Mechanical ventilation in ARDS requires protective ventilation and PEEP. Airway closer has to be overcome to reduce lung heterogeneity, AOP is measured globally with a ventilator PV curve without PEEP. EIT derived PV curve is another method that could determine heterogeneity of AOP between both lung. This study aims to determine whether AOP measured with EIT derived PV curve is similar to AOP on the ventilator PV curve and see if AOP is different between lungs. If airway closer is higher on one lung, global AOP on the ventilator PV curve probably estimates the other lung.
Scientific justification:
In one third of Acute Respiratory Distress Syndrome (ARDS), tidal inflation starts when an
airway opening pressure (AOP) is overcome 1. This phenomenon of airway closure has been
underestimated and misinterpreted. Recent research demonstrates that airway closure is a
matter of concern as it participates to the heterogeneity of tidal ventilation distribution
and it can amplify Ventilator Induced Lung Injury (VILI). The detection of airway closure and
the measurement of AOP need a pressure volume curve at low flow and no positive end
expiratory pressure (PEEP). However, this will measure a global AOP whereas ventilation is
heterogeneous between the two lungs in ARDS. EIT is an interesting monitoring tool that could
allow EIT derived PV curve construction with measurement of regional AOP2, right vs left
lung. The investigor wants to compare global AOP on ventilator PV curve with left and right
lung EIT derived AOP measurements. Recent Covid 19 pneumoniae is responsible for numerous
acute respiratory distress with severe hypoxemia. Phenotypes are discussed with differences
in terms of respiratory mechanics. It is therefore important to describe specifically Covid
19 patients with ARDS.
Strategy description:
Patients with moderate to severe ARDS equipped with EIT will be included. PEEP will be
titrated with PEEP-EIT method. A classical low flow PV curve from without PEEP will be done,
the acquisition of EIT data during PV curve will be analysed secondary with a dedicated
software. PV curve on the ventilator will be analysed to determine if there is an airway
closer phenomenon. Reconstruction of EIT derived PV curve will determine, first: if there is
a left and/or right lung airway closer phenomenon, and second: the value of each lung AOP.
Follow up description:
- Measurement of ventilator pressures, flow and volume before/during/after the PV curve.
- Last chest X Ray and arterial blood gases,
- Haemodynamic data.
- Inclusion criteria:
- Patients hospitalized in the ICU and who suffered moderate to severe ARDS (Berlin
criteria) equipped EIT over the age of 18.
- Exclusion criteria:
- Broncho-pleural leaks
- ECMO
- Pregnant or breastfeeding woman.
- Guardianship or curatorship
- Deprived of liberty
- No health insurance
- Impossibility to correctly position the EIT belt (e.g., dressings, chest
drainage, etc.)
- Contra indications to EIT (e.g., implantable cardiac defibrillator, pacemaker,
instable spinal lesions)
HOPITAL HAUT-LEVEQUE - Service Réanimation thoracique
Pessac, France