Organ procurement (also called surgical recovery) is a surgical procedure that removes organs or tissues for reuse, typically for organ transplantation.
Procedures If the organ donor is human, most countries require that the donor be legally dead for consideration of organ transplantation (e.g., cardiac death or brain death). For some organs, a living donor can be the source of the organ. For example, living donors can donate one kidney or part of their liver to a well-matched recipient. Organs cannot be procured after the heart has stopped beating for a long time. Thus, donation after brain death is generally preferred because the organs are still receiving blood from the donor's heart until minutes before being removed from the body and placed on ice. To standardize brain death evaluation, the American Academy of Neurology (AAN) updated guidelines in 2010, requiring coma with known cause, absent brain stem reflexes, and apnea; recent practices emphasize critical care coordination to optimize donor stability and increase procurement rates. Donation after circulatory death (DCD), also called donation after cardiac death, refers to organ donation from patients in whom life-sustaining treatment is withdrawn and death is declared following irreversible cessation of circulatory and respiratory function; organs are procured after a short, defined no-touch observation period following circulatory arrest. DCD donors may have variable residual brain activity at the time of withdrawal of support, and protocols (including the length of the mandatory observation interval after circulation stops) differ between jurisdictions. For example, UK guidance typically applies a 2–5 minute observation period in controlled DCD pathways, while other countries use different timings within their local protocols. This occurs in situations where, based on the patient's advance directive or the family's wishes, the patient is going to be withdrawn from life support. After this decision has been made, the family is contacted for consideration for organ donation. Once life support has been withdrawn, there is a 2-5 minute waiting period to ensure that the potential donor's heart does not start beating again spontaneously. After this waiting period, the organ procurement surgery begins as quickly as possible to minimize time that the organs are not being perfused with blood. DCD had been the norm for organ donors until 'brain death' became a legal definition in the United States in 1981. Since then, most donors have been brain-dead. After consent and clinical donor evaluation, donor-recipient matching (based on blood type, tissue typing, size, medical urgency and geography) is coordinated in the United States via the Organ Procurement and Transplantation Network (OPTN), operated under contract by UNOS. The OPTN maintains the national matching algorithms and allocation policy documents. Coordination between teams working on different organs is often necessary in case of multiple-organ procurement. For trauma patients, successful procurement requires extensive collaboration between trauma teams and organ procurement organizations to ensure viable organs amid physiological instability. Multiple-organ procurement models are also developed from slaughtered pigs to reduce the use of laboratory animals. The quality of the organ is then certified. If the heart stopped beating for too long, the organ becomes unusable and cannot be used for transplant.
Preservation and transport After organ procurement, the organs are often rushed to the site of the recipient for transplantation or preserved for later study. The faster the organ is transplanted into the recipient, the better the outcome. While the organ is being transported, it is either stored in an icy cold solution to help preserve it, or it is connected to a miniature organ perfusion system which pumps an icy solution (sometimes enriched with potassium) through the organ. This time during transport is called the "cold ischemia time". Cold ischemia time targets vary by organ. Historically, hearts and lungs have been transplanted within about six hours of procurement, and livers within a window up to ~24 hours, although shorter times generally improve outcomes. Advances in ex-vivo perfusion and normothermic preservation (e.g., portable organ perfusion systems for heart, lung and liver) have extended safe preservation intervals in some settings and improved early graft assessment, allowing clinically successful transplantation of organs that would previously have exceeded conventional cold ischemia limits. For kidney transplants, as the cold ischemia time increases, the risk of delayed function of the kidney increases. Sometimes, the kidney function is delayed enough that the recipient requires temporary dialysis until the transplanted kidney begins to function. Recent advancements include hypothermic (4-10 °C) or normothermic (37 °C) machine perfusion, widely used for kidneys and emerging for hearts/lungs/livers, potentially increasing viability and addressing shortages. In the case of DCD, the first technique established for organ procurement was super-rapid recovery. Hypothermic perfusion of kidneys is a relatively widespread practice. For the heart, normothermic preservation has been used in which the heart is provided with warm oxygenated blood and so continues to beat ex-vivo during its preservation. This technique has also been applied to lungs and led to the emergence of donor lung reconditioning centres in North America. For the liver, hypothermic and normothermic techniques are being used with evidence to suggest that both may be beneficial. There is ongoing research and development to improve machine perfusion and alternative approaches such as novel cryoprotectant solvents to improve organ viability and availability – such as by increasing preservation durations. In the case of the cornea, normothermic transportation of cadaver corneal endothelial tissue and also full donor corneal transportation in thermo-reversible gelation polymer cocktails have been reported.
Ethical issues
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