About this trial
This multicenter, physiological, observational study hypothesizes that in moderate to severe ARDS, trunk inclination unloads the chest wall, but its impact on lung mechanics depends on PEEP levels and lung recruitability.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Intubated moderate and severe ARDS according to the Berlin definition (PaO2/FiO2 ratio <= 200 mmHg)
Under continuous sedation with or without paralysis
Disqualifiers
Age <18 years
Bronchopleural fistula
Pure COPD exacerbation
Contraindication to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode belt placement)
Trial population
Intubated mechanically ventilated ARDS patients will be considered for enrollment
Trial design
Other
Prospective
Treatments tested in this trial
Specific lung recruitment maneuvers and decremental PEEP steps
Other interventionSpecific lung recruitment maneuvers will be performed to measure the potential for lung recruitment. Followed by a decremental PEEP steps to determine lung mechanics at different PEEP levels. These process will be repeated when patients change to another position. Electrical impedance tomography signals, synchronized signals of airway pressure and flow, esophageal pressure will be recorded continuously.
Treatment groups
Trial outcomes
Primary outcomes
Transpulmonary driving pressure (ΔPL)
Physiological parameter calculated as end-inspiratory transpulmonary pressure minus end-expiratory transpulmonary pressure. Transpulmonary pressure is monitored continuously in real time using an esophageal balloon catheter.
Secondary outcomes
Percentage of overdistension and collapse
Global and regional information, derived from electrical impedance tomography (EIT) through a decremental PEEP trial from 24cmH2O to 6cmH2O. Collapse and overdistention were calculated assuming zero collapse at PEEP = 24 cm H2O (or lower if not tolerated) and zero overdistention at PEEP = 6 cm H2O, according to a method proposed by Costa. Therefore, the reported percentages of collapse and overdistension refer to relative percentages of modifiable collapse and overdistension.
Lung compliance (Clung)
Physiological parameter calculated as the tidal volume divided by the transpulmonary driving pressure (ΔPL). Global lung compliance uses tidal volume measured by the ventilator. Regional lung compliance uses regional tidal volume derived from electrical impedance tomography (EIT) regional ventilation distribution. Transpulmonary pressure is monitored continuously in real time using an esophageal balloon catheter.
Respiratory system compliance (Crs)
Physiological parameter calculated as tidal volume divided by the driving pressure (driving pressure = plateau airway pressure minus total positive end-expiratory pressure). Tidal volume is measured by the ventilator. Plateau pressure and total PEEP are obtained during end-inspiratory and end-expiratory occlusive pauses on the ventilator, respectively.
Chest wall compliance (Ccw)
Physiological parameter calculated as tidal volume divided by chest wall driving pressure, where chest wall driving pressure is the change in esophageal pressure between end-inspiration and end-expiration. Tidal volume is measured by the ventilator. Esophageal pressure is monitored continuously in real time using an esophageal balloon catheter.
Sponsors and contacts
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