Maintenance and Creep Fluids Dominate ICU Fluid Volume in Ventilated Adults

Maintenance and creep fluids, not resuscitation fluids, made up most of the fluid volume given to mechanically ventilated adults in intensive care units (ICUs) across 41 countries. The findings come from a prospective observational cohort study published in JAMA. Fluid practices also varied substantially from site to site.

The Practice of Fluid Therapy in Critically Ill Invasively Ventilated Patients (PRoFLUID) study described fluid therapy by dose, indication, and type. The investigators noted that earlier studies and guidelines focused mainly on resuscitation, and that nonresuscitation fluids have been studied less systematically. From April 2024 to July 2025, the study enrolled consecutive adults at 206 ICUs in 41 countries. Patients qualified if they started invasive mechanical ventilation within 3 days of ICU admission and received ventilation for at least 24 hours

Among the 2454 patients analyzed (median age, 63 years), median daily fluid input peaked at 3.0L on study day 1 and declined to 2.6L through day 6. Median daily fluid balance fell from 0.9L on day 1 to less than 0.3L by day 3 and stayed near neutral through day 6. Over the first 3 days after intubation, maintenance and replacement fluids made up 31.9% of total volume and resuscitation fluids made up 16.0%. Creep fluids, which are used to deliver medications and keep catheters patent, made up 30.9%.

Balanced isotonic crystalloids made up 48.9% of prescribed intravenous fluids, followed by 0.9% sodium chloride at 27.0%. Synthetic colloids accounted for 1.3%. After adjustment for case mix, the estimated total fluid volume for a typical patient ranged from 2.1L per study day at more restrictive ICUs to 3.9L at more liberal ICUs. Use of balanced solutions ranged from 20.3% at the 10th percentile of sites to 96.7% at the 90th percentile.

The authors wrote that the findings point to a need for harmonized guidance. They said the data suggest attention should also go toward minimizing unnecessary maintenance fluids and hidden fluid sources. The authors noted that the observational design cannot assess causality and that fluids given before intubation were not recorded. They also noted that participating ICUs may have had more interest in fluid and vasopressor therapy than others, which could limit how far the results generalize.

Source: Blok SG, de Grooth HJ, Pisani L, et al. Fluid therapy in mechanically ventilated critically ill adult patients. JAMA. Published online October 14, 2026. doi:10.1001/jama.2026.21291