CORD-19:06d4c2299cf3f4604baaee1309a54daa5d4ec2a7 / 5482-5487
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Blood Transfusion Services
Abstract
'Blood' is a fluid tissue, composed from various cells with complex functions (erythrocytes, red cells -oxygen carriers; leucocytes and lymphocytes, white cells -immune response to disease; and thrombocytes -clotting factor), which are carried by plasma. Blood is vital as carrying oxygen, nutrients, and other essential elements to the tissues and removing residues of cellular metabolism. It also carries various clotting factors which normally intervene when bleeding occurs.
Blood donation is a benevolent gesture of offering blood for patients in need. Every healthy individual 18 to 65 years of age can donate blood, about 7 ml per kg body weight, up to a maximum of 450 ml whole blood per donation. The interval between two whole blood donations has to be at least 72 days. Voluntary nonremunerated blood donation is considered a cornerstone of blood safety and it is advocated and supported by many international bodies, such as World Health Organization, the International Federation of Red Cross and Red Crescent Societies, and the International Federation of Blood Donor Organizations (see Relevant Websites).
Blood transfusion is a medical treatment in which blood, blood components, or blood products are collected and prepared from a healthy person (a donor) and administered to the patient being treated. The most appropriate blood transfusion therapy should provide for the missing or reduced element. Transfusion of whole blood can be life-saving in situations such as massive blood loss due to trauma or extensive surgery. Blood component therapy is used to treat conditions in which the specific element is missing; for example, severe anemia (a reduction in oxygen supply to vital organs) or an abnormal decrease in the number of platelets. People suffering from sickle-cell disease may require frequent transfusion of red cell concentrates. In the case of hemophilia, the administration of the missing clotting factor is required. Blood transfusion treatment is usually performed in health-care settings.
Blood transfusion service is an organization which deals with various aspects of the blood transfusion chain, from the potential donor (information and selection of donors, blood collection, blood testing, blood processing, blood storage, blood transportation) to the potential recipient (selection and distribution of appropriate components for transfusion), and should link to the clinical interface or administration of blood and patient follow-up.
This process is usually carried out by organizations or health departments operating at a local, regional, or national level. In some countries blood services are hospital based. The range of responsibilities of the hospital blood banks varies, therefore, according to the organization of the national health-care system. Usually, the hospital transfusion department bears the responsibilities of storage, selection (compatibility testing), and distribution of blood components according to medical prescription.
A blood component results from separation of collected whole blood through centrifugation at various speeds. Components include red cells, white cells, thrombocytes, and plasma. Each component has specific characteristics, including a special storage temperature and shelf life (e.g., thrombocytes must be stored at þ21 C; plasma must be frozen at -40 C). Blood components can also be collected from the individual donor through apheresis procedures (separation of the required component from collected blood during the donation procedure, with the remaining being returned to the donor at the end of the separation process). The procedure can be fully or partially automated.
In separating blood derivatives or components, raw plasma is subject to industrial fractionation procedures. These procedures must follow the pharmaceutical current good manufacturing practices (cGMP) so that resulting products comply with required safety standards. The purified and concentrated coagulation factors (e.g., Factor VIII, Factor IX) and human albumin are usually prepared as 5% or 20% solutions, and immune globulins are the most frequently used blood derivatives.
Technological progress has been achieved in obtaining recombinant coagulation factors, as well as volume replacement solutions and plasma expanders, in the continuous search to identify responses to an insufficient blood supply which is increasingly exposed to safety threats.
Being a complex but undeniable life source, blood has been given historically mythical attributes. After unsuccessful transfusions of blood from animals to humans, and sometimes from humans to humans as well, it was only after 1900, when Karl Landsteiner discovered the ABO major blood groups, that blood transfusion therapy became possible. The history of blood transfusion has shown that once the blood group compatibility barrier had been overcome, there are infectious threats to which increased attention must be given. Blood-borne pathogens can be transferred with the donor's blood to the recipient patient. Such pathogens may be viruses (e.g., HIV/ AIDS, hepatitis B and C), parasites (e.g., malaria, Chagas' disease), bacteria (e.g., syphilis, brucellosis), or prions (e.g., vCJD).
