Introduction: It is unclear if the rate of IVF administration in sepsis impacts glycocalyx breakdown and endothelial dysfunction. This study aims to measure the effect of rapid versus slow fluid bolus in a septic pig model on the integrity of the glycocalyx by measuring the serum levels of heparin sulfate and syndecan-1, breakdown products of the glycocalyx. In addition, we measured central blood volume (blood volume in the heart and lungs) to determine the effect of fluid administration rate on intravascular volume. Methods: A porcine septic shock model using lipopolysaccharide (LPS)-induced endotoxemia was used. We randomized twenty-two anesthetized piglets (25–35 kg) to receive two fluid boluses of 20 mL/kg each 30 minutes apart, with 11 receiving the fluid bolus over 5 minutes and 11 receiving it over 20 minutes. We monitored central blood volume index (CBVI) using a validated ultrasound dilution system (COstatus). Serial measurements of glycocalyx degradation markers, heparin sulfate, syndecan-1, and CBVI were obtained every 30 min for 4 measurements after onset of septic shock. Study variables were summarized as mean (SD) by fast vs slow IVF groups across measurement time points. To assess the mean trends in outcomes (syndecan-1, Heparin sulfate, CBVI) between the two groups over time, a linear mixed-effects model with an autoregressive AR (1) within-subject correlation structure was applied. Results: In the 2 hours after septic shock onset, serum heparan sulfate and syndecan-1 levels showed no significant differences (p = 0.403 and 0.496, respectively). Baseline-adjusted mean CBVI over the 4 measurements was greater in the slow IVF group than the fast group; however, the difference fell short of statistical significance (p=0.069), indicating a non-significant trend toward greater central blood volume with slower infusion. Mean (SE) central blood volumes were 9.8 (0.39), 9.6 (0.44), 8.6 (0.64), 7.5 (0.68), and 7.1 (0.82) in the Fast Flow group, and 10.0 (0.31), 11.0 (0.41), 10.0 (0.59), 8.9 (0.53), and 8.4 (0.46) in the Slow Flow group. Conclusions: There was no difference in glycocalyx degradation between an IV fluid bolus in a porcine model of septic shock given over 5 minutes compared with 20 minutes. Central blood volumes trended greater in the slow IVF group compared with the fast IVF group.
Levenbrown et al. (Sun,) studied this question.