GC222 I Want To Donate My Organs
A UK General Medical Council guidance topic addressing the principles and processes by which individuals can express their wish to donate organs after death, including consent, registration, and the roles of healthcare professionals in facilitating organ donation.
I Want to Donate My Organs: Brain Death, Organ Donation & Psychological Issues
Lecture Map
This lecture (GC 222 / WCS 28) covers the entire pipeline of deceased organ donation — from identifying a potential donor, through confirming brain death, to managing the physiologically unstable brain-dead patient so that transplantable organs remain viable. It also touches on the Hong Kong consent framework (opt-in vs opt-out), communication ethics with families, and the clinical referral trigger mnemonic GIVE.
- As a medical student or junior doctor, you may be the first to identify a patient who meets referral criteria for organ donation. Knowing when and how to trigger the process is a core clinical responsibility.
- Brain death testing is a fundamental ICU concept that intersects with GC 005 (The Patient is Critically Ill) and renal replacement therapy lectures.
- The management of systemic physiological instability in brain death directly tests your understanding of neurophysiology, endocrinology (cranial diabetes insipidus), cardiovascular physiology (Cushing reflex, autonomic storm), and critical care targets.
- Know the clinical referral trigger for deceased organ donation (GIVE).
- Understand the general criteria for deceased organ and tissue donation in Hong Kong.
- Distinguish brain death donors from cardiac death donors.
- Describe the diagnosis of brain death — preconditions, clinical brainstem tests, and when confirmatory tests are needed.
- Explain the pathophysiology of systemic instability in imminent brain death.
- State the management targets for imminent brain death patients.
- Understand the opt-in vs opt-out system.
- Know the dos and don'ts when communicating with families of potential donors.
Core Concepts & Mechanisms
The deceased organ donation process follows a strict sequential pathway: Identify → Inform ODC → Assess → Confirm brain death → Family consent → Manage donor → Organ recovery. [1]
High Yield — The Process is Sequential
Every step must be completed before proceeding to the next. You do NOT discuss organ donation with the family before brain death is certified. This is both an ethical and practical requirement — the family must first understand that their loved one has died (brain death = legal death) before being asked about donation.
GIVE: GCS < 5, Irreversible brain injury, Ventilated, End of life care — call the Organ Donation Coordinator (ODC) when these criteria are met. [1]
Why this mnemonic matters from first principles:
- GCS < 5: A GCS this low (E1V1M3 or worse) suggests devastating brain injury with minimal residual function. These patients are candidates for evolving to brain death.
- Irreversible brain injury: The injury must be one from which recovery is not expected (e.g., massive intracranial haemorrhage, severe traumatic brain injury, large ischaemic stroke). If the injury is potentially reversible, the patient is not a candidate.
- Ventilated: Brain death testing requires the patient to be on mechanical ventilation — the apnoea test is performed on a ventilated patient. Also, organ perfusion is maintained via ventilatory and cardiovascular support.
- End of life care: The clinical team has determined that further active treatment is futile and the trajectory is toward death.
Exam Trap
You do NOT need to wait for brain death to be confirmed before calling the ODC. The referral trigger (GIVE) is about identifying potential donors early so the ODC can begin assessment. Early referral is key.
No age limit in general for deceased organ donation. [1]
Types of donors: (1) Brain death donors — donate both organs and tissue; (2) Cardiac death donors — donate tissue only (corneas, skin, bones). However, organ donation after cardiac death is increasing worldwide. [1]
| Criterion | Detail | Why |
|---|---|---|
| No age limit | Even elderly patients may have viable organs | Organ function matters more than age |
| Adequate organ function | Must have functioning organs to transplant | Non-functioning organs are useless for recipients |
| No severe/systemic infection | Risk of transmitting infection to immunosuppressed recipient | Exception: localized infections may be acceptable |
| No HIV infection | HK currently does not accept; some countries do | Risk of HIV transmission; international variation exists |
| Cancers contraindicated | For organs, skin, and bone donation | Risk of cancer transmission to recipient |
| Exception: primary brain tumours | These rarely metastasize outside the CNS | Therefore peripheral organs are safe to transplant |
| Selected cancers may allow cornea donation | Cornea is avascular → lower metastatic risk | Case-by-case consideration |
High Yield — Cancer and Organ Donation
Cancers are contraindicated in organs, skin and bone donation, EXCEPT primary brain tumours. Selected deceased with cancer may be considered for cornea donation. [1] This is a classic exam discriminator — students often think all cancer patients are excluded.
