Continuing Education Activity

Organ transplantation involves removing an organ from a person (the donor) and placing it into another person (the recipient). This procedure is performed on patients with end-stage organ failure, potentially increasing life expectancy and improving the quality of life for recipients. The most commonly transplanted organs are the kidneys, liver, heart, and lungs, with pancreatic and intestinal transplants being less common. Recent advancements include vascularized composite allografts, such as face, hand, and penis transplants, for reconstructive procedures. Non-vital tissues such as bones, corneas, and tendons can also be transplanted. 

This activity reviews the concerns and implications of organ donation, retrieval, and transplantation for the recipient. Successful organ procurement from patients with trauma requires extensive coordination between trauma teams and organ procurement organizations. Early detection protocols and timely notifications to an organ procurement organization in the emergency department are crucial to enhancing donation rates. Dedicated protocols for brain death declaration, the involvement of trauma surgeons in donor councils, and efficient teamwork between treatment and procurement teams are crucial for maximizing organ donations and achieving optimal patient outcomes. 

Objectives:

• Identify brain death in patients with trauma who are potential organ donors.

• Assess the critical pathway of organ procurement from patients with trauma using current guidelines.

• Evaluate the concepts associated with organ retrieval based on patient death related to brain death or circulatory collapse.

• Implement clinical judgment within an interprofessional healthcare team to improve trauma organ procurement.

Introduction

Organ transplantation involves removing an organ from a person (the donor) and placing it into another (the recipient). This procedure is performed on patients with end-stage organ failure, potentially increasing life expectancy and improving the quality of life for recipients. The most commonly transplanted solid organs are the kidneys, liver, heart, and lungs. Pancreatic and intestinal transplants are also performed but are less common. Recently, vascularized composite allografts, such as those for the face, hand, and penis, have been used in reconstructive procedures.[1][2] Non-vital tissues, such as bones, corneas, and tendons, can also be transplanted. Organ Organ donations can come from living or deceased donors, with deceased donors being more common.

Deceased patients are the major contributors to donor organs, with the most common causes of death being cerebrovascular accidents and traumatic brain injuries. In recent years, opioid overdoses have also become a significant source of deceased organ donations.[3][4] The dead donor rule requires that patients must be declared dead before the harvesting of donor organs. Donations can arise from patients who have suffered either brain death or circulatory death. Brain death is a clinical diagnosis defined as the permanent loss of brain function. This condition requires an irreversible loss of consciousness, an absence of brain stem reflexes, and a lack of spontaneous respiration.[5][6][7] The diagnosis of brain death is made before organ harvesting.

Circulatory death is defined as the irreversible loss of cardiopulmonary function.[8][9] Donations after circulatory death have been increasing in an attempt to address the global mismatch between organ demand and supply.[10][11] This process involves withdrawing life-sustaining treatment and then declaring death after the permanent cessation of circulation. The decision to withdraw care must be made before discussing organ donation to avoid conflicts of interest. In addition, members of the organ procurement or transplant teams should not be involved in the process of care withdrawal or the declaration of death.[12]

Although living donations are less common, they still increase the existing donor pool.[13] In 2019, more than 7300 living donations were made in the United States, saving patients from potentially long waits on the transplant list. The most frequently donated organ is a kidney, although portions of the liver or lung are also transplanted. More recently, living donations of vascularized composite allografts have been explored.[14] 

The 3 main types of living donations are directed, nondirected, and paired donations, with directed donation being the most common. In directed donations, the donor designates their organ to a specific recipient, most frequently a family member or close social acquaintance. In nondirected or generous donations, the donor does not specify a recipient, and the organ is matched to a suitable patient. Paired donations are more complicated and generally involve 2 (or more) patients (recipients) with a willing donor who is not a compatible match. These pairs are then grouped, and the organs are "traded" to ensure all patients receive a compatible transplant.

