163 20 Organ Donation Process and Management of the Organ Donor THOMAS A NAKAGAWA, MUDIT MATHUR, AND ANTHONY A SOCHET • Successful organ recovery for transplantation requires perioper ative donor mana[.]
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Organ Donation Process and
Management of the Organ Donor
THOMAS A NAKAGAWA, MUDIT MATHUR, AND ANTHONY A SOCHET
• Successful organ recovery for transplantation requires
perioper-ative donor management expertise to correct physiologic
derangements associated with neurologic death.
• A collaborative, multidisciplinary approach to end-of-life care
and donation requires early referral to the organ procurement
organization, allowing medical professionals to dialogue and
improve authorization rates while supporting families with
end-of-life care decisions.
• Determination of neurologic death in children is based on
clinical criteria that are consistent across the age spectrum.
PEARLS
• Donation after circulatory death (DCD) permits donation from patients who have suffered a catastrophic brain injury but do not progress to neurologic death.
• The sustained practice of pediatric DCD donation accounts for roughly 10% of all DCD donors nationally.
• Patient and graft survival for organs, especially kidneys, transplanted from DCD donors is comparable to organ transplants from donation after neurologic death.
• Neonatal donation provides another valuable opportunity
to recover organs for transplantation.
A significant gap continues to exist between the numbers of organ
transplants and transplant recipients on the national waiting list
in the United States.1 Children less than 18 years of age account
for approximately 1.5% of all patients waiting for a transplant.1
The majority of children and adults have end-stage renal failure
and are waiting for a renal transplant, followed by those with
hepatic disease waiting for a liver.1 Despite fewer pediatric donors
following neurologic death, the total number of pediatric
trans-plants is increasing.1 There is also a continued increase in children
receiving organ transplants from pediatric donors.1–3
Unfortu-nately, children still die waiting for a life-saving transplant The
highest death rate observed occurs in those less than 1 year of
age.1–3 At the same time, the proportion of children removed as a
transplant candidate from the waitlist and die because their
un-derlying illness progresses continues to increase.1 Taken in sum,
there is a growing need for donated organs and improved
thera-pies to preserve existing organ function for those awaiting
transplantation The global importance of organ donation is
rec-ognized and supported by the American Academy of Pediatrics
(AAP) and other organizations.3 , 4 The AAP emphasizes education,
the need to shape public policy, and a system in which organ
procurement, distribution, and costs are fair and equitable to
children and adults.4
Each state has laws and regulations for the determination of
death that have been modeled after the Uniform Determination
of Death Act (UDDA) in most cases.5 The UDDA provides a
definition of death, stating that an individual who has sustained
either (1) irreversible cessation of circulatory and respiratory functions or (2) irreversible cessation of all functions of the entire brain (including the brainstem) is dead A determination of death must be made in accordance with accepted medical standards Criteria for the determination of death have been es-tablished in national guidelines for adults and children.6–8 In accordance with the dead donor rule, donation can only occur after death has been declared Donation cannot result in the death of the patient.9 An ethical discussion about defining and determining death and the dead donor rule are beyond the scope
of this chapter (see Chapter 18)
Organ donation can occur following neurologic death (dona-tion after brain death [DBD]), following circulatory death (donation after circulatory death [DCD]), or through living do-nation The vast majority of organs are recovered following death established by neurologic criteria Donor organs potentially recovered for transplantation are dependent on the type of dona-tion Organs recovered from DBD include the heart, lungs, liver, kidneys, pancreas, and intestines Organs recovered following DCD include lung, liver, kidneys, and pancreas Additionally, hearts have been recovered from DCD donors.10 , 11 Tissues including skin, bone, cartilage, heart valves, and corneas can be recovered from both DBD and DCD donors
Most pediatric deaths occur in intensive care units (ICUs) following the unplanned withdrawal of life-sustaining medical therapies,12 making opportunities for pediatric donation a rare event Missed opportunities for organ donation occur for many
Trang 2reasons, but the majority can be accounted for when a family
declines the option of donation Families may not have been
provided the opportunity for donation because the medical team
did not recognize donor eligibility Approaching families about
donation at an inappropriate time, failing to develop a shared
cognitive model for the concept of brain or circulatory death,
unreliable or misleading educational resources, and racial barriers
may also contribute to declined authorization rates.3 , 13–16 Even
after authorization, potential organs for transplantation may
be-come unsuitable because of caregivers’ lack of familiarity with
appropriate donor management, damage during recovery prior
to transplantation, and medical examiner or coroner denials.13
Families who authorize donation are more likely to comprehend
neurologic death and report a positive hospital experience
com-pared with families that choose not to authorize donation.17
Unique aspects related to pediatric organ donation and
trans-plantation are listed in eBox 20.1
Process of Organ Donation
Organ donation should be viewed as a process Like many other
aspects in medicine, this process evolves over time and includes
(1) identification of a potential donor, (2) determination of
neu-rologic death in a timely manner, (3) authorization for organ
donation, (4) perioperative management of the donor, and
(5) recovery of organs for transplantation The donation process
begins when a critically ill or injured child is identified as a
