood transfusions of predeposited blood?
51. How is the intraoperative salvage of blood for autologous blood transfusions accomplished? What are some relative contraindications to the intraoperative salvage of blood?
52. What are some complications that may accompany the intraoperative salvage of blood for autologous blood transfusions?
53. What is the hemodilution technique for autologous blood transfusions? What are some advantages of this technique?
Answers*
Blood therapy procedures
1. Routine typing of the recipient’s blood tests for the presence of A or B or both A and B antigens on the recipient’s red blood cells and for the presence of anti-A or anti-B antibodies in their serum. It also tests for the presence or absence of Rh(D) antigen on the red blood cell. The purpose of typing the recipient’s blood is to avoid the transfusion of incompatible blood to the recipient. This may occur if the patient has antibodies to A or B or to A and B in their serum and they are transfused red blood cells that have the corresponding antigen on the red blood cells. Likewise, if a recipient lacks the Rh(D) antigen, the transfusion of the Rh(D)+ blood would be incompatible. The risk of transfusing patients who have not had this typing done, or who have had it done incorrectly and the blood is incompatible, is a transfusion reaction. In this case, the transfusion would result in disastrous, rapid intravascular hemolysis. (372-373)
2. Crossmatching of blood is done to test for a serious transfusion reaction before the administration of the blood to the recipient. A crossmatch test is accomplished by incubating the recipient’s plasma with the donor’s red blood cells. There are three steps to the process, which in its entirety takes about 45 minutes to perform. The first phase is the immediate phase, in which the blood is tested for ABO compatibility at room temperature. It also tests for incompatibilities in the M, N, P, and Lewis groups. The second phase is the incubation phase, which tests for the presence of antibodies at 37° C. Albumin or a low ionic strength saline solution is added to the products of the first phase to cause the agglutination of weak or incomplete antibodies that are present. The last phase is the antiglobulin phase, in which antiglobulin is added to the products of the second phase. Incomplete antibodies in the Rh, Kell, Duffy, and Kidd systems will be detected by this step. In each phase, incompatible blood will result in agglutination during the crossmatch test. (372-373)
3. In emergency situations in which acute large blood loss requires rapid administration of blood, there may be inadequate time to perform a type-and-cross or even to wait for type-specific blood. In these situations, O-negative packed red blood cells are administered because they lack the A, B, and Rh(D) antigens. O-negative red blood cells cannot be hemolyzed by anti-A or anti-B antibodies that may be present in the patient’s blood and is therefore termed the universal donor. After the administration of 2 units of O-negative packed red blood cells, subsequent blood transfusions may have to be continued with O-negative blood. The concern is that the transfusion of blood that is the patient’s type may result in major intravascular hemolysis of donor red blood cells by increasing titers of transfused anti-A and anti-B antibodies. The risk of continued use of O-negative packed red blood cells under these conditions is minor hemolysis of donor red blood cells and hyperbilirubinemia. In most centers, however, the need for O-negative blood is rare. Subsequent transfusions with the patient’s own blood type is usually possible and preferred. (372-373)
4. Type-specific blood refers to blood that has only been typed for the A, B, and Rh antigens. Type-specific blood testing is merely the first phase, or the immediate phase, of the crossmatch. It requires only about 5 minutes to perform. The chance of a significant hemolytic reaction with the transfusion of type-specific blood to a patient is about 1 in 1000. Type-specific blood is most frequently transfused in emergent situations in which time does not allow for a formal crossmatch. (372-373)
