Effect of Electric Impedance Tomography-Guided PEEP Titration

Study Overview
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Brief Summary
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Acute respiratory syndrome distress (ARDS) is a clinical common syndrome with high mortality. Mechanical ventilation (MV) is the cornerstone of management of ARDS but can lead to ventilator-induced lung injury. Positive end-expiratory pressure (PEEP), as one of main component of MV, has been widely used in the clinical practice. However, how to best set PEEP is still a difficult problem for moderate to severe ARDS patients. EIT, an imaging tool evaluating the regional ventilation distribution at the bedside, can achieve the individual PEEP selection for all mechanically ventilated patients. This article compared the effect of PEEP titrated guided by EIT with fraction of inspired oxygen (FiO2)-PEEP table on the ventilation-perfusion mismatch.

Official Title
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Effect of Electric Impedance Tomography-Guided PEEP Titration on the Ventilation-perfusion Mismatch in Moderate or Severe ARDS

Conditions
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ARDS, Human

Intervention / Treatment
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* Device: PEEP selection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Intubated patients with moderate and severe ARDS (Berlin definition, PaO2/FiO2 ≤200 mmHg at PEEP 5 cmH2O) undergoing deep sedation on controlled mechanical ventilation within72 hours after ARDS onset Exclusion Criteria: age <18 years old patient undergoing legal protection contra-indications to EIT (e. g. severe chest trauma or wounds) pneumothorax patient undergoing ECMO pregnancy

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: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: EIT-PEEP strategy<br>PEEP selected by EIT which remained at 15 min | Device: PEEP selection<br>* Electric impedance tomography-guided PEEP titration<br>|
| Experimental: Low FiO2-PEEP strategy<br>PEEP selected by low FiO2-PEEP table which remained at 15 min | Device: PEEP selection<br>* Electric impedance tomography-guided PEEP titration<br>|
| Experimental: High FiO2-PEEP strategy<br>PEEP selected by high FiO2-PEEP table which remained at 15 min | Device: PEEP selection<br>* Electric impedance tomography-guided PEEP titration<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in ventilation-perfusion mismatch between EIT-PEEP, low-PEEP, and high PEEP | EIT-PEEP was obtained by EIT, low-PEEP was obtained by low FIO2-PEEP table, and high-PEEP was obtained by high FIO2-PEEP table. | up to 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| difference in center of ventilation (COV) between EIT-PEEP, low-PEEP, and high PEEP | COV was obtained by EIT monitoring | up to 24 hours | 
| Difference in dead space measured with EIT between EIT-PEEP, low-PEEP, and high PEEP | dead space was obtained by EIT monitoring | up to 24 hours | 
| Difference in shunt measured with EIT between EIT-PEEP, low-PEEP, and high PEEP | shunt was obtained by EIT monitoring | up to 24 hours | 
| Difference in wasted ventilation measured with EIT between EIT-PEEP, low-PEEP, and high PEEP | wasted ventilation was obtained by EIT monitoring | up to 24 hours | 
| Difference in wasted perfusion measured with EIT between EIT-PEEP, low-PEEP, and high PEEP | wasted perfusion was obtained by EIT monitoring | up to 24 hours | 
| ventilation distribution measured with EIT between EIT-PEEP, low-PEEP, and high PEEP | ventilation distribution was obtained by EIT in difference regions | up to 24 hours | 
| perfusion distribution measured with EIT between EIT-PEEP, low-PEEP, and high PEEP | perfusion distribution was obtained by EIT in difference regions | up to 24 hours | 
| Correlations between ventilation-perfusion mismatch and overdistension and lung collapses | Overdistension (%) and lung collapses (%) will be assessed by EIT. These two values cannot be measured separately. V/Q mismatch will be computed by EIT, and expressed in %. Correlation will be performed by linear regression. | up to 24 hours | 
| recruitment-to-inflation (R/I) ratio | recruitment-to-inflation (R/I) ratio was computed between the two PEEP levels | up to 24 hours | 
| PaO2/FIO2 | PaO2/FIO2 was obtained by gas analysis | up to 24 hours | 
| respiratory system mechanics | respiratory system compliance included lung compliance, chest wall compliance, and respiratory system compliance. respiratory system resistance will be computed as the inverse of compliance. | up to 24 hours | 
| Correlation between V/Q mismatch markers and recruitability | Recruitability will be assessed between 15 and 5 cmH2O by respiratory mechanics, as the recruited volumes value (in mL). R/I ratio will be derived from these data (no unit). V/Q mismatch will be computed by EIT, and expressed in %. Correlation will be performed by linear regression. | up to 24 hours |