[Perioperative management of the brain-dead organ donor : Anesthesia between ethics and evidence].

Background: The number of organs donated after brain death in Germany is far lower than the demand. This underlines the importance of providing the brain-dead donor with optimal medical care throughout the donation process to decrease the risk of graft dysfunction. Several international guidelines and national recommendations guide the intensivists in organ-protective intensive care management of the brain-dead donor.

Objective: The anesthetist is a key member during organ retrieval procedures and plays a crucial role in physiological donor management; however, evidence-based recommendations for the perioperative anesthetic management, drug treatment strategies and target values are lacking. Anesthesia literature about donor management is scarce and predominantly composed of reviews of practice, with little exploration of the scientific foundations. The aim of this review is to guide the anesthetist in the organ-protective perioperative therapy. The pathophysiological changes in patients who progress to brain death are briefly summarized. The available evidence, guidelines and expert opinions regarding medical treatment strategies and therapeutic goals in organ-protective therapy are reviewed. The ethical and pathophysiological considerations regarding the performance of anesthesia during organ retrieval are discussed.

Methods: This review is based on a selective literature search in PubMed for publications regarding organ donation after brain death (keywords: "brain dead donor", "organ procurement", "organ protective therapy", "donor preconditioning", "perioperative donor management", "ethical considerations of brain dead donor"). International guidelines, national recommendations and expert opinions were given special consideration.

Results: Overall, the evidence for optimal perioperative organ-protective care of the brain-dead donor is limited. Most elements in the current recommendations and guidelines are based on pathophysiological reasoning, epidemiological observations or extrapolations from general organ-protective management strategies, and not on evidence from randomized controlled trials. National and international recommendations on treatment goals and drug therapy differ considerably in some aspects. The therapy concepts applied are very heterogeneous. Apart from medical challenges, the ethical circumstances are an additional burden for the entire treatment team. Whether anesthesia is reasonable during organ retrieval remains unclear. There is uncertainty about possible organ-protective effects of anesthetic drugs. Furthermore, ethical considerations raise the question of whether the determination of brain death and the use of anesthetic drugs during the procedure of organ retrieval are compatible with each other.

Conclusion: Due to the lack of evidence, perioperative treatment should be guided by intensive care therapy strategies. The discussion about using anesthetic drugs during organ retrieval remains controversial. Pathophysiological considerations support the use of volatile anesthetics because of possible organ-protective effects. The use of neuromuscular blocking is justified to control any possible motor response resulting from spinal cord reflexes, whereas there is no evidence for a benefit from using opioids. Apart from that, it seems ethically problematic to anesthetise a brain-dead donor. Consequently, knowledge about the pathophysiological processes caused by brain death and about organ-protective therapy concepts are just as much a basic requirement as the consideration of ethical problems in organ donation after brain death. Only then are the caregivers able to do justice to both the organ recipient and the organ donor, as well as their relatives in this challenging situation.