Description of Respiratory Mechanics in Patients With SARS-CoV-2 Associated ARDS

Study Overview
=================
Brief Summary
-----------------
The aim of this observationnal study is to describe respiratory mechanics and lung recruitement in patients with SARS-CoV-2 Associated Acute Respiratory Distress Syndrome who underwent invasive ventilation on endotracheal tube, admitted to the medical ICU of Angers university hospital . Statics measurements of respiratory system compliance were performed at 2 differents levels of PEEP (15 cmH2O and 5 cmH2O). The recruited volume is computed as the difference between the volume expired from PEEP 15 to 5 cmH2O and the volume predicted by compliance at PEEP 5 cmH2O . The recruitment-to-Inflation (R/I) ratio (i.e. the ratio between the recruited lung compliance and CRS at PEEP 5 cmH2O) is used to assess lung recruitability. A R/I ratio value higher than or equal to 0.5 was used to define highly recruiter patients.

Detailed Description
-----------------
The investigators perform an observational prospective study in patients admitted to medical ICU in Angers University hospital with a confirmed COVID 19 pneumonia and who require invasive ventilation on endotracheal tube. Participants receive initially deep sedation and neuromuscular blockers for 24 hours and are ventilated in volume-controlled mode with a tidal volume of 6 mL/kg of predicted body weight, a constant inspiratory flow of 60 L/minute and a respiratory rate adjusted to maintain pH above 7.35 when possible. A PEEP decremental trial from 15 to 5 cmH2O was performed (15 minutes by step). Esophageal pressure monitoring and electrical impedance tomography (EIT) are collected if available. Arterial blood gases and respiratory mechanics are measured at the end of each step. The recruitment-to-Inflation (R/I) ratio (i.e. the ratio between the recruited lung compliance and CRS at PEEP 5 cmH2O) is used to assess lung recruitability. A R/I ratio value higher than or equal to 0.5 is used to define highly recruiter patients. By the end of the recording time, a low-flow (5 L/min) inflation from PEEP 5 cmH2O (tidal volume = 6ml/kg PBW) is then performed after a prolonged expiration to identify a potential airway closure and the corresponding airway opening pressure (AOP). Investigators perform these measurements at day 1, day 5 and day 10 from ICU admission if participants still require controlled ventilation. The investigators also collect clinical data about each participant (past medical history, ICU discharge, hospital discharge, date of death, ventilator acquired pneumonia, thromboembolic event, use of NO, use of ECMO or renal replacement therapy).

Official Title
-----------------
Evaluation of Respiratory Mechanics and Lung Recruitment in Patients With SARS-CoV-2 Associated Acute Respiratory Distress Syndrome

Conditions
-----------------
Acute Respiratory Distress Syndrome, COVID

Intervention / Treatment
-----------------
* Other: PEEP trial


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: ARDS criteria according to Berlin classification criteria Invasive mechanical ventilation on endotracheal tube SARS Cov-2 infection Exclusion Criteria: pneumothorax

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: PEEP trial|Measurement of Recruitment-to-Inflation Ratio|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recruitment-to Inflation ratio (R/I ratio) | no unit | Day 1 | 
| Recruitment-to Inflation ratio (R/I ratio) | no unit | Day 5 | 
| Recruitment-to Inflation ratio (R/I ratio) | no unit | Day 10 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PaO2/FiO2 (mmHg) | Arterial blood gases | Day 1 | 
| PaO2/FiO2 (mmHg) | Arterial blood gases | Day 5 | 
| PaO2/FiO2 (mmHg) | Arterial blood gases | Day 10 | 
| Lung volume recruited (VRec) | mL | Day 1 | 
| Lung volume recruited (VRec) | mL | Day 5 | 
| Lung volume recruited (VRec) | mL | Day 10 | 
| Plateau pressure (cm H2O) | Obtained by inspiratory pause of 5 seconds | Day 1 | 
| Plateau pressure (cm H2O) | Obtained by inspiratory pause of 5 seconds | Day 5 | 
| Plateau pressure (cm H2O) | Obtained by inspiratory pause of 5 seconds | Day 10 | 
| Oesophagal pressure (cm H2O) |  | Day 1 | 
| Oesophagal pressure (cm H2O) |  | Day 5 | 
| Oesophagal pressure (cm H2O) |  | Day 10 | 
| weight (Kg) |  | Day 1 | 
| weight (Kg) |  | Day 5 | 
| weight (Kg) |  | Day 10 | 
| urine output (mL) |  | day 1 | 
| urine output (mL) |  | day 5 | 
| urine output (mL) |  | day 10 | 
| serum creatinine (Umo/L) |  | day 1 | 
| serum creatinine (Umo/L) |  | day 5 | 
| serum creatinine (Umo/L) |  | day 10 | 
| Mean arterial pressure (mmHg) |  | day 1 | 
| Mean arterial pressure (mmHg) |  | day 5 | 
| Mean arterial pressure (mmHg) |  | day 10 | 
| Peak Pressure (cm H2O) |  | Day 1 | 
| Peak Pressure (cm H2O) |  | Day 5 | 
| Peak Pressure (cm H2O) |  | Day 10 | 
| PEEP total (cm H2O) | Obtained by expiratory pause of 5 seconds | Day 1 | 
| PEEP total (cm H2O) | Obtained by expiratory pause of 5 seconds | Day 5 | 
| PEEP total (cm H2O) | Obtained by expiratory pause of 5 seconds | Day 10 | 
| PEP Set (cm H2O) |  | Day 1 | 
| PEP Set (cm H2O) |  | Day 5 | 
| PEP Set (cm H2O) |  | Day 10 | 
| Height (cm) |  | Day 1 | 
| Airway pening pressure (cm H2O) |  | day 1 | 
| Airway pening pressure (cm H2O) |  | day 5 | 
| Airway pening pressure (cm H2O) |  | day 10 | 
| Expired volume in PEEP setted at 15 cmH2O (mL) | respiratory rate decreased to 10 /min, expired tidal volume displayed by the ventilator is noted | Day 1 | 
| Expired volume in PEEP setted at 15 cmH2O (mL) | respiratory rate decreased to 10 /min, expired tidal volume displayed by the ventilator is noted | Day 5 | 
| Expired volume in PEEP setted at 15 cmH2O (mL) | respiratory rate decreased to 10 /min, expired tidal volume displayed by the ventilator is noted | Day 10 | 
| Expired volume in PEEP setted at 5 cmH2O (mL) | respiratory rate decreased to 10 /min, expired tidal volume displayed by the ventilator is noted | Day 1 | 
| Expired volume in PEEP setted at 5 cmH2O (mL) | respiratory rate decreased to 10 /min, expired tidal volume displayed by the ventilator is noted | Day 5 | 
| Expired volume in PEEP setted at 5 cmH2O (mL) | respiratory rate decreased to 10 /min, expired tidal volume displayed by the ventilator is noted | Day 10 | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
COVID, Acute Respiratory Distress Syndrome, SARS CoV-2, Lung recruitability, Respiratory mechanics