potential donor, with an early or timely referral to the organ
pro-curement organization (OPO) A federal mandate requires
notifi-cation of the designated OPO for any impending death Early
involvement and timely notification prior to the determination of
death generates a greater amount of time for collaboration with
the OPO.18 This best practice permits coordination of the
dona-tion process with the medical team.3 , 4 , 14 , 18–20 Ensuring OPO
gagement and the intensive care team’s understanding of the
en-tire donation process is essential to eliminate confusion that may
disrupt the donation process Ensuring this best practice not only
improves authorization rates but also assists families with
under-standing and coping with end-of-life care issues A protective
stance with parents or guardians of children because of
precon-ceptions about donor eligibility may have the unintended
conse-quence of denying families the opportunity to help or save the life
of another person.21 Prior to approaching the family, the medical
team and OPO should discuss potential donor suitability and
coordinate the best way to approach a family about organ
dona-tion.3 , 4 , 14 , 18 , 19 Many national and international organizations have
emphasized donation as a routine part of end-of-life care and have
adopted this collaborative best practice to increase authorization
and recovery of organs for transplantation.3 , 4 , 18 , 20 , 22 , 23 Discussions
about donation with parents or guardians may differ from spouse
or relatives of adult donors Contrary to the traditional approach
of the OPO coordinator requesting donation and decoupling the
death and authorization process, one study found that the timing
of organ donation discussions did not appear to influence
dona-tion decisions.24 Parents want sufficient time to discuss end-of-life
care issues, including donation, and may prefer discussions
re-garding donation with the pediatric intensivist or a member of the
healthcare team they have come to trust.3 , 24 Few families of
either adults or children appear to suffer psychological harm by
having the option of donation presented to them.21 In addition to
collaboration with the OPO, successful authorization for
pediat-ric donation may include the engagement of palliative care
specialists Palliative providers may act as an additional resource to assist the ICU team and provide family support during end-of-life care discussions and organ donation.25 , 26
The benefits of organ donation extend beyond the transplant recipient There are psychological and social benefits for the potential donor’s family Organ donation may assist families in finding solace in the belief that their child’s death was not without meaning and helped or saved the life of other people.3 , 27 Knowing that their child will be remembered after death is one important way that organ donation helps families heal
Role of the Pediatric Intensivist and Critical Care Team in the Process of Organ Donation
Management of critically ill children and pediatric organ donors
is best accomplished at a tertiary or quaternary pediatric facility that provides specialized pediatric critical care expertise required
to manage this select group of patients.14 , 18 Medical management
of the potential pediatric organ donor requires knowledge of the physiologic derangements associated with this patient population Hemodynamic instability, alterations in oxygenation and ventila-tion, metabolic and endocrine abnormalities, and coagulation disturbances are common Support and care of the family pro-vided by a team of physicians, nurses, social workers, chaplains, family service providers, organ donation specialists, and other support staff trained in the unique aspects of pediatric medicine are integral to the care of these children and their families.3 , 14 , 18
The pediatric intensivist is central in coordinating care to ensure the successful recovery of organs from pediatric donors
The integral involvement of the pediatric intensivist and criti-cal care team in the management of criticriti-cally ill and injured children has been a foundation of clinical practice in many suc-cessful pediatric centers Involvement of critical care specialists— especially in pediatric donation, in which there is a limited and decreasing number of donors—improves the quality and number
of organs recovered.14 , 18 Caring for the critically ill child and the child’s family through all phases of illness, including end-of-life issues, should be a seamless transition The continuum of care for the dying patient who progresses to death and becomes a donor requires the expertise of the pediatric intensivist and critical care team to preserve the option of donation.8 Patient management to prevent deterioration of organ systems and subsequent loss of transplantable organs while helping family members deal with the death of their child is fundamental to facilitating the donation process and successful recovery of organs for transplantation National and international best practices for deceased organ donation emphasize that patient management should preserve the option of donation for potential donors prior to and after declara-tion of death.3 , 4 , 14 , 17–20 , 22 , 23
Preconceptions about eligibility for donation by the critical care team may not be current or accurate Suitability of donor organs for transplantation is best assessed by the OPO.18 Thresholds for acceptable organ dysfunction can vary according to time of evalu-ation, transplant program comfort levels, and recipient urgency For example, serial echocardiograms may demonstrate donor re-sponse to effective medical therapy, enabling cardiac recovery for transplantation: a positive blood culture or bacterial meningitis may not preclude organ donation if antibiotic therapy has been administered.18 In the United States health policy changes have impacted donor eligibility The HIV Organ Policy Equity Act en-acted in 2013 allows HIV-positive donors to donate organs for transplantation into HIV-positive recipients Additionally, organs
Trang 3• eBOX 20.1 Unique Issues With Pediatric Organ
Donation and Transplantation
•
Parents and guardians must act as surrogate decision makers without ben-efit of being guided by the donor’s wishes, as is often possible with adults.
