Surgery SC028: I Want To Donate My Organs: Brain Death, Organ Donation, Psychosocial Issues Flashcards
What organs can you donate
- Kidney
- Liver
- Heart
- Lung
- Small bowel
- Pancreas
- Limbs (controversial)
- Face (controversial)
(9. Tissues: Blood, Bone marrow, Bone, Skin, Cornea)
When and to Whom: Deceased donor: - Kidney - Liver - Heart - Lung - Small bowel - Pancreas (- Limbs, Face) —> a public resource —> system of equitable allocation
Living donor: - Kidney - Liver - Lung - Small bowel - Pancreas —> a dedicated gift —> to beloved family member —> only consideration: benefit of recipient justifiable to risk to donor
Deceased donors: Brain death vs Cardiac death
Donation after cardiac death (DCD):
- Controlled (cardiac event after gradual withdrawal of life support) vs Uncontrolled (harvest organ after sudden cardiac arrest (more sudden / emergent))
- More ***ischaemic injury and worse outcome
—> e.g. biliary injury of liver —> primary non-function (after putting in the organ it never functioned)
Donation after brain death (DBD):
- Permanent and irreversible cessation of function of brain constitutes one of the various criteria in the medical diagnosis of death
- All donations in HK are DBD
***Criteria of Brain death
No grey zone in definition
Definition:
- Irreversible cessation of brainstem function
- Diagnosis established by documentation of
—> Irreversible **coma
—> Irreversible loss of **brain stem reflexes and **respiratory centre function
—> Demonstration of cessation of **intracranial blood flow by imaging
Clinical:
1. Deep coma with an established and irreversible etiology
2. No CNS depressants / hypothermia / all electrolyte disturbances already corrected
3. No spontaneous movements except spinal reflexes (e.g. knee jerk)
4. Apnea test: Apnea even under presence of hypercapnia
5. No brain stem reflexes
(Vegetative state patients still maintain certain brainstem functions which may enable spontaneous breathing / some brainstem responses, the cerebrum may be able to perceive / react to external stimulus, therefore a patient in vegetative state is not considered dead)
Special tests (optional):
- EEG
- Cerebral angiogram
- Cerebral blood flow scan
Diagnosis of Brain death:
- Clinicians ***not involved with organ transplant (usually by ICU doctor, neurologist, neurosurgeons)
- Appropriate qualification
- Independent assessment by ***2 separate clinicians at 2 different time
- One need to exclude ***reversible cause of coma
- X Effect of sedative drugs / muscle relaxant
- X Hypothermia (<35oC)
- X Metabolic / Endocrine disturbances (should be no profound abnormality of electrolyte, acid-base balance, blood glucose concentration)
- X Arterial hypotension - Neuromuscular function is intact (to make sure if brain stem reflexes are intact they can be elicited)
Definition of Brain death:
- Legal recognition (e.g. USA) (i.e. have brain death law support)
- Medical recognition e.g. HK
***Clinical test of Brain stem function
- Both pupil fixed and non-reactive to light
- Corneal reflex absent
- Vestibulo-ocular reflex absent (no eye movement on cold caloric test)
- No gag / cough reflex
- No motor response in cranial nerve distribution to stimulation to face, limbs, trunk
- Apnea test
- take off ventilator briefly —> allow PCO2 rise —> no respiratory movement with arterial PCO2 >8 kPa and pH <7.3
Confirmatory test would be needed if:
- No clear cause of coma
- Possible metabolic effect / drug effects
- Cranial nerves cannot be adequately tested
- Cervical vertebral / cord injury
- CVS instability precluding apnea test
- Severe hypoxaemic respiratory failure precluding apnea test
Confirmatory test:
- ***Four vessel radio-contrast angiography with digital subtraction
—> demonstrate absence of intracranial blood flow
***S/S of Imminent brain death patient
Loss of brain stem function —> Systemic physiologic instability
1. Unstable BP (hyper / hypoBP)
- Hypertensive phase:
—> ↑ICP: **Cushing reflex —> ↑arterial BP in compensation to overcome ↑ICP to ensure adequate cerebral perfusion pressure
—> Autonomic / **Sympathetic storm: release of ***catecholamines resulting in hyperdynamic states, tachycardia, peipheral vasoconstriction, hypertension
- Hypotensive phase:
—> ***Sympathetic outflow loss, catecholamine depletion, myocardial dysfunction, intense peripheral vasodilatation, hypovolaemia, electrolyte disturbance and endocrine changes
- Cardiac arrhythmia
- Atrial / Ventricular dysrhythmias, conduction blocks
- ∵ electrolyte + acid-base disturbances, hypothermia, ↓myocardial contractility, inotrope use, ↑ICP - Loss of temperature regulation
- ∵ loss of hypothalamic temperature regulation
- hypothermia can induce coagulopathy, haemolysis, leftward shift of OxyHb dissociation curve (higher affinity) - Hormonal imbalance (Cranial DI)
- ∵ posterior hypothalamic-pituitary deficiency
- polyuria, hypovolaemia, hypotension, hypovolaemic hyperNa - Loss of respiratory function
- need ventilatory support - Electrolyte disturbance
Proper management of imminent brain death patients is necessary
- Stabilise the patient
