Background: Most radiological procedures require administration of contrast media.Contrast-induced acute kidney injury (CI-AKI) is the third cause of hospital acquired AKI.Extracellular volume expansion reduced contrast-induced tubulo-toxic effects.We aimed to test if control of hydration by bioimpedance is useful to reduce incidence of CI-AKI.
Methods: 50 patients undergoing contrast medium infusion of 100-150 ml of iopamidol for abdominal or thoracic computer tomography were enrolled and randomly assigned to receive standard CI-AKI protocol prevention or Bioimpedance-based hydration protocol.Standard CI-AKI protocol consisted in administration,1day before and 1day after the administration of contrast media,at least 1 ml/kg/h of saline solution,1 mg/kg/h of sodium bicarbonate and N-acetyl-cysteine twice a day.In the bioimpedance-based protocol,a mild over-hydration (within +1 and +3)was obtained the day of the procedure and the next 3 days with the infusion of saline solution plus 1 mg/kg/h of sodium bicarbonate and N-acetyl-cysteine twice a day.Bioimpedance was performed daily with Body Composition Monitor(BCM -Fresenius Medical Care®)to evaluate the hydration status.Laboratory and clinical examination were performed daily after the procedure for 3 days.CI-AKI was defined as a rise in sCr of 0.5 mg/dl 48hrs after a radiological procedure
Results: 49 patients were enrolled(63±14yrs;GFR64±31ml/min/1.73m2):29 patients were included in the bioimpedance-based protocol harm and 20 patients in standard protocol harm.For a comparable age,sCr and GFR at baseline,incidence of AKI was significantly lower in bioimpedance-based than in standard protocol(14%vs40%,respectively;P=0.04).In multivariate analysis adjusted for age,the bioimpedance-based protocol(OR0.17 if performed;95%CI 0.03-0.99;P<0.05)and high baseline GFR(OR0.92 for 1 ml/min/1.73m2 increase;95%CI0.87-0.98;P=0.005)reduced the risk of CI-AKI (Fig. 1).
Conclusions: The bioimpedance-based control of hydration is useful to reduce CI-AKI incidence in patients undergoing abdominal or thoracic computer tomography.