| Feature | Brain Death Donor | Cardiac Death Donor |
|---|---|---|
| Definition | Irreversible cessation of brainstem function | Cessation of cardiac function (heart stops) |
| Ventilation | Still on ventilator — organs perfused | Not on ventilator — organs become ischaemic quickly |
| What can be donated | Organs AND tissue (heart, lungs, liver, kidneys, pancreas, corneas, skin, bone) | Tissue only (corneas, skin, bones) in HK currently |
| Status in HK | Currently only brain death donors are accepted for deceased organ donation | Growing worldwide but limited in HK |
Currently only brain death donors are accepted for deceased organ donation in Hong Kong. [1]
Why is this distinction important?
- After cardiac death, warm ischaemia time damages organs rapidly. Brain-dead patients still have intact circulation (maintained by ventilator and drugs), so organs remain perfused and viable.
- Donation after cardiac death (DCD) protocols exist internationally with controlled withdrawal of life support — HK is not yet routinely using this pathway for organ donation but it is increasing globally.
Diagnosis of Brain Death
Brain death = irreversible cessation of brainstem function, established by documentation of: (1) irreversible coma, (2) irreversible loss of brainstem reflex responses and respiratory center function, (3) demonstration of cessation of intracranial blood flow. [1]
From first principles: The brainstem houses the reticular activating system (consciousness), cranial nerve nuclei (reflexes), and the respiratory centre (medulla). If all brainstem functions are permanently lost, the person cannot maintain consciousness, breathe spontaneously, or exhibit any cranial nerve reflexes — they are dead, even though the heart may still beat with mechanical support.
The diagnosis of brain death is made by the separate examination of two doctors who have no relations with the organ transplant service to carry out two separate tests. [1]
Why two doctors?
- Eliminates individual error
- Ensures independence from the transplant team (avoids conflict of interest)
- The two examinations are done separately (not simultaneously)
Before you can even begin brainstem testing, you must rule out anything that might mimic brain death:
Must exclude: (1) Effect of sedative drugs and/or muscle relaxants, (2) Hypothermia (body temperature < 35°C), (3) Metabolic and endocrine disturbance — no profound abnormality of electrolyte, acid-base balance, or blood glucose concentration, (4) Arterial hypotension, (5) Neuromuscular function is intact. [1]
| Precondition to Exclude | Why |
|---|---|
| Sedative drugs / muscle relaxants | These depress brainstem function reversibly; must wait for drug clearance or check levels |
| Hypothermia ( < 35°C) | Hypothermia profoundly depresses neural function; at low temperatures, EEG may be flat but the patient could recover with rewarming |
| Metabolic/endocrine disturbance | Severe hyponatraemia, hyperglycaemia, or profound hypothyroidism can cause deep coma mimicking brain death |
| Arterial hypotension | Inadequate cerebral perfusion from systemic hypotension can suppress brainstem reflexes without true brainstem death |
| Neuromuscular function intact | If the patient has received neuromuscular blocking agents, motor responses cannot be assessed; must ensure agents have worn off |
Critical Exam Point
You CANNOT diagnose brain death if the patient is hypothermic ( < 35°C), has residual sedatives/paralytics on board, has uncorrected severe metabolic derangement, or is hypotensive. These are preconditions that must be met FIRST.