Living donations are generally considered safe, as studies have shown limited harmful outcomes. However, patients must be closely monitored for potential medical and psychological harm.[15][16] Long-term studies have not indicated any adverse psychological outcomes associated with living donations and high levels of overall life satisfaction, both for directed and nondirected donations.[17][18] Non-donors who are unable to donate due to a negative match or withdrawal from consideration generally report lower levels of life satisfaction compared to living donors.[19]

The number of patients awaiting organ transplantation far outstrips the availability of donor organs. In the United States, it is estimated that a new patient is added to the transplant list approximately every 10 minutes, and 20 patients die every day while awaiting transplant. In 2019, surgeons performed nearly 40,000 transplants, but over 110,000 patients remained on the waiting list at the end of the year. Consent for organ donation can be provided through various means, including a signed donor designation, designation on a driver's license, or signed consent from the deceased's next of kin. Notably, it is estimated that only 30% to 40% of potential donors in the United States ultimately become organ donors.[20] While approximately 80% of Americans support organ donation, only 40% have made appropriate designations to donate their organs after death. This discrepancy can be attributed, in part, to how the donation question is presented.[21] In the United States, the system operates under an opt-in model, where the default is not to be an organ donor, necessitating an active decision to become one.

In an alternative strategy, the presumed consent system, citizens are considered organ donors unless they actively opt out of the system. This strategy, commonly used in retirement savings, has demonstrated mixed results in practice, leading to increased organ donation in countries with low rates but not producing significant increases in others.[22][23] Critics of this strategy argue that the policy is unethical, as failing to object does not constitute informed consent.[24] Furthermore, others have demonstrated that simply expanding the pool of potential donors will not increase the number of transplants performed without the necessary infrastructure in place.[25]

Function

The Function of Transplantation in Patients With Trauma

Patients with traumatic injuries should undergo evaluation and resuscitation following the Advanced Trauma Life Support (ATLS) protocol developed by the American College of Surgeons (ACS), which includes conducting proper primary and secondary surveys.[26][27] The primary focus of clinicians should be on the patient's well-being during active resuscitation.[28] However, recognizing potential organ donors can enhance the availability and viability of donor organs.

The ACS mandates that all verified trauma centers establish a relationship with an organ procurement organization to notify them when a potential organ donor becomes available. Local organ procurement organizations facilitate the coordination of organ donation, which includes evaluating potential donors, obtaining consent for organ donation, managing organ allocation, and overseeing the procurement process. Contacting the local organ procurement organization is the initial step in the "critical pathway"—a systematic approach to deceased organ donation.

The critical pathway comprises 5 phases, which may overlap, as mentioned below.[29]

• Phase I: Identification of potential organ donors and referral to organ procurement organization.
• Phase II: Declaration of death and acquisition of consent for organ donation.
• Phase III: Donor evaluation.
• Phase IV: Donor management.
• Phase V: Organ procurement.

Trauma donors are generally younger and have fewer comorbidities than non-trauma donors. On average, trauma donors are more likely to yield additional organs (excluding kidneys) and produce a higher yield per donor. Higher rates of organ donation were observed in patients who suffered traumatic brain injury compared to traumatic cardiac arrest and in pediatric patients compared to adults. Lower donation rates are associated with cardiac arrest or dysfunction, likely due to inadequate organ perfusion.[30][31][32]

Issues of Concern

Medical ethics are a set of values used to navigate complicated situations and are founded on patient autonomy, beneficence, nonmaleficence, and justice.[33] All 4 concepts are relevant in organ transplantation, and specific instances can conflict.[34] Much of the ethical framework surrounding organ transplantation is grounded in the dead donor rule, which states that a patient must be declared dead before their vital organs can be removed. This rule is particularly relevant in donations after circulatory death, where the patient's circulatory function must cease irreversibly before organ procurement begins. While most donations after circulatory death arise from neurologic injuries, end-stage pulmonary and neuromuscular disorders are also known causes.

