Transfusion medicine

• Hemovigilance is the surveillance for complications resulting from blood donation or blood product transfusion, the evaluation of the complication data and the resulting quality improvement practices that are instituted as a result of the collected and analyzed data

NHSN hemovigilance module adverse reaction codes, severity codes and imputability

Case definition	Severity	Imputability
Definitive: the adverse reaction fulfills all of the case definition criteria	Nonsevere: medical intervention (e.g., symptomatic treatment) is required but there is minimal risk of permanent damage to the transfusion recipient	Definite: there is conclusive evidence that the reaction can be attributed to the transfusion
Probable: the adverse reaction meets some of the clinical signs and symptoms or radiologic, laboratory evidence or available information but does not meet all definitive case definition criteria	Severe: inpatient hospitalization or prolonged hospitalization is directly attributable to the transfusion reaction, persistent or significant disability or incapacity of the patient as a result of the reaction or a medical or surgical intervention is necessary to preclude permanent damage or impairment of a body function	Probable: there are other potential causes present that could explain the recipient's symptoms but transfusion is the most likely cause of the reaction
Possible: the reported clinical signs or symptoms, radiologic or laboratory evidence and available information are not sufficient to meet definitive or probable case definition criteria	Life threatening: major intervention was required after the transfusion reaction (e.g., vasopressors, intubation, transfer to intensive care) to prevent death	Possible: there are other potential causes that are most likely; however, transfusion cannot be ruled out
	Death: the recipient died as a result of the transfusion reaction	Doubtful: there is evidence clearing in favor of a cause other than the transfusion but transfusion cannot be excluded
	Not determined: the severity of the adverse reaction is unknown or not stated	Ruled out: there is conclusive evidence beyond reasonable doubt of a cause other than the transfusion
		Not determined: the relationship between the reaction and transfusion is unknown or not stated

Table modified from: Transfusion 2015;55:703

Contributed by Erica Swenson, D.O.

• eCFR: 606.170 Adverse Reaction File [Accessed 6 December 2024], American Association of Blood Banks: Standards for Blood Banks and Transfusion Services, 33rd Edition, 2022, AABB: Circular of Information for the Use of Human Blood and Blood Components [Accessed 6 December 2024])

A 56 year old woman with a refractory / recurrent plasma cell neoplasm and multiple allergies to medications has received multiple transfusions of red blood cell and platelet units over years. She has had multiple mild allergic transfusion reactions, which the clinical team treated with Benadryl and steroids. She presents to the outpatient infusion clinic for a platelet transfusion (see image above). Premedication is not administered. 15 minutes into the platelet transfusion, she develops hives, itching, chest tightness, difficulty breathing, throat swelling, oxygen desaturation to 78% on room air and hypotension with blood pressure of 78/52. A code is called, epinephrine is administered, the patient is intubated and admitted to the medical intensive care unit. What is the case definition, severity and imputability of this transfusion reaction?

1. Case definition: definitive; severity: life threatening; imputability: definite
2. Case definition: definitive; severity: nonsevere; imputability: definite
3. Case definition: possible; severity: nonsevere; imputability: definite
4. Case definition: possible; severity: severe; imputability: probable
5. Case definition: probable; severity: severe; imputability: probable

A. Case definition: definitive; severity: life threatening; imputability: definite. The case definition is definitive as the patient presented with 2 or more of the diagnostic criteria during the transfusion. The patient had hypotension, respiratory distress, itching and hives. The severity is life threatening as the patient required intubation and admission to the intensive care unit. The imputability is definite as the reaction occurred during the transfusion and no other risk factors were noted. Answers B - E are incorrect because they did not list the correct case definition, severity or imputability.

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Reference: Hemovigilance

Which transfusion adverse event was mitigated after collection of hemovigilance data through the United Kingdom's Serious Hazards of Transfusion (SHOT)?

1. Allergic reaction
2. Febrile nonhemolytic transfusion reaction (FNHTR)
3. Transfusion associated circulatory overload (TACO)
4. Transfusion associated graft versus host disease (TA GVHD)
5. Transfusion related acute lung injury (TRALI)

E. Transfusion related acute lung injury (TRALI). Hemovigilance data collected through the United Kingdom's Serious Hazards of Transfusion (SHOT) found an association between transfusion related acute lung injury (TRALI) and plasma and platelet products donated by female patients. Low risk TRALI donor strategies, including collecting plasma from men and never pregnant women, were instituted in the early 2000s. In a meta analysis, patient populations prone to develop TRALI were found to have a significant reduction in TRALI risk (OR, 0.51; 95% CI, 0.29 - 0.90). Answer A is incorrect because premedication is not supported for the prevention of an allergic reaction. If allergic reactions are severe and recurrent, washing of red blood cell units may be considered. Answer B is incorrect because febrile nonhemolytic transfusion reaction incidence has decreased with universal leukoreduction. Answer C is incorrect because transfusion associated circulatory overload can possibly be mitigated by slow transfusion rate (1 mL/kg/hr) but data is lacking. Answer D is incorrect because transfusion associated graft versus host disease can be mitigated with irradiation and pathogen inactivation technologies (Transfusion 2015;55:164, J Hosp Med 2020 Nov;15:684, Transfusion 2004;44:25, Transfusion 2004;44:16, Transfusion 2018 ;58:1506).

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Reference: Hemovigilance