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Critical Closing Pressure and PCO₂ Gap in Fluid Resuscitation for Septic Shock

NCT07043192 · Status: ACTIVE_NOT_RECRUITING · Type: OBSERVATIONAL · Enrollment: 60

Last updated 2025-07-03

No results posted yet for this study

Summary

This study is based on the following key hypotheses:

PvaCO₂ (Venous-to-Arterial CO₂ Gap) Hypothesis:

Changes in PvaCO₂ (ΔPvaCO₂) following fluid resuscitation correlate with changes in cardiac output (CO) and can serve as a reliable predictor of fluid responsiveness in septic shock patients.

The relationship between PvaCO₂ and CO is influenced by metabolic factors (VCO₂), hemodynamic status, and the Haldane effect (oxygenation-dependent CO₂ binding to hemoglobin).

Pcrit (Critical Closing Pressure) \& TPP (Tissue Perfusion Pressure) Hypothesis:

Elevated Pcrit and reduced TPP (TPP = MAP - Pcrit) are associated with impaired microcirculatory flow and worse clinical outcomes (e.g., 28-day mortality, organ dysfunction).

Restoring the "vascular waterfall" phenomenon (Pcrit \> mean systemic filling pressure) may improve macrocirculation-microcirculation coupling and tissue oxygenation.

2\. Study Design Overview 2.1 Study Type Prospective observational cohort with a retrospective validation arm using external databases (e.g., MIMIC-IV).

Single-center study (Peking Union Medical College Hospital ICU). 2.2 Study Population Inclusion Criteria Adults (18-80 years) with septic shock (Sepsis-3 criteria + vasopressor-dependent hypotension + lactate \>2 mmol/L).

Requires invasive hemodynamic monitoring (arterial line, central venous catheter).

Undergoing fluid challenge (clinically indicated). Exclusion Criteria Pregnancy, non-septic shock (e.g., cardiogenic), mechanical circulatory support (ECMO/IABP).

Severe COPD, intracardiac shunts, or conditions interfering with CO₂/VO₂ measurements.

2.3 Interventions \& Measurements Fluid Resuscitation Protocol 500 mL 4% gelatin infused over 15 min (pressure bag at 300 mmHg). Hemodynamic/metabolic data collected pre- and post-fluid challenge (within 10 min).

Key Data Collected

Hemodynamics:

MAP, CVP, CO (PiCCO/ultrasound), Pcrit (derived from MAP-CO curve fitting). TPP = MAP - Pcrit.

Metabolic Parameters:

PvaCO₂, CvaCO₂, VCO₂, VO₂ (Es-COVX module). Lactate, ScvO₂, Hb, arterial/venous blood gases.

Outcomes:

Primary: 28-day mortality. Secondary: Lactate clearance, AKI incidence, ICU length of stay, vasopressor requirements.

Conditions

  • Septic Shock
  • Fluid Resuscitation
  • Tissue Perfusion Pressure
  • Carbon Dioxide Pressure

Sponsors & Collaborators

  • Peking Union Medical College

    lead OTHER

Eligibility

Min Age
18 Years
Max Age
80 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2025-04-18
Primary Completion
2026-02-01
Completion
2026-02-01

Countries

  • China

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07043192 on ClinicalTrials.gov