Currently, after withdrawing life-sustaining care, clinicians await the cessation of cardiopulmonary function to declare death. Following this, they observe a "hands-off" period (typically 5 minutes) to ensure no auto-resuscitation occurs. The donation is canceled if death is not declared within a predesignated period (usually 60 minutes). Some have questioned the utility of this approach in patients who elect to withdraw care and wish to donate their vital organs. In these cases, waiting for death can lead to ischemia, reducing the quality of donor organs or resulting in non-donation. 

In 2016, Canada introduced Medical Assistance in Dying (MAID) for grievous and irremediable suffering cases. With an estimated 2000 cases of euthanasia per year, this may present another avenue for increasing organ availability. From 2016 to 2019, 30 patients made donations, resulting in a total of 74 organs donated.[35] Voluntary euthanasia differs from the traditional withdrawal of care in two key respects: euthanasia requires first-person consent, and the primary intent is to end life. In contrast, the withdrawal of care aims to comfort the patient with an adverse effect (the principle of the double effect).[36] 

Rethinking the dead donor rule could allow these patients to donate their organs before death, thus fulfilling their wishes.[37] Advocates of this approach argue that withdrawing care with a do-not-resuscitate order in place is equivalent to death, and waiting for "irreversibility" does more harm than good.[38] Opponents, however, contend that this approach could violate the principle of nonmaleficence and lead to a loss of public trust, ultimately decreasing organ availability. Nonetheless, a 2015 study suggested that approximately 70% of Americans would support organ donation before death.[39]

Clinical Significance

Donation After Brain Death

Brain death is defined as the irreversible loss of consciousness, absence of brainstem reflexes, and persistent apnea. It is a clinical diagnosis made by two independent physicians. The most common causes are cerebrovascular accidents and traumatic brain injuries, but brain death can also occur secondary to anoxia or brain tumors. To diagnose brain death, the patient must be in an irreversible coma with a known cause and completely unresponsive to mechanical stimuli. All reversible causes of coma must be excluded. Additionally, the patient must be weaned off depressant medications (such as alcohol, opioids, and anesthetics) and neuromuscular-blocking agents. The patient cannot be hypothermic (core body temperature <35 °C) or hypotensive (mean arterial pressure <60 mm Hg). Severe acid-base and electrolyte abnormalities must also be ruled out. All brainstem reflexes should be assessed, including the pupillary, corneal, oculocephalic, vestibular, and cough or gag reflexes. Spinal reflexes remain in up to 75% of patients, and their presence does not preclude a diagnosis of brain death.

The apnea test evaluates ventilatory drive. The patient is disconnected from the ventilator for 10 minutes, and a positive test is indicated by absent respiratory effort and increasing PaCO₂ levels. The apnea test should be halted, and the patient should be reconnected to the ventilator if they experience hypotension, hypoxemia, or cardiac arrhythmias. A false-positive apnea test can occur in sedated patients or those with high cervical injuries affecting diaphragmatic function. While brain death is primarily a clinical diagnosis, additional testing can support the diagnosis, especially in the presence of confounding factors. Electroencephalography (EEG) is a commonly used noninvasive method to assess brain electrical activity, and it is often conducted at the bedside. However, EEG can be significantly influenced by sedation, hypothermia, and metabolic derangements, which can limit its reliability. In contrast, cerebral angiography, transcranial Doppler ultrasound, and cerebral scintigraphy assess cerebral blood flow and are not influenced by central nervous system depression, hypothermia, or metabolic disorders. Therefore, these tests are highly useful as confirmatory tests for brain death.[40][41]

Donation After Circulatory Death

Circulatory death is defined as the permanent absence of respiration and circulation and is increasingly utilized to expand the pool of potential organ donors. Typically, donation after circulatory death patients have suffered a neurologic injury but do not meet brain death criteria. Less commonly, patients with respiratory or neurodegenerative diseases may electively withdraw treatment. Initially restricted to kidney transplants, this practice has expanded to include liver, lung, and pancreatic transplants. One of the primary challenges of donation after circulatory death is balancing the assurance of donor death while minimizing ischemic damage to the intended organs.

