Anaesthesia for Transplant Surgery

General Principles Applicable to All Transplant Surgery

Preoperative Assessment

• Full cardiac evaluation (ECG, echocardiogram, sometimes stress testing or coronary angiography)
• Assessment for pulmonary hypertension
• Review of current immunosuppressant medications and their side effects (hypertension, nephrotoxicity from cyclosporine/tacrolimus, metabolic effects)
• Airway assessment, aspiration risk stratification
• Electrolyte and coagulation status

Drug Pharmacology in Organ Failure

• Renal failure: reduced excretion of renally cleared drugs; prolonged action of morphine (active metabolites), rocuronium, vecuronium
• Liver failure: reduced protein binding (raised free drug fraction), impaired CYP450 metabolism, altered volume of distribution from ascites/oedema
• Immunosuppressants (tacrolimus, cyclosporin, mycophenolate) have significant drug interactions - especially with volatile agents, opioids, and NSAIDs

1. Renal (Kidney) Transplant Anaesthesia

Patient Profile

• Chronic hypertension, LV hypertrophy, ischaemic heart disease
• Anaemia, platelet dysfunction, uraemic gastropathy
• Electrolyte disturbances (especially hyperkalaemia)
• Peripheral and autonomic neuropathy
• Arteriovenous fistula access

Cardiac Evaluation

Intraoperative Management

• General anaesthesia with endotracheal intubation is the standard approach
• Aspiration risk is elevated due to uraemic gastropathy, obesity, and diabetes; an oral antacid + IV H2-blocker should be considered pre-induction
• Rapid-sequence induction (RSI) is preferred
• Succinylcholine can be used if potassium is within normal limits (it raises K⁺ by 0.5-1.0 mEq/L transiently for 10-15 min); otherwise use rocuronium 1.2 mg/kg (modified RSI) - intubating conditions are comparable at this dose
• Rocuronium has prolonged duration of action in ESRD and should be used cautiously

• Standard non-invasive monitors may suffice for younger, healthier recipients
• Intra-arterial BP monitoring is beneficial in uncontrolled hypertension or cardiac disease; place contralateral to any AV fistula; femoral arterial access on the side of kidney implantation is contraindicated (thrombosis/haematoma risk)
• CVP is used historically to guide fluid therapy (aiming for 10-12 mmHg traditionally; more recent conservative targets of 7-9 mmHg are acceptable with no increase in graft failure)
• CVP poorly predicts fluid responsiveness; alternative tools (oesophageal Doppler, pulse contour analysis) are under investigation
• PA catheter or TOE may be considered for patients with advanced cardiac disease or pulmonary hypertension

• Combined IV and inhaled anaesthetics; volatile agents reduce the stress response and are well tolerated
• Avoid isoflurane / desflurane specifically if any concerns about renal perfusion (though modern evidence for nephrotoxicity of isoflurane is not strong)
• Avoid NSAIDs
• Opioid dosing must account for reduced renal clearance of active metabolites (e.g., morphine-6-glucuronide)

• Balanced crystalloid solutions (e.g., Plasma-Lyte, Hartmann's) are preferred over normal saline - saline causes hyperchloraemic acidosis leading to dangerous hyperkalaemia in anuric ESRD patients; some centres use potassium-free buffered dialysate solutions
• Traditional approach: large volume crystalloid (up to 60-100 mL/kg) to achieve CVP 10-12 mmHg before reperfusion
• More conservative approach: limit crystalloid to 15 mL/kg/h, targeting CVP 7-9 mmHg (no significant increase in graft failure)
• Colloids (particularly HES starches) have concerns about renal toxicity and should be used cautiously
• Postoperative fluids must account for urine output from the new graft

• Ensure adequate preload before vascular clamp release
• Dopamine (low-dose) has historically been used to promote urine output, though evidence is debated
• Mannitol and frusemide (furosemide) are commonly given at reperfusion to promote graft diuresis

