[Efficacy analysis of inferior vena cava variability combined with difference of central venous-to-arterial partial pressure of carbon dioxide on guiding fluid resuscitation in patients with septic shock].

Objective: To investigate the effect of inferior vena cava variability (IVCV) combined with difference of central venous-to-arterial partial pressure of carbon dioxide (Pcv-aCO) on guiding fluid resuscitation in septic shock.

Methods: Patients with septic shock admitted to the department of critical care medicine of Jiangxi Provincial People's Hospital from January 1, 2018 to December 31, 2020 were enrolled, and they were divided into control group and observation group according to random number table method. Patients in both groups were given fluid resuscitation according to septic shock fluid resuscitation guidelines. The patients in the control group received fluid resuscitation strictly according to the early goal-directed therapy (EGDT) strategy. Resuscitation target: central venous pressure (CVP) 12-15 cmHO (1 cmHO≈0.098 kPa), mean arterial pressure (MAP) > 65 mmHg (1 mmHg≈0.133 kPa), mean urine volume (UO) > 0.5 mL×kg×h, central venous oxygen saturation (ScvO) > 0.70. In the observation group, the endpoint of resuscitation was evaluated by IVCV dynamically monitored by bedside ultrasound and Pcv-aCO. Resuscitation target: fixed filling of inferior vena cava with diameter > 2 cm, IVCV < 18%, and Pcv-aCO < 6 mmHg. The changes in recovery indexes before and 6 hours and 24 hours of resuscitation of the two groups were recorded, and the 6-hour efficiency of fluid resuscitation, 6-hour lactate clearance rate (LCR) and 6-hour and 24-hour total volume of resuscitation were also recorded; at the same time, the duration of mechanical ventilation, length of intensive care unit (ICU) stay, 28-day mortality and the incidence of acute renal failure and acute pulmonary edema between the two groups were compared.

Results: A total of 80 patients were enrolled in the analysis, with 40 in the control group and 40 in the observation group. The MAP, CVP and ScvO at 6 hours and 24 hours of resuscitation in the two groups were significantly higher than those before resuscitation, while Pcv-aCO and blood lactic acid (Lac) were significantly decreased, and UO was increased gradually with the extension of resuscitation time, indicating that both resuscitation endpoint evaluation schemes could alleviate the shock state of patients. Compared with before resuscitation, IVCV at 6 hours and 24 hours of resuscitation in the observation group were decreased significantly [(17.54±4.52)%, (18.32±3.64)% vs. (27.49±10.56)%, both P < 0.05]. Compared with the control group, MAP and ScvO at 6 hours of resuscitation in the observation group were significantly increased [MAP (mmHg): 69.09±4.64 vs. 66.37±4.32, ScvO: 0.666±0.033 vs. 0.645±0.035, both P < 0.05], 24-hour MAP was increased significantly (mmHg: 75.16±3.28 vs. 70.12±2.18, P < 0.05), but CVP was relatively lowered (cmHO: 9.25±1.49 vs. 10.25±1.05, P < 0.05), indicating that the fluid resuscitation efficiency was higher in the observation group. Compared with the control group, 6-hour LCR in the observation group was significantly increased [(55.64±6.23)% vs. (52.45±4.52)%, P < 0.05], 6-hour and 24-hour total volume of resuscitation was significantly decreased (mL: 2 860.73±658.32 vs. 3 568.54±856.43, 4 768.65±1 085.65 vs. 5 385.34±1 354.83, both P < 0.05), the duration of mechanical ventilation was significantly shortened (days: 6.78±3.45 vs. 8.45±2.85, P < 0.05), while the incidence of acute pulmonary edema was significantly decreased [2.5% (1/40) vs. 20.0% (8/40), P < 0.05]. There was no significant difference in the length of ICU stay, 28-day mortality or incidence of acute renal failure between the two groups.

Conclusions: Dynamic monitoring of IVCV and Pcv-aCO can effectively guide the early fluid resuscitation of patients with septic shock, and compared with EGDT, it can significantly shorten the duration of mechanical ventilation, reduce the amount of fluid resuscitation, and reduce the incidence of acute pulmonary edema. Combined with its non-invasive characteristics, it has certain clinical advantages.