[Epidemiological support in blood surveillance]

Thirty years of hemovigilance - Achievements and future perspectives

Since its emergence in the early 1990s, hemovigilance has gradually evolved from a blood safety concept focused on surveillance of adverse reactions and events in patients, to a well-defined system that monitors the entire transfusion chain and improves its safety. The importance of hemovigilance has been recognized globally in a relatively short time, but the level of its implementation varies significantly between countries. The cooperation of international organizations has significantly contributed to the promotion, implementation, and education in this field. Thanks to initiatives taken, the safety of transfusion practice has been improved in many segments, primarily related to the risks of adverse events in recipients of blood components. In parallel with changing transfusion practice, the hemovigilance process has also matured. In addition to the reduction of existing risks and the early detection of emerging risks, hemovigilance has also embraced the principles of patient blood management. Research in hemovigilance is more increasingly focused on specific categories of patients, specific blood components and methods of their preparation, rare reactions, and transfusion efficacy and efficiency. A proactive approach and use of big data can play an important role in achieving these goals. Additional and sustained efforts should be made to prevent underreporting of events and to improve data comparability through clear definitions and grading systems. This review provides a historical overview of hemovigilance and its achievements, current challenges, and future plans.

Hemovigilance: A new beginning in India

Hemovigilance plays an essential role in ensuring patient safety with regard to blood transfusions. The data generated through the hemovigilance system helps in framing important changes in the whole blood transfusion process which are useful for better patient safety. This article briefly describes the history of hemovigilance, why the need of hemovigilance was felt and also illustrates about the Hemovigilance Program of India.

The importance of hemovigilance in the transmission of infectious diseases

Background

Hemovigilance is an organized system of surveillance throughout the transfusion chain intended to evaluate information in order to prevent the appearance or recurrence of adverse reactions related to the use of blood products.

Objective

The aims of this study were to assess the late reporting of incidents related to possible seroconversion in respect to age, marital status and ethnical background, annual variations in late reporting, the number of reports opened and closed, seroconversion of donors and transfusions of blood products within the window period.

Methods

This retrospective, descriptive study used data on blood donations in the blood bank in Uberaba during the period from 2004 to 2011. Some socio-epidemiological characteristics of the donors and serology test results of donors and recipients were analyzed in respect to the late reporting of incidents related to possible seroconversion. The Chi-square test, odds ratio and a regression model were used for statistical analysis.

Results

From 2004 to 2011, the blood bank in Uberaba collected 117,857 blood bags, 284 (0.24%) of which were investigated for late reported incidents. The profile of the donors was less than 29 years old, unmarried and non-Whites. Differences in age (p-value < 0.0001), marital status (p-value = 0.0002) and ethnical background (p-value < 0.0001) were found to be statistically significant. There was no statistical difference between men and women (0.24% and 0.23% respectively; p-value = 0.951). The number of late reported incidents increased until 2008 followed by a downward trend until 2011. There were twelve cases of seroconversion in subsequent donations (seven human immunodeficiency virus, four hepatitis B and one hepatitis C) with proven human immunodeficiency virus infection after screening of only one recipient.

Conclusion

The twelve cases of seroconversion in donors with subsequent infection proven in one recipient underscores the importance of this tool to increase transfusion safety.

[Evaluation of the immediate transfusion reaction incident reporting system at the Brest University Hospital Center]

The Haemovigilance Unit of Brest University Hospital has had a reporting system of transfusion reactions since october 1994. Reporting "any unexpected or undesirable effect due or likely to be due to the administering of blood cell components" must be done on an answering machine immediately or in the next eight hours. The main goal of the evaluation of this epidemiological surveillance system was to assess its sensitivity, its positive predictive value, its acceptability, its timeliness and its simplicity, according to the Centers for Disease Control criteria. An exhaustive monitoring of the immediate transfusion reactions (ITR) occurring within the 24 hours following the procedure was conducted from April 1, to June 30, 1998. Two sources of information were used, the spontaneous notification to the Haemovigilance Unit using the answering machine, and a telephone survey of the nurse responsible for the transfusion or post-transfusion follow-up. During the survey, 19 ITR, among which 12 were reported to the Haemovigilance Unit on the answering machine, were recorded. The incidence rate of the I.T.R. was estimated at 5@1000 transfused blood cell components. The sensitivity of the notification system was estimated at 63% (95% confidence interval: 41-85) and the positive predictive value at 70% (95% confidence interval: 48-92). This notification system is operational. The function of sanitary alert is ensured at the primary level of the system surveillance. The undernotification of the ITR (37% of false negative) must be corrected by specific recommendations.

[Evaluation of the actual traceability of labile blood products using medical records]

The traceability of blood products is an essential part of haemovigilance and transfusion safety. A pilot survey assessed the actual traceability by analysing transfusion information collected from medical records of a representative sample of 390 labile blood products transfused in a French university hospital. Transfusion and distribution forms were missing in 2.3% and 6.9% respectively. Availability and validity of transfusion information varied according to the nature of the expected information, elements of patients' records and types of wards. The location where the transfusion was performed was false or ambiguous in 38% of cases in surgery. Crude traceability, evaluated by the feedback of validated distribution forms, was estimated at 85.2% whereas actual traceability was estimated at 81.9% (SD 1.7%). High availability (98.7%) of at least one of the two sheets of the distribution form in medical records, or in the blood bank, revealed that a significant improvement of traceability should come from a better compliance to the rules of information transmission. The actual traceability differed significantly according to clinical services (worse in surgery) and was lower in case of autologous or absence of previous transfusion. An analysis of markers of good traceability should suggest efficient evolution of organization and information systems. This pilot study shows the relevance and feasibility of this kind of survey which could interestingly be performed on a large national representative random sample.

[Immuno-hemolytic transfusion reactions. IV. Analysis, risks and prevention]

The immunological risk of red blood cell transfusions now seems higher than the viral risk. According to studies, severe accidents due to blood incompatibility occur with a frequency estimated at 1/6000 to 1/29000; despite technical progress, the risk does not significantly diminish. The majority of accidents do not originate from laboratory or production stages but from defects in the application of clinical procedures. Preventive measures are based on (i) the elaboration of clinical guidelines, (ii) the compliance to strict rules in carrying out bedside ABO check, and (iii) the realization and interpretation of antibody screening tests. The implementation of quality assurance systems and of the epidemiological surveillance system, which define the basis of a prevention policy, leads to the expectation of an improvement of transfusion safety.