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Veno-arterial CO2 gap-guided early resuscitation for septic shock

Veno-arterial Carbon Dioxide Partial Pressure Difference (CO2gap) for Early Resuscitation of Septic Shock: A Multicenter Prospective Randomized Trial (CARBON)

Not applicable Interventional University Hospital, Clermont-Ferrand · NCT07179276

This trial tests whether using the veno-arterial CO2 gap instead of lactate to guide early resuscitation helps adults with septic shock survive.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment750 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity Hospital, Clermont-Ferrand Academic / other
Locations27 sites (Angers and 26 other locations)
Trial IDNCT07179276 on ClinicalTrials.gov

What this trial studies

The CARBON trial compares a veno-arterial carbon dioxide partial pressure difference (CO2gap)-guided resuscitation strategy with a lactate level-guided strategy in adults with septic shock. Participants are adults admitted to participating ICUs who meet Sepsis-3 criteria, have lactate >2 mmol/L, require vasopressors, and are enrolled early in shock. Patients are managed according to the assigned algorithm with serial CO2gap or lactate measurements used to guide fluids, vasopressors, and other hemodynamic therapy, and mortality is the primary outcome. The trial is conducted at university and regional hospitals in France to determine if CO2gap-guided care reduces deaths compared with standard lactate-guided resuscitation.

Who should consider this trial

Good fit: Adults (≥18) recently admitted to a participating ICU with septic shock per Sepsis-3, a lactate >2 mmol/L, and needing vasopressors within 12 hours of shock onset are the intended participants.

Not a fit: Patients with non-septic causes of hypotension, shock present for more than 12 hours, decisions to limit life-sustaining treatment, or imminent death are unlikely to benefit from enrollment.

Why it matters

Potential benefit: If successful, this approach could reduce deaths by more accurately detecting and correcting tissue hypoperfusion during early septic shock.

How similar studies have performed: Observational studies show the CO2 gap correlates with tissue hypoperfusion, but randomized evidence for CO2gap-guided resuscitation versus lactate guidance is limited, so this approach remains relatively unproven.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Patients aged 18 years or older AND
* Acutely admitted to a study ICU AND
* Primary diagnosis of septic shock according to the Sepsis-3 criteria and defined as:

  * A suspected or documented site of infection or positive blood culture AND
  * Acute increase of at least 2 points in the Sequential Organ Failure Assessment (SOFA) score consequent to the infection AND
  * Having a serum lactate level \>2 mmol/l AND
  * Requirement of vasopressors (any dose of norepinephrine) to maintain mean arterial pressure (MAP) ≥65 mmHg despite adequate fluid resuscitation (at least 1L of IV fluid in the last 24 hours prior to screening)

Exclusion Criteria:

* Septic shock for more than 12 hours at the time of screening
* Primary cause of hypotension not due to sepsis (e.g., acute bleeding)
* Decision not to resuscitate (or to limit full care) or not to intubate taken before obtaining consent
* Death is deemed to be imminent or inevitable or patients with an underlying disease process with a life expectancy of less than 3 months
* Anticipated surgery during the first 24 hours after randomization
* Patient or their relatives' refusal to participate
* Patients participating in another RCT with interventions possibly compromising the primary outcome
* Prior enrollment in the CARBON trial
* Known to be pregnant.
* Legal protection (i.e., incompetence to provide consent and no guardian or incarceration)
* No affiliation with the French health care system

Where this trial is running

Angers and 26 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Sepsis - to Reduce Mortality in the Intensive Care UnitSeptic ShocklactateCO2 gapresuscitation strategiesepsishemodynamic therapy
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.