In the late 1980s the transmission of the HIV virus by blood, blood components, and by pharmaceutically manufactured blood derivatives raised important concerns. A large number of patients chronically depending on therapy with blood components or derivatives were proven to be infected with HIV and other blood-borne pathogens. These findings led to more firm regulations of the entire blood transfusion area, with patient protection being of central importance. Intensive work in the field of quality assurance of blood-banking operations, including viral inactivation of blood derivatives, was initiated. For a more comprehensive overview of the history of blood transfusion, see Starr (1998) .
Other crisis situations, such as the variant Creutzfeldt-Jakob disease (vCJD) infections (mad cow disease), severe acute respiratory syndrome (SARS), or avian flu epidemics, have strongly affected the availability of the blood supply at times. A more complete list of infectious agents which can be transmitted by blood transfusion is presented in Table 1 . It is important to note that these agents in their early stage of infection induce a healthy carrier state with few or no symptoms of disease.
The safety and availability of and access to adequate blood supplies remain challenges in many parts of the world. According to the WHO global database for blood safety, 81 million units of whole blood and 20 million liters of plasma were donated annually in the period 2001-2002. Analysis of blood donations in relation to the human development index (HDI -United Nations indicators) showed that 82% of the world's population, which lives in low and medium HDI countries, has access to only 39% of the total blood supply. This limited access has a dramatic impact on the capacity to respond to various health needs of the population, and the strong links between blood availability and maternal mortality rates have been demonstrated. The differences in blood donation rates reflect not only the degree of awareness of the population with respect to blood transfusion, but also the level of development of health care in which the blood service is embedded. With mounting safety requirements and technological progress, blood transfusion services have become an increasingly expensive part of public health. In countries with restricted resources, the safety of blood transfusion is of particular concern, especially because these countries often have high prevalence rates of HIV, hepatitis B and C, and other particular blood-borne diseases. (See Relevant Websites for the WHO global database on blood safety.) An appropriate blood supply -defined as a situation in which no patient will die due to lack of appropriate treatment with blood or blood components -varies from one country to another.
Important components of blood safety are:
. Organization and regulatory framework for the blood transfusion services; . Safe blood donors -education, recruitment, retention;
. Testing of all blood units and further processing; Table 1 Transfusion-transmitted infectious diseases
Remarks with respect to geographical distribution or generated disease . Appropriate use of blood and blood components at the clinical site; . Hemovigilance, reporting and follow-up on safety issues and transfusion outcomes.
WHO-integrated strategy for blood safety recommends nationally coordinated blood services with quality systems functional in all areas and a blood supply based on voluntary nonremunerated blood donors from low-risk populations that is appropriately tested (100% for blood-borne pathogens, blood grouping, and compatibility testing), processed, stored, and distributed, as well as adequately used at the hospital site (alternatives to transfusion should be available), including posttransfusion follow-up.
The blood transfusion service should be integrated with the health-care system of a country. Its appropriateness depends on the strength of public health interventions, the level of health service delivery, and on the health status of the population and existing patterns of disease.
The blood transfusion service usually functions under government responsibility. A national blood policy and plan should define the vision and the steps required for strengthening quality, safety, availability, and access to adequate blood supplies. A national blood program for defined periods of time will allow addressing priorities and monitoring progress in the field. Constantly updated, dedicated, legal provisions and regulatory frameworks are part of the supportive mechanisms to implementation. Appropriate and sustainable resources, including funding mechanisms, are vital.
Involvement of the various stakeholders in the process is essential, and a dedicated national commission can play an advisory function at a high decision-making level with respect to blood safety issues, as well as enhance dialogue among interested parties, such as blood transfusion specialists, clinicians, and patients.
Experience has shown that the organization of blood services on a nationally coordinated basis ensures harmonized quality standards along the blood chain and increases consistency in delivery of products, information, and statistics. In addition, such organization has been proven to be more cost effective owing to economies of scale.