• There is age-related variation in the timing associated with determination
of brain death.
• There are technical challenges related to surgical procedures in smaller
children and infants.
• Acquisition and use of organs recovered from children may be limited by
size and weight constraints.
• Specialized care required for the management of critically ill children
and pediatric organ donors may be lacking at institutions without pediatric
expertise.
Trang 4from hepatitis-positive donors are now being transplanted
Al-though these situations may be uncommon for pediatric patients,
it emphasizes the need to be aware of the latest developments in
public policy and use the expertise of the OPO as part of
high-quality end-of-life care.18
Collaboration with investigative teams, medical examiners,
and coroners in cases of accidental or nonaccidental death is
im-perative to determine cause of death and allow the donation
process to proceed.13 , 18 Preservation of evidence and early
consultation and discussions with the coroner, medical examiner,
or forensic team may result in requests for additional noninvasive
imaging needed to supplement the death investigation without
precluding donation
Determination of Neurologic Death
Most organ donations occur following neurologic death;
there-fore, the determination of neurologic death must precede any
efforts to recover organs Timely and efficient determination of
neurologic death is important for several reasons: it allows the
family to begin the grieving process as they prepare for the loss
of a loved one; if donation is planned, organ preservation and
preparation for recovery can begin; and if donation is not
planned, medical therapies can be stopped, permitting
redistri-bution of scarce ICU resources to other critically ill and injured
patients Determination of neurologic death must never be
rushed or take priority over the needs of the patient or the family
Appropriate emotional support for the family should be
pro-vided, including adequate time to grieve with their child after
death has occurred Determination of neurologic death in
chil-dren is a clinical process based on specific criteria consistent
across the age spectrum Criteria for the determination of
neuro-logic death in infants and children in the United States were
re-vised in 2011.6 , 7 These guidelines outline the minimum criteria
to determine neurologic death for infants greater than 37 weeks
estimated gestational age to 18 years of age The guidelines do
not challenge the definition but rather provide criteria for the
determination of death Although examination criteria for
in-fants, children, and adults are similar, determination of
irrevers-ible injury and neurologic death can be more challenging in
younger patients because of physiologic and anatomic
differ-ences, along with differences in the mechanism of injury in
in-fants and children.6–8 Hypoxic-ischemic or traumatic brain
inju-ries are the most common causes of neurologic death for infants
and children.28 Two chronologically distinct, unbiased,
indepen-dent neurologic examinations and age-based recommendations
are a primary difference between adult and pediatric guidelines
to determine neurologic death.6–8 eBox 20.2 lists the
recom-mended observation periods based on the current pediatric
guidelines for the determination of neurologic death A clinical
history, known cause of coma, and neurologic injury consistent
with the clinical presentation are prerequisites to establish that an
irreversible condition has occurred Neurologic criteria to
deter-mine death in infants and children are listed in eBox 20.3
Nor-mal physiologic parameters must be established and maintained
before a determination of neurologic death or neurodiagnostic
testing can be meaningful Coma and apnea must coexist In
ad-dition, confounding variables must be corrected before an
evalu-ation of neurologic death
Conditions that may interfere with the neurologic
examina-tion or factors capable of causing a comatose state imitating
brain death should be considered, corrected, and ruled out
These include hypothermia, hypotension, severe hepatic or renal dysfunction, inborn errors of metabolism, metabolic distur-bances including hypoglycemia, and toxic or iatrogenic inges-tions Toxins can interfere with the neurologic examination and should be considered in cases in which a definitive etiology of coma cannot be established Longer-acting or continuous infusion of sedative agents and recent administration of neuro-muscular blocking agents can interfere with the neurologic ex-amination When determining the appropriate timing of the clinical examination, the half-life of previously administered agents must be considered End-organ dysfunction and the use
of therapeutic hypothermia can delay pharmacologic clearance Adequate time for clearance of sedatives and neuromuscular blocking agents must be provided Testing for drug intoxica-tion—including barbiturates, opiates, and alcohol—should be performed as indicated Clearance of neuromuscular blocking agents can be confirmed by use of a nerve stimulator
