Organ Donation Dr James F Peerless May 2013. Objectives Background Brain-stem death Donation after...

Organ Donation

Dr James F PeerlessMay 2013

Objectives

• Background• Brain-stem death• Donation after brain

death• Donation after circulatory

death• Ethical issues

Syllabus• Annex C

– Anaesthesia for neurosurgery, neuroradiology and neuro critical care • NA_IK_23 Explains the issues related to the management of organ donation in neuro-critical care

– General, urological and gynaecological surgery • GU_IK_04 Recalls/ describes the ethical considerations of cadaveric and live-related organ donation

for the donor [and relatives], recipient and society as a whole

– Trauma and stabilisation• MT_IK_09 Describes the specific ethical and ethnic issues associated with managing the multiply

injured patient, including issues that relate to brain stem death and organ donation

• Annex F– Domain 8: End of life care

• 8.1 Manages the process of withholding or withdrawing treatment with the multi-disciplinary team• 8.2 Discusses end of life care with patients and their families/surrogates• 8.3 Manages palliative care of the critically ill patient• 8.4 Performs brain-stem death testing• 8.5 Manages the physiological support of the organ donor• 8.6 Manages donation following cardiac death

History

• Organ transplantation is the removal of an organ and placement in another site– Either allograft or autograft

• Numerous accounts throughout history– Issues mainly limited by degradation of organs and host

rejection– 1905: first corneal transplant– 1950: first successful kidney transplant

• Holy grail is the generation of organs from patients’ stem cells

Types of Donor

• DBD/HBD– Donation after brain death– Heart beating donor

• DCD/NHBD– Donation after cardiac death– Non-heart beating donor

• Living donors

Introduction

• Organ transplantation offers hope to patients with end-stage organ failure.

• Can help bereaved families find solace• Advances in medicine and an ageing population

have brought about a demand which far outstrips organ availability

• UK has a low donor rate compared with many European countries– Spain 34 pmp– UK 16 pmp

Introduction

• Number of DBD patients is decreasing due to:– Fewer young people dying of catastrophic

cerebrovascular events– Advances in treatment of traumatic brain injury

and intracranial haemorrhage

Statistics for 2011/12

• 1 088 deceased donors– 436 DCD donors– 652 DBD donors

• On 31 March 2012, there were 7 636 patients on the transplant list

• During 2011/12:– 508 patients died whilst on the list– 819 patients were removed from the list

• Ill-health• Ineligible

Source: Transplant activity in the UK, 2011-2012, NHS Blood and Transplant

777 770 751 764 793 809 899 959 1010 1088

2388 23962241 2196

2385 23812552 2644 2695

2905

780079977877

6698

6142

56735654

7219

7655 7636

0

1000

2000

3000

4000

5000

6000

7000

8000

2002-2003 2003-2004 2004-2005 2005-2006 2006-2007 2007-2008 2008-2009 2009-2010 2010-2011 2011-2012

Year

Nu

mb

er

Donors

Transplants

Transplant list

Number of deceased donors and transplants in the UK, 1 April 2002 - 31 March 2012,and patients on the active transplant lists at 31 March

Source: Transplant activity in the UK, 2011-2012, NHS Blood and Transplant

1 Hearts – in addition to age criteria, donors who died due to myocardial infarction are excluded

0

10

20

30

40

50

60

70

80

90

100

Organs fromactual DBD

donors

Donor agecriteria met

Consent fororgan donation

Organs offeredfor donation

Organs retrievedfor transplant

Organstransplanted

Pe

rce

nta

ge

Kidney Liver Pancreas Heart Lungs

Donation and transplantation rates of organs from DBD organ donors in the UK, 1 April 2011 – 31 March 2012

% of all organs

% of all organsmeeting age

criteria1

86%85%

30%

24%21%

86%85%

41%

25%28%

1

Transplanted:

Source: Transplant activity in the UK, 2011-2012, NHS Blood and Transplant

Donation and transplantation rates of organs from DCD organ donors in the UK, 1 April 2011 – 31 March 2012

