Fluid and vasopressor management in septic shock remains controversial. In this randomized controlled trial, we evaluated the efficacy of dynamic measures (stroke volume change during passive leg raise) to guide resuscitation and improve patient outcome.Will resuscitation guided by dynamic assessments of fluid responsiveness in patients with septic shock improve patient outcomes?and Methods: Prospective, multicenter, randomized clinical trial at 13 hospitals in the United States and United Kingdom. Patients presented to Emergency Rooms with sepsis associated hypotension and anticipated Intensive Care Unit (ICU) admission. Intervention arm patients were assessed for fluid responsiveness before clinically driven fluid bolus or increase in vasopressors. The protocol included reassessment and therapy as indicated by the PLR result. The control arm received Usual Care. Primary clinical outcome was positive fluid balance at 72 hours or ICU discharge, whichever occurred first.In modified-ITT (mITT) analysis including 83 Intervention and 41 Usual Care eligible patients, fluid balance at 72 hours or ICU discharge was significantly lower (-1.37L favoring Intervention arm, 0.65 ± 2.85L Intervention arm vs. 2.02 ± 3.44L Usual Care arm, p=0.021. Fewer patients required renal replacement therapy (5.1% vs 17.5%, p=0.04) or mechanical ventilation (17.7% vs 34.1%, p=0.04) in the Intervention arm compared to Usual Care. In the all-randomized Intent to Treat (ITT) population (102 Intervention, 48 Usual Care) there were no significant differences in safety signals.Physiologically informed fluid and vasopressor resuscitation using passive leg raise-induced stroke volume change to guide management of septic shock is safe and demonstrated lower net fluid balance and reductions in the risk of renal and respiratory failure. Dynamic assessments to guide fluid administration may improve outcomes for septic shock patients compared with Usual Care.