All of the following must be absent for a diagnosis of brain death: [1]
| Test | What You're Testing | Expected Finding in Brain Death |
|---|---|---|
| Pupillary light reflex | CN II (afferent) → CN III (efferent) | Both pupils fixed and do not respond to light (usually dilated, but fixed is the key criterion) |
| Corneal reflex | CN V (afferent) → CN VII (efferent) | Absent — no blink when cornea is touched |
| Vestibulo-ocular reflex (cold caloric testing) | CN VIII (afferent) → CN III, VI (efferent) | No eye movement when 50mL of ice-cold water is instilled into the ear canal |
| Gag reflex | CN IX (afferent) → CN X (efferent) | Absent |
| Cough reflex | CN X | Absent — no cough when suction catheter passed down endotracheal tube |
| Motor response in cranial nerve distribution | Motor nuclei of CN V, VII | No motor response to stimulation of face, limbs, or trunk |
| Apnoea test | Medullary respiratory centre | No respiratory movement with arterial PCO2 > 8 kPa and pH < 7.3 |
Why the apnoea test has specific thresholds:
- The respiratory centre is the most resistant brainstem structure to hypoxia/ischaemia. If it fails to respond to the most powerful physiological stimulus for breathing (high CO2, low pH), it is definitively non-functional.
- PCO2 > 8 kPa (~60 mmHg) represents a supra-maximal stimulus. You pre-oxygenate the patient, disconnect the ventilator, and observe. CO2 rises approximately 0.3–0.4 kPa/min. You allow CO2 to reach > 8 kPa while monitoring.
- pH < 7.3 ensures the acidosis is sufficient to maximally stimulate any residual respiratory drive.
High Yield — Apnoea Test Parameters
No respiratory movement with arterial PCO2 > 8 kPa AND pH < 7.3. [1] Know these exact numbers — they are commonly tested in MCQ format.
Confirmatory tests are needed if: (1) No clear cause of coma, (2) Possible metabolic effect or drug effects, (3) Cranial nerves cannot be adequately tested, (4) Cervical vertebral or cord injury, (5) Cardiovascular instability precluding apnoea test, (6) Severe hypoxaemic respiratory failure precluding apnoea test. [1]
Confirmatory test: Four-vessel radio-contrast angiography with digital subtraction — to demonstrate absence of intracranial blood flow. [1]
Why four-vessel angiography?
- If clinical testing cannot be reliably performed (e.g., facial trauma prevents corneal reflex testing, or the patient is too unstable for the apnoea test), you need an objective, definitive test.
- Four-vessel angiography (bilateral internal carotid arteries + bilateral vertebral arteries) shows whether there is any intracranial blood flow. If there is no flow, the brain has no perfusion and is dead.
- Other confirmatory tests used internationally include transcranial Doppler, CT angiography, and nuclear perfusion scans, but the lecture specifies four-vessel angiography with digital subtraction.
Opt-In (adopted in Hong Kong now): People must actively sign up to a register to donate their organs after death (Centralised Organ Donation Register, CODR: codr.gov.hk). If a person doesn't register, the family will make the decision at the time of death. [1]
Opt-Out: Organ donation will occur automatically unless a specific request is made before death for organs not to be taken. [1]
| System | How It Works | Countries | Ethical Implication |
|---|---|---|---|
| Opt-In | Must actively register; family decides if not registered | Hong Kong, USA, Japan | Respects individual autonomy but leads to lower donation rates |
| Opt-Out | Presumed consent; must actively refuse | Spain, Belgium, Austria, Wales | Higher donation rates but raises concerns about informed consent |
Why does this matter?
- Hong Kong has a severe organ shortage. As of the lecture, HK uses opt-in, meaning many potential donors are lost because they never registered and families decline.
- Understanding the CODR and being able to counsel patients/families about registration is part of your clinical duty.
Dos: (1) Do identify and make referral to ODC when there is a potential organ donor. (2) Do maintain vital signs and haemodynamic stability of the potential organ donor. (3) Do respect family regarding the option of organ donation. (4) Do assure confidentiality of donor's record. [1]
Don'ts: (1) Don't discuss choice of organ donation BEFORE brain death certification. (2) Don't screen cases for the transplant team. (3) Don't take away the chance of 'those' willing to donate and 'those' waiting for a transplant. [1]
Critical Communication Rule
DO NOT discuss organ donation with the family BEFORE brain death has been certified. [1] The family must first process that their loved one is dead. Raising donation prematurely destroys trust, causes distress, and may lead to refusal even from willing families.
