Renal fluid responsiveness during oliguria.

Rationale:

A decline in urine output below 0.5 ml/kg/h (oliguria) puts critically ill patients at risk to develop acute kidney injury, which is associated with a higher mortality and morbidity rate. To attenuate this risk, patients are often given intravenous resuscitation fluids in an attempt to improve diuresis. However these fluids can accumulate when urine output does not improve, resulting in volume overload, edema and subsequent organ damage. Currently there are no clinical parameters to help physicians predict whether an oliguric patient will be fluid responsive, and whether this is beneficial in terms of outcome.



Objective:

The objective of this study is to identify potential predictors of renal fluid responsiveness and whether fluid responsive patients have more favorable outcomes as opposed to fluid unresponsive patients.



Study design:

This will be a prospective intervention study.



Study population:

All critically ill patients admitted to the ICU with oliguria (urine output < 0.5ml/kg/h) for 2 consecutive hours are eligible for inclusion. We will exclude patients with other indications for fluid therapy or unable to safely receive additional fluids.



Intervention:

All subjects will receive an intravenous infusion between 500 to 1000 ml of 0.9% saline or Ringer’s Lactate administered in 10 minutes.



Main study parameters/endpoints:

The main study parameter is renal fluid responsiveness after fluid therapy. Fluid responsiveness is defined as an increase in urine output to ≥ 0.5 ml/kg/h after fluid therapy. Hemodynamic, urine and plasma parameters will be collected to identify possible predictors, and patients will be followed till the 28th day after inclusion or discharge to identify possible differences in renal outcome between groups.

Are there any clinical parameters to help physicians predict whether an oliguric critically ill patient will be fluid responsive, and is it beneficial in terms of outcome?

1. T0 = Inclusion, start measurements;

2. T30(minutes) - T90 = Fluid therapy;

3. T240 = end of measurements;

4. Follow-up until discharge or day 28.

All subjects will receive an intravenous infusion of 1500 ml of 0.9% saline during 1 hour.