Effect of Shenfu Injection on the Vascular Waterfall Phenomenon in Patients With Septic Shock

All enrolled patients with septic shock will receive a single intravenous infusion of Shenfu Injection (manufactured by China Resources Sanjiu Pharmaceutical Co., Ltd.).

The drug dose is 100 mL, diluted in 250 mL of normal saline, infused over 1 hour after initial hemodynamic stabilization.

Hemodynamic and microcirculatory parameters are measured before infusion and 3 hours after infusion, including vascular waterfall difference (critical closure pressure minus mean systemic filling pressure) and related physiological variables.

No control or placebo arm is included in this study.

All participants in the study will receive a single intravenous infusion of Shenfu Injection, a traditional Chinese medicine produced by China Resources Sanjiu Pharmaceutical Co., Ltd. The injection contains extracts of Ginseng Radix et Rhizoma and Aconiti Lateralis Radix Praeparata.

Each dose consists of 100 mL Shenfu Injection, diluted in 250 mL normal saline, and administered through continuous intravenous infusion over 1 hour after initial hemodynamic stabilization according to Surviving Sepsis Campaign guidelines.

Hemodynamic measurements will be performed before infusion (within 30 minutes) and at 3 hours after infusion. Variables include critical closure pressure (Pcc), mean systemic filling pressure (Pmsf), cardiac index, systemic vascular resistance, central venous oxygen saturation, arterial-venous CO₂ difference, and blood lactate concentration.

No other investigational drugs, placebos, or control interventions are administered in this study.

Cardiac index (L/min/m²) represents cardiac output standardized by body surface area and indicates overall pump function.

CI will be measured continuously using the PiCCO hemodynamic monitoring system through arterial thermodilution.

Values before Shenfu Injection and 3 hours post-infusion will be compared to evaluate changes in cardiac performance.

Stroke index (mL/m²) reflects the amount of blood ejected from the left ventricle per beat per body-surface area, used to assess stroke volume changes.

Measured using the PiCCO system and calculated automatically from thermodilution data.

Pcc (mmHg) is obtained by plotting ventricular output against mean arterial pressure during ventilator inspiratory hold maneuvers.

It represents the pressure below which small vessels collapse and microcirculatory flow ceases.

Analyzing Pcc before and after infusion will help assess whether Shenfu Injection modifies microvascular closing pressure.

Pmsf (mmHg) is the theoretical pressure at zero venous flow reflecting venous capacitance and circulating volume.

It will be estimated from the venous return curve during inspiratory hold. Comparing values pre- and post-infusion will show any effect of Shenfu Injection on mean systemic pressure and stressed volume.

ScvO₂ (%) measures oxygen content in central venous blood and reflects balance between oxygen delivery and consumption.

Obtained from central venous blood gas analysis. An increase may indicate improved tissue oxygenation after treatment.

Pcv-aCO₂ (mmHg) is the difference between central venous and arterial partial pressures of CO₂, reflecting adequacy of cardiac output and tissue perfusion.

Measured simultaneously from arterial and central venous samples by blood gas analyzer.

Blood lactate (mmol/L) is a biochemical marker of anaerobic metabolism and tissue hypoxia.

Measured from arterial blood gas. Reduction after infusion may indicate improvement in microcirculatory perfusion.

Average norepinephrine infusion rate (µg/kg/min) required to maintain mean arterial pressure ≥ 65 mmHg will be recorded.

Decreased dose after infusion may suggest improved vasomotor tone or systemic perfusion.