Postoperative Management

• Continue fluid management based on graft urine output
• Early graft function (immediate urine output) is the goal; delayed graft function requires dialysis support
• Immunosuppression induction (e.g., basiliximab or anti-thymocyte globulin) is typically administered intraoperatively or immediately post-op
• Monitor for post-reperfusion hyperkalaemia - Miller's Anesthesia, 10e, p. 8584-8590

2. Liver Transplant Anaesthesia

Preoperative Considerations

• Patients typically have end-stage liver disease: cirrhosis, portal hypertension, hepatorenal syndrome, coagulopathy, thrombocytopaenia, encephalopathy, large-volume ascites
• Assess for hepatopulmonary syndrome (shunting, hypoxia) and portopulmonary hypertension
• Cardiovascular: cirrhotic cardiomyopathy is common (hyperdynamic circulation with low SVR); paradoxically, systolic function may appear preserved at rest but decompensates under stress
• Renal function may already be compromised (hepatorenal syndrome); anticipate need for haemofiltration
• Coagulation: these patients are often in a "rebalanced" coagulopathy state; routine coagulation tests (PT, APTT) correlate poorly with actual bleeding risk; TEG/ROTEM is preferred to guide blood product therapy

The Three Phases of Liver Transplantation

• Haemorrhage is the dominant problem; large-volume blood loss and massive fluid shifts from ascites drainage
• Blood products, large-bore IV access, rapid infuser (Level 1), arterial line, CVP/PA catheter or TOE
• Autologous cell salvage is used in many centres

• Reduced venous return and cardiac output; may need vasopressors and volume to maintain MAP
• Citrate metabolism is lost (no liver); citrate from blood products accumulates, causing hypocalcaemia and hypomagnesaemia
• Lactate is not metabolised - metabolic acidosis develops
• Preparation for reperfusion: normalise pH, maintain K⁺ in low-normal range; treatment may require insulin/dextrose, calcium, bicarbonate, hyperventilation
• Some centres use veno-venous bypass (VVB) to decompress portal system during this phase, though many now avoid it with the piggyback technique

• On unclamping, cold acidic hyperkalemic blood from the graft is released into the circulation
• Post-reperfusion syndrome (PRS): sudden drop in MAP >30% for >1 min within the first 5 min of reperfusion; occurs in ~20-30% of cases
• Consequences: acute rise in CVP (RV strain), systemic vasodilation, arrhythmias, and potentially cardiac arrest
• A bolus of CaCl₂ should be given to prevent hyperkalaemia-related arrhythmias
• Vasopressors (noradrenaline, vasopressin) and inotropes are frequently required
• After a successfully functioning graft establishes, K⁺ is taken up by hepatocytes - hypokalaemia then requires aggressive replacement
• Fluid, red cells, and blood products should be guided by ongoing clinical blood loss and TEG/ROTEM
• Maintain haematocrit 26-32% - Miller's Anesthesia, 10e, p. 6417-6418

Monitoring for Liver Transplant

• Arterial line (radial or femoral), CVP (via large-bore central line), PA catheter or TOE
• TOE/PA catheter helps guide fluid and inotrope management especially at reperfusion
• TEG or ROTEM is strongly preferred for coagulation-guided blood product administration
• Urine output catheter; temperature monitoring (hypothermia is a major risk)
• Glucose monitoring (graft function restoration normalises glucose)

Key Pharmacological Points

• Avoid hepatically metabolised drugs until new graft is functioning
• Vecuronium and rocuronium are suitable but may have prolonged action; cisatracurium (Hofmann elimination) is ideal as it is independent of organ function
• Volatile anaesthetics are acceptable; isoflurane/sevoflurane are standard

3. Heart Transplant Anaesthesia

Patient Profile

Anaesthetic Management

• The anaesthesiologist typically places lines while the patient is awake given the haemodynamic instability
• Standard monitors + arterial line, large-bore IV access, central line, PA catheter or TOE
• These patients are often on IV inotropes (dobutamine, milrinone) or IABP/ECMO - these must continue until CPB

