EIT During FCV in the Intensive Care Unit

Study Overview
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Brief Summary
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The goal of this clinical trial is to study the effects of Flow Controlled Ventilation (FCV) following conventional mechanical ventilation (Pressure or Volume Controlled Ventilation) in postcardiac surgery ICU-patients to allow for future power calculations and to obtain experience with FCV. The main questions it aims to answer are: What is the effect of FCV on the lung volume measured by Electrical Impedance Tomography (EIT)? What is the effect of FCV on the minute volume? What is the effect of FCV on the mechanical power and dissipated energy? Participants will be ventilated with PCV at baseline and then switched to FCV for 90 minutes while the lung volume, minute volume and mechanical power and dissipated energy levels are measured.

Official Title
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Electrical Impedance Tomography During Flow Controlled Ventilation in the Intensive Care Unit

Conditions
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Post-cardiac Surgery

Intervention / Treatment
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* Device: Flow Controlled Ventilation (FCV)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years or older; Informed consent form signed by the subject or a legal representative; Controlled mechanical ventilation via an endotracheal tube - FiO2 ≤50% and PEEP 10 cmH2O or lower Exclusion Criteria: Severe sputum stasis or production requiring frequent bronchial suctioning (more than 5 times per nurse shift) Severe respiratory insufficiency defined as a PaO2 to FiO2 ratio of <100mmHg or moderate to severe ARDS according to the Berlin definition of ARDS Untreated pneumothorax (i.e. no pleural drainage) Hemodynamic instability defined as a mean arterial pressure below 60mmHg not responding to fluids and/or vasopressors or a noradrenalin dose >0.4mg/kg/min Excessive subcutaneous emphysema (prevents proper functioning of the EIT device) Thoracic wounds, bandages or other obstruction which prevent proper functioning of the EIT device High (>15 mmHg) or instable (an increase in sedation or osmotherapy is required) intracranial pressure An inner tube diameter of 6mm or less

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Intervention Model: Sequential Assignment
Interventional Model Description: PCV at baseline, followed by 90 minutes of FCV and finished with 30 minutes of PCV
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Postcardiac surgery ICU-patients<br>After postcardiac surgery patients are brought to the ICU and are ventilated on PCV (Pressure Controlled Ventilation). Measurements of the lung volume (by Electrical Impedance Tomography; EIT), the minute volume and Mechanical Power/Dissipated energy are started and continued for the duration of the study. After a few minutes the patient is switched to FCV (Flow Controlled Ventilation) for 90 minutes and afterwards PCV is resumed with the measurements lasting for another 30 minutes (total study time 120 minutes). | Device: Flow Controlled Ventilation (FCV)<br>* FCV is started with the same settings as PCV (PEEP, Ppeak, FiO2) and after 30 minutes FCV is optimized concerning the driving pressure and PEEP using the dynamic compliance. After a total of 60 minutes the flow is adjusted based on the arterial blood gas.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| End-expiratory lung volume | The difference in End-expiratory lung volume (EELV) between PCV and FCV is measured using the difference in End-expiratory lung impedance (EELI) and tidal volume at baseline | Baseline EELV compared to after 30 minutes of FCV (same ventilator settings) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Minute volume | The difference in minute volume between PCV and FCV with a stable PaCO2 | The difference in minute volume between PCV at baseline and after 90 minutes of FCV (after optimization of FCV) | 
| Mechanical Power | The difference in Mechanical Power between PCV and FCV are measured by using our own produced Pressure-Volume loops | The difference in Mechanical Power between PCV at baseline and after 90 minutes of FCV (after FCV optimization) | 
| Dissipated energy | The difference in Dissipated energy between PCV and FCV are measured by using our own produced Pressure-Volume loops | The difference in Dissipated energy between PCV at baseline and after 90 minutes of FCV (after FCV optimization) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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FCV, EIT, Mechanical Power, Minute volume, Dissipated energy, ICU