呼气末二氧化碳分压联合被动抬腿试验对脓毒性休克机械通气患者容量反应性的预测价值OA

Objective To evaluate the value of partial pressure of end-tidal carbon dioxide(PETCO2)combined with passive leg raising(PLR)in predicting fluid responsiveness in patients with septic shock undergoing mechanical ventilation.Methods A prospective cohort study was conducted.Patients with septic shock who underwent tracheal intubation and mechanical ventilation in the department of critical care medicine of the Affiliated Hospital of Guizhou Medical University from March 2025 to November 2025 were enrolled as the research subjects.All patients underwent PLR.PETCO2 was recorded before PLR(baseline,T0)and during PLR(T1).Left ventricular outflow tract velocity time integral(VTI)was measured by echocardiography,and cardiac output(CO)was calculated.A PLR-induced ΔCO≥10%was defined as fluid responsiveness positive.The Pearson correlation analysis method was used to evaluate the correlation between the PLR-induced ΔPETCO2%and ΔCO%induced by PLR,and the predictive performance of ΔPETCO2 was assessed using the receiver operator characteristic curve(ROC curve).Results A total of 142 patients were included,comprising 119(83.8%)in the fluid responsiveness positive group and 23(16.2%)in the fluid responsiveness negative group.At T1,cardiac index(CI),stroke volume(SV),VTI,CO,and PETCO2 were significantly increased compared with T0 in the fluid responsiveness positive group.The CI and CO in the fluid responsiveness negative group were increased compared to T0,but the magnitude of the increase was relatively small,and PETCO2 in the fluid responsiveness positive group was significantly higher than that fluid responsiveness negative group(all P<0.05).Further comparison of the changes(Δ)in these parameters between the two groups revealed that ΔCI,ΔSV,ΔVTI,ΔCO,and ΔPETCO2 were significantly higher in the fluid responsiveness positive group than in the fluid responsiveness negative group[ΔCI(mL·s-1·m-2):7.00(4.83,10.17)vs.1.17(0.50,2.67);ΔSV(mL):8.42(5.70,11.78)vs.1.35(0.53,2.98);ΔVTI(cm):3.13(2.31,4.11)vs.0.60(0.20,0.95);ΔCO(L/min):0.72(0.51,1.09)vs.0.12(0.04,0.28);ΔPETCO2(mmHg,1 mmHg≈0.133 kPa):5.0(4.0,6.0)vs.2.0(0.5,2.0);all P<0.05].The Pearson correlation analysis showed thatΔPETCO2%was positively correlated with ΔCO%(r=0.350,P<0.001).The ROC curve analysis showed that PETCO2 combined with PLR had a certain predictive effect on the volume responsiveness of patients with septic shock undergoing mechanical ventilation,area under the curve(AUC)of ΔPETCO2 for predicting fluid responsiveness=0.876,with a 95%confidence interval(95%CI)was 0.787-0.965.At an optimal cut-off value of 0.092,the sensitivity was 87.0%and the specificity was 79.8%.Conclusions PETCO2 combined with PLR effectively predicts fluid responsiveness in patients with septic shock undergoing mechanical ventilation.This method is noninvasive,simple,and reproducible,providing a practical bedside tool for individualized fluid management in the intensive care unit(ICU).