Evaluation of the potential deceased organ donor (adult)

INTRODUCTION — Organ transplantation remains the best therapeutic option for many patients with end-stage organ failure. As of October 2023, there were 103,615 patients on the United Network for Organ Sharing (UNOS) waiting list for an organ transplant in the United States, but there were only 42,889 transplants performed in 2022, and 6216 patients died while waiting for a transplant [1]. There were 14,904 deceased donors that yielded 36,421 transplanted organs, averaging 2.44 organs per deceased donor. There is a marked imbalance between the supply and demand for organs, with a severe scarcity of deceased organ donors. Thus, it is imperative that critical care clinicians identify each potential organ donor, ultimately saving additional lives through transplantation.

This topic will review the evaluation of the adult patient for potential deceased organ donation. Management of the deceased adult organ donor and evaluation and management of the potential deceased pediatric organ donor are discussed separately:

●(See "Management of the deceased organ donor".)

●(See "Assessment of the pediatric patient for potential organ donation".)

●(See "Management of the potential pediatric organ donor following neurologic death".)

TYPES OF DECEASED ORGAN DONORS — Seventy percent of organ donors in the United States are deceased, and 65 percent of those are deceased by neurologic criteria, also referred to as brain death (donation after brain death [DBD]), with the remaining organ donors being deceased by circulatory death (donation after circulatory death [DCD]) [1]. The number of DCD donors has risen dramatically over the last decade from 15 to 35 percent of deceased donors.

Donation after brain death — Most (80 percent) organs from deceased donors are procured after declaration of death by neurologic criteria, also known as "brain death." Brain death in the United States is defined as the complete and irreversible cessation of cerebral and brainstem function ("whole brain death"). Brain death is a relatively uncommon event, occurring in approximately 1 percent of all deaths [2]. The three most common causes of brain death are trauma, cerebrovascular accident, and anoxia, with the incidence of anoxic brain death increasing, in part due to nonmedical drug overdose [1]. The diagnosis of brain death is usually established by neurologic examination at the bed side, although ancillary tests may be required when clinical criteria cannot be applied. (See "Diagnosis of brain death".)

The concept of brain death was first reported in 1959, when two French neurologists described 23 ventilated patients with "coma dépassé" or "irretrievable coma" with absent motor and brainstem reflexes and apnea when disconnected from the ventilator [3]. Subsequently in 1968, an ad hoc committee at Harvard Medical School defined brain death as the state of irreversible coma characterized by unresponsiveness and lack of receptivity, absence of spontaneous movement and breathing, absence of brainstem reflexes, and a flat or isoelectric electroencephalogram (EEG) [4]. This was the first report to suggest that a patient could be diagnosed as brain dead and still have a heartbeat. This led to the Uniform Determination of Death Act (UDDA) in 1980, which defined death in an individual who has sustained either irreversible cessation of circulatory and respiratory functions or irreversible cessation of all functions of the entire brain, including the brain stem [5].

Brain death is associated with significant pathophysiological abnormalities that can threaten organ viability. These issues and their management are discussed separately. (See "Management of the potential pediatric organ donor following neurologic death", section on 'Pathophysiologic consequences of neurologic death' and "Management of the deceased organ donor", section on 'Steps to optimize organ function'.)

In spite of the multitude of possible insults to the organs after brain death, organ donation from a brain-dead donor has the advantage of shorter warm ischemic time, since there is blood flow to the organ up to the time of aortic cross-clamping in the operating room. In general, DBD organs have less initial graft dysfunction than DCD organs, but overall graft survival is equivalent [6].

Donation after circulatory death — Because of the severe shortage of donated organs and the limited number of brain-dead donors, another option for organ donation is donation after circulatory death (DCD; also known as donation after circulatory determination of death [DCDD] or non-heart-beating donation [NHBD]). Circulatory death can occur under different circumstances that can lead to organ donation. In 1995, an international workshop on non-heart-beating donors in Maastricht (Netherlands) devised a four-category classification for DCD (table 1). This was subsequently revised to the modified Maastricht classification of DCD that allowed subclassification due to location of cardiac arrest (in or out of the hospital) (table 2). In the United States, Maastricht category III (controlled withdrawal of life support) is the most common scenario for organ donation after circulatory death. Category II (uncontrolled cardiac arrest with unsuccessful resuscitation) is used much less frequently in the United States but is used more commonly in Europe [7]. An international collaborative has provided a statement to expand controlled DCD in the world to offer more patients the opportunity of organ donation and to help countries progress toward self-sufficiency in organ transplantation [8].

A number of mechanically ventilated patients suffer either significant neurologic injuries but do not progress to brain death (eg, stroke) or suffer severe critical illnesses (eg, cardiac arrest, multiple trauma), with no hope for survival. When it is apparent that the patient is not going to survive, and after end-of-life discussions with the clinicians, the family may decide to withdraw life-sustaining therapies and treat the patient with comfort measures only. After the family has made the decision to withdraw treatment, and if the patient is deemed to be a potential donor, then the family may be approached for authorization for organ donation. The decision to withdraw treatment must be made separately and independently from any discussion about organ donation, to avoid possible conflict of interest that the family may perceive [9]. After authorization is obtained, a plan is made for the controlled withdrawal of life support (Maastricht category III). A surgical team from the transplant center needs to arrive prior to extubation. Extubation from mechanical ventilation can occur in the operating room, perioperative area, or intensive care unit (ICU) depending upon the hospital's facilities and policy. Extubation and administration of intravenous (IV) medications for comfort are performed by hospital staff under the supervision of the hospital clinician. The transplant surgical team is prohibited from being in the room, involved in the comfort treatment of the patient, and involved in the declaration of death [10].

If the patient experiences circulatory arrest, with absence of respiration and responsiveness determined by the attending clinician in the allotted time (usually 60 to 90 minutes from withdrawal of ventilatory support), a mandatory waiting period of at least two minutes and not more than five minutes is observed for autoresuscitation [11]. After the mandatory waiting period, the clinician reassesses the patient for permanence of circulatory arrest, apnea, and unresponsiveness, and if present, then death is declared [12]. After the waiting period and death declaration, the organs are procured expeditiously. If the patient does not expire in the allotted time, the patient is no longer considered a potential donor; they are returned to the ICU, and comfort care is continued. (See "Management of the deceased organ donor", section on 'Donation after circulatory death' and 'Circulatory death' below.)

