Critical care specialists, the missing link in organ procurement for transplantation

Abstract

The procurement process for organ donation begins with the identification of potential organ donors in emergency or critical care units (CCU), followed by their clinical evaluation, diagnostic procedures, and therapeutic interventions, mostly conducted in CCUs. It concludes with the request for organ donation and, if accepted, the retrieval of organs. Despite most interventions occurring in detection units, there has been a neglect of the strategic role played by critical care specialists (CCS) in managing and caring for brain-dead or near-brain-death patients. Questions arise: Are they willing to undertake this responsibility? Do they fully comprehend the nature of organ procurement? Are they aware of the specific interventions required to maintain possible organ donors in optimal physiological condition? Our objective is to examine the role of CCS in organ procurement and propose ways to enhance it, ultimately aiming to increase and enhance organ donation rates.

Key Words: Organ procurement, Transplantation, Brain death, Cardiac death, Organ donation

Core Tip: Procurement organ donation is the key issue for organ transplantation. Most possible organ donors stay in critical care units, making their physicians a strategic partner to manage those patients, cross talk with organ local procurement coordinator and enhance all the process of organ donation.

INTRODUCTION

Possible organ donors often present to healthcare services following a catastrophic event, typically of a neurocritical nature such as trauma or stroke, progressing to brain death and possibly to donation after brain death (DBD). Alternatively, they may arrive after a witnessed or unwitnessed in- or out-of-hospital cardiac arrest or following a "controlled" cardiac death and possibly a donation after cardiac death (DCD). The distribution of each donor type is primarily influenced by local legislation, healthcare resources, and the diligence in performing cardiac resuscitation efforts.

Regardless of the circumstances, both DBD and DCD organ donors rely entirely on the expertise of critical care specialists (CCS) and their dedicated efforts. To assess the validity of this claim, we will examine the process that possible and potential organ donors undergo in critical care units (CCU) and explore the challenges they may encounter.

Procurement process: First stages

Individuals experiencing severe encephalic damage due to trauma, gunshots, falls, stroke, or brain hemorrhage, among other causes, arrive at an emergency room (ER) and are identified by physicians or registered nurses as possible organ donors. These healthcare professionals are responsible for conducting a prompt diagnostic evaluation, initiating initial therapeutic interventions aimed at improving the patient's health, and referring the patient to local procurement coordinators (LPC). If the ER professionals fail to identify and/or refer the possible donor to the LPC, the LPC can also initiate the process during their routine visits as part of their responsibilities.

Once a possible donor is identified, a computed tomography scan (CT) or nuclear magnetic resonance (NMR) scan is typically conducted to establish a precise anatomical diagnosis, assess the severity of the situation, and determine the most appropriate type of surgical, medical, or combined treatment. Following this initial evaluation, the patient is then transferred either to the surgery room or to the CCU.

In the CCU, the patient should receive hemodynamic stabilization, ventilation support, and neuroprotective measures, including sedation, neuromuscular blockade, prevention of hypercapnia, and management of elevated intracranial pressure. Subsequently, the patient may either experience clinical improvement or progressive deterioration, depending on the original and subsequent brain damage and the quality, effectiveness, and timeliness of the treatment provided. In the case of deterioration, the patient may remain in a comatose stage, progress to brain death, or experience cardiac death.

Clinical management of possible organ donors in CCU

Severely ill patients in CCU typically require mechanical ventilation, intravenous fluids, vasoactive drugs, nutritional and metabolic support, and often undergo invasive procedures and various drug therapies. Brain-dead or close-to-brain-death patients, as well as other neurocritical patients such as those assessed by APACHE[1] or SOFA[2], share similar critical care requirements. Therefore, it is advisable to implement therapeutic actions that have demonstrated benefits for critical care patients, irrespective of their specific pathologies.

Recent recommendations aimed at improving outcomes for possible organ donors in CCU include: (1) Administering isotonic intravenous fluids such as NaCl 0.9% or Ringer lactate; (2) Transfusing blood products to achieve a hemoglobin level greater than 7.0 g/dL; (3) Administering vasoactive drugs if volume replacement is insufficient to sustain hemodynamics; (4) Providing protective mechanical ventilation with a tidal volume of 6-8 mL per predicted body weight in kilograms and a positive end-expiratory pressure of 8-10 cm H₂O; (5) Maintaining mild hypothermia with a body temperature of 34-35 °C; and (6) Offering hormone replacement therapy, including arginine vasopressin if diabetes insipidus supervenes, corticosteroids if any deficits are demonstrated, thyroid hormones in cases of hemodynamic instability, and if the left ventricular ejection fraction is less than 45%[3].

Regrettably, these recommendations are not entirely evidence-based but represent the result of balanced expert thinking[4,5].

