Background: Mini-fluid challenge may predict fluid responsiveness and limit fluid overload. This study was designed to explore the minimal infusion volume in effectively predicting fluid responsiveness in septic shock patients.Methods: ICU septic shock patients with indwelling pulmonary artery catheter received five sequential intravenous boluses of 100 mL 4% gelatin. Cardiac output was measured with thermodilution before fluid challenge (baseline) and three minutes after each bolus. Fluid

more »

... nsiveness (FR) was defined as an increase in CO greater than 10% after 500 mL fluid infusion. The smallest volume which can perform an effective fluid challenge was analyzed. Results: Forty-seven patients were included in this prospective study. After 500 mL volume expansion, thirty-six patients presented with FR (77%) and 11 patients were fluid nonresponders. A mini fluid of 100 mL colloid had a poor predictive value (AUC = 0.67, p > 0.05). The minimal volume required to predict FR in a mini fluid challenge was 200 mL. An increase in CO greater than 5.2% after 200 mL colloid infusion was able to predict FR with a sensitivity of 83.3% and specificity of 90.9%. The AUC under the ROC curve was 0.93 (95% CI: 0.84 – 1, p < 0.05). Conclusion: In septic shock patients, a minimal volume of 200 mL 4% gelatin could reliably detect fluid responders and nonresponders.Trial registration: ClinicalTrial.gov (NCT01941472). Registered on 13 September 2013.