Central venous-arterial CO2 gap to arterial-central venous O2 content difference ratio in guiding of fluid resuscitation of patients with septic shock.

BACKGROUND: Tissue hypoperfusion can persist despite meeting early goal-directed therapy targets, while excessive resuscitation poses risks. The study focuses on the utility of central venous-arterial CO2 gap to arterial-central venous O2 content difference ratio (Pv-aCO2/Ca-vO2) can serve as a valuable tool for guiding fluid resuscitation in patients with septic shock. METHODS: A prospective study was conducted in a Chinese intensive care unit from July 1, 2020 to March 31, 2025. The study cohort comprised individuals who have been diagnosed with septic shock. The patients were allocated into 2 groups: control group: after receiving early goal directed therapy target fluid resuscitation for 6h, no additional fluid replacement was required; experimental group: fluid resuscitation should be continued until Pv-aCO2/Ca-vO2 ≤ 1.8 mm Hg/mL. The fundamental data, clinical characteristics, prognostic factors, and complications were comprehensively collected and analyzed. Finally, the reliability of Pv-aCO2/Ca-vO2 as parameter for determining fluid resuscitation targets in septic shock patients was evaluated. RESULTS: A total of 321 patients were enrolled in the study. There were no significant differences in fundamental data and clinical characteristics among the 2 groups. At baseline, no significant differences were observed between the control and experimental groups regarding the total decannulation rate, duration of mechanical ventilation, and length of stay in the intensive care unit (P >.05). However, the experimental group exhibited a significantly lower 28-day mortality rate compared to the control group (P .05). Nonetheless, the incidence of renal insufficiency or the requirement for renal replacement therapy was significantly lower in the experimental group than in the control group (P .05). However, at time points T12 and T24, the total fluid replacement volume was significantly higher in the experimental group compared to the control group (P <.05). CONCLUSIONS: Pv-aCO2/Ca-vO2 may serve as a reliable parameter for determining the fluid resuscitation target in patients with septic shock.