- facilitate brain death examination - Manage the potential donor
- optimise function and viability of all transplantable organs
Management of Imminent brain death patients
Targets:
- Arterial SBP 100-140 / MAP ~65 —> ensure adequate organ perfusion
- HR 60-120 bpm
- Hourly urine output ~100 mL
- SaO2 >90%
- Body temp >36oC
- Normal ranges for serum glucose, K, Ca, PO4, Mg
Management:
1. BP control
Hypertensive (>=180):
- Labetalol infusion (titrate until desire BP achieved, stop when <140)
Hypotensive (<=90):
Determine cause of HypoHT
- Fluid replacement if hypovolaemic (Ringer’s lactate / Normal saline)
—> Na >145: D5 infusion (chance of hyperglycaemia + osmotic diuresis)
—> Na 130-145: Half-half solution
—> Na <130: Normal saline
- Vasopressor support
—> Noradrenaline / Dopamine / Vasopressin IV - IV Hydrocortisone for patients with haemodynamic instability
2. Control arrhythmia
3. Maintain body temp (Bair Hugger warming system if <=35oC)
- Monitor SaO2 >90%
- Supplemental O2
- ETT suction
- Chest physiotherapy
- Optimise tidal volume 6-8 ml/kg/min
- Add PEEP 5-10 cmH2O
- Increase FiO2
- Keep peak inspiratory pressure <35 cmH2O to minimise potential of both oxygen toxicity and barotrauma (lung not transplantable if damaged) - Urine output
- >200 ml/hr —> IV DDAVP to correct Cranial DI, replace volume deficit (rule out osmotic diuresis due to hyperglycaemia)
- <30 ml/hr —> check Foley patency, if dehydrated —> give fluid, if oliguria with adequate hydration —> give furosemide - Euglycaemic control (<12)
- give insulin (Actrapid)
Absolute contraindications in organ donation
- Presence of serious transmissible disease (e.g. HIV)
- Presence of other systemic infections (e.g. bacteraemia)
- Presence of extracranial malignancy (risk of donor-transmitted malignancy)
No age limit for liver donation:
- Liver does not age
- Liver has amazing power of regeneration
Organ transplantation in HK
- Opt-in system
- Very low deceased donor rate
- 60-70% transplant are living donor
- Increasing discrepancy in demand and supply
—> Increase in number of patients waiting
—> Increase in waiting time
—> Increase in mortality on waiting list
—> Increase in living donation
Opt-in vs Opt-out
Opt-in (in HK):
- People must actively sign up to a register to donate their organs after death (Centralised Organ Donation Register (CODR))
- If a person does not register, the family will make the decision at time of death
- even if person registered, family wish is still respected
Opt-out:
- Organ donation will occur automatically unless a specific request is made before death for organ not to be taken
Ethical concerns in Liver transplantation
- Luck (drawing lots)
- First come, first serve (waiting time)
- Value of individual
- age, gender, ethnicity, religion, social class, occupation - Utility (best outcome, the fittest)
- Urgency status (the sickest)
- Technical considerations (e.g. graft size, vascular status)
HK now based on 3 principles:
- Justice (equitable?)
- Utility
- Urgency status (MELD score)
Advantages and Disadvantages of living donor
Advantages:
- Early transplantation
- No waiting time (∵ to loved ones)
- Planned operation —> allow optimisation of recipient status
- Immunologic advantage (if from related person)
Disadvantages:
- Risks of living donor
- Suffering of living donor
- Guilt feeling if transplant operation fails
Donor selection in living donor
- Voluntary informed consent
- risks, potential benefits, long term outcomes of both donor and recipient
- risks: sepsis, liver failure, acute MI, cerebrovascular accident, PE, duodenal stress ulcer - Acceptable operative risk (for both donor and recipient)
1, 2 —> most important —> therefore developed criteria: >18, <60, no past medical illness that may cause complications
- Absence of transmissible disease
- Suitable graft
- **Blood group
- **Tissue typing
- ***Organ function
- Anatomy and size
HK: Human Organ Transplant Ordinance (Cap 465)
Purpose:
- To prohibit commerical dealings
- To restrict living donor transplantation
- Genetically related
- Marriage >3 years
- Approval from HOT board (if unrelated persons, family, altruistic donor) - To restrict transplant of imported organs
- First offence / conviction: fine at level 5 / imprisonment for 3 months
Human Organ Transplant (HOT) Board:
- 9 members:
—> Chairman + Vice-chairman (NOT registered doctor)
—> 4 members from medical sector
—> 3 members (1 from social work, legal, non-medical)
Function of HOT board:
- To give approval to the removal / transplant of a restricted organ (from unrelated donor)
- To receive / keep record of information / document required by the Ordinance
Ethical and legal issues of organ transplant
- Organs from executed prisoners
- Transplanting bad guys
- Paid living unrelated donation
- lack of quality control: donor evaluation, matching, operation, follow up
- middle man gains most
- donor gets only minor in return - Age limit for living donor
- HK: HOT Ordinance still mandate living donor >=18 yo currently - Risk / Benefit
- Risk of living donation vs Benefit of recipient
- Minimum acceptable figure of benefit: 5 year of 60%
- Donor risk should be <0.5%