However, heterogeneity exists in the critical care management of possible donors. For instance, the Canada-DONATE cohort study revealed variations in monitoring and drug therapies across different centers, particularly concerning hormonal therapies and the timing of their administration (before or after death certification)[6]. This diversity may be attributed to differences in knowledge depth regarding brain death determination or physician engagement in procurement activities. A recent study in Brazil highlighted that more experienced, formally trained individuals, or those who have conducted over 10 brain death protocols tend to perform better compared to less experienced physicians[7].

It would be prudent to approach CCS cautiously regarding their attitudes, knowledge, and confidence in managing possible organ donors, diagnosing brain death, and participating in organ procurement. These competencies are known to correlate with national organ donation statistics. By seeking this information, authorities in the field could design and implement formal training courses provided by local or national organ procurement organizations[8]. Notably, there are instances demonstrating significant and positive linear correlations between national organ donation rates and staff members' average positive attitudes toward donation, acceptance of the brain death concept, and average confidence in donation-related tasks. Conversely, there is a significant negative correlation between CCS' average educational needs and the national donation rate[8].

On the flip side, various experiences illustrate the extent to which CCS, including physicians, may grapple with confusion about their role in organ procurement, the legal and ethical validity of organ donation and transplantation, and the concept of brain death. For instance, in a survey conducted by Siddiqui et al[9] among CCS, despite most respondents being physicians who correctly identified brain death and supported organ donation, many expressed concerns about their religion potentially opposing organ donation and doubted the fairness of organ distribution by authorities. Interestingly, while a majority would be willing to receive an organ if needed, only about a third would consider becoming organ donors themselves. This reluctance extended to their willingness to participate in organ donation consent interviews with family members, with similar numbers[9].

Another noteworthy example is found in Skowronski et al[10]’s meta-analysis exploring the concept of brain death. Despite the majority of healthcare professionals accepting brain death, a subset still believed it was an "irreversible coma", leading to the notion that organ donation caused death. Moreover, some included studies indicated a lack of trust among healthcare workers in their colleagues' diagnostic abilities regarding donation after circulatory death. Additionally, there were professionals not in favor of invasive procedures for possible donor maintenance[10].

These findings may vary across regions, religious faiths, or cultural environments. However, common factors such as beliefs, attitudes, and especially the level of education could potentially influence the overall support CCS may offer to organ procurement and donation.

What is brain death and DBD

In 1968, an ad hoc Harvard Committee defined brain death as a permanent coma and loss of all brainstem function, coupled with the inability to breathe in the setting of an adequate stimulus (i.e., hypercarbia and acidosis). These criteria, used simultaneously with a silent electroencephalogram, identified 185 of 187 patients who developed a cardiac arrest soon after the tests were performed. The other two still had reactive pupils due to drug intoxications and did not experience a cardiac arrest, correctly identified as such[11].

As the complete loss of the brainstem's reticular activating system is the most robust predictor of permanence in a comatose state, most of the neurologic assessment focuses on demonstrating the loss of all brainstem reflexes and the absence of respiratory effort even after significant CO₂ retention (≥ 60 mmHg)[12]. This issue is known as the apnea test, which is performed by a neurologist to positively diagnose brain death.

Nevertheless, diagnosing brain death may not be as expeditious as expected due to variations in the knowledge and experience of physicians. Even in academic hospitals, heterogeneity and unreliability can exist because physicians may not consistently follow a structured protocol or complete all necessary steps for a proper diagnosis. This underscores the critical role of the CCS as a close collaborator in specialized tasks, such as a careful neurological examination and the apnea test[13].

From a technical standpoint, brain death diagnosis is straightforward if a CT or NMR scan reveals an anatomical brain catastrophe associated with a complete absence of brainstem reflexes in a hemodynamically and metabolically stable, mechanically ventilated patient. However, the way a CCS approaches this situation is not always a binary decision. If their perspective is that death is solely defined as cardiac, or if they believe the patient's situation is far from terminal, doubts about the diagnosis may arise. In such instances, it is understandable that the CCS could be reluctant to perform an apnea test, authorize the proceeding to ask the patient's relatives for donation, or even allow the LPC to carry out their own work.

Factors that also contribute to doubts about brain death diagnosis include: (1) Insufficient knowledge about brain death or how to properly diagnose it; (2) Insufficient or no experience in possible donor maintenance; (3) Poor training in brain death meaning[14]; (4) Lack of support for brain death diagnosis or organ donation, especially for certain patient groups, such as children[15]; (5) Lack of conviction that organ transplantation genuinely helps recipients; (6) Ignorance about the proportion of the local population supporting organ donation; (7) Lack of confidence in the ethical behavior of LPC; (8) Doubts about the ethics surrounding the concept of brain death and/or its clinical applications[16]; (9) Apprehension about the legal environment or whether the current local legislation supports organ donation; and (10) Influence of nurse attitudes on physicians' opinions about organ donation[17].

DCD

A DCD is an individual who has experienced a devastating and irreversible brain injury, is or may be close to death, but does not meet formal brain death criteria (for example, by still exhibiting some neurological reflexes). This situation precludes the performance of an apnea test, and concurrently, the family has decided to allow a natural death based on cardiac arrest. Donation after circulatory death describes the retrieval of organs for transplantation purposes following death confirmation using circulatory criteria[18].

