Renal · 6 min
Renal — last-night quick guide
AKI prevention, ESRD anesthetic, contrast-induced nephropathy, drug clearance.
Rule
AKI prevention
Identify high-risk: age, baseline CKD, diabetes, contrast load, hypotension, nephrotoxin exposure. Strategy: maintain MAP ≥65-75 (elderly + CKD higher), avoid nephrotoxins (NSAIDs, aminoglycosides, ACE-I day-of), normovolemia (not over- or under-resuscitated), TIVA + balanced anesthesia. Goal urine output 0.5 mL/kg/hr but NOT a perfect predictor.
ESRD anesthetic considerations
| Issue | Action |
|---|---|
| HyperK day-of | Check K; avoid succ if K >5.5 |
| AV fistula limb | No BP cuff, no IV in that arm |
| Dialysis schedule | Optimal: surgery 6-24h after HD |
| Drug clearance | Avoid morphine (M6G accumulates), meperidine (normeperidine), atracurium-pref (Hofmann); roc OK; cisatracurium OK |
| Volume | Careful — overload causes pulmonary edema; consider CVP/echo guidance |
| Heparin | Often heparin-coated dialyzers; bleeding risk |
Rule
Contrast-induced nephropathy (CIN) prevention
Hydrate with 0.9% saline 1-1.5 mL/kg/hr × 6-12h pre + post. Minimize contrast volume. Use iso-osmolar/low-osmolar contrast. N-acetylcysteine (NAC) — controversial, evidence weak; some still give 600 mg PO BID × 4 doses. AVOID: NSAIDs, ACE-I day of contrast.
Watch out
Watch K during transfusion
Old PRBCs accumulate K (up to 30-40 mEq/L by 21 days). Massive transfusion → hyperK + hypocalcemia. Calcium 1 g IV per 4-6 units. Use fresh PRBCs (<14 days) for renal failure patients.