• A balanced, cardiac-sparing induction is used; opioid-based or etomidate-based techniques are preferred to avoid precipitous drops in SVR or cardiac output
• Avoid agents that cause myocardial depression (e.g., propofol in large doses) or vasodilatation in patients with marginal cardiac output
• RSI principles if aspiration risk

• Orthotopic heart transplantation (OHT) is the standard; bicaval anastomotic technique is now preferred over biatrial (fewer arrhythmias, less TR, lower pacemaker requirement, better outcomes)
• After CPB and reperfusion: 1g methylprednisolone IV given immediately before reperfusion for immunosuppression
• Weaning from CPB requires inotropic support (dopamine, dobutamine, adrenaline/epinephrine, isoproterenol)
• If RV failure against elevated pulmonary vascular resistance: inhaled nitric oxide or inhaled prostacyclin (iloprost)
• Failing LV despite inotropes: IABP or temporary LVAD/MCS

Post-transplant Physiology: Cardiac Denervation (Critical Concept)

• Resting heart rate is higher (no vagal tone): typically 90-110 bpm
• No reflex responses to changing preload/afterload (baroreceptor reflex is absent)
• Drugs that work via indirect/neural mechanisms will not affect heart rate:
  • Atropine and glycopyrrolate do NOT increase HR
  • Fentanyl does NOT cause bradycardia via neural mechanism
  • Meperidine/pancuronium do NOT cause tachycardia via neural mechanism
• Direct-acting drugs ARE effective:
  • Epinephrine, isoproterenol, direct beta-agonists work normally via myocardial adrenergic receptors
  • Dopamine also works as it has direct adrenergic effects
• NMB reversal: Because atropine cannot increase HR to counter neostigmine's muscarinic effects, the combination of neostigmine/glycopyrrolate is associated with case reports of bradycardia/cardiac arrest. Sugammadex is preferred for NMB reversal in heart transplant recipients
• Dexmedetomidine should be used with extreme caution - cardiac arrest has been reported, particularly with concomitant acute cellular rejection - Miller's Anesthesia, 10e, p. 7712-7714

4. Lung Transplant Anaesthesia

Preoperative

• Assessment focuses on graft function (if re-operation), risk of infection, immunosuppression effects (hypertension, CKD from cyclosporin/tacrolimus), and evidence of chronic rejection - particularly bronchiolitis obliterans syndrome
• Anti-rejection drugs must be continued perioperatively

Intraoperative

• Single lung transplant: imbalance between native and donor lung - risk of dynamic hyperinflation of the native (emphysematous) lung and inadequate ventilation of the donor lung
• Double lung transplant: Sequential implantation; may require CPB or VV-ECMO support
• Double-lumen endobronchial tube (DLT) is required for independent lung ventilation; placement must be careful not to disrupt bronchial anastomosis in recipients who have previously been transplanted
• Reduced compliance, elevated A-a gradient
• Strict aseptic technique throughout - these patients are profoundly immunosuppressed
• Supplemental steroids should be given if there is any concern about adrenal suppression from chronic steroid use

Postoperative

• Aim for early extubation where possible
• Risks: diminished cough reflex, elevated pneumonia risk, increased bronchial reactivity, bronchospasm, and low threshold for pulmonary oedema (impaired lymphatic drainage of donor lung)
• Pulmonary oedema can manifest as primary graft dysfunction (PGD) - the most serious early complication

5. Pancreas and Combined Kidney-Pancreas Transplant

• Patient has Type 1 DM with associated autonomic neuropathy, accelerated cardiovascular disease
• Blood sugar management perioperatively (tight glucose control with insulin infusion; graft function restores endogenous insulin)
• Exocrine drainage (bladder or enteric) - watch for intraperitoneal complications
• Longer surgical time than kidney alone

Summary Table

Recent Evidence Update