Dr Richard Pugh Consultant Anaesthetics/ Intensive Care Medicine May 2010
The brainstem: Midbrain, pons, medulla Consciousness Cardiovascular and respiratory regulation Sleep- wake cycle Integration of sensory and motor function
1976 and 1979 Conference of Medical Royal Colleges and their Faculties statements, diagnosis of brain death : Preconditions Exclusions Clinical tests Brain death = death
No pupillary reflexes No corneal reflex Absent vestibulocochlear reflex No motor response to trigeminal nerve stimulation Absent cough/ gag reflex Apnoea
8000 7655 7877 7980 7000 7219 6698 6000 6142 5000 5532 5604 5654 5673 Donors Number 4000 Transplants Transplant list 3000 2311 2247 2388 2396 2241 2196 2385 2381 2552 2640 2000 1000 773 745 777 770 751 764 793 809 900 959 0 2000-2001 2001-2002 2002-2003 2003-2004 2004-2005 2005-2006 2006-2007 2007-2008 2008-2009 2009-2010 Year
Number of donations after Brainstem Death, 2003-8
As numbers of potential brainstem donors decrease, essential to: Maximise identification of potential BSD donors Optimise the function of organs which have potential for donation: Increase numbers of organs that may be donated Minimise recipient morbidity and mortality
< 25% potential BSD donors lost due to cardiovascular collapse Donor management protocol associated with: 87% decrease in number of donors lost due to cardiovascular collapse Significant increase in number of donated organs per donor Salim J Trauma 2006
Patho-physiological change Approx incidence Hypotension 80% Diabetes insipidus 65% Disseminated intravascular coagulation 30% Cardiac arrhythmias 30% Pulmonary oedema 20% Metabolic acidosis 10%
Midbrain ischaemia: Increased vagal activity Bradycardia Pontine ischaemia Medullary ischaemia Spinal cord ischaemia
Midbrain ischaemia Pontine ischaemia: Sympathetic stimulation Baro-receptor response to hypertension Bradycardia and hypertension Cushing reflex Medullary ischaemia Spinal cord ischaemia
Midbrain ischaemia Pontine ischaemia Medullary ischaemia: Unopposed sympathetic storm Tachycardia/ hypertension Spinal cord ischaemia
Midbrain ischaemia Pontine ischaemia Medullary ischaemia Spinal cord ischaemia: Loss of sympathetic tone Bradycardia/ hypotension
Profound instability... Hyperdynamic/ hypertensive episodes Cardiovascular collapse: Vasodilatation Impaired myocardial contractility Hypovolaemia (e.g. Diabetes insipidus)
Use short-acting agents! Depending on heart rate: GTN Esmolol or Labetalol SNP in event of refractory hypertension
Management of hypotension/ hypoperfusion: Impact on organs: Average systolic blood pressure < 80 mm Hg associated with kidney wastage Urine output< 100 ml in final hour associated with reduced kidney graft function at one year Lucas Transplantation 1987
Parameter Target Heart rate Blood pressure ScvO2 >70% Sinus rhythm 60-100 pm Mean arterial pressure 65-90 mm Hg Systolic blood pressure 100-160 mm Hg Lactate Stroke volume or pulse pressure variation < 2 mmol/l Normal Cardiac index > 2.1 L/min/m 2
Management of hypotension/ hypoperfusion: Guides to fluid therapy? Which fluid? Which vasopressor? Role of thyroid hormones? Echocardiography?
CVP monitoring is strongly recommended for potential BSD donors* In the presence of hypotension, decreased CI (if applicable), ScvO2< 70% or lactate > 2 mmol/l: CVP 8-12 mm Hg Normal SVV (or PVV), if applicable *e.g. Canadian Council for Donation and Transplantation Shemie CMAJ 2006; 174 (6): S13
Pulse pressure variation (LiDCO) Murugan Crit Care Med 2009
HES 200/ 0.6 HES 130/ 0.4 Cittanova Lancet 1996 and Blasco BJA 2008
Very high levels of catecholamine are damaging to heart muscle Noradrenaline administration may be associated with reduced recipient cardiac and renal function Rona G. J Mol Cell Cardiol. 1985; 17: 291 306 Schnuelle P. Transplantation 2001; 72: 455 63 Dominguez. Transplant Proc. 2009; 41: 2668-9 Post-mortem histology: Cardiac myocytes with associated contraction band necrosis following catastrophic brain injury
Posterior pituitary function lost < 80% BSD Vasopressin deficiency will contribute to haemodynamic instability: Diabetes insipidus, and hypovolaemia Contribute to vasoparesis
Vasopressin infusion: Seems to improve cardiovascular stability Decrease catecholamine requirement Prevent and treat diabetes insipidus Dose< 2.4 U/ hour unlikely to have direct adverse effects on organ perfusion Chen Circulation 1999; 100(19 Suppl):II244-II246 Pennefather Transplantation 1995; 59(1):58-62; Kinoshita Transpl Int 1990; 3(1):15-18
Vasopressin vs. Noradrenaline: Trend to reduced progression of renal injury Reduced requirement for RRT
Myocardial injury present >40% BSD If evidence of decreased cardiac output, despite attempts to optimise pre-load: Dobutamine
BSD associated with decreased TRH and TSH Thyroid deficiency associated with impaired myocardial contractility and vasoparesis
Unclear efficacy: Some studies have reported improved rates of retrievable organs and organ survival with thyroid hormone, T3 Rosendale Transplantation 2003 Abdelnour J Heart Lung Transplant 2009 Venkateswaran European Heart Journal 2009
To aid haemodynamic management To aid consideration of cardiac donation: Echocardiography abnormalities are common (e.g. 20% patients with BSD due to SAH) Concern if LVEF< 40% However, may evaluate response to fluid manipulation/ dobutamine Venkateswaran Eur J Echocardiography 2005
Patho-physiololgy: ALI/ ARDS Atelectasis Aspiration Nosocomial pneumonia Neurogenic pulmonary oedema
General aims: Minimise ventilator- induced lung injury Ensure lung recruitment Enable secretion clearance Avoid fluid overload
Parameter Target PaO2, SaO2 PaO2> 10 kpa, SaO2> 95% With minimal FiO2 PEEP PaCO2 Minimum 5 cm H2O Increase as required to maintain PaO2> 10 kpa, SaO2> 95% with FiO2 0.4 5-5.5 kpa Peak airway pressure Tidal volume < 30 cm H2O < 8 ml/kg
Maintain regular turning, physiotherapy and tracheal suctioning Appropriate sensitivity of assisted spontaneous modes of ventilation Chest x-ray and gram stain/ culture of respiratory specimens Bronchoscopy may be requested
Competing needs of different organs Hypernatraemia can be common Use of vasopressin or DDAVP for diabetes insipidus
Vasopressin Thyroid hormone Insulin Avoidance of hyperglycaemia shouldbe associated with improved graft function Methylprednisolone Seems to improve outcome after kidney, liver, heart and lung transplantation Kotsch K, Ann Surg 2008 Selck Am J Transplant 2008 Rosendale Transplantation 2003
Red blood cell transfusion: Hb < 9 g/dl in presence of haemodynamic instability/ hypoperfusion Hb 7 g/dl is probably appropriate in other situations
Intensive Care Society. Guidelines for adult organ and tissue donation 2005 Shemie et al.organ donor management in Canada: recommendations of the forum on Medical Management to Optimize Donor Organ Potential. CMAJ 2006; 174(6):S13-S32 Kutsogiannis et al. Medical management to optimize donor organ potential: review of the literature. CJA 2006; 53(8):820-30