Although kidneys are transplanted most frequently after DCD, liver, pancreas, and lungs may also be procured. If the lungs are recovered, the donor will require nonemergent intubation to inflate the lungs, with either mechanical ventilation or continuous positive airway pressure. In a large retrospective review of DCD lung transplantation in the International Society for Heart and Lung Transplantation (ISLHT) Registry, the five-year survival rate of 61 percent was equivalent to that of lungs from brain-dead donors [13]. Cardiac transplantation after DCD has been performed in Australia and the United Kingdom since 2015 and has been performed in adults in the United States since 2019 [14,15]. There are two strategies for reperfusion of the asystolic DCD heart, including direct procurement and then normothermic ex-vivo machine perfusion or thoracoabdominal normothermic regional perfusion in situ with exclusion of the cerebral vasculature to avoid perfusion to the brain. Both of these techniques are described in detail in the International Society of Heart and Lung Transplantation's consensus statement on heart and lung procurement [16]. Cardiac transplantation from DCD donors in the United States is gaining popularity, with early trials showing similar six-month graft survival to hearts from brain-dead donors [17,18].

RESPONSIBILITIES OF THE CLINICIAN

Identification of the potential organ donor — Identification of the potential deceased organ donor is the initial step in the organ donation process. A potential organ donor is typically a mechanically ventilated intensive care unit (ICU) patient with severe brain injury. Although the primary goal of the critical care clinician is to stabilize and aggressively treat the severely injured patient, unfortunately for some patients, the injury is so severe that the patient progresses to brain death. It is at this time that the clinician must realize that the patient has the potential to save multiple other patients' lives with organ donation. The focus of the clinician needs to shift from aggressive care to declaring the patient dead by neurologic criteria, compassionately informing and explaining to the grieving family that their loved one has died, and continuing supportive treatment of the patient to preserve the possibility of organ donation. Organ donation may provide the only solace to a distraught family coping with the tragic loss of a loved one [19]. Thus, every effort should be made to identify each potential organ donor, to allow emotional closure for the family and to avoid additional lives being lost on the transplant waiting list. (See 'Referral to the organ procurement organization' below.)

There are no universally accepted criteria or definitions for potential deceased organ donors. The following are commonly used clinical criteria (or "triggers") that should prompt a referral from the hospital to the local organ procurement organization (OPO) [20]:

●Any mechanically ventilated patient with one or more of the following:

•Glasgow Coma Scale score <5 without sedation (table 3)

•Brain death examinations being considered

•Withdrawal of life support being considered

•Do-not-resuscitate or comfort care being considered

•The family brings up the topic of organ donation

Referral to the organ procurement organization — Once a patient has been identified as a potential deceased organ donor (see 'Identification of the potential organ donor' above), the clinician or other hospital representative must alert the local OPO about the potential referral. A list of local OPOs is available on the Internet.

To avoid missing the opportunity for donation, the Centers for Medicare and Medicaid Services (CMS) have instituted federal regulations requiring all hospitals to establish a relationship with an OPO and to notify the local OPO of all imminent deaths in a timely manner (within one hour) so the OPO can assess the patient's potential for organ donation [21]. Early and timely referrals to the OPO allow for the evaluation of the medical, legal, and behavioral suitability for organ donation prior to discussions with the family about extubation or the withdrawal of life-sustaining therapy. CMS regulations stipulate that all potential donors should be referred to the OPO and that the OPO should determine suitability for organ donation, rather than the hospital ruling out a patient as a potential donor [21]. Importantly, the OPO should be contacted prior to any mention of donation to the patient's family. (See 'Responsibilities of the organ procurement organization' below.)

When notifying the OPO of a potential donor referral, the clinician should have the patient's chart available and should be prepared to provide the following information:

●Patient's name, age, date of birth, sex, race, and medical record number

●Patient's admitting diagnosis

●Ventilator status of the patient

●Neurologic status of the patient

●Plan for brain death testing

●Patient's current vital signs, labs, and medications

●Patient's past medical history

●Family's understanding of the patient's event/status

A representative of the OPO will typically perform an initial screen on the telephone to determine if the patient has any immediate contraindications to donation (see 'Initial donor screening' below). If there are no contraindications, an OPO coordinator will travel to the hospital to obtain authorization for donation, evaluate the patient for donor suitability, and coordinate the organ donation process. The clinician and hospital staff work in cooperation with the OPO coordinator to help facilitate this process. This may involve several meetings ("huddles") in which the OPO coordinator, clinician, and hospital staff come together to establish a plan, outline individual responsibilities, and discuss communication with the patient's family or next of kin (NOK). (See 'Responsibilities of the organ procurement organization' below.)

Family communication — The clinician's responsibility is to keep the family informed of the patient's clinical status, prognosis, and pertinent test results (eg, results of computed tomography [CT] of the head); answer their questions; and provide compassionate care. They should avoid bringing up the topic of organ donation. Any questions that the family has about organ donation should be deferred to the OPO.

Determination/declaration of death — Determination and declaration of death are the responsibilities of the clinician and are required before the surgical removal of organs for transplantation. Determination of death differs for neurologic death (brain death) and circulatory death. Once death has been determined, the clinician informs the patient's family or NOK that the patient is deceased and documents a death note stating that the examination has been performed.

Brain death — The clinician is responsible for determining and declaring the diagnosis of brain death according to state law and institutional policy. Importantly, the clinician who declares brain death cannot be the clinician who recovers the donated organs from the patient. Documentation of brain death should include the date and time of death, and results of the clinical examination, apnea test, and any ancillary testing. Most hospitals have an established brain death policy to ensure that documentation and determination of brain death have been properly performed. The clinician should refer to their respective hospital's brain death policy to determine appropriate institutional practice.

