This thesis used a systems approach to evaluate the performance of the Blood Transfusion System (BTS) in Santa Catarina, Brazil. The BTS was assessed against its own goals - providing safe blood in sufficient quantity when needed to improve health.
This research combines descriptive and analytical components using quantitative and qualitative methods. The study begins with a description of the BTS in Santa Catarina including baseline data on the determinants of BTS performance in terms of availability and safety of blood supply. Samples of regular donors, first-time donors, lapsed donors and non-donors, were surveyed about their perceptions, experiences and motivations.
The infection safety issues were investigated by estimating the prevalence of serologic markers for transmissible infectious diseases among donors. From these data, and the estimable proportions of donors with early undetectable infections, the residual risks of blood transfusion transmitted diseases during years 1999 to 2001 were estimated.
The use and appropriateness of red blood cell (RBC) transfusions was reviewed through a retrospective audit of the medical records of patients who received RBC transfusions at three public hospitals in Santa Catarina. A sample of clinicians was also surveyed concerning their blood prescribing practices for RBC and other blood products; these responses were assessed for consistency with international guidelines on transfusion.
In Santa Catarina the blood collection services are a combination of hospital based and regional blood collection centimes. Decentralization of the BTS has improved accessibility of donors and prescribers but hinders standardization.
The survey of donors and non-donors indicated that generally misconceptions did not appear to prevent the recruitment of blood donors in Santa Catarina. However, misconceptions such as contracting HTV infection through blood donation are still very prevalent among non-donors and may indicate that risk perception has been a factor in non-participation. Donors who identified intrinsic motivations such as the desire to help people or awareness of need for blood were more likely to remain in the system. Operational factors such as the opening hours and proximity of the blood collection facility were also important factors in the decision to return to donate.
There was a significant variation in the donor prevalence of all transfusion transmissible diseases across the BTS locations. Replacement and voluntary donations were equally safe; male and female donors also were equally safe but females were more often deferred, usually due to anaemia. First-time donors were less safe: remarkably, they were 22 times more likely to be positive for serologic markers for infectious diseases than repeat donors. This is very important given the frequency of first-time donors in the Santa Catarina BTS (61% compared to 23% in Australia, 13% in Canada and 19% in the USA).
Introduction of more expensive screening methods such as Nucleic Acid Amplification Technique (NAT) would reduce the 'window period' of undetectable infectiousness. But unless the high prevalence of transmissible infections is reduced in the source donor population in Santa Catarina the post-screening risk will remain well above risk levels in countries such as the USA, Australia and Canada. The general trend of modem blood banking to minimize risk and public expectation of absolute safety challenges all BTS, especially those with lower income, to provide safe affordable blood products. The cost of implementing new testing such as NAT would require highly trained professionals, new laboratory facilities, communication and transport infrastructure with high costs and a limited yield. The estimated annual yield for NAT in Santa Catarina considering the current production of blood units would be one additional positive unit for HTV and two for HCV. Investing in the retention of repeat donors compared to NAT testing would have a much higher yield for safety of blood supply.
There is a variation in reported transfusion practices among clinicians in Santa Catarina. The variation did not appear to be associated with age or years of practice but rather an institutional phenomenon.
In Santa Catarina RBC recipients were more likely to be male aged 40 to 80 years with diagnosis of neoplasms. Nearly half of the RBC recipients received at least one potentially inappropriate RBC transfusion. Transfusions were more likely to be inappropriate when given a single-unit therapy for anaemia.
Collectively the assessment of the performance of the Santa Catarina BTS led to the conclusions that the blood supply produced was sufficient to meet the demand. The relative under usage of blood products compared to countries like the USA and Australia is most likely explained by the lower complexity of hospital procedures and less access to the health care system itself. Furthermore, blood supply could be increased substantially should the need arise by reducing inappropriate transfusions - a reform needed to achieve the BTS safety and efficacy goals. The Santa Catarina blood supply is one of the safest in Brazil and favourable in comparison with other South American countries. However, residual risk of transfusion-transmitted diseases remains well above corresponding risk in wealthier countries with lower community prevalences of blood-transmissible infections.
Based on the findings of the Santa Catarina BTS assessment a variety of strategies would be recommended to improve performance:
i) decrease inappropriate use of blood by developing Brazilian consensus guidelines for transfusion, auditing transfusion practices and giving feedback to clinicians to reduce inappropriate transfusion. This would improve patient care and enable existing blood supplies to go further;
ii) adopt of strategies to reduce the prevalence of infectious diseases among the general population, such as intensification of immunization for HBV, to reducing risks of transfusion-transmitted diseases;
iii) encourage replacement of blood by family members and friends - it is as safe as voluntary donations and powerfully motivates donation;
iv) retain repeat donors as a key strategy for blood safety by approximating donation sites to donors, extending opening hours and ensuring repeat donors feel especially welcomed by the BTS;
v) allow for substantial regional variation in the community prevalence of HTV, HCV and HBV and design local screening strategies that match the sub-region;
vi) evaluate carefully infection safety investments with potentially low yields if they impose high opportunity costs that prevent implementation of other safety initiatives, bearing in mind the need for community confidence in blood safety and high standards.