Hemodynamic Effect of Different Replacement Fluid Protocols During Therapeutic Apheresis Evaluated With <scp>CRIT‐LINE</scp>

In therapeutic apheresis (TA) procedures, it is essential to administrate human albumin solution (HAS) to prevent hypotensive episodes. The CRIT-LINE monitor is used in hemodialysis to estimate changes in relative blood volume (RBV) to prevent such hypotensive episodes. The aim of this study was to evaluate the change in RBV during therapeutic plasma exchange (TPE) and double filtration plasmapheresis (DFPP) according to different fluid replacement protocols in order to identify the best protocol. A retrospective case series study was conducted on three patients with CIDP at a tertiary center. Each patient's TA sessions were evaluated with the CRIT-LINE monitor to compare fluid replacement protocols. The following protocols were evaluated for TPE: (TPE1) 100% volume replacement with 4% albumin supplementation; (TPE2) a combination of a 70% volume with 4% albumin and 30% normal saline in the initial phase of the session; and (TPE3) the same combination with normal saline in the final phase of the session. With regard to DFPP, the following protocols were evaluated: DFPP1: continuous infusion of 4% albumin throughout the entire session, and DFPP2: 4% albumin the last 20 min of the session. For the three patients, during the TPE sessions, the nadir for RBV was -10% to -13%, -11% to -17%, and -17% to -20% for TPE1, TPE2, and TPE3 protocols, respectively. Hypotensive episodes were observed in three patients with a combination of fluid replacement with normal saline infused at the end of the session (TPE3). In the DFPP sessions, the nadir for the change in RBV was -7% to -15% and -10% to -20% for DFPP1 and DFPP2 protocols, respectively. The nadir for RBV was higher with albumin infusion at the end of the session. Our results suggest a potentially crucial role of continuous RBV monitoring during TA to identify the better substitution fluid protocol and prevent hypotension during sessions.