Following the early period of the HIV/AIDS epidemic, the blood transfusion community began to realize that production of blood should take place in a more controlled environment. In order to accomplish this, two specific initiatives were taken: (1) quality standards for blood components were established, as well as for the raw plasma used in pharmaceutical processing, and (2) quality management systems were implemented to ensure that products meet the established standards. This has generated enhanced work of national and international organizations to support both the development and implementation of quality and safety standards for the blood services and deliverables (e.g., Council of Europe ''Guide to the Preparation, Use and Quality Assurance of Blood Components,'' AABB Standard for Blood Banks). These standards are all grounded in more general standards, such as the ISO 9000series standards and the current good manufacturing practice (cGMP) guidelines for medicinal products for human and veterinary use (e.g., EU published by the European Commission). These specify basic requirements and principles for quality management, including personnel management and training, premises and equipment layout, production operations and requirements for standard operating procedures, design and methods for ensuring maintenance and documentation for all activities, how to perform quality controls, contract manufacture and analysis, and how to perform and document self-inspection. Monitoring the compliance to defined standards is part of a regular process of quality assessment and control.
In line with the above, WHO developed a comprehensive training program (including interactive toolkit and external quality assessment schemes) in quality management principles for the blood service.
According to data available from various sources and studies, voluntary nonremunerated regular blood donors recruited from low-risk populations carry a much lower risk of infections. The safe blood donors are the cornerstone of a safe blood supply and therefore an important and central point in WHO recommendations as well as those emerging from the IFRCRCS, the ISBT, and other international organizations concerned.
Establishing a pool of safe blood donors requires longterm commitments to education, information, and social involvement. Efforts in this respect have been particularly enhanced with the World Blood Donor Day, which became a global event after its endorsement by the World Health Assembly in 2005. Co-sponsored by WHO, the International Federation of Red Cross and Red Crescent Societies (IFRCRCS), International Federation of Blood Donor Organizations (IFBDO/FIODS) and International Society of Blood Transfusion (ISBT), it aims to increase awareness toward blood donation and enhance the different steps in the process of education, recruitment, and retention of low-risk donors and establishment of youth donor programs.
Safe donor selection criteria -the education to healthy lifestyles -proved to be highly effective in the prevention of sexually transmitted infections, including HIV/AIDS. The 'Club 25' initiative in Africa (youth initiative promoting lifestyles and regular blood donation, aiming for about 20 blood donations by the age of 25) led to a dramatic decrease in transfusion-transmitted infections and related risks, to the mutual benefit of donors and recipient patients.
Collected blood needs to be screened for blood-borne pathogens prior to transfusion. Basic screening includes tests for HIV, hepatitis B, hepatitis C, and syphilis. In some parts of the world, additional tests are necessary for local epidemiological threats. It is the responsibility of health authorities to outline a national strategy for screening of all donated blood and specify the most appropriate testing and diagnostic algorithms to be used. In addition, testing for ABO and RhD blood groups, as well as screening for irregular antibodies, are performed to avoid an incompatible (hemolytic) transfusion reaction.
Reliable testing of blood units requires the following:
1. Uninterrupted supply of high-quality test systems; this includes procurement, supply, central storage, and distribution of reagents and materials to ensure continuity of testing; 2.. Maintenance of a quality assurance system and good laboratory practice, including the use of standard operating procedures (SOPs) for all aspects of blood screening and processing; 3. Continuous training of staff members in all aspects of blood screening and processing of blood units, including storage and transportation of blood products.
Collected whole blood can be stored for a time depending on the mixture of anticoagulant preservation solution used. The whole blood unit may be separated into major blood components -red cell concentrates, fresh frozen plasma, and platelet concentrate -to increase efficiency of use. Processing of donated blood into its different components reduces the occurrence of adverse transfusion reactions and tailors therapeutic response to the particular needs of the patient. Since each blood component can be stored according to its specific requirements, effectiveness is increased and shelf-life adjusted. For example, fresh frozen plasma can be stored at -40 C for 24 months, platelet suspended in plasma or suspension media (T-SOL) can be stored at þ20-24 C for 3-5 days, and red cells suspended in an additive solution (SAG-MAN or ADSOL) can be used up to 45 days if stored at þ4 C.