Why "Don't screen cases for the transplant team"?
- Your job is to identify and refer. The ODC and transplant team have the expertise to assess suitability. If you pre-screen and incorrectly rule someone out, you might deny organs to waiting recipients.
Why "Don't take away the chance"?
- Even if you personally feel a patient wouldn't be a suitable donor, or if the situation seems delicate, you should still refer. Let the ODC make the assessment. Many families actually find comfort in donation — it gives meaning to their loss.
Physiological Instability in Imminent Brain Death
When the brainstem dies, it can no longer regulate the autonomic nervous system, hormonal axes, temperature, or respiration. The result is a cascade of systemic physiological instability that threatens organ viability. Understanding this is critical because managing these derangements determines whether the organs are transplantable.
Loss of brainstem function results in systemic physiologic instability: unstable blood pressure, cardiac arrhythmia, loss of temperature regulation, hormonal imbalance (cranial diabetes insipidus), loss of respiratory function, electrolyte disturbance. [1]
Blood Pressure Instability — Biphasic Pattern
↑ICP → ↑arterial blood pressure to ensure adequate cerebral perfusion pressure (Cushing's reflex). Autonomic/Sympathetic storm → release of catecholamines → hyperdynamic state → tachycardia, peripheral vasoconstriction, hypertension. [1]
First principles explanation:
- As ICP rises, cerebral perfusion pressure (CPP = MAP - ICP) falls. The brainstem detects this and triggers a massive sympathetic discharge (Cushing reflex) to raise MAP and maintain CPP.
- This "sympathetic storm" floods the circulation with catecholamines (norepinephrine, epinephrine), causing severe hypertension, tachycardia, and vasoconstriction.
- This phase is dangerous because it can cause myocardial injury (catecholamine cardiotoxicity), pulmonary oedema, and end-organ damage to transplantable organs.
Sympathetic outflow loss, catecholamine depletion, myocardial dysfunction, intense peripheral vasodilatation, hypovolaemia, electrolyte disturbance, and endocrine changes. [1]
First principles explanation:
- Once the brainstem is completely dead, sympathetic outflow ceases. The catecholamine surge exhausts the adrenal reserves.
- Without sympathetic tone, peripheral vasodilation is unopposed → blood pools in the periphery → blood pressure drops.
- Myocardial dysfunction from the prior catecholamine storm compounds the problem.
- Hypovolaemia develops from diabetes insipidus (see below) and third-spacing.
Atrial and ventricular dysrhythmias, conduction blocks. Due to electrolyte and acid-base disturbances, hypothermia, decreased myocardial contractility, inotrope use, and increased ICP. [1]
Why multiple causes?
- Electrolyte shifts (hypernatraemia from DI, hypokalaemia, hypocalcaemia) directly affect myocardial cell membrane potentials.
- Hypothermia slows conduction and can precipitate ventricular fibrillation.
- Prior catecholamine storm damages myocardium.
- Note: Atropine will NOT work for bradycardia in brain death because the vagal nucleus is dead. The bradycardia is from loss of sympathetic tone, not excessive vagal tone.
Due to loss of hypothalamic temperature regulation. Hypothermia can induce coagulopathy, haemolysis, and leftward shift of oxyhaemoglobin dissociation curve. [1]
First principles:
- The hypothalamus is the thermostat of the body. When it dies, the patient becomes poikilothermic (body temperature drifts toward ambient temperature).
- In an air-conditioned ICU, this means hypothermia.
- Coagulopathy: Clotting enzymes function optimally at 37°C; hypothermia impairs the coagulation cascade.
- Haemolysis: Cold-induced RBC lysis.
- Left shift of O2-Hb dissociation curve: Haemoglobin binds O2 more tightly, reducing O2 delivery to tissues → organ damage.
Due to posterior hypothalamic-pituitary deficiency. Causes polyuria, hypovolaemia, hypotension, and hypovolaemic hypernatraemia. [1]
First principles:
- ADH (vasopressin) is produced in the hypothalamus and stored in the posterior pituitary. When the hypothalamus dies, ADH secretion stops.