There may be situations in which these conditions cannot be corrected and an ancillary study may be required to assist with the determination of neurologic death For instance, the use of barbi-turate coma in traumatic brain injury may require a prolonged observation period to ensure that measured levels are in the low-
to mid-therapeutic range before a clinical determination of neu-rologic death can occur Barbiturates reduce cerebral blood flow (CBF); however, there is no evidence that high-dose barbiturate therapy completely arrests CBF Radionuclide CBF study or cere-bral arteriography can be used in patients receiving high-dose barbiturate therapy to demonstrate the absence of CBF.6 , 7
Patients receiving targeted temperature management and hy-pothermia protocols require adequate time for drug clearance following rewarming prior to initiating testing for neurologic death Current adult and pediatric guidelines in the United States and Canada recommend a minimum core body temperature of .35°C (95°F).6–9 , 29 The United States pediatric guidelines suggest waiting at least 24 hours following rewarming before instituting testing for neurologic death.6 , 7 A period greater than 24 hours following targeted temperature management may be required to determine neurologic prognostication and ensure that diagnostic error does not occur when determining neurologic death.30–33
Testing for Apnea
Apnea testing is a critical and essential component of the clinical examination to determine neurologic death Testing for apnea will result in respiratory acidosis and potential hypoxemia Therefore testing must be performed safely with special attention
to maintaining ideal oxygenation and hemodynamics Apnea testing should be performed only after the patient has met the clinical criteria for neurologic death.6 , 7 Apnea testing must allow adequate time for the partial pressure of carbon dioxide (Paco2)
to increase to levels that would normally stimulate respiration Baseline Paco2 should be measured and allowed to rise to 60 mm
Hg or greater and 20 mm Hg above the baseline to account for
infants and children with chronic respiratory disease or insuffi-ciency who may breathe only in response to supranormal Paco2
levels.6 , 7 The patient should be continually observed for any spontaneous respiratory movements over a 5- to 10-minute pe-riod or longer, with documentation of arterial blood gas(es) reaching the targeted threshold During apnea, the Paco2 rises approximately 3 to 5 mm Hg/min.6 , 7 Venous blood gas measure-ments have not been sufficiently studied to document elevated
CO2 during apnea testing
Trang 5• eBOX 20.2 Recommended Observation Periods to
Determine Brain Death in Infants and
Children
• Term infants (37 weeks’ estimated gestational age) to 30 days of age: Two
examinations and apnea tests separated by at least 24 hours a
• More than 30 days to 18 years of age: Two examinations and apnea tests
separated by at least 12 hours b
a The observation period may be decreased if an approved ancillary study is used A second clinical
examination and apnea test must be performed following the ancillary study to declare death.
• eBOX 20.3 Neurologic Examination Criteria for
Brain Death Determination in Infants and Children
1 Coma Patient must lack all evidence of responsiveness Noxious stimuli should not produce a motor response other than spinally mediated reflexes.
2 Apnea The patient must have the complete absence of documented respiratory effort (if feasible) by formal apnea testing demonstrating a
Pa co2 60 mm Hg and 20 mm Hg increase above baseline Paco2.
3 Loss of all brainstem reflexes, including:
• Midposition or fully dilated pupils that do not respond to light
• Absence of movement of bulbar musculature, including facial and oropharyngeal muscles
• Absent gag, cough, sucking, and rooting reflexes
• Absent corneal reflexes
• Absent oculovestibular reflexes
4 Flaccid tone and absence of spontaneous or induced movements, excluding spinal cord events such as reflex withdrawal or spinal myoclonus.
5 Reversible conditions or conditions that can interfere with the neurologic examination must be excluded prior to brain death testing.
Data from Nakagawa TA, Ashwal S, Mathur M, et al Guidelines for the determination of brain death in
infants and children: an update of the 1987 Task Force recommendations Crit Care Med
2011;39(9):2139–2155; and Nakagawa TA, Ashwal S, Mathur M, et al Clinical report—Guidelines for
the determination of brain death in infants and children: an update of the 1987 task force
recom-mendations Pediatrics 2011;128(3):e720–740.
Data from Nakagawa TA, Ashwal S, Mathur M, et al Guidelines for the determination of brain death in infants and children: an update of the 1987 Task Force recommendations Crit Care Med 2011;39(9):2139–2155; and Nakagawa TA, Ashwal S, Mathur M, et al Clinical report—Guidelines for the determination of brain death in infants and children: an update of the 1987 task force recom-mendations Pediatrics 2011;128(3):e720–740.