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). Furthermore, the length of hospital stay was significantly reduced in the experimental group relative to the control group (P <.05). The incidence of heart failure or pulmonary edema, hepatic insufficiency, gastrointestinal bleeding, cerebrovascular accidents, and coronary heart disease or myocardial ischemia did not differ significantly between the 2 groups (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). In terms of the total fluid replacement volume at time point T6, no statistically significant differences were identified between the control and experimental groups (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.