Suggested guidelines are available for assisting the clinician in determining brain death [22]. A large, multidisciplinary, international panel has formulated a consensus statement of recommendations on the determination of brain death, which represents the most current and extensive review of the data (The World Brain Death Project) [23]. A discussion of the clinical criteria and ancillary tests used to establish the diagnosis of brain death is presented separately:

●(See "Diagnosis of brain death", section on 'Diagnosis: Clinical criteria'.)

●(See "Diagnosis of brain death", section on 'Ancillary tests'.)

Circulatory death — The clinician is responsible for determining and declaring the diagnosis of circulatory death. Once the patient's family has made the decision to withdraw life-sustaining treatments and the OPO coordinator has obtained authorization for organ donation from the family, a plan is made for withdrawal of life support.

The OPO typically requests 24 hours to prepare for a donation after circulatory death (DCD) organ procurement, but families may want to withdraw care sooner than this and sometimes within a few hours. The OPO needs time to assess the donor's organ potential, run organ match lists with the United Network for Organ Sharing (UNOS), contact the transplant centers on the match list, obtain blood for HLA and serologic infectious disease testing, and find available transplant surgeon(s). If a non-local transplant center accepts a thoracic organ, they will typically need at least 12 hours to arrange a private jet for transportation. If the abdominal organs are the only organs to be procured and a local surgeon is available, the earliest a DCD operating room can be scheduled is in six to eight hours. If the family demands the extubation to be performed in less than four hours, this would limit donation to only the kidneys since serologies for infectious diseases need at least six hours to perform. Thus, it is important to inform the OPO early in a possible DCD case, so they can perform some of these tasks earlier and limit the delay in going to the operating room.

The clinician and hospital staff are responsible for extubation and administration of intravenous (IV) medications for comfort and sedation as appropriate. Full disclosure to the family regarding any medications and/or interventions that are solely for the organ donation process (eg, heparin, bronchoscopy) is necessary, and informed consent is required. A surgical team from the transplant center must arrive prior to extubation of the patient. Extubation from mechanical ventilation can occur in the operating room, perioperative area, or ICU depending upon the hospital's facilities and policy. Importantly, the transplant surgical team cannot be allowed in the room and should not be involved in the comfort treatment of the patient or the declaration of death. (See "Withholding and withdrawing ventilatory support in adults in the intensive care unit".)

Following withdrawal of life support, the patient is observed until circulatory function ceases. Determination of circulatory death is based upon cardiorespiratory criteria (permanent absence of respiration, circulation, and responsiveness). The declaration of cardiac death is based upon permanent loss of circulation (absent pulse pressure on an arterial line) and not cardiac electrical activity (ie, asystole). In a patient with pulseless electrical activity, waiting for asystole to occur adds unnecessary warm ischemic time to the organs [9,24]. Most hospital protocols mandate that if circulatory arrest does not occur within 60 to 90 minutes from withdrawal of ventilator support, the patient should be returned to the ICU and organ procurement is aborted. If the patient develops circulatory arrest in the allotted time, the clinician documents the time and a mandatory waiting period of at least two minutes and not more than five minutes is observed for autoresuscitation (ie, return of spontaneous circulation) [9,11,24,25]. After the waiting period and reconfirmation of absent pulse, respiration, and responsiveness, the patient is declared dead, and the organs are then procured by the surgical team. If lungs are being procured, the donor is reintubated and the lungs inflated with either continuous positive airway pressure (CPAP) or mechanical ventilation.

Predicting time of death after withdrawal of life support — From the perspective of the transplant team, the awaiting recipient, the potential donor family, and the hospital resources utilized, it would be advantageous to predict which patients will or will not expire in the 60 minutes after withdrawal of care [20]. Several studies have developed and evaluated criteria to predict the likelihood of death after extubation [26-31]. As examples:

●In one study of 43 patients, the University of Wisconsin Donation after Cardiac Death Evaluation Tool, which assigns scores to clinical parameters observed during a 10 minute spontaneous breathing trial, correctly predicted the likelihood of death within 60 minutes with a rate of 84 percent [26].

●A prospective study of 533 patients evaluated the utility of the UNOS DCD consensus committee criteria for prediction of death within 60 minutes after withdrawal of life-sustaining treatment (table 4) [27]. A total of 29, 52, 65, and 82 percent of patients with 0, 1, 2, and 3 UNOS DCD criteria, respectively, died within 60 minutes of withdrawal of life support.

●Another prospective study of 178 patients examined the utility of a predictive score for cardiac death in patients in a coma with irreversible brain injury (DCD-N score) based upon four clinical parameters (corneal reflex, cough reflex, best motor response, and oxygenation index) [28]. A DCD-N score of 3 or more had a sensitivity of 72 percent and specificity of 78 percent for predicting death within 60 minutes of withdrawal of life-sustaining treatment.

The clinical judgment of the intensivist has been found to predict death within 60 and 120 minutes with a sensitivity of 73 and 89 percent, respectively, and a specificity of 56 and 25 percent, respectively [29]. Other factors that may predict death after withdrawal of life support include controlled mechanical ventilation [29], mean arterial pressure [30], age, fraction of inspired oxygen (FiO₂), and mode of ventilation [31].

Two factors that are difficult to assess prior to extubation and can have a significant impact on whether the patient will expire in the allotted time are the patency of the upper airway and the amount of sedation the patient will receive for comfort measures. Patients with a difficult intubation, laryngeal edema, cervical trauma, or sleep apnea may have more difficulty maintaining their airway, particularly when receiving sedatives and narcotics. This may quickly lead to hypoventilation and hypoxemia and subsequent circulatory arrest.

With each DCD case, the benefit of recovering an organ must be weighed against the cost of an unsuccessful attempt. A consensus statement by the Society of Critical Care Medicine/American College of Chest Physicians/Association of Organ Procurement Organization (AOPO) regarding DCD stated, "In order to maximize the potential of adult DCD donors, an increase in the number of unsuccessful cases must be acceptable" [20]. Since the best predictive tools are inaccurate 30 percent of the time, some OPOs are not using any predictive tools but rather pursuing DCD if the patient has an organ that is deemed transplantable. Our OPO uses this strategy and recovers organs on average from 65 percent of DCD patients, which is comparable to using the predictive tools.

