What are the methods used to optimise the potential organ donor and the physiological values targeted?
System
Methods for Optimisation
Targets
Cardiovascular System
- Use invasive haemodynamic monitoring:
- CVC should be inserted in right IJV or SCV
- Arterial line in Left radial or brachial artery due to order vessels are ligated
- Cardiac output monitoring to guide fluids and vasopressor therapy if hypotensive or EF <40%
- Correct hypovolaemia:
- Crystalloid or colloid infusions titrated to achieve euvolaemia
- Avoid volume overload as organs susceptible to capillary leakage
- Correct hypotension
- Vasopressin 1-4 units/h is first-line therapeutic agent
- Less likely to cause metabolic acidosis or pulmonary hypertension
- Treats diabetes insipidus
- Reduce catecholamines and use as sparingly as possible
- Vasopressin 1-4 units/h is first-line therapeutic agent
- Optimise cardiac output:
- Inotropic support may be required if cardiac index not improved with fluid therapy required
- Dopamine (first line) or dobutamine inotropes of choice
- Treat arrhythmias aggressively
- Thyroid hormone replacement may improve cardiac function
- Perform investigations where possible:
- 12-lead ECG (to exclude Q-waves)
- Troponin level in all cardiac arrest cases
- Echocardiogram
- Mean Arterial Pressure (MAP): 60-80 mmHg
- Central Venous Pressure (CVP): 4-10 mmHg
- Pulmonary Artery Wedge Pressure (PAWP): 10-15 mmHg
- Heart Rate: 60-100 bpm
- Rhythm: sinus rhythm is desirable
- Cardiac Index (CI): >2.1L/min
- ScvO2 : 60 %
- Systemmic Vascular Resistance Index (SVRI): 1800 – 2400 dynes*sec/cm5/m2
Respiratory System
- Lung recruitment maneuvers and PEEP following apnoea test
- Continue VAP prevention measures:
- 30-45 degrees head up tilt
- Tight endotracheal cuff
- Patient positioning as per unit protocol
- Review ventilation, ensure lung protective strategy:
- Tidal volumes 4-8 ml/kg ideal body weight
- Optimum PEEP (5-10 cmH2O)
- Peak inspiratory pressures limited to <30 cmH2O
- Minimize FiO2 if lungs are to be transplanted
- Reinstate chest physiotherapy and regular suctioning
- If required perform bronchoscopy, bronchial lavage and toilet for therapeutic purposes
- Avoid high extravascular lung water:
- Early use of methylprednisolone 15 mg/kg given intravenously
- Avoid positive fluid balance
- Perform CXR (post recruitment procedure where possible)
- PaO2: 10 kPa FiO2 <}0.4 as able)
- PaCO2: 5 – 6.5 kPa (or higher as long as pH >7.25)
- Tidal Volumes: 4-8 ml/kg ideal body weight
- PEEP: 5-10 cmH2O
- Peak inspiratory pressure: <30 cmH2O
Endocrine & Metabolic System
- Correct electrolyte abnormalities:
- Hypernatremia (associated with poor liver graft function)
- Hypokalemia
- Manage Diabetes Insipidus:
- Maintain Na+ <155 mmol/L with 5% dextrose
- Maintain urine output about 1 - 2 ml/kg/h with vasopressin 1 U bolus and 0.5 - 4.0 U/h infusion
- If failure to control diuresis, intermittent desmopressin may be required
- Commence early hormone replacement
- Methylprednisolone - diminishes inflammatory response
- 15 mg/kg to max 1g
- Improves outcomes in lung transplant
- No current role for T3:
- Associated with adverse effects such as arrhythmias
- Methylprednisolone - diminishes inflammatory response
- Correct hyperglycemia:
- Insulin infusion to maintain plasma glucose 4-10 mmol/L
- Start at minimum 1 unit/h and add a glucose containing fluid if required
- Correct hypothermia aiming temperature 36-37.5°C:
- Warmed intravenous fluids
- Warming blankets
- Heated and humidified inspired gases
- Stop nephrotoxic drugs
- Temperature: 36 – 37.5°C
- Blood glucose: 4.0 – 10.0 mmol/l
- Urine output: 0.5 – 2.0 ml/kg/hour
Haematological System
- Correct DIC and coagulopathy:
- Treat with products if required
- Avoid antifibrinolytics which may cause microthrombi
- Maintain haemoglobin at >70 g/dL to optimise oxygen delivery
- Ensure appropriate thromboembolic prophylaxis continued:
- Anti-embolic stockings and sequential compression devices
- Low molecular weight heparin