ARDS
Conditions
Brief summary
The purpose of this study is to demonstrate that mechanical ventilation guided by the diaphragm EMG signal (also know as neurally adjusted ventilatory assist \[NAVA\]) is superior compared to pressure support and pressure control ventilation.
Interventions
DEVICEMechanical ventilation
The mechanical ventilator is set to different ventilation modes as described in the individual arms.
Sponsors
University Medical Center Nijmegen
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
* intubated, mechanically ventilated patients * meeting criteria for ARDS * mean arterial blood pressure \> 65 mmHg (with or w/o vasopressors)
Exclusion criteria
* pregnancy * increased intracranial pressure * contra-indication naso-gastric tube * diagnosed neuro-muscular disorder * recent (\<12 hours) use of muscle relaxants * exclusion from sedation interruption protocol as used in our institution * open chest or- abdomen * very high inspiratory flow rate during supported ventilation * inability to obtain informed consent
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pressure-time product of the diaphragm | average of last 15 minutes of each study arm | The pressure-time product of the transdiaphragmatic pressure (Pdi) during inspiration is obtained for each breath by multiplying the corresponding mean inspiratory Pdi signal above the end-expiratory baseline by the inspiration time. Breath-by-breath data are ensemble-averaged over the last 15 minutes of each study arm. |
| Patient - ventilator asynchrony index | average of last 15 minutes of each study arm