Blood is a scarce resource and should always be used with care. As with any medical procedure, it carries also a measurable risk to the recipient patient. In evaluating the indication for blood transfusion therapy, the benefits for the patient should outweigh the risks. Several international recommendations and guidelines have been developed in this respect, but these are not always available and in many circumstances the process continues to rest on historically based practices and the clinical experience of the attending physicians.
The training of clinical users in the adequate use of blood is an important endeavor which requires constant updates not only regarding scientific progress and technologies but also the availability of and access to alternatives to blood (e.g., volume replacement solutions). Strengthening the cooperation with other sectors of health care (i.e., primary health care) may help reduce blood usage through (1) early diagnosis and treatment of diseases or conditions which may lead to the need for blood transfusion (obstetric antenatal care, iron substitution); (2) pre-operative blood collection for auto-transfusion; (3) intra-operative normo-volemic hemodilution;
(4) per-operative and post-operative blood salvage.
Blood usage in Western Europe and North America shows a moderate decrease in number of units used, mostly due to modern surgical techniques, such as endoscopic interventions with minimal tissue injury. To further respond to blood availability challenges, increasing attention is given to the development of blood substitutes and oxygen carriers. The Network for Advancement of Transfusion Alternatives also aims to reduce unnecessary blood transfusion and provides additional information.
The word 'hemovigilance' is derived from the word 'pharmacovigilance,' which encompasses activities and systems to collect information useful in supervising medicinal products, with particular reference to adverse drug reactions in human beings, and to evaluate such information scientifically. It comprises a set of surveillance procedures covering the whole transfusion chain (from the collection of blood and its components to the follow-up of the transfused patient).
The aim of hemovigilance is to detect, collect, and analyze all information of unexpected or undesirable effects resulting from the therapeutic use of blood and blood components in order to correct their cause, prevent recurrence, and improve the safety of blood transfusion. Adverse reactions are defined as reactions which are harmful and unintended and which occur at doses normally used for prophylaxis, diagnosis, or treatment of various conditions.
Hemovigilance concerns blood components (e.g., whole blood, erythrocyte concentrates, platelet concentrates, and fresh frozen plasma). Pharmacovigilance in transfusion medicine concerns plasma derivatives (e.g., clotting factor concentrates, immunoglobulins, albumin, and other fractionated products).
Reporting of serious adverse events related to transfusion therapy appears to be one of the oldest reporting systems in place. However, the development of national hemovigilance systems poses increasing challenges due to the various taxonomies in use, the limited resources for supportive informative technologies, and, mainly, the need for enhanced communication between blood services and hospital services. The increasing role of the patient in this process is expected to strengthen hemovigilance at its operational level. Several websites provide data on hemovigilance (national and regional), such as those from the United Kingdom, the European Haemovigilance Network, and the Danish Haemovigilance Network.
Botulism is a rare, severe, neuroparalytic disease caused by accidental or intentional exposure to seven distinct botulinum toxins (BoNTs, A-G types) that affect humans and a variety of domestic and wild lower animals. The disease is characterized by symmetrical cranial nerve palsies that may be followed by descending, symmetric flaccid paralysis of voluntary muscles, which may lead to death because of respiratory or heart failure.
Botulinum toxins are neurotoxins of extreme potency and lethality (they can be lethal at doses as low as 1 mg/kg orally) released by vegetative cell death and lysis. Four toxigenic anaerobic Gram-positive spore-forming bacteria of the genus Clostridium produce the botulinum toxins: the classic C. botulinum that produces type A, B, C, D, E, and F toxins (BoNT/A-F), C. argentinense that produces type G toxin (BoNT/G), and two rare strains of C. butyricum and C. baratii that produce types E and F botulinum-like toxins, respectively.
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