AKI: Investigations AKI biomarkers S. creatinine NGAL (neutrophil gelatinase-associated lipocalin), IL-18, KIM-1, Cystatin C, and L-FABP BUN/creatinine (>20 ?pre-renal, <10-15?ATN) Urine: concentrated, SG>1.018, osmolality >350 mosm/l; urine Na <10 mmol/l and the FeNa<1% ?pre-renal Ultrasound
AKI: Management Ensure a non-obstructed outlet, Treat underlying illness, Maintain an adequate renal perfusion, correction of fluid depletion reversal of hypotension Avoid nephrotoxic agents, Adjust dose of renally excreted drugs, and Renal replacement therapy (RRT) should an indication arise.
AKI Management: Fluid therapy Type: crystalloids vs colloids (high MW hetastarch×) Rate: 10–15 ml/kg (large bore cannula) End points: MAP (65-90 mmHg), CVP (8-12 mmHg), pulse pressure variation, CO, ScvO 2 /SvO 2, PAOP, UO, lactic acidosis, and skin perfusion. RI Safety: hypervolaemia is avoided Fluids should be given early & targeted 1)Type, 2)Rate, 3)End points, 4)Safety limits
AKI : Vasoactive and inotropic drugs Vasopressors : norepinephrine phenylephrine low-dose vasopressin, terlipressin Ino-constrictors: epinephrine dopamine Inodilators: Dobutamine dopexamine Livosimendan Chronotropy Intra-aortic balloon counterpulsation Natruritic peptides The choice of drug should be driven by hemodynamic characteristics of the patient
Low-dose dopamine “renal dose” 1–3 mcg/kg/min produces preferential dopaminergic (and β -adrenergic effects) over α -adrenergic actions (>5 mcg/kg/min) and thereby causes renal vasodilation and increases urinary output. Improve UOP but confers no significant protection from renal dysfunction Fenoldopam mesylate is a selective dopamine α -1 receptor agonist that can improve renal blood flow without increasing cardiac output
AKI: Diuretics Diuretics have traditionally been used to ‘convert’ the oliguric state to non-oliguric…..? ATN. The use of diuretics should be restricted to the treatment of volume overload and occasionally hyperkalaemia Caution is advised as there is reasonable concern that excessive reliance on diuretics might delay initiation of RRT.
AKI: RRT Clinical uraemia, Severe hyperkalaemia, Persistant acidosis, and Non-responsive volume/fluid overload Early vs late!
AKI: Dose adjustments Nephrotoxics : avoid Loading dose: OK Maintenance: ↑ intervals/ Dialysable vs non dialyasable Creatinine clearance ? Dilution effect of FT !