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Organ Donation

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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  1. Organ Donation Dr James F Peerless May 2013

  2. Objectives • Background • Brain-stem death • Donation after brain death • Donation after circulatory death • Ethical issues

  3. 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

  4. 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

  5. Types of Donor • DBD/HBD • Donation after brain death • Heart beating donor • DCD/NHBD • Donation after cardiac death • Non-heart beating donor • Living donors

  6. 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

  7. 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

  8. 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

  9. 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

  10. Brain stem death

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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)

  17. 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

  18. Donation after Brain Death

  19. 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

  20. DBD • Brain stem death causes widespread physiological changes • Cardiovascular • Respiratory • Endocrine • Metabolic • Haematological

  21. 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.

  22. 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

  23. 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

  24. Pulmonary • Dysfunction common • Worsening existing condition • Pneumonia • Aspiration • Related to TBI • Neurogenic pulmonary oedema

  25. 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

  26. 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

  27. Donation after Circulatory Death

  28. 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

  29. 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

  30. 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

  31. DCD - Organs • Kidney (2 hours) • Liver (30 minutes) • Pancreas (3o minutes) • Lung (1 hour) • Tissue • Cornea • Bone • Skin • Heart valves

  32. DCD - Contraindications • No age limit • HIV • vCJD • Haematological malignancy • Active invasive Ca within last three years

  33. 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

  34. 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

  35. 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

  36. 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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