0

10

20

30

40

50

60

70

80

90

100

Organs fromactual DCD

donors

Donor agecriteria met

Consent fororgan donation

Organs offeredfor donation

Organs retrievedfor transplant

Organstransplanted

Pe

rce

nta

ge

Kidney Liver Pancreas Lungs

% of all organs

% of all organsmeeting age

criteria

82%

30%

12%

4%

82%

30%

20%

6%

Transplanted:

Approaching the Family

• Doctors’ task is to identify suitable donors• SN-ODs are specially trained to discuss organ

donation with relatives, and have a higher consent success rate.

• Essential that requests are made with sensitivity and compassion

Brain stem death

Brain stem Death

• A state of irreversible loss of consciousness associated with the loss of central respiratory drive

• Accepted as equivalent to somatic/cardiorespiratory death as it represented a state when “the body as an integrated whole has ceased to function”.

World Medical Association, 1968

Diagnosis of brain stem death

Brain stem death is diagnosed in three stages: 1. It must be established that the patient has

suffered an event of known aetiology resulting in irreversible brain damage with apnoeic coma

2. Reversible causes of coma must be excluded3. A set of bedside clinical tests of brain stem

function are undertaken to confirm the diagnosis of brain stem death

Reversible Causes of Coma

• Sedative drugs– Beware prolonged action, especially in presence of hypothermia,

renal failure and hepatic failure

• Neuromuscular blocking agents

• Hypothermia– Core temperature must be >34°C

• Circulatory, metabolic or endocrine disturbances– Pathophysiological changes commonly occur following brain stem

compression and death.

The Test

• Absent pupillary light reflex• Absent corneal reflex• Absent vestibulo-ocular reflex• No motor response to central stimulation• Absent gag reflex• Absent cough reflex• Absence of respiratory movements during

apnoea test

Apnoea Test

• Patient pre-oxygenated (FiO2 1.0) for 10 minutes– Allow PaCO2 to rise to 5.0kPa.

• Patient is disconnected from ventilator– O2 passed down ETT via suction catheter at 6 Lmin-1 to maintain

oxygenation

• Direct clinical observation to confirm apnoea over 10 minute period– PaCO2 is allowed to rise to >6.65kPa.

• If respiratory threshold of 6.65 kPa not exceeded after 10 minutes:– Apnoea continued and PaCO2 rechecked until threshold exceeded.

Notes on brain stem testing

Brain stem testing must be performed by at least two medical practitioners:

• registered with the GMC for more than five years• at least one should be a consultant, and competent in testing• not members of the transplant team

Two sets of tests are performed: • to remove the risk of observer error• to re-assure the family• no strict time interval between tests (clinical judgment)

Notes on brain stem testing

Time of death: • legal time of death is when the first set of tests indicates

brain stem death

Spinal reflexes: • Peripheral muscle movements in response to peripheral

stimulation– neural pathways in the spinal cord with no higher neural input.

• May occur following peripheral stimulation both during testing and at other times– should be explained to relatives

Donation after Brain Death

DBD

• Donation from heartbeating donors offers advantages due to the minimal time between loss of circulation and cold perfusion

• Important to recognise the changes that occur in a DBD and actively manage these– Suboptimal management reduces quality and

quantity of number of organs for transplantation

DBD

• Brain stem death causes widespread physiological changes– Cardiovascular– Respiratory– Endocrine– Metabolic– Haematological

Pathophysiology

• Coning– Increased ICP HTN to maintain CPP– High ICP brain herniation, pontine ischaemia and

a hyperadrenergic state– Pulmonary hypertension occurs– Increased afterload (both sides) myocardial

ischaemia and NPO– Cushing’s Reflex – occurs in 1/3 patients secondary

to baroreceptor activity and midbrain activation of the PNS.