Although this type of death certification might be easier to understand and accept, it faces challenges when applied to organ donation. Similar to the brain death concept, it also entails ethical and legal issues that impede its implementation. An ethical concern could be that the CCS may be perceived as having a conflict of interest by deciding to withdraw treatment and subsequently proposing deceased donation. A legal issue may arise if local law interprets that life-saving therapeutic intervention could be neglected or withdrawn to obtain organ donors[18]. Nonetheless, from a technical perspective, it's crucial to consider that the period before and immediately after the patient's death is associated with severe poor tissue perfusion that jeopardizes the later transplanted organ function. To ensure ethical and clinical standards are met, the DCD Maastricht classification was developed[19]. This classification delineates the various conditions leading to DCD, determining how DCD is performed and whether it is feasible to perform (Table 1).

Table 1 Modified Maastricht classification of donation after cardiac death and the locations where it is mainly practiced[19].

Category	Description	Type of DCD	Locations practiced
I	Dead on arrival	Uncontrolled	ED in a transplant center
II	Unsuccessful resuscitation	Uncontrolled	ED in a transplant center
III	Anticipated cardiac arrest	Controlled	ICU and ED
IV	Cardiac arrest in a brain-dead donor	Controlled	ICU and ED
V	Unexpected arrest in ICU patient	Uncontrolled	ED in a transplant center

Despite the differences of Maastricht I, II and V from III and IV types, post transplantation clinical outcomes are similar to brain death derived organs[18]. DCD: Donation after cardiac death; ICU: Intensive care unit; ED: Emergency department.

Asking for organ donation

When a critical care specialist faces a potential donor, regardless of the mechanism of death, it is suggested to consider the appropriateness of discussing organ donation with the patient's relatives. The appropriateness will depend on the legislation of each country (opt-in or opt-out, and their variations) and the specifications of the law (such as who is responsible for death communication and organ donation communication, as these roles may be assigned to different professionals). Nonetheless, some considerations before conducting the interview are: (1) Ensure that all clinical information has been previously given to the family. It must be assured that all relatives understand the patient’s critical status and that all treatments have been futile; (2) Ensure that the family feels that the critical care unit operates under ethical standards, and that the entire personnel is dedicated to healing patients; (3) Meet with the family in a private and quiet room and assure that the former issues have been addressed; (4) Explain the expected turn of the patient’s condition, i.e., with or without further treatment, death is imminent. Be clear that a cardiac arrest is imminent or relatively soon; (5) Ensure that the patient’s death (brain or cardiac) has been officially declared before proceeding to the next steps; (6) If the patient is a DBD, ensure that the family understands the concept of brain death, meaning they understand that their relative is dead and there is no “miracle” that will bring them back to life; (7) Decide who is the most appropriate person to conduct the interview, a decision that must align with legal requirements. If the local legislation states that the CCS must decide or conduct the interview, then they must decide. On the other hand, if the law states that the local procurement professional or coordinator is the one responsible for donation requests, then those professionals must decide. The presence of individuals during the interview depends on each legislation, for example, just one of the aforementioned professionals, or both of them. Leadership during the interview, or who can intervene, also depends on these factors. If there are any doubts or the law is not specific on this point, it is suggested to always consult with the LPC. Several studies describe higher donation rates when organ procurement personnel ask for consent, particularly when they are properly trained[20]; (8) Despite there are no rules to achieve 100% organ donation, best practices to maximize it were studied and discussed by Chandler et al[20] some years ago and they can certainly be very useful to follow; and (9) In countries where presumed consent to donation is the rule (i.e., opt-out), it is possible that the aforementioned suggestions do not apply. Nevertheless, it is always advisable to maintain fair and ethical communication with the family.

CONCLUSION

Final considerations

The CCS plays a crucial role in the procurement process and, therefore, should be well-trained and conscious of how the treatment they provide can impact possible donor outcomes. However, it's essential for them to be aware that they do participate in this process, even if they believe otherwise.

If you, as the reader, are a CCS who was unaware of your role in the procurement process, there's no need to panic. You are not alone, and it is never too late to learn. This information is intended to educate you and your colleagues on the basics of possible and potential donor management. If you now have more questions than before (which is normal), always trust the procurement teams in your healthcare institutions, even if they hold a lower rank (such as nurses). They are the ones familiar with your local legislation, understand every step the possible donor must follow, are experts in managing dead or close-to-death patients to better preserve organs for transplantation, and are well-versed in the population's views on organ donation. They maintain constant communication with local and national authorities, providing the support needed to obtain more and better organs from patients who will die under one of the conditions explained in this issue.

With this knowledge, CCS have the power to transform themselves from being “the missing link” in organ procurement for transplantation to becoming the “connecting link” in this complex clinical care management.