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DONOR MAINTENANCE. Essentials in Organ Donation. Importance. Eurotransplant. Waiting list. Transplants. Demand for transplantable organs > supply. http://www.eurotransplant.nl/?id=statistics. Conversion rate of potential to actual organ donors → 60%
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DONOR MAINTENANCE Essentials in Organ Donation
Importance Eurotransplant Waiting list Transplants Demand for transplantable organs > supply http://www.eurotransplant.nl/?id=statistics
Conversion rate of potential to actual organ donors → 60% Donors lost due to inadequate maintenance → 25% Probably the % of lost organs is more important Importance It is the simultaneous medical management of up to 7 recipients Wood KE, Coursin DB. Curr Opin Anaesthesiol, 2007
Importance Aggressive donor management • Minimizes donors lost during maintenance • Recovers organs initially defined as medically unsuitable • Increases the numbers of organs procured and transplanted with good outcomes Gasser M, Waaga A, Laskowski I. Transplant Rev, 2001 Salim A, Martin M, Brown C, et al. J Trauma, 2006
Maintenance Goal Respiratory Cardiovascular Hormonal Prevention or correction of brain death-induced functional alterations Coagulation Thermo-regulation Electrolyte and Acid-Base Patient care becomes donor maintenance when BD ensues
Pathophysiology:Rostro-Caudal Ischemia and Herniation Cerebrum Vagal activation Bradycardia Hypotension Midbrain Pons Mixed Vagal and Sympathetic stimulation (Cushing response) Bradycardia Hypertension Irregular breathing Sympathetic stimulation (autonomic storm) Tachycardia Hypertension Apnoea Medulla oblongata Spinal cord Sympathetic deactivation Bradycardia Hypotension Hypothalamus Thermoregulatory impairment Hypophysis ADH TSH, T3, ACTH, cortisol?
Hypotension In Brain-Death HYPOVOLEMIA • ABSOLUTE • Initial injury: inadequate resuscitation, fluid leaking, decreased oncotic pressure (crystalloids) • Treatment of ICP: fluid restriction, urea, mannitol, diuretics • Hyperglycemia-induced osmotic diuresis • Diabetes insipidus • Hypothermic “cold” diuresis • Effective hypovolemia: loss of vasomotor tone and pooling in venous capacitance bed, rewarming • RELATIVE • Vasodilatation: spinal shock, catecholamine depletion, loss of autoregulation, relative adrenal insufficiency (trauma or critical illness), endocrinopathy of BD, sepsis Wood KE, et al. New Engl J Med, 2004
Sudden hypotension First: correct hypovolemia Invasive hemodynamic monitoring: arterial and central venous lines Hemodynamic targets: MAP ≥ 60 mmHg , CVP < 12 mmHg • MAP < 60 mmHg & CVP ≥ 12 mmHg Hemodynamic targets: CI ≥ 2,5 L/min/m2 SVR ≈ 1000 dynes/sec/cm5 MAP 60 mmHg, CVP < 12 mmHg PAC Targets not met Vasoactive amines & inotropes to maintain CIand MAP after adequate vascular filling
Hemodynamic Stabilization • Dopamine < 10-12 μg/Kg/min • Dobutamine < 15 μg /Kg/min • Norepinephrine 0,05 - 0,1 μg /Kg/min • Epinephrine 0,05 - 0,1 μg /Kg/min • Vasopressin 1 U bolus 0,5 - 4 U/h Vasoactive amines& inotropes: maximal doses • Targets not met • Persisting haemodynamic instability • Hormonal therapy ????? • Some ensuring findings… • ….but a weak level of evidence to support it
Ventilatory Support • Goals • PaO2 > 80 mmHg (> 10,7 kPa) • PaCO2 35 - 40 mmHg (4,7-5,3 kPa) • pH 7,35 - 7,45 • Tidal Volume 6 - 7 mL/Kg • PEEP +5 cm H2O • Adjust FiO2 for target PaO2 • Respiratory hygiene: suction and turn every 2 h
Urine Output Polyuria (UO ≥ 4 ml/kg/hr) • Osmotic diuresis • Hypothermic “cold” diuresis • Replace all hourly UO (0.2 NaCl or 5%DW5) • DDAVP 1-2 μg every 4-6 h • Correct hyperglycaemia Olyguria (UO < 0.5 ml/kg/hr) → • DIABETES INSIPIDUS • Serum Na > 155 mmol/L • Serum Osmolarity >300 mOsm/L • Urinary gravity < 1005 • Urinary Osmolarity < 300 mOsm/L • Targets • Serum Na 130–150 mmol/L • UO 1–3 ml/kg/h Reassess hemodynamic status
Hypothermia • Hemodynamic instability • Arrhythmia • Coagulation imbalance • Renal dysfunction • Electrolytic imbalance • Lack of hypothalamic temperature regulation • Vasodilatation • Metabolism • Absence of vasoconstriction andshivering • Large volumes of room temperaturefluids. Warm intravenous fluids, use forced air warming blankets, and heat humidification of the ventilator circuit Maintain Core Temperature > 37ºC and < 38ºC Prevent hypothermia rather than treat it
Glycemia and Electrolyte • Maintain Glycaemia 80-140 mg/dL • Use insulin pump infusion if necessary • Maintain Serum Na > 135 and < 150 mmol/L • Choose crystalloids accordingly • H2O by nasogastric tube for hypernatremia • Don’t correct too quickly • Maintain Serum K> 3 and < 5 mmol/L • Maintain normal ranges for Serum Ca, Mg, P
Coagulopathy • Obtain blood, urine and sputum cultures. • Start broad spectrum antibiotics (if not yet started) • Monitor and Treat • Endpoints: • INR < 2.0 • PLT count > 50.000/mm3 or no active bleeding • Hb ≥ 8 g/dL • Prior use of anticoagulants • Dilution and consumption of factors with hemorrhagic shock • DIC due to tissue factor release • Hypothermia Suspected infection Transport of the donor to the OR • Maintain strict monitoring
Donor Maintenance: key points Timing of monitoring • EKG • Invasive arterial pressure • CVP • Pulsoximetry • Core temperature CONTINUOUSLY HOURLY • URINE OUTPUT • Blood glucose • Na, Cl, K • Urea, creatinine • Hemogram & Coagulation tests • ABG EVERY 4-6 HRS
Donor Maintenance: key points • Optimize organ perfusion • Maintain urine output • Maintain oxygenation • Maintain normothermia • Maintain normoglycaemia • Maintain Acid-Base • Treat electrolytes disturbance • Prevent/treat infections Perform maintenance timely and aggressively because…
Donor Maintenance: key points Optimal management of the existing donor pool.. Waiting list ..is the most immediate and practical solution to organ donor crisis Transplants Wood KE, Coursin DB. Curr Opin Anaesthesiol, 2007