In a 74‑year‑old woman with moderate chronic kidney disease (serum creatinine 1.4 mg/dL, estimated glomerular filtration rate ≈40 mL/min), what is the safest anesthetic technique and which peri‑operative strategies should be employed to prevent acute kidney injury?

Anesthetic Management for 74-Year-Old Female with Moderate CKD

The safest anesthetic approach is either regional or general anesthesia administered with meticulous attention to hemodynamic stability and dose reduction—the technique itself matters less than how carefully it is delivered, with both requiring 30-50% dose reduction of all agents and strict avoidance of hypotension (>20% drop from baseline systolic BP) to prevent acute kidney injury. 1

Choice of Anesthetic Technique

Regional vs. General Anesthesia

• Neither regional nor general anesthesia demonstrates superior outcomes in elderly patients when comparing mortality or length of stay—the critical factor is sympathetic administration tailored to the patient's pathophysiology rather than the technique selected. 1

• Regional anesthesia with minimal or no sedation may offer advantages by reducing hypotension, delirium, cardiorespiratory complications, and opioid requirements. 1, 2, 3

• However, if the patient requires heavy sedation to tolerate regional anesthesia (common in those with cognitive dysfunction), these benefits are negated and general anesthesia may be preferable. 1

If Choosing Regional Anesthesia

• Use 30-50% lower doses of local anesthetics than standard adult dosing due to age-related alterations in pharmacokinetics and pharmacodynamics. 1, 2, 3

• Minimize or avoid sedation entirely to preserve consciousness for early detection of complications and maintain respiratory drive. 2, 4

• For spinal anesthesia specifically, use low-dose intrathecal bupivacaine (<10 mg) to minimize hypotension risk. 2, 4

• Never administer spinal and general anesthesia simultaneously, as this causes precipitous blood pressure drops. 2, 4

If Choosing General Anesthesia

• Reduce all induction agent doses by 30-50% from standard adult dosing—elderly patients are exquisitely sensitive to relative overdose causing myocardial depression, impaired blood pressure homeostasis, and delayed recovery. 1, 3

• Implement depth of anesthesia monitoring (BIS or entropy) to prevent relative overdose and facilitate faster emergence. 1, 2

• Sevoflurane is safe for patients with renal dysfunction when used at fresh gas flows >1 L/min—avoid flows ≤800 mL/min which may increase risk of renal injury. 5, 6

Critical Preventive Measures for AKI

Hemodynamic Management (Most Important)

• Avoid hypotension defined as >20% drop in systolic blood pressure from pre-induction baseline—this is the single most important modifiable risk factor for AKI. 1

• Consider arterial line placement before induction to enable beat-to-beat blood pressure monitoring and prevent hypotensive episodes that occur between non-invasive measurements. 1, 2

• Administer fluid therapy in small divided boluses with careful assessment of response—elderly patients with poorly compliant ventricles are prone to fluid overload. 1

Pre-operative Assessment

• Document baseline eGFR (approximately 40 mL/min with creatinine 1.4 mg/dL) before surgical incision as part of the WHO checklist modification for elderly patients. 1

• Measure hemoglobin concentration pre-operatively—anemia combined with operative blood loss increases mortality in patients >65 years. 1

Intra-operative Monitoring

• Monitor core temperature continuously (tympanic/pharyngeal/oesophageal)—hypothermia impairs renal perfusion and increases AKI risk. 1

• Consider cerebral oxygen saturation monitoring—desaturation >15% may indicate systemic hypoperfusion affecting kidneys. 1, 2

• Assess positioning and padding every 30 minutes—prolonged hypotension combined with pressure on bony prominences increases tissue ischemia risk. 1

End-of-Surgery Bundle

• Measure lactate or base deficit to assess adequacy of tissue perfusion. 1

• Document core temperature, hemoglobin concentration, and fluid requirements before leaving the operating theater. 1

• Prescribe age-adjusted AND renal function-adjusted doses of all postoperative medications—this patient requires dose modifications for any renally cleared drugs. 1

Post-operative Care

• Plan for enhanced monitoring—patients with predicted peri-operative mortality >10% should be admitted to level 2 or 3 critical care. 1, 2

• Implement multimodal opioid-sparing analgesia with paracetamol as first-line therapy—NSAIDs should be avoided or used with extreme caution given baseline renal dysfunction. 1

• Continue basic monitoring on the ward with Modified Early Warning Scores and Critical Care Outreach availability. 1

Common Pitfalls to Avoid

• Do not use standard adult dosing for any anesthetic agent—this invariably leads to relative overdose with prolonged hypotension and increased AKI risk. 1, 3

• Do not assume regional anesthesia is automatically superior—heavy sedation negates its benefits and may worsen outcomes. 1, 3

• Do not rely on central venous pressure for fluid management—it correlates poorly with blood volume in elderly patients with poorly compliant vasculature. 1

• Do not use sevoflurane at fresh gas flows ≤800 mL/min—this increases risk of compound A formation and potential nephrotoxicity. 5

• Do not neglect to measure post-operative creatinine—up to 14% of patients may not have creatinine measured post-operatively, missing AKI diagnosis entirely. 7