Anaesthesia in Renal Failure

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Chronic kidney disease (CKD) stage 4-5 (eGFR <30 mL/min) and acute kidney injury (AKI) present significant perioperative risks due to fluid overload, electrolyte abnormalities, coagulopathy, and altered drug metabolism. Pathophysiology: Reduced GFR (drug accumulation), anaemia (reduced oxygen carrying capacity), coagulopathy (platelet dysfunction, impaired aggregation), fluid overload (sodium/water retention), electrolyte abnormalities (hyperkalaemia, metabolic acidosis, hypocalcaemia, hyperphosphataemia), cardiovascular disease (LVH, heart failure, accelerated atherosclerosis), autonomic neuropathy (gastroparesis, orthostatic hypotension). Preoperative preparation: Dialysis timing (last dialysis ideally <24 hours pre-op to avoid fluid overload and anticoagulation effects from heparin), potassium <5.5 mmol/L (emergency treatment if >6.5 with calcium gluconate 10 mL 10%, insulin 10 units + dextrose 50 g, salbutamol nebuliser, bicarbonate if pH <7.2), fluid status optimisation (dry weight assessment), Hb >80 g/L (transfuse if symptomatic or surgery with high blood loss risk), clotting assessment (consider DDAVP 0.3 μg/kg if bleeding risk—improves platelet function). Drug considerations: Avoid/reduce nephrotoxins (NSAIDs, aminoglycosides, contrast dye), dose adjustment for renally cleared drugs (morphine-6-glucuronide accumulates—use fentanyl or remifentanil; atracurium/cisatracurium preferred—Hofmann elimination, not renal), antibiotic dosing (vancomycin, aminoglycosides require levels). Anaesthetic technique: Regional preferred if coagulation adequate (avoid epidural if platelets <80-100 or therapeutic anticoagulation); GA with careful fluid management (avoid overload, use balanced crystalloids not saline to prevent hyperchloraemic acidosis), avoid hypotension (maintain renal perfusion), mannitol and furosemide not renoprotective (avoid routine use). Monitoring: Arterial line (frequent K+ and ABG), central access if vasopressors needed, urine output (if not anuric), cardiac output monitoring if unstable, blood glucose (insulin resistance common). Postoperative: Continue monitoring for fluid overload, hyperkalaemia, bleeding; early nephrology consultation if new AKI or worsening CKD; dialysis if indicated (refractory hyperkalaemia, fluid overload, severe acidosis, uraemic symptoms). Indigenous patients: 3-4× higher CKD rates, often present late with complications; culturally sensitive approach to dialysis and transplantation discussions essential. [1-10]