Role of End-Tidal CO2 During Passive Leg Raising to Predict Fluid Responsiveness in ICU

ConditionsCirculatory Failure Critical Illness Hypovolemia

Trial statusNot yet recruiting

Trial phaseNot listed

Trial typeObservational

Biological sexAll

Age18+

SponsorIzmir Katip Celebi University

About this trial

This prospective observational study evaluates whether monitoring changes in exhaled carbon dioxide (End-Tidal CO2 or EtCO2) during a "Passive Leg Raising" (PLR) test can reliably predict fluid responsiveness in critically ill patients.

In the Intensive Care Unit (ICU), fluid management is a critical balance; while fluid is necessary for tissue perfusion, overload can lead to severe complications. Traditional static measurements (like central venous pressure) are often unreliable for guiding therapy. Dynamic tests like PLR are preferred as they simulate a fluid bolus reversibly by shifting blood from the legs to the heart.

Researchers will observe mechanically ventilated patients planned for fluid resuscitation. The study compares the accuracy of non-invasive EtCO2 changes during PLR against a reference standard "Mini Fluid Challenge" (100 mL fluid administration). Fluid responsiveness will be confirmed using echocardiographic measurements (LVOT-VTI) or arterial pressure changes. The goal is to validate EtCO2 as a practical, real-time tool for safe fluid management.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Patients aged 18 years or older.

Patients who have been followed in the intensive care unit (ICU) with mechanical ventilation support for at least 24 hours.

Patients for whom a mini fluid challenge (MFC) is clinically planned by the intensive care team.

Patients for whom informed consent has been obtained from first-degree relatives or a legal representative.

Disqualifiers

Patients younger than 18 years of age.

Pregnant patients.

Patients without consent from first-degree relatives or a legal representative.

Patients with known deep vein thrombosis (DVT) in the leg veins (risk of embolism during leg raising).

Trial population

The study population consists of adult patients (aged 18 years or older) admitted to the Intensive Care Unit (ICU) of a university hospital. Eligible participants are those who have been receiving mechanical ventilation support for at least 24 hours and have been identified by the primary intensive care team as requiring a fluid responsiveness assessment via a mini fluid challenge. The cohort includes patients with circulatory failure or suspected hypovolemia where fluid resuscitation is clinically indicated. Patients with contraindications to passive leg raising (e.g., intracranial hypertension, deep vein thrombosis), spontaneous breathing, or severe cardiac valve pathologies are excluded.

Trial design

Design model

Cohort

Time perspective

Prospective

Treatments tested in this trial

Not listed

Trial groups

68 Participants

are grouped into 2 trial groups

Group A: Fluid Responders

Group B: Fluid Non-Responders

Trial outcomes

Primary outcomes

Change in End-Tidal Carbon Dioxide (Delta EtCO2) during Passive Leg Raising (PLR)

The absolute difference in End-Tidal CO2 (EtCO2) levels will be calculated between the baseline measurement (T0, patient semi-recumbent at 45°) and the measurement taken during the Passive Leg Raising test (T1, patient supine with legs raised to 45°). The diagnostic accuracy of this Delta EtCO2 will be evaluated by comparing it against the patient's fluid responsiveness status (Responder vs. Non-Responder) determined by the subsequent Mini Fluid Challenge.

Time frame