NCT07492030

Validation of the Use of the Arteriovenous Tension Difference in CO2 Under Hyperbaric Conditions

Use of Central Venous-arterial Carbon Dioxide Tension Difference to Diagnose Low Cardiac Output in Patients With Septic Shock Undergoing Hyperbaric Oxygen Therapy

• Status: Not Yet Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 74 (estimated)
• Sponsor: University Hospital, Lille · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The central venous-arterial carbon dioxide tension difference is used daily in intensive care to establish peripheral tissue hypoperfusion, mainly mediated by a low cardiac index. The partial pressures of gases (oxygen, carbon dioxide) increase in the blood of patients breathing 100% oxygen in hyperbaric conditions. Thus, the validity of this biomarker in situations of acute circulatory failure during a hyperbaric oxygen therapy session has not been established. The objective of the study is therefore to establish the diagnostic performance of the central venous-arterial carbon dioxide tension difference in the diagnosis of a low cardiac index in patients with septic shock undergoing hyperbaric oxygen therapy for necrotizing fasciitis.

Detailed description

Adult patients diagnosed with necrotizing fasciitis and receiving OHB treatment for the first time will be offered participation in the study if they meet the following inclusion criteria: * Diagnosis of necrotizing fasciitis complicated by septic shock as defined by the Surviving Sepsis Campaign * Indication for HBOT according to the criteria of the 2016 European Consensus Conference * Patient intubated and ventilated prior to the HBOT session, receiving intravenous sedation at doses sufficient to be in a passive ventilation state * Patient equipped with a central venous line in the superior vena cava allowing central venous blood gas analysis * Patient with an arterial catheter allowing arterial blood gas analysis

Conditions

• Necrotizing Fascitis
• Cellulitis
• Septic Shock

Interventions

Type	Name	Description
OTHER	Echography	Cardiac output is estimated by taking three measurements of the time-velocity integral using pulsed Doppler at the level of the left ventricular outflow tract, known as the subaortic time-velocity integral (TVI). The systolic ejection volume is calculated by multiplying the subaortic TVI by the area of the aortic outflow tract diameter. Cardiac output is calculated by multiplying this systolic ejection volume by the patient's heart rate. The cardiac index is calculated by dividing cardiac output by the patient's calculated body surface area. Blood gas sampled from central arterial and venous catheters at the four stages of the experimental plan Cardiac output and blood gases will be measured: * After 15 minutes of ventilation on a hyperbaric ventilator at ambient pressure in the chamber with FIO2 equivalent to that of the intensive care unit (T0). * After 15 minutes at maximum treatment pressure, i.e., 2.5 ATA under FIO2 at 1 (T1) * After 75 minutes at the plateau following the star

Timeline

• Start date: 2026-03-15
• Primary completion: 2027-09-15
• Completion: 2028-03-15
• First posted: 2026-03-25
• Last updated: 2026-03-25

Locations

1 site across 1 country: France