Day-2 post-laparotomy oliguria — stage, bundle, fluids and dialysis triggers

Model answer

(A) Stage 1 by both doors, high-risk by every factor, bundle by the trials (4 marks). Creatinine 1.8-fold sits in the 1.5–1.9 stage-1 band and 9 hours of urine below 0.5 mL/kg/h sits in the 6–12-hour stage-1 band — either alone defines AKI (0.3 mg/dL in 48 hours, 1.5-fold in 7 days, or 6-hour oliguria), and staging takes the worse of the two, which here agree.^[1] He carries the full bedside risk set: older age, emergency major surgery, hypotension on pressors, vancomycin and contrast exposure — the cohorts' list (age, CKD, diabetes, heart failure, shock, nephrotoxins) applied to one patient.^[4][5] Deploy the four-plank KDIGO bundle — haemodynamic optimisation with monitoring, volume restoration, nephrotoxin/contrast avoidance, no hyperglycaemia — quoting PrevAKI (55.1 versus 71.7%, ARR 16.6% single-centre) through BigpAK-2 (14.4 versus 22.3%, OR 0.57, NNT 12, multicentre, no harm).^[18][19]

(B) Balanced liberal fluids, pressure floor with volume first, drugs reviewed (3 marks). Prescribe balanced crystalloids without overload and without RELIEF-style restriction (3.7 versus 6.1 L raised AKI 8.6 versus 5.0% with no survival gain) — balanced fluids beat saline on sepsis mortality (OR 0.84) and starch on AKI (OR 0.80) — holding MAP 65–70 per ESICM while giving volume before pressors, since both hypotension depth and cumulative noradrenaline independently predict AKI.^[17][20][21] Switch vancomycin to AUC-guided dosing (less AKI than trough-guided, OR 0.625) and avoid further contrast and nephrotoxins per the bundle's third plank.^[32][19]

(C) No dialysis today, triggers written, follow-up booked (3 marks). Without hyperkalaemia, acidosis, oedema, BUN above 112 or 72-hour oliguria, STARRT-AKI governs: accelerated RRT matched standard mortality (43.9 versus 43.7%) with more dependence and harm — and AKIKI shows half such patients never need dialysis — while ELAIN's early benefit stays quoted only as the contradicted single-centre outlier.^[38][39][42] Write the five triggers and the AKIKI-2 floor (pushing past 72-hour oliguria/BUN 112 to BUN 140 gained nothing and raised death, HR 1.65).^[40] Book focused kidney health assessment after discharge: even mild AKI carries adjusted 1-year mortality near trebled (HR 2.96), postoperative creatinine dips overestimate recovery, and follow-up is essential not optional.^[10][4]