Changes of cardiac output and velocity time integral in blood return at the end of renal replacement therapy predict fluid responsiveness in critically Ill patients with acute circulatory failure.

Objectives: To observe if blood return, also defined as the blood infusion test (BIT) could predict fluid responsiveness in critically ill patients with acute circulatory failure and renal replacement therapy (RRT).

Methods: This was a single-center, prospective, diagnostic accuracy study. Before BIT, the passive leg raise test (PLRT) was performed to record the change of cardiac output (ΔCO) by pulse contour analysis, and ΔCO >  = 10% was defined as the fluid responder. Meanwhile, the change in velocity time integral (ΔVTI) was recorded by ultrasound. Later, the ΔCO and ΔVTI during BIT were recorded 5-10 min after PLRT. The receiver-operating characteristic curves of ΔCO and ΔVTI of BIT were performed in predicting the fluid responder defined by PLRT.

Results: A total of 43 patients with acute circulatory failure undergoing RRT were enrolled in the present study, and 25 patients (58.1%) were recognized as responders during PLRT. According to the receiver-operating characteristic curves, the cutoff value of ΔCO was 10% and ΔVTI was 9% during BIT with the area under curve of 0.96 and 0.94, respectively.

Conclusions: BIT in RRT could identify fluid responsiveness in critically ill patients with shock.

Trial Registration: ChiCTR-DDD-17010534. Registered on 30/01/2017 (retrospective registration).