Acute Respiratory Distress Syndrome
Conditions
Brief summary
Prospective, physiological study to systematically assess the effects of high positive end-expiratory pressure (PEEP) with and without inspiratory synchronization in patients with moderate to severe acute respiratory distress syndrome (ARDS) exhibiting intense inspiratory effort while on assisted ventilation.
Detailed description
This prospective, physiological, randomized, cross-over study will be conducted in the 20-bed general ICU of the Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy. Patients with ARDS will be screened for eligibility. ARDS will be defined according to the Berlin Definition. Intubated patients fulfilling ARDS criteria, undergoing assisted ventilation as per clinical decision and exhibiting intense inspiratory effort (occlusion pressure equal or greater than 13 cmH2O) will be enrolled. Patients will be placed in a 30°-45° head up position during all study phases. According to our institution protocol, pressure support setting will be selected by the attending physician to target a predefined tidal volume range of 6-8 mL/kg of predicted body weight (PBW) (female PBW \[kg\] = 45.5 + 0.91 \[cm of height - 152.4\]; male PBW \[kg\] = 50 + 0.91 \[cm of height - 152.4\]).The lowest pressure support level allowed will be 7 cmH2O, even if Vt \<8 ml/Kg PBW is not achieved. In each patient, four different ventilator settings will be applied in a random order. Each step will last 45 minutes.
Interventions
OTHERMechanical Ventilation
Respiratory support through mechanical ventilator
Sponsors
Fondazione Policlinico Universitario Agostino Gemelli IRCCS
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* (a) ARDS according to the Berlin definition (ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) ≤ 300 mmHg); * (b) assisted ventilation, as prescribed by the attending physician * (c) intense inspiratory effort, defined as a negative deflection in the airway pressure equal or greater than 13 cmH2O in the first breath recorded during an end-expiratory occlusion
Exclusion criteria
Pregnancy, clinically documented barotrauma, contraindication to electrical impedance tomography (EIT) use (e.g., presence of pacemaker or automatic implantable cardioverter defibrillator), impossibility to place the EIT belt in the right position (e.g., presence of surgical wounds dressing), and any contraindication to the insertion of a nasogastric tube (eg, recent upper-gastrointestinal surgery, esophageal varices), chest tubes with active air leaks, fever.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Inspiratory effort | 45 minutes | The negative deflection in esophageal pressure during inspiration |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Respiratory mechanics | 45 minutes | Respiratory mechanics assessed by end-inspiratory occlusion |
| Lung mechanics | 45 minutes | Respiratory mechanics assessed by esophageal pressure monitoring during an end-inspiratory occlusion |
| Work of breathing | 45 minutes | Esopghageal pressure pressure-time product per minute |
| Respiratory rate | 45 minutes | Respiratory rate per minute |
| Regional Tidal volume distribution | 45 minutes | Distribution of tidal volume in the different lung zones, assessed by electrical impedance tomography |
| Oxygenation | 45 minutes | Ratio of PaO2 to FiO2 |
| Pendelluft | 45 minutes | Occurrence of intra-tidal shift of gas within different lung regions at beginning of inspiration |
| Carbon dioxide | 45 minutes | Blood carbon dioxide, as assessed by arterial blood gas analysis |
| Tidal volume | 45 minutes | Average Tidal volume received by the patient |
| Dynamic transpulmonary driving pressure | 45 minutes | The average positive swing in transpulmonary driving pressure during tidal breathing |
| Alveolar recruitment | 45 minutes | Change in end-expiratory lung impedance, assessed by electrical impedance tomography |
Countries
Italy
Outcome results
None listed