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Organ Donation. Dr James F Peerless May 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

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Organ Donation

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Organ Donation

Dr James F Peerless

May 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

      • 8.1Manages 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

      • 8.3Manages palliative care of the critically ill patient

      • 8.4Performs brain-stem death testing

      • 8.5Manages the physiological support of the organ donor

      • 8.6Manages 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


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:

  • It must be established that the patient has suffered an event of known aetiology resulting in irreversible brain damage with apnoeic coma

  • Reversible causes of coma must be excluded

  • 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, pontineischaemia 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

  • Dead on arrival

  • Unsuccessful resuscitation

  • Awaiting cardiac arrest

  • Cardiac arrest in DBD

  • 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


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