Currently, the literature is virtually blank on gatro-enteral versus intravenous fluid substitution in patients with conditions requiring intensive care unit treatment. Designing a large, confirmatory randomized-controlled clinical trial requires an appropriate primary endpoint and an estimate of the effect size. As outlined above, reliable data to provide this information is lacking. The present pilot study is going to close this gap.

The overall objective is to define an appropriate primary endpoint for the conduct of a larger randomized trial, in which the hypothesis that gastro-enteral fluid therapy by gastric or jejunal probe is not inferior to intravenous fluid therapy in events such as sepsis can be investigated.

To obtain data for the design of a mentioned confirmatory RCT, this pilot study aims to evaluate differences between gastroenterally and intravenously fluid-substituted patients regarding clinical outcomes indices (such as regurgitation, thirst, serum sodium, arterial pressure, urinary volume, body weight, edema), changes in bioimpedance spectroscopy-derived markers, fluid overload, kidney failure, mortality and SOFA-Scores.

We aim to recruit from two distinct hospitals (AKH Wien, ICU 13i3 and ICU 13i2 and Kaiser Franz Josef Spital, D-Intensiv of the 1st medical department): Patients who are newly intubated receive fluid therapy according to two different procedures (parenteral vs. enteral) in clinical practice. To compare the efficacy of the two, a random assignment is without alternative to control for many unknown variables which are likely to impact the outcome of fluid therapy in ICU patients.