Tailored Hydration Based on Bioimpedance Analysis for Prevention of Contrast Induced Acute Kidney Injury

Prevention of Contrast-Induced Acute Kidney Injury: Standard Versus Short Hydration Protocol in Patients With Normal Fluid Status Assessed by the Bioimpedance Analysis (The HYDRA II Study)

The aim of this study was to evaluate, in patients with "normal fluid status" assessed by the bio-impedance analysis, whether two different protocol of IV isotonic saline infusion are associated with different volume expansion and differing risks for Contrast Induced Acute Kidney Injury in patients undergoing coronary angiographic procedure.

Iodinated contrast media are a well-recognized cause of iatrogenic acute kidney injury in patients undergoing imaging diagnostic or therapeutic procedures (contrast-induced acute kidney injury, CI-AKI). Extracellular volume expansion at the time of contrast media administration may represent important protective strategies that play a major role in the prevention CI-AKI.

Bio-impedance analysis is an inexpensive, rapid, and accurate tool for evaluating a patient's hydration status, and can be performed at the bedside within minutes [Maioli, Journal of American College Cardiology 1014;63:1387-94]. In this study we defined patients with "lower fluid status" with high risk of CI-AKI (Male with resistance/ height ratio > 315 Ohm/meter and Female > 380 Ohm/meter). Bio-impedance analysis IVA may represent the optimal tool to monitor the adequacy of volume expansion and protective strategy delivery.

Infusing a standardized amount of fluid before the procedure may not result in the same effects in all patients. Moreover, standardized fluid infusion for 24 hours in patients that present with "normal fluid status" assessed by the bioimpedance analysis, can represent a too expensive preventive option both in terms of care and discomfort for the patient. In this study we analyze the possibility of a non-inferiority preventive protocol that involves a lower infusion of saline solution with a shorter administration time.

Inclusion Criteria:

• consecutive patients admitted in Cardiology Unit for coronary or peripheral angiography with "normal fluid status" assessed on the basis bio-impedance analysis (Male with resistance/height ratio < 315 Ohm/meter and female < 380 Ohm/meter)

Exclusion Criteria:

• contrast medium administration within the 10 days
• end stage renal failure requiring dialysis
• no ability to evaluation the state of hydration with bio impedance
• refused to give informed consent