- Without ADH, the collecting ducts cannot reabsorb water → massive dilute polyuria (can be > 500mL/hr).
- This leads to profound dehydration (hypovolaemia → hypotension) and concentration of serum sodium (hypernatraemia).
- Cranial DI is the hallmark endocrine complication of brain death and must be treated with desmopressin (DDAVP) and fluid replacement.
Loss of respiratory function [1]
- The medullary respiratory centres are dead → no spontaneous breathing.
- The patient is fully ventilator-dependent.
- Without ventilatory support, there is no gas exchange, and all organs fail within minutes.
Electrolyte disturbance [1]
- Driven by DI (hypernatraemia, possible hypokalaemia), hypothermia, acid-base derangements, and hormonal imbalances.
- Must be actively monitored and corrected to prevent arrhythmias and organ dysfunction.
Management of Imminent Brain Death Patients
Stabilize the patient — facilitate brain death examination. Manage the "potential donor" — to optimize the function and viability of all transplantable organs. [1]
Targets: (1) Maintain arterial SBP 100–140 mmHg / MAP ~65 mmHg, (2) Maintain heart rate 60–120 bpm, (3) Maintain hourly urine output ~100 mL, (4) Maintain SaO2 > 90%, (5) Maintain body temperature > 36°C, (6) Maintain normal ranges for serum glucose, potassium, calcium, phosphate, magnesium. [1]
| Parameter | Target | Rationale |
|---|---|---|
| SBP | 100–140 mmHg / MAP ~65 mmHg | Ensures adequate organ perfusion without overloading the heart |
| Heart Rate | 60–120 bpm | Avoids haemodynamic compromise from bradycardia or tachycardia |
| Urine Output | ~100 mL/hr | Ensures renal perfusion; also indicates DI if grossly elevated |
| SaO2 | > 90% | Prevents hypoxic organ damage |
| Temperature | > 36°C | Prevents coagulopathy, arrhythmia, and haemolysis from hypothermia |
| Glucose, K+, Ca2+, PO4, Mg2+ | Normal ranges | Electrolyte derangements cause arrhythmias and organ dysfunction |
High Yield — Management Targets
Memorize the exact targets above. They are commonly tested in SAQ format: "List the targets for management of an imminent brain death patient."
Practical management principles (from CCOT Guideline, referenced in lecture):
- Hypotension: IV fluid resuscitation (crystalloid/colloid), vasopressors (noradrenaline, vasopressin) if needed.
- DI: Desmopressin (DDAVP) + fluid replacement (typically hypotonic fluids or D5W to correct hypernatraemia).
- Hypothermia: Active warming (warming blankets, warmed IV fluids).
- Arrhythmias: Correct underlying cause (electrolytes, temperature, volume status).
- Endocrine: Some protocols include thyroid hormone replacement (T3/T4), hydrocortisone (for adrenal insufficiency from hypothalamic-pituitary axis loss), and insulin for hyperglycaemia.
1. Early referral to ODC using GIVE (GCS < 5, Irreversible brain injury, Ventilated, End of life care). [1]
2. DO NOT discuss choice of organ donation with family before brain death certification. [1]
3. Currently only brain death donors are accepted for deceased organ donation in Hong Kong. [1]
4. Brain death is diagnosed by two separate examinations by two doctors with no relation to the transplant service. [1]
5. Systemic physiological instability is expected in imminent brain death patients. [1]
6. Management of imminent brain death needs clinical expertise, vigilance, and ability to address multiple clinical problems effectively and simultaneously. [1]
7. Collaboration with ODCs and Critical Care staff can further improve potential donor management. [1]
Integration with Related Material
- ICU's major duty includes supporting failing organs to buy time for recovery or provide definitive treatment. In the context of brain death, ICU support is used not for the patient's recovery (which is impossible) but to preserve organ function for transplantation.
- Understanding ICU monitoring (arterial lines, CVP, PA catheters) is essential for managing brain-dead donors.
- Deceased kidney donors must have no known history of kidney disease, long-standing HT or DM, and must have normal renal function.
- Donor nephrectomy in deceased donors is typically open (faster, allows multi-organ retrieval) vs. laparoscopic for living donors (minimally invasive, faster recovery for the living patient).