The Maastricht classification system categorizes these patients into 5 categories based on the type of circulatory death, location, and other factors. Controlled and uncontrolled circulatory deaths are the 2 defined forms.[42][43] Uncontrolled donation after circulatory death is commonly observed when a patient arrives dead at the emergency department or receives insufficient resuscitation upon arrival. Additionally, unexpected cardiac arrests in the intensive care unit are also classified as uncontrolled. Due to their sudden and unexpected nature, organ donations in this group are more challenging to facilitate. End-organ ischemia has likely already begun, necessitating steps to halt this progression while obtaining consent and preparing for organ procurement. Uncontrolled donation after circulatory death often results in limited options, typically restricted to kidney-only donation or possibly no donation due to ischemic injury. In contrast, controlled donation after circulatory death occurs when a patient experiences an anticipated cardiac arrest. In these cases, the decision to withdraw care precedes the decision to donate, and the declaration of death is typically made in the operating room.

Life-sustaining care is withdrawn, and the patient is monitored until cardiopulmonary function ceases. After a waiting period (often 5 minutes to ensure no spontaneous resumption of cardiac function), the patient can be declared dead, and organ procurement can commence. In approximately 20% of cases, the donor is not declared dead within a predetermined period (usually 60 minutes), leading to the abortion of organ procurement. Members of the procurement team are not involved in the process of care withdrawal or declaration of death and should not enter the operating room until death is officially declared.[44] While organs from donation after circulatory death are at higher risk for ischemia, research indicates comparable outcomes to donation after brain death organs in kidney, liver, lung, and pancreatic transplantation.[45][46][47][48]

Organ Procurement

Following the declaration of death and necessary preparations, the process of organ retrieval begins in the operating room. The patient is prepped and draped sterilely, and the intended organs are carefully mobilized. Subsequently, the donor undergoes exsanguination, and blood is rapidly replaced with a preservation solution. These solutions are hypothermic (typically between 5 and 10 °C) and rapidly lower the temperature of the organs, reducing metabolic activity and facilitating preservation.

Rapid cooling can be further enhanced by using topical ice. After cooling, the intended organs are extracted, placed in sterile containers on ice, and transported to another location for implantation. Typically, the heart or lungs are removed first, followed by the liver and kidneys. Vascular conduits may be used during organ removal to aid in vascular reconstruction during implantation. After the removal of solid organs, other tissues such as bones, corneas, and tendons may also be harvested.

Enhancing Healthcare Team Outcomes

Successful organ procurement in patients with traumatic causes of death requires extensive coordination and teamwork among various healthcare teams. Many factors can influence the number of organ donations. Early detection protocols with prompt referral to an organ procurement organization in the emergency department can increase the likelihood of successful organ procurement. Implementing a specified protocol for declaring brain death and notifying the organ procurement organization can lead to more organ donations per trauma admission. In addition, including trauma surgeons on the organ donor council can also enhance organ donation rates.[49][50][51] 

Notifying the organ procurement organization is particularly important, as they are responsible for the procurement process. These organizations are responsible for increasing the number of available donors and coordinating the donation process. Trained and experienced healthcare professionals can provide counseling to families regarding brain death, explain the importance of organ donation, and obtain consent from the family if necessary.[52] After obtaining consent, the organ procurement organization assists with donor evaluation and organ allocation. They consider various factors, including blood and human leukocyte antigen matching, organ or recipient location, and illness severity, to allocate available organs. Once the organs are allocated, the procurement process can begin.

The acquisition of donor organs requires extensive teamwork due to the involvement of multiple healthcare teams. The treatment team and procurement teams operate independently to avoid conflicts of interest. The treatment team must work independently to withdraw care while keeping the transplant team informed for prompt organ retrieval. Several procurement teams often retrieve different organs for transplantation, requiring coordination among themselves. In heart or lung transplantation cases, the initial organ implantation often occurs in the same operating room to limit ischemic time, adding further complexity. Extensive coordination and cooperation among the trauma team, organ procurement organization, treatment team, procurement teams, and supporting staff are crucial for maximizing the number of organs procured and achieving the best patient outcomes.