Cardiovascular Collapse Phase

• Following herniation– Loss of sympathetic activity reduction in

vascular tone• Vasodilatation and hypotension• Reduced cardiac output• Reduced preload and afterload reduced aortic

diastolic pressure reduced myocardial perfusion

Endocrine

• Diabetes insipidus– Pituitary ischaemia reduced ADH secretion

• High fluid losses• Electrolyte disturbances

• Metabolic rate– Reduced movement, reduced activity– Reduced circulating [T3]

• Hypothermia– Hypothalamic dysfunction

Pulmonary

• Dysfunction common• Worsening existing condition

– Pneumonia– Aspiration

• Related to TBI– Neurogenic pulmonary oedema

Haematological

• Tissue thromboplastin– Released by ischaemic brain tissue– Leads to a number of coagulopathic disorders,

including DIC• Need to cross-match 4 units for organ

harvesting

DBD

• All systems need to be preserved and optimized as best as possible to enhance chance of successful organ transplantation

• Retrieval teams will request blood sampling– Pre-transplantation renal function– Coagulation

• Maintain cardiovascular stability• Monitor fluid balance

Donation after Circulatory Death

DCD

• The retrieval of organs for transplantation following death confirmed by circulatory criteria

• Has been reintroduced to help contribute to donor numbers

• DCD should be considered in all patients where continued treatment is futile, but do not meet brain death criteria

When & where

• Modified Maasticht Classification of DCDs

I. Dead on arrivalII. Unsuccessful resuscitationIII. Awaiting cardiac arrestIV. Cardiac arrest in DBDV. Unexpected cardiac arrest in critically ill

patient

Organ retrieval quality

• Warm ischaemia time limits the type of organs that can be successfully retrieved

• Causes irreversible damage due to accumulation of ischaemic metabolites

• Warm ischaemia– Commences when SAP < 50 mmHg, SaO2 <70 %, until cold

perfusion initiated• Cold ischaemia

– From cold perfusion to warm circulation following transplantation

DCD - Organs

• Kidney (2 hours)• Liver (30 minutes)• Pancreas (3o minutes)• Lung (1 hour)• Tissue

– Cornea– Bone– Skin– Heart valves

DCD - Contraindications

• No age limit

• HIV• vCJD• Haematological malignancy• Active invasive Ca within last three years

DCD - The process

• Decision to withdraw made• Transplant coordinator involvement• Discussion with family• [coroner referral]• Continue current levels of treatment

– Controversies regarding escalation• Retrieval team prepraed in theatre• Withdrawal of treatment occurs

DCD - Ethical Issues

• Potential for conflict of interest with DCD patients regarding withdrawal of treatment, end of life care, and suitability for organ donation

• Concerns about adjusting end of life care to facilitate donation

• Uncertainty regarding how soon organ retrieval can begin following circulatory death

Summary

• Recognition and treatment of physiological changes during DBD increase chance of successful organ donation

• DCDs make a modest but increasing contribution to the donor pool

• Decisions regarding organ donation should be routinely incorporated into end-of-life care

References• ICS Working Group on Organ & Tissue Donation. Guidelines for Adult

Organ and Tissue Donation. UK Intensive Care Society, 2005.• Dunne K, Doherty P. Donation after circulatory death. Continuing

Education in Anaesthesia, Critical Care & Pain, 2011; 11(3): 83-6• Manara A, Murphy P, O’Callaghan G. Donation after circulatory death.

British Journal of Anaesthesia, 2012; 108 (supplement 1): i108-i121• Gordon J, McKinlay J. Physiological Changes after Brain Stem Death

and Management of the Heart-beating Donor. Continuing Education in Anaesthesia, Critical Care & Pain, 2012; 12(5): 225-9

• Statistics and Clinical Audit, NHS Blood and Transplant. Overview of Organ Donation and Transplantation. NHS Blood and Transplant, 2012. http://organdonation.nhs.uk/statistics/transplant_activity_report/current_activity_reports/ukt/activity_report_2011_12.pdf