- Donor evaluation includes Hx, drug Hx, CXR, echocardiography, hormonal optimization (especially thyroid hormone).
- Harvesting order: heart → lung → liver → kidney → cornea, bone, skin (shortest ischaemia tolerance first).
- Organs are immediately immersed in ice cold water after explantation.
- Post-transplant: immunosuppressants (steroids, CNI, antimetabolite), antimicrobial prophylaxis, routine endomyocardial biopsy for rejection screening.
Exam Intelligence
- MCQ: Testing GIVE mnemonic components, preconditions for brain death testing, specific brainstem reflex tests, apnoea test thresholds, contraindications to organ donation.
- SAQ: "List the clinical tests for brainstem death" or "List the management targets for an imminent brain death patient" — structured listing with brief explanation.
- Minicase: A trauma patient with GCS 3, ventilated — when would you refer? What preconditions must be met before brain death testing?
| Trap | Correct Answer | Why Students Get It Wrong |
|---|---|---|
| "Can a patient with cancer donate organs?" | No, except primary brain tumours (organs) and selected cases for corneas | Students either say "never" or "always" — the exception is key |
| "When do you discuss organ donation with the family?" | Only AFTER brain death is certified | Students think you should discuss early to save time |
| "What temperature excludes brain death testing?" | < 35°C | Confused with hypothermia protocols for cardiac arrest (32–36°C) |
| "What PCO2 threshold for apnoea test?" | > 8 kPa | Confused with normal PCO2 (~5.3 kPa) or ventilator targets |
| "Can cardiac death donors donate organs in HK?" | No — currently only tissue (corneas, skin, bones) | Students assume DCD is standard everywhere |
| "What causes polyuria in brain death?" | Cranial diabetes insipidus from posterior hypothalamic-pituitary failure | Confused with osmotic diuresis from hyperglycaemia |
| "Does atropine work for bradycardia in brain death?" | No — vagal nucleus is dead; bradycardia is from loss of sympathetic tone | Students reflexively say atropine for any bradycardia |
After thorough review of all indexed past papers (2016–2025 Fourth Summative MCQ, SAQ, and Minicase papers), no specific questions directly matching the organ donation / brain death lecture content were identified in the provided indexed past paper context. This is not uncommon for this niche topic — it may appear as part of a larger critical care or ethics question stem that was not fully indexed, or it may be tested in clinical/OSCE settings.
If any relevant questions are identified in future exam paper releases, they would likely test:
- GIVE mnemonic
- Preconditions for brain death testing
- Brainstem reflex tests
- Apnoea test thresholds
- Management targets for imminent brain death
High Yield Summary
1. GIVE mnemonic — GCS < 5, Irreversible brain injury, Ventilated, End of life care → Call ODC.
2. Brain death = irreversible cessation of brainstem function — diagnosed by 2 independent doctors, 2 separate exams, no relation to transplant team.
3. Preconditions: Exclude sedatives/paralytics, hypothermia ( < 35°C), metabolic disturbance, hypotension, neuromuscular blockade.
4. Brainstem tests: Fixed pupils, absent corneal reflex, absent vestibulo-ocular reflex, absent gag/cough, no motor response in cranial nerve distribution, apnoea test (no breathing with PCO2 > 8 kPa and pH < 7.3).
5. Confirmatory test (when clinical testing insufficient): Four-vessel angiography showing absent intracranial blood flow.
6. HK system: Opt-in (CODR). Only brain death donors for organ donation. Cardiac death donors → tissue only.
7. Cancer contraindicated except primary brain tumours (organs) and selected cases (corneas).
8. Don't discuss donation before brain death certification.
9. Physiological instability: BP instability (Cushing reflex → sympathetic storm → then hypotension), arrhythmias, hypothermia, cranial DI, respiratory failure, electrolyte disturbance.
10. Management targets: SBP 100–140/MAP ~65, HR 60–120, UO ~100 mL/hr, SaO2 > 90%, Temp > 36°C, normal electrolytes/glucose.
Active Recall - Organ Donation & Brain Death
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