Driving Pressure Guided VT in ARDS Patients

Study Overview
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Brief Summary
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A prospective physiologic study, in participants with COVID-19 related or non-COVID-19 related acute respiratory distress syndrome (ARDS) requiring mechanical ventilation less than 48 hours. The investigators assessed the effect of different tidal volume guided by different levels of driving pressure on ventilation inhomogeneity and ventilation/perfusion mismatch by electrical impedance tomography (EIT) in supine and/or prone position.

Detailed Description
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Once enrolled, an EIT dedicated belt containing 16 electrodes was placed around the participant's chest at the fifth or sixth intercostal space and connected it to an EIT monitor (PulmoVista 500; Dräger Medical GmbH, Lübeck, Germany). Data were collected in the enrolled day (Day 1),Day 3 and Day 7 including demographic and anthropometric data, a baseline arterial blood gas measurement, and ventilation parameters including type of supplemental oxygen, respiratory rate, fractional concentration of oxygen in inspired air (FiO2). Volume control mode without spontaneous breathing, PEEP will be set according to best respiratory compliance method, and tidal volume (VT) will be set to reach three levels of driving pressure (High 14-15cmH2O, moderate 10-11 cmH2O, and low 7-8 cmH2O). Each level of VT was maintained 10 minutes in supine and/or prone position. In the last minutes of each phase，the participants received instructions of end expiratory occlusion lasting at least 10 seconds and, 1 seconds after the start, a bolus of 10 mL of 10% NaCl solution was injected via the central venous catheter. Clinical data and outcome will be collected.

Official Title
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Safety of Driving Pressure-guided Tidal Volume Setting in ARDS Patients-From the Perspective of EIT

Conditions
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ARDS

Intervention / Treatment
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* Device: driving pressure guided tidal volume


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: aged ≥ 18 years old admitted to intensive care unit with a moderate to severe ARDS invasive mechanical ventilation Exclusion Criteria: contraindications for prone position ventilation Past chronic respiratory diseases (long-term family oxygen therapy for chronic respiratory diseases such as pulmonary fibrosis or COPD) New York Heart Association class above II gave written or witnessed verbal informed consent. Contraindications to the use of EIT (e.g., presence of pacemaker or chest surgical wounds dressing) or prone position (as decided by the attending physician) Impending ECMO (on the basis of clinical judgment, including clinical and physiological parameters).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: testing arm<br>ventilated with different VT using an EIT monitor (PulmoVista® 500, Dräger, Lübeck, Germany) | Device: driving pressure guided tidal volume<br>* Volume control mode without spontaneous breathing, PEEP will be set according to best respiratory compliance method, and tidal volume (VT) will be set to reach three levels of driving pressure (High 14-15cmH2O, moderate 10-11 cmH2O, and low 7-8 cmH2O). Each level of VT was maintained 10 minutes in supine and/or prone position.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| regional compliance using EIT | regional compliance using EIT | Day 1 | 
| regional ventilation | regional ventilation using EIT | Day 1 | 
| regional perfusion | regional perfusion using EIT | Day 1 | 
| Region-ventilation-delay | Region-ventilation-delay using EIT | Day 1 | 
| driving pressure | measurement as one index of respiratory compliance | Day 3 | 
| the number of regional lung ventilation | regional ventilation measuring by EIT | Day 3 | 
| the number of regional lung perfusion | regional perfusion measuring by EIT | Day 3 | 
| the number of region-ventilation-delay (RVD) | the RVD measuring by EIT | Day 3 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Value of ventilation-perfusion (V/Q) mismatch | V/Q mismatch was quantified as the percentage of pixels that were classified as ventilated but not perfused (dead space fraction) plus the percentage of those perfused but not ventilated (shunt fraction). | Day 1 | 
| Value of ventilation-perfusion (V/Q) mismatch | V/Q mismatch was quantified as the percentage of pixels that were classified as ventilated | Day 3 | 
| Value of ventilation-perfusion (V/Q) mismatch | V/Q mismatch was quantified as the percentage of pixels that were classified as ventilated | Day 7 | 
| The Global Inhomogeneity (GI) index | higher values indicating less homogenous ventilation | Day 1 | 
| The Global Inhomogeneity (GI) index | higher values indicating less homogenous ventilation | Day 3 | 
| The Global Inhomogeneity (GI) index | higher values indicating less homogenous ventilation | Day 7 | 
| Blood gas | PaO2 | Day 1 | 
| Ventilation free day | ventilation free day in day 28 | Day 28 | 
| 28 day mortality | death in day 28 | Day 28 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ARDS, ventilation and perfusion matching, ventilation inhomogeneity