Optimization of organ function — Optimal donor management is essential in both the ICU and in the operating room to maximize the function of transplanted organs, as well as the quality of life and survival benefits conveyed to the recipients. Specific details regarding the management of the potential deceased organ donor prior to organ procurement are discussed separately. (See "Management of the deceased organ donor".)

For donation after brain death (DBD) donors, once brain death has been declared and consent for donation has been obtained, the OPO is responsible for medical management of the donor until the time of organ procurement (see 'Coordination of donor management' below). The OPO also assumes all medical costs associated with care of the donor, including routine care, diagnostic testing, procedures, and operating room costs. Nursing care continues to be provided by the hospital staff in collaboration with the OPO coordinator. By contrast, DCD donors remain under the care of the clinician and all care is directed by the clinician until the time of organ procurement. The OPO also assumes all costs of the care of a DCD donor, starting once authorization has been obtained and ending with procurement in the operating room or at 90 minutes if the patient does not expire.

RESPONSIBILITIES OF THE ORGAN PROCUREMENT ORGANIZATION — The Organ Procurement and Transplantation Network (OPTN), which is responsible for organ allocation and policy development, is comprised of 56 organ procurement organizations (OPOs), over 250 transplant centers, and 156 histocompatibility laboratories. Each OPO has a federally assigned geographic region, or donation service area (DSA), and is responsible for identifying potential donors, obtaining authorization, managing the donor to optimize organ function, allocating organs, and preserving all organs in their assigned area [32]. The OPO collaborates with the donor hospital's medical staff to achieve these goals. The transplant centers are responsible for registering recipients on the United Network for Organ Sharing (UNOS) waitlist, reviewing and accepting organ offers, and procuring and transplanting the organs. The OPO also works closely with the transplant centers during the allocation process to facilitate placement of the organs with recipients according to organ-specific allocation schemes, arrange the procurement of operating room time, and label and package the organs for transportation.

Initial donor screening — The organ donor referral from a hospital will be initially screened to exclude obvious patients who cannot be donors. Common screening questions include:

●What is the age of the patient?

●Is the patient currently on a ventilator?

●Does the patient have an active malignancy or a history of malignancy?

●Are brain death examinations planned?

●Is the family ready to withdraw support?

Immediate contraindications to donation — The following patient characteristics are generally considered to be absolute contraindications to deceased organ donation:

●Age >90 years. (There are several anecdotal cases of successful liver donation from nonagenarians.)

●Not on a ventilator.

●History of active metastatic cancer.

●History of active hematologic malignancy.

●History of active melanoma.

●History of Creutzfeldt-Jakob disease.

All other patients are evaluated on an individual basis, as discussed below. (See 'Evaluation of donor suitability' below.)

Authorization for organ donation — Before any organ donation can proceed there must be authorization for the organ procurement. There are two different systems of authorization. The authorization can be active, in which the donor (premortem authorization) or next of kin (NOK) must consent to organ donation upon the donor's death ("opt-in system"). The other option is when the legislature of a country has stipulated that all citizens are automatically consented (presumed consent) for organ donation upon their death, unless they object and refuse donation ("opt-out system"). The United States has an opt-in system, but many countries in Europe have an opt-out system. Although it would seem logical that an opt-out system would have higher organ donation rates, one study showed no significant difference in deceased donors per million population (20.3 versus 15.4) or in total solid organs transplanted per million population (63.6 versus 61.7) between opt-out and opt-in countries, respectively [33].

Since 1998, the Centers for Medicare and Medicaid Services (CMS) has required that authorization for organ donation must be performed by a "designated requestor," which is defined as either an OPO staff member or a hospital staff member who has been trained by the OPO to be qualified to request authorization for donation [21]. Authorization for organ donation should not be obtained by the clinician caring for the patient, unless the patient is a "designated requestor." Several studies have shown increased authorization rates when the family is approached by trained OPO personnel, who can spend time with the family in a quiet setting to explain the donation process [34-42].

The Uniform Anatomical Gift Act (UAGA) was first enacted in 1968 to permit individuals older than 18 years to donate their organs and tissues after death. In 2006, the UAGA was revised to simplify the consent process, enabling individuals to consent to organ donation by expressing their wish when obtaining a driver's license, joining a state or national registry of organ donors, or by writing their wish in a will or other advance directive. This "First Person Authorization" (FPA) of an adult for organ donation via one of these three methods is legally binding and cannot be revoked by family or NOK.

OPOs have access to all donor registries when notified of a potential donor. The OPO coordinator notifies the family of the potential donor's registry status during the initial conversation regarding donation options. A patient on the registry has already provided authorization for donation, and no additional consent or authorization is needed from the family. The only exception to this is a patient under 18 years of age who signed up on the registry upon obtaining a driver's license; such a patient is considered to be a minor, and the legal parent or guardian can rescind authorization. If the patient is not on the registry, authorization for donation must be obtained from the NOK as defined by the state of residence. Given the many different religious, cultural, ethnic, and emotional views that the donor's family may have, the OPO representative must approach the donor family with sensitivity and discretion. The OPO coordinator must explain in detail the options for donation to the NOK to obtain informed authorization. CMS has specified a list of requirements that the OPO must perform to obtain authorization (table 5) [43]. The family's knowledge of the patient's prior decision about donation is significantly associated with the family's willingness to donate [37,44,45].

The optimal timing of the approach for consent has not been clearly defined. Some studies have found increased authorization rates when the request for organ donation was separated by time and personnel, or "decoupled" from the time the family was informed of the diagnosis of brain death [38,46], although another study found conflicting results [47]. In our OPO experience, approaching the family at a separate time, by an experienced OPO staff member, increases the likelihood of donation. This separation between declaring the patient brain dead and making an approach allows families to dissociate their feelings about the clinician's efforts to save their loved one from the OPO's request to offer the chance of life to a waiting recipient. If the clinician caring for the patient wishes to be involved in the organ donation discussion, the clinician should collaborate with the OPO staff and approach the family jointly at an appropriate time [48].

