A Net Ultrafiltration Challenge to Predict Preload-dependence (UF CHALLENGE)

"The fast ultrafiltration challenge will be performed once in all enrolled participants, in the order defined by randomization. The fast ultrafiltration challenge consists of the net removal of 250 ml of ultrafiltrate by setting net ultrafiltration rate to 1000 ml/h, applied for 15 minutes. The cardiac output will be measured before and after the UF challenge, by mean of the transpulmonary thermodilution technique, and its relative variation from baseline will be quantified to evaluate the impact of the UF challenge on cardiac preload.~The UF challenge will be preceded and immediately followed by a postural change maneuver to assess the presence or absence of preload dependence. The postural change maneuver is positive in case of a +10% variation in continuous cardiac index over 1 minute, and is considered as the reference diagnostic test to which UF challenge diagnostic performance will be compared."

"The slow ultrafiltration challenge will be performed once in all enrolled participants, in the order defined by randomization. The slow ultrafiltration challenge consists of the net removal of 250 ml of ultrafiltrate by setting net ultrafiltration rate to 500 ml/h, applied for 30 minutes. The cardiac output will be measured before and after the UF challenge, by mean of the transpulmonary thermodilution technique, and its relative variation from baseline will be quantified to evaluate the impact of the UF challenge on cardiac preload.~The UF challenge will be preceded and immediately followed by a postural change maneuver to assess the presence or absence of preload dependence. The postural change maneuver is positive in case of a +10% variation in continuous cardiac index over 1 minute, and is considered as the reference diagnostic test to which UF challenge diagnostic performance will be compared."