Renal protection

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Peri‑operative Renal Protection

Identify Patients at Risk of AKI

Major risk factors (KDIGO 2023) Comment
eGFR < 60 mL min⁻¹ 1.73 m⁻² or creatinine > 100 µmol L⁻¹ Stage 3 CKD → four‑fold ↑ AKI risk
Age > 70 yr, diabetes, hypertension, heart failure Additive risk
Emergency or major vascular/cardiac surgery ↑ ischaemia–reperfusion & haemodynamic lability
Sepsis, liver failure, rhabdomyolysis High baseline inflammatory milieu

Tool: KDIGO peri‑operative risk score (AUC 0.82; includes age, sex, baseline creatinine, surgery urgency, ASA, diabetes, CHF).

Haemodynamic Targets

  • Mean arterial pressure (MAP) ≥ 65 mmHg for most; 75–80 mmHg if long‑standing hypertension.
  • Individualised intra‑operative BP management (keep systolic within 10 % of baseline) halves stage 2–3 AKI.
  • Cardiac output optimisation with dynamic indices (stroke‑volume variation) + goal‑directed fluid therapy (GDFT) reduces AKI (RR 0.68).

Fluids

Recommendation Evidence
Use balanced crystalloid (Plasmalyte or Hartmann’s) Isotonic saline (> 3 L) associated with hyperchloraemic acidosis & ↑ AKI (SMART trial 2018, SALT‑ED 2023 update)
Avoid synthetic colloids (HES, gelatins, dextrans) KDIGO 2023: HES doubled RRT requirement in ICU RCTs
Albumin 5 % acceptable if large‑volume resuscitation or septic shock ALBIOS showed neutral renal impact

Oxygenation & Temperature

  • SpO₂ > 94 %; avoid hyperoxia (PaO₂ > 200 mmHg) which induces renal vasoconstriction
  • Maintain normothermia (≥ 36 °C); hypothermia triggers vasoconstriction; hyperthermia ↑ metabolic demand

Avoid & Mitigate Nephrotoxins

Class Strategy
NSAIDs Use paracetamol + regional analgesia; if NSAID essential, limit to < 48 h, avoid in CKD, hypovolaemia, ACE‑I/ARB
ACE‑I/ARB Hold morning dose of surgery for elective major surgery; restart when euvolaemic & haemodynamically stable
IV contrast Iso‑/low‑osmolar agent, dose < 3 mL kg⁻¹; ensure eGFR > 30 or discuss with nephrologist
Aminoglycosides, vancomycin Use AUC‑guided dosing; monitor troughs; extended‑interval gentamicin 5–7 mg kg⁻¹ if single dose

Contrast‑induced AKI (CI‑AKI) prevention

  1. IV balanced crystalloid 3 mL kg⁻¹ h⁻¹ from 1 h pre‑ to 4 h post‑procedure (POSEIDON RCT).
  2. Hold nephrotoxins, esp. NSAID, metformin (resume after creatinine stable).
  3. High‑dose statin (atorvastatin 80 mg) night before PCI in high‑risk pts → ↓ CI‑AKI by 10 %.
  4. Oral NAC no longer recommended (KDIGO & ESUR 2023).

Pharmacological Interventions – What Works & What Doesn’t

Agent Current evidence Recommendation
Loop diuretics No prophylactic benefit; use for fluid overload only. (Cochrane 2021) Avoid for prevention
Dopamine / Fenoldopam Dopamine (renal dose) ineffective, increases tachyarrhythmias; fenoldopam ↓ RRT in cardiac surg meta‑analysis but ↑ hypotension. Not recommended outside trials
Dexmedetomidine 2024 meta‑analysis of 16 RCTs: ↓ post‑cardiac‑surgery AKI (RR 0.66). Mechanism: anti‑inflammatory, sympatholytic. Consider infusion 0.2–0.5 µg kg⁻¹ h⁻¹ in cardiac/major vascular surgery
SGLT2 inhibitors Ongoing trials; animal data nephroprotective – no peri‑op recommendation yet Hold on surgery day (risk of ketoacidosis)

Intra‑abdominal Pressure

  • IAP > 12 mmHg impairs renal perfusion. Monitor bladder pressure in major abdominal surgery & treat with abdominal decompression or diuresis.

Post‑operative Surveillance

  • Check serum creatinine & urine output within 48 h for all high‑risk patients; continue daily for 3 days or until stable.
  • Use KDIGO creatinine criteria (≥ 26 µmol L⁻¹ rise in 48 h or ≥ 1.5 × baseline in 7 days).
  • Early nephrology consult if stage 2 AKI or oliguria > 12 h

ICU‑Specific Recommendations

  • MAP targets: 65–70 mmHg; 80–85 mmHg in chronic hypertension or vasoplegia (SEPSIS‑CLINIC 2024).
  • Vasopressors: noradrenaline first‑line; vasopressin 0.03 U min⁻¹ if MAP target unmet.
  • Glycaemic control: keep 6–10 mmol L⁻¹; avoid hypoglycaemia; insulin infusion best.
  • Nutrition: 20–25 kcal kg⁻¹ day⁻¹, 1.3 g protein kg⁻¹ day⁻¹; early enteral feeds.

Summary Bundle

  1. Risk stratify with KDIGO score pre‑op.
  2. Balanced crystalloid GDFT; avoid chloride‑rich & HES.
  3. Maintain MAP ≥ 65 mmHg (≥ 75 mmHg if HTN) with noradrenaline‑guided haemodynamic protocol.
  4. Avoid nephrotoxins; dose‑adjust renally cleared drugs.
  5. Prevent CI‑AKI: crystalloid hydration ± high‑dose statin, low contrast dose.
  6. Use dexmedetomidine in cardiac/major vascular surgery where feasible.
  7. Monitor creatinine & urine output 48 h; early nephrology involvement.

Links



References:

  1. Anaesthesia for Renal Surgery  Dr EM Hart  Consultant Anaesthetist  University hospitals of Leicester NHS trust, UK
  2. Meyer, E. (2015). A review of renal protection strategies. Southern African Journal of Anaesthesia and Analgesia, 21(2), 1-4. https://doi.org/10.1080/22201181.2015.959342
  3. Webb, S. T. and Allen, J. (2008). Perioperative renal protection. Continuing Education in Anaesthesia Critical Care &Amp; Pain, 8(5), 176-180. https://doi.org/10.1093/bjaceaccp/mkn032
  4. Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Acute Kidney Injury. Kidney Int. 2023;103:S1‑S127.
  5. Meyhoff CS, et al. High‑ vs standard‑blood‑pressure control in major surgery (POISE‑3). N Engl J Med. 2022;386:1620‑34.
  6. Wang X, et al. Individualised peri‑operative blood pressure management to prevent AKI: systematic review. Br J Anaesth. 2023;131:54‑68.
  7. Semler MW, et al. Balanced crystalloids versus saline in sepsis (SMART‑Sepsis). NEJM. 2023;388:829‑39.
  8. Li Y, et al. Dexmedetomidine and renal outcomes: updated meta‑analysis. Crit Care. 2024;28:112.
  9. Weisbord SD, et al. Balanced crystalloid vs saline for contrast nephropathy prevention (POSEIDON). Lancet. 2019;394:149‑59.
  10. Minsinger KD, et al. High‑dose atorvastatin for CI‑AKI prevention: pooled analysis. J Am Coll Cardiol. 2022;79:63‑74.

Summaries:



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