Evaluation of donor suitability — The OPO coordinator is responsible for determining suitability of the donor for transplantation. This requires a thorough review of the patient's medical record to identify any medical condition that would preclude organ donation or be transmissible to the recipient. The OPTN has mandated certain tasks that the OPO must perform on every organ donor.

Medical and social history — The OPO coordinator reviews the patient's medical chart for any history of malignancy, active infection, or other diseases that may affect transplanted organ function, such as diabetes or hypertension. The OPO coordinator also obtains a detailed medical and social history from the patient's family or NOK, if available, including a history of smoking, alcohol consumption, and use of nonprescription drugs. The patient's travel history should also be reviewed, particularly to endemic areas of transmissible parasites (eg, Strongyloides, Trypanosoma cruzi [Chagas disease]) and viruses (eg, Zika).

To reduce the risk of viral transmission of HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) through organ transplantation, the United States Public Health Service (USPHS) developed and revised a set of criteria (table 6) to identify donors who have risk factors for acute HIV, HBV, and HCV infection [49]. These risk criteria include donor behavioral characteristics that could place the potential recipient at increased risk of viral disease transmission and do not refer to the quality of the organ. In obtaining the donor's medical, social, and sexual history from the medical record and from available family or friends, the OPO coordinator must also determine if the donor meets any of these risk criteria within the past 30 days. If the donor meets any of the criteria, or if the donor's history cannot be ascertained, the donor is considered to be at risk for acute HIV, HBV, or HCV infection, and the transplant surgeons and recipients must verify that they have been informed of the risk prior to accepting organs from these donors. Such organs are more likely to be discarded, despite the fact that recipient and graft survival of these organs are generally comparable with that of organs from donors without risk of HIV, HBV, and HCV infection [50]. In accepting an organ with risk for HIV, HBV, and HCV, the surgeon and recipient must weigh the small risk of donor-derived infection with the risk of death on the waiting list. (See 'Infection' below.)

The concept of donors at risk for acute HIV, HBV, or HCV was developed to identify donors at risk of recent viral infection who might have false-negative serologic testing for these viruses. False-negative testing can occur when patients are tested during the "serologic window period" between the time of acute infection and the formation of antibodies detectable by serologic testing. To decrease the chance of viral transmission during the serologic window period, OPTN policy requires nucleic acid amplification testing (NAT) for HIV, HBV, and HCV on all donors. The NAT window period is much shorter than the antibody (serologic) window, and NAT becomes positive within days of infection (11 to 13 days for HIV, three to five days for HCV, and 20 to 22 days for HBV) [51]. For most exposures, NAT testing decreases the risk of infection during the serologic window period by approximately 10-fold. Thus, the goal is to identify donors with negative serology and negative NAT testing for HIV, HBV, and HCV who are at higher risk for recent acquisition of the viruses and could inadvertently transmit the infection to the recipient. The risk of infection during the NAT window period is extremely low if the risk behavior occurred more than three weeks prior to the NAT testing. (See 'Infectious disease testing' below.)

The risk of viral transmission varies widely among the increased-risk behaviors. Donors with intravenous (IV) drug use carry the highest risk of HCV transmission during the NAT window period of 0.32 percent, while donors with a history of incarceration have a very low rate of 0.008 percent. The risk of HIV transmission with a negative NAT is <0.1 percent regardless of the behavior [52,53].

Malignancy — In general, a history of past or current malignancy in the potential donor is not an absolute contraindication to organ donation. When a donor presents with an active or prior history of malignancy, the final decision about organ suitability rests with the transplant team and potential recipient. The risk of cancer transmission from the donor to the recipient must be weighed against the risk of the recipient not receiving an organ. If death of the recipient is imminent without a transplant, then accepting a low risk of malignancy transmission may be reasonable. The recipient must be fully aware of the risk and provide informed consent to proceed with transplantation [54].

Reported rates of donor-derived tumor transmission to organ recipients are highly variable, ranging from 0 to 42 percent, depending upon the source of the data [54]. Much of these data have come from the Israel Penn International Transplant Tumor Registry, which has followed organ recipients from donors with known malignancies for over 40 years. The data were obtained from voluntary reporting of index cases, and therefore, may be prone to overestimation [55]. UNOS has also collected outcome data on recipients from donors with active or previous malignancies since 1996, but reporting the data was not mandated by the OPTN policy until 2005, and therefore, earlier data may be prone to underestimation. In 2008, the Ad Hoc Disease Transmission Advisory Committee of OPTN formed a subcommittee to examine the donor-related malignancy transmission data and evaluate the risk of developing a malignancy in the recipient. They defined six risk categories (none, minimal, low, intermediate, high, and unknown) for donor-related tumor transmission with recommended clinical use and suggested risk categorization for specific tumor types (table 7) [56]:

●Malignancies not involving the central nervous system (CNS) – Patients with metastatic cancer, choriocarcinoma, melanoma, lung cancer, or breast cancer (stage >0) have a high rate of transmission and are a contraindication for organ donation. In addition, patients with a history of aggressive tumors with the potential for late metastases, such as melanoma, leukemia, lymphoma, breast, and colon cancer, are considered high risk for transmission and are a contraindication for organ donation [57]. Nonmelanoma skin cancer without metastases, in situ carcinomas, and some small thyroid carcinomas have a minimal risk of transmission. A kidney with a completely resected, small, solitary, well-differentiated renal cell carcinoma may be usable for transplantation [56]. In general, patients with a history of a treated malignancy and patients who are disease free for more than five years, with a high probability of cure, may be considered for organ donation.

●CNS malignancies – Primary CNS malignancies are generally considered to have a low rate of metastasis, and patients with nonmetastatic primary CNS malignancies can be considered for organ donation. Tumor transmission rates are highly variable, depending upon the source of the data, and range from 0 to 23 percent [20]. Violation of the blood-brain barrier, other than with an uncomplicated biopsy, may increase the risk of tumor transmission. In one study of 62 recipients of organs from donors with an active CNS malignancy, the overall rate of tumor transmission was 23 percent [58]. Risk factors for tumor transmission included high-grade tumors, the presence of a ventriculoperitoneal or ventriculoatrial shunt, previous craniotomy, and systemic chemotherapy. Patients with one or more of these risk factors had a higher risk of tumor transmission compared with those who had no risk factors (53 versus 7 percent). A subsequent study of 228 donors with a primary brain tumor found no transmission of the CNS malignancy in any of the 778 organ recipients, including 262 transplants from donors with high-grade tumors and 494 from donors with previous neurosurgical intervention or radiotherapy [59]. Transplant survival was equivalent to that of matched controls. These findings suggest that the risk of cancer transmission is much less than previously thought.

Metastases to the brain can be misdiagnosed as primary CNS tumors or intracranial hemorrhage, and transplantation of organs from these donors has a poor prognosis for the recipients. In a study of 42 recipients of organs from patients with misdiagnosed primary CNS tumors, 74 percent developed a donor-derived malignancy and 64 percent developed metastatic disease; the five-year survival rate was 32 percent [60]. Thus, in donors who present with unexplained intracranial hemorrhage or a suspected primary CNS neoplasm without a biopsy, an evaluation for metastatic disease should be considered.

Infection — Organ donors are typically in the intensive care unit (ICU) and frequently have community-acquired or nosocomial infections. The risk of transmitting an infection to a potential recipient must be considered before organ procurement.

●Bacteremia/bacterial sepsis – In general, bacterial donor infections that are treated with appropriate antibiotics are not a contraindication to organ donation. If a potential donor is found to be bacteremic, appropriate antibiotic therapy should be administered as soon as possible. Delaying organ procurement until the donor has received antibiotics for at least 48 hours is reasonable.

Multiple studies have demonstrated very low rates (0 to 8 percent) of donor-derived infections in the recipient [61-64]. In these studies, appropriate antibiotics were administered to the donors before organ procurement and continued in the recipient for four to seven days. In one report, no adverse outcomes in terms of survival and graft function were observed in the recipients of bacteremic donors [62].

●Meningitis – Bacterial meningitis, treated with appropriate antibiotic therapy, is not a contraindication to organ donation. Several studies have reported successful organ retrieval from donors with documented or assumed bacterial meningitis who were treated with appropriate antibiotics prior to organ procurement, with no transmission of infection to the recipient and no reduction in patient survival [65-68]. There are no guidelines for the optimal duration of donor antibiotic treatment before organ procurement, but some experts suggest treating for 24 to 48 hours. The organ recipient should also be treated with the same antibiotic regimen for 5 to 10 days.

Patients with viral or parasitic encephalitis should not be considered for organ donation [69]. Donor-to-recipient transmission has been reported for West Nile virus, rabies virus [70], lymphocytic choriomeningitis virus [71], and Balamuthia mandrillaris with very poor recipient outcomes.

●HIV, hepatitis B, and hepatitis C – The use of organs from donors who are HIV-infected is contraindicated for HIV-uninfected recipients due to the risk of viral transmission [20]. Transplantation of organs from HIV-infected donors into HIV-infected recipients has been reported, but this practice remains experimental. A National Institutes of Health (NIH)-sponsored, multicenter study of organ transplantation from HIV-infected donors to HIV-infected recipients under a research protocol is underway. Patients who are seronegative for HIV but meet risk behavioral criteria (table 6) for HIV infection should not be excluded as organ donors, but the transplant team and potential recipient must be notified:

•(See "Kidney transplantation in adults: Kidney transplantation in patients with HIV", section on 'Donors with HIV'.)

•(See "Lung transplantation: Deceased donor evaluation", section on 'Donor infection'.)

The use of organs from donors infected with HBV and/or HCV is not contraindicated, but the suitability of such organs depends upon several factors, including the serologic status of both the donor and the recipient. The risk of viral transmission from a donor who tests positive for anti-hepatitis B core (anti-HBc) antibody, but negative for HBV DNA and hepatitis B surface antigen (HBsAg), is low. These issues are discussed in more detail elsewhere:

•(See "Kidney transplantation in adults: Hepatitis B virus infection in kidney transplant recipients", section on 'Suitable donors' and "Kidney transplantation in adults: Hepatitis B virus infection in kidney transplant recipients", section on 'Considerations for donor selection'.)

•(See "Liver transplantation in adults: Deceased donor evaluation and selection", section on 'Hepatitis B virus-positive donors'.)

•(See "Hepatitis C virus infection in kidney donors".)

•(See "Liver transplantation in adults: Deceased donor evaluation and selection", section on 'Hepatitis C virus-positive donors'.)

•(See "Lung transplantation: Deceased donor evaluation", section on 'Donor infection'.)

Laboratory testing and procedures

Routine blood and urine tests — The following laboratory tests are performed on all deceased donors:

●Complete blood count

●Serum electrolytes, blood urea nitrogen (BUN), and creatinine

●Liver function tests

●Urinalysis

●Arterial blood gas (ABG)

●Prothrombin time (PT)/international normalized ratio (INR) and activated partial thromboplastin time (aPTT)

●Blood, sputum, and urine cultures

Laboratory tests are repeated depending upon the clinical condition of the donor. The OPTN requires certain laboratory tests to be performed within a certain time frame prior to organ offers. As examples, a urinalysis is required within 24 hours of cross-clamping, an ABG and a chest radiograph are required within two to three hours of lung offers, and liver function tests are required within 12 hours of liver offers. Blood for serologic testing for HIV, HCV, and HBV must be drawn within 96 hours of procurement. A plasma and serum sample must be drawn within 24 hours of procurement and stored frozen for 10 years. This sample is used to detect donor-derived infections and diseases retrospectively should they occur in the recipient.

ABO blood typing — ABO blood typing must be performed on two different blood samples, drawn at separate times, with congruent results. ABO subtyping must be performed on all donors with blood type A to determine if the blood type is non-A1, since blood type A, non-A1 donors (eg, blood type A2) can be used for low titer blood type B recipients. ABO subtyping can only be reported if there is congruence between the two samples. The blood type must be verified by two qualified health care professionals, with source documentation, and reported to UNOS prior to the match run.

Histocompatibility testing — All deceased donors must have human leukocyte antigen (HLA) typing of antigens A, B, Bw4, Bw6, C, DR, DR51/52/53, DQA1, DQB1, and DPB1. Many OPOs send the donor's blood samples to a reference lab for HLA typing. However, if the donor is at an academic hospital or transplant center, HLA testing is typically performed at the institution's tissue typing laboratory. The results must be available before any kidney or pancreas is offered to the transplant centers on the match run. The HLA results must be available before final acceptance of an offer for heart or lung donors, if required by the transplant program. The OPO provides donor blood or lymph nodes to the transplant centers for direct crossmatching for kidney donation. (See "Kidney transplantation in adults: Overview of HLA sensitization and crossmatch testing", section on 'HLA typing'.)

Infectious disease testing — All organ donors are tested for various infectious diseases that can be transmitted to a recipient. Infectious disease testing requirements include the following:

●HIV antibody (anti-HIV) donor screening test or HIV antigen/antibody (Ag/Ab) combination test

●HIV RNA nucleic acid amplification test (NAT)

●Hepatitis B surface antigen (HBsAg) donor screening test

●Hepatitis B core antibody (anti-HBc) donor screening test

●Hepatitis B DNA NAT

●Hepatitis C virus antibody (anti-HCV) donor screening test

●Hepatitis C RNA NAT

●Cytomegalovirus antibody (anti-CMV) donor screening or diagnostic test

●Epstein-Barr virus antibody (anti-EBV) donor screening or diagnostic test

●Syphilis donor screening or diagnostic test

●Toxoplasma immunoglobulin G (IgG) antibody test

●Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) NAT on a lower respiratory sample for lung donors

The donor specimen should be collected within 96 hours before organ procurement with the result available at the time of procurement. To ensure accuracy, infectious disease serologic testing should be performed on donor blood that is not hemodiluted. Hemodilution may occur with massive blood product transfusion or shock resuscitated with large volumes of IV crystalloid and colloidal fluids. The OPO must document all blood products, colloids, and crystalloids that the donor received during the hospitalization. Hemodilution is determined by a US Food and Drug Administration (FDA) hemodilution calculation. If the donor's blood sample is determined to be hemodiluted, then a pretransfusion blood sample should be utilized, if available, for repeat testing.

Additional organ-specific testing — Depending upon the organs available for donation, additional testing may be required:

●Echocardiography is required for potential heart donors; a cardiac catheterization may be required for older heart donors (>40 years) or those with significant risk factors for coronary heart disease.

●Fiberoptic bronchoscopy is required for potential lung donors. Computed tomography (CT) of the chest is also frequently requested.

●A percutaneous liver biopsy may be requested for liver donors with obesity, positive testing for HCV, or history of alcoholism.

Allocation of organs — The donor's medical history, physical examination, and all testing results are uploaded into DonorNet, a UNOS-based computer program that will allow a match run with patients on the waiting lists to be generated for each organ. The match run provides a sequential list of potential recipients for each organ, based upon OPTN allocation policy for that specific organ. A tenet of OPTN allocation policy is that organ offers are not biased by race, ethnicity, sex, religion, political influence, national origin, financial status, or geographic location. Prior to 2017, the allocation schemes gave priority to local transplant centers in the OPO's DSA, with the intent to decrease cold ischemic time. This policy was legally challenged on the basis of geographic disparity, and now all organs are allocated on concentric circles of specified miles (250, 500, 1000) from the donor hospital. The policy is intended to provide an equitable distribution of organs to those recipients most in need. Effective March 2023, a new policy for matching lung transplant candidates with donors is the first to utilize an approach known as continuous distribution. It is projected to decrease deaths on the waitlist and provide more lung transplants for the most medically urgent candidates.

Each organ has a unique algorithm that is followed to generate the match run. The OPO must follow the rank order of the match run in making organ offers to the transplant program. Each transplant center has one hour to open the electronic offer and to respond to the offer by accepting or declining the organ. After the organs have been allocated, an operating room-procurement time is arranged. (See "Kidney transplantation in adults: Organ sharing", section on 'National deceased-donor kidney allocation policy'.)

Coordination of donor management — The evaluation and management of an organ donor traditionally occurs in the donor's hospital. The OPO uses the donor hospital's ICU, nursing staff, ancillary services, and operating room for procurement of organs. The time from declaration of brain death to organ procurement is typically between 24 and 72 hours, depending upon the number of organs procured.

Organ recovery centers — Alternatively, donor management and organ procurement can take place at a dedicated organ recovery center (ORC) that is independent of any hospital or transplant center [72,73]. These OPO-based ORCs are typically equipped with an ICU, laboratory, portable radiograph equipment, CT scanner, cardiac catheterization lab, and organ and tissue surgical suites. After authorization for organ donation is obtained, the OPO transfers the donor from the hospital to the recovery center by ambulance or plane, and diagnostic testing and management of the donor occurs in the ORC under the supervision of a medical director. After allocation of the organs, the transplant surgeons travel to the ORC and procure the organs in the surgical suite. This model for organ recovery has been shown to decrease surgeons' time and air travel, cold ischemic time, and cost, while increasing organ yield [74-76]. One study showed that the lung donation rate increased from 20 to 34 percent with a donor lung management protocol at a specialized donor recovery center [77]. Other studies have demonstrated the specialized donor recovery center to be less costly and more effective, particularly for thoracic organ donors [78], and to be an ideal setting for organ donor management research studies [79]. Additional benefits of an OPO-based facility include appropriate surgical equipment, operating room staff familiar with organ procurement, and favorable operating room time, allowing the surgeons to operate during the day rather than at night.

More recently, OPOs have built ORCs in transplant centers or community hospitals. The benefits of a hospital-based ORC include the ability to use the facilities of the hospital (eg, laboratory, CT scanner, cardiac catheterization laboratory), which decreases initial building cost, but the downside is the need to compete with living patients for these same facilities [80]. At present, there are 28 ORCs out of 56 OPOs (50 percent) in the United States, and more are opening every year.

STRATEGIES TO EXPAND THE DONOR ORGAN SUPPLY — As outcomes have continued to improve after solid organ transplantation, the demand has remained consistently higher than the supply of transplantable organs. Several approaches have been developed to address this need:

●Hepatitis C-positive donors – The advent of direct-acting antivirals (DAAs) has revolutionized the therapy for hepatitis C virus (HCV) and enabled the safe transplantation of HCV-positive hearts, lungs [81,82], kidneys, and livers into HCV-positive and HCV-negative recipients. The use of HCV-positive donor organs is discussed in more detail elsewhere. (See "Hepatitis C virus infection in kidney donors" and "Hepatitis C virus infection in liver transplant candidates and recipients".)

●HIV-positive donors – HIV-positive patients with an undetectable viral load and a CD4 count >200 have been able to undergo kidney and liver transplantation successfully. Historically, the donors were always HIV negative. However, transplantation of HIV-positive, deceased-donor kidneys into HIV-positive recipients has been reported to be safe and effective. A more detailed discussion of kidney transplantation in HIV-infected individuals is presented separately. (See "Kidney transplantation in adults: Kidney transplantation in patients with HIV".)

●HLA-incompatible donors – Advances in human leukocyte antigen (HLA) desensitization strategies have enabled the transplantation of kidneys into HLA-incompatible recipients. This is discussed in more detail elsewhere. (See "Kidney transplantation in adults: HLA-incompatible transplantation".)

●Normothermic ex vivo perfusion – Standard approaches to organ preservation have included cold storage for kidneys, pancreases, livers, hearts, and lungs as well as cold pulsatile preservation for kidneys. Normothermic ex vivo perfusion has been described for clinical lung, liver, and kidney transplantation and has shown promising results. (See "Lung transplantation: Donor lung procurement and preservation", section on 'Normothermic ex-vivo perfusion (after cold static preservation)' and "Liver transplantation in adults: Deceased donor evaluation and selection", section on 'Machine liver perfusion'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Kidney transplantation" and "Society guideline links: Management of potential deceased organ donors".)

SUMMARY AND RECOMMENDATIONS

●General principles – Organ transplantation remains the best therapeutic option for many patients with end-stage organ failure. However, there is a marked imbalance between the supply and demand for organs, with a severe scarcity of deceased organ donors. Thus, it is imperative that critical care clinicians identify each potential organ donor, ultimately saving additional lives through transplantation. (See 'Introduction' above.)

●Types of deceased organ donors – Seventy percent of organ donors are deceased, and 65 percent of those are deceased by neurologic criteria, also referred to as brain death (donation after brain death [DBD]), with the remaining organ donors being deceased by circulatory death (donation after circulatory death [DCD]). DCD donors have increased significantly over the last decade. (See 'Types of deceased organ donors' above.)

●Responsibilities of the clinician – In the evaluation of the potential deceased organ donor, responsibilities of the clinician include the following:

•Identification of the potential deceased organ donor – This is the initial step in the organ donation process. There are no universally accepted criteria or definitions for potential deceased organ donors. Commonly used clinical criteria (or "triggers") that should prompt a referral from the hospital to the local organ procurement organization (OPO) include any mechanically ventilated patient with one or more of the following (see 'Identification of the potential organ donor' above):

-Glasgow Coma Scale score <5 without sedation (table 3)

-Brain death examinations being considered

-Withdrawal of life support being considered

-Do-not-resuscitate or comfort care being considered

-The family brings up the topic of organ donation

•Referral to the OPO – Once a patient has been identified as a potential deceased organ donor, the clinician or a hospital representative must alert the local OPO about the potential referral. A list of local OPOs is available on the Internet. The Centers for Medicare and Medicaid Services (CMS) have instituted federal regulations requiring all hospitals to notify the local OPO of all imminent deaths in a timely manner (within one hour) so the OPO can assess the patient's potential for organ donation. Importantly, the OPO should be contacted prior to any mention of donation to the patient's family. (See 'Referral to the organ procurement organization' above.)

•Family communication – The clinician's responsibility is to keep the family informed of the patient's deteriorating clinical status, poor prognosis, and pertinent test results; answer their questions; and provide compassionate care. They should avoid bringing up the topic of organ donation. Any questions that the family has about organ donation should be deferred to the OPO. (See 'Family communication' above.)

•Determination/declaration of death – Determination and declaration of death are the responsibilities of the clinician and are required before the surgical removal of organs for transplantation. Determination of death differs for neurologic death (brain death) and circulatory death. Once death has been determined, the clinician informs the patient's family or next of kin (NOK) that the patient is deceased and documents a death note stating that the examination has been performed. (See 'Determination/declaration of death' above.)

•Optimization of organ function – Optimal donor management is essential in both the intensive care unit (ICU) and in the operating room to maximize the function of transplanted organs, as well as the quality of life and survival benefits conveyed to the recipients. For DND donors, once brain death has been declared and consent for donation has been obtained, the OPO is responsible for medical management of the donor until the time of organ procurement. Nursing care continues to be provided by the hospital staff in collaboration with the OPO coordinator. By contrast, DCD donors remain under the care of the clinician and all care is directed by the clinician until the time of organ procurement. (See 'Optimization of organ function' above.)

●Responsibilities of the OPO – In the evaluation of the potential deceased organ donor, the responsibilities of the OPO are to identify potential donors, obtain authorization for donation, manage the donor to optimize organ function, allocate organs, and preserve all organs in their assigned donation service area (DSA) [32]. The OPO collaborates with the donor hospital's medical staff to achieve these goals. The OPO also works closely with the transplant centers during the allocation process to facilitate acceptance of the organs, arrange procurement operating room time, and label and package the organs for transportation. (See 'Responsibilities of the organ procurement organization' above.)