Clinical Application of Electrical Impedance Tomography for Individual Adjustment of Ventilator Settings

Study Overview
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Brief Summary
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First clinical application of an algorithm for individual adjustment of ventilator settings using electrical impedance tomography.

Detailed Description
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In patients suffering from early Acute Respiratory Distress Syndrome (ARDS), an algorithm for individual adjustment of positive end-expiratory pressure and tidal volume will be applied. After optimization of ventilator settings according to the ARDS Network protocol, lung stress and strain, driving pressure, respiratory system compliance (Crs), regional ventilation delay and PaO2 / FiO2 ratio will be recorded. Subsequently, ventilator settings will be adjusted using an algorithm aiming at recruitment and avoiding tidal recruitment and overdistension using electrical impedance tomography (EIT). After 4 hours of EIT-based optimization ventilator settings, lung stress and strain, driving pressure, respiratory system compliance (Crs), regional ventilation delay and PaO2 / FiO2 ratio will be recorded again. The results will be compared to the ARDS Network approach.

Official Title
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Pilot Clinical Study on Patient-Specific Adjustment of Ventilator Settings Using Electrical Impedance Tomography in Patients With Acute Respiratory Distress Syndrome

Conditions
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ARDS

Intervention / Treatment
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* Other: Adjustment of ventilator settings by EIT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Acute Respiratory Distress Syndrome (according to Berlin Definition) Exclusion Criteria: Hemodynamic Instability (defined as mean arterial pressure < 65 mmHg OR heart rate < 40 / min OR heart rate > 150 / min OR cardiac index < 2.0 l/min/m^2 DESPITE adequate fluid resuscitation and adequate therapy with inotropes and / or vasopressors) Thoracic burns or severe skin injuries High frequency oscillatory ventilation Pregnancy Severe chronic obstructive pulmonary disease (GOLD IV) Esophageal varices > grade I Esophageal resection Invasive ventilation prior to study inclusion for more than 72 hours after onset of ARDS Inspiratory oxygen requirement > 80%

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: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Adjustment of ventilator settings by EIT<br>Individual Adjustment of Ventilator settings using an algorithm based on electrical impedance tomography. | Other: Adjustment of ventilator settings by EIT<br>* Diagnostic maneuvers (change in tidal volume, recruitment maneuvers) will be performed to detect overdistention, tidal recruitment and recruitability. Tidal volume will be reduced if overdistention is detected by EIT. Positive end-expiratory pressure will be increased if tidal recruitment or recruitability are detected.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stress | Percentage of patients with lung stress (defined as trans-pulmonary pressure during an end-inspiratory hold) below 27 mbar after 4 hours of adjustment of ventilator settings with the algorithm. | 4 hours | 
| Strain | Percentage of patients with lung strain (defined as end-inspiratory lung volume divided by functional residual capacity) below 2.0 after 4 hours of adjustment of ventilator settings with the algorithm. | 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Compliance | Respiratory system compliance (defined as expiratory tidal volume divided by driving pressure) will be measured after 4 hours of adjustment of ventilator settings with the algorithm | 4 hours | 
| Driving Pressure | Driving Pressure (defined as difference between airway plateau pressure and positive end-expiratory pressure) will be measured after 4 hours of adjustment of ventilator settings with the algorithm | 4 hours | 
| Standard Deviation of regional ventilation delay | Standard Deviation of regional ventilation delay, (as described in the publication of Muders et al, Crit Care Med Vol. 40, pp 903-911, 2012) will be measured after 4 hours of adjustment of ventilator settings with the algorithm | 4 hours | 
| PaO2 / FiO2 Ratio | The ratio between arterial partial pressure of oxygen (PaO2) and fraction of inspired oxygen (FiO2) will be measured after 4 hours of adjustment of ventilator settings with the algorithm | 4 hours |