Anesthesia for Organ Procurement

Introduction

Organ transplantation requires the donation and successful procurement of a human organ. The success of organ transplantation relies on a functioning donor graft. The majority of organs used for transplantation in the United States are from donors after the declaration of neurologic death (donation after neurologic death, DND). Organs from donation after circulatory (cardiac) death (DCD) and living organ donation are in the minority, however, they remain an important source of donors. Organs procured from these sources have different characteristics and present varying challenges in management. For instance, DND donors often have significant physiologic alterations and hemodynamic instability that is associated with neurologic death. These alterations and instability, if not treated, will lead to organ deterioration and may prevent the organ from being suitable for transplantation. In contrast, DCD donors have an obligatory period of hypotension of varying duration before cardiac arrest. The resulting compromise in perfusion can exacerbate reperfusion injury and lead to an increased incidence of posttransplant biliary dysfunction.

The shortage of organs is a worldwide problem and is the most important obstacle in organ transplantation. The gap between the number of patients waiting for transplant and the available organs has widened ( Fig. 61.1 ). In 2015, more than 119,000 transplant candidates were wait-listed in the United States through the United Network for Organ Sharing. Of these, 33,000 candidates underwent transplant surgery. The majority of candidates were awaiting kidney grafts, with a smaller number awaiting liver, heart, and lung grafts. Many strategies were implemented to decrease the gap between the demand and supply, including public awareness campaigns and updates to the organ allocation system. Organ donation rates and the number of organs transplanted per donor vary substantially across geographic regions. Per 100 eligible deaths in the United States in 2016, the organ donation rate was 72.3, ranging from 52.9 to a high of 93.3 (Israni OPTN 2016 Annual Data Report). To increase the number of organs for transplant, many programs have expanded the donor pool by using extended criteria donors (ECDs). Not surprisingly, the number of organs transplanted per donor varies according to donor category: ECD, DCD, or standard criteria donor (SCD). The number of organs transplanted from DCD donors is similar to ECDs, primarily attributable to the ability of the kidney to tolerate the longer periods of ischemia associated with organ procurement after DCD. The use of living-related and living-unrelated donors is widespread in countries with moral or legal objections to neurologic death and is an important worldwide donor source. Many policies have been proposed to promote the best practices in organ donation. There are several areas that have the potential to expand the donor pool, which include deaths that are not referred to the organ sharing agencies and organs that have been procured, but unused for transplant.

Organ transplantation is a complex process that requires close coordination among many specialized teams. Procurement organizations, transplant coordinators, social workers, nurses, surgeons, internists, intensivists, and anesthesiologists are involved in the process. To maximize the number of organs transplanted and to preserve the best possible function of donated organs, anesthesiologists need to understand the pathophysiologic derangements associated with donation and ischemia-reperfusion injury. In addition, anesthesiologists must be aware of the ethical and legal issues related to the declaration of death and organ donation.

Management of Organ Donors After Declaration of Neurologic Death

DND (also called after declaration of brain death) provides the majority of donated organs in the United States. Organ procurement from DND donors can only occur after the declaration of death. The concept of neurologic death emerged in the 1950s. In 1968, a Harvard Ad Hoc Committee on Irreversible Coma established a set of criteria that has been widely used for the determination of neurologic death. In the United States, the Uniform Determination of Death Act was approved in 1981 by the National Conference of Commissioners on Uniform State Laws, in cooperation with the American Medical Association, the American Bar Association, and the President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research. Although the criteria for the declaration of neurologic death were based on ethical principles established several decades ago, the criteria remain valid today.

Although the concept of neurologic death has been widely accepted in Western cultures, minor variations in definition and implementation exist in different countries. Despite these differences, the clinical criteria are similar. A larger difference exists among different cultures in accepting and implementing the neurologic death criteria. In fact, neurologic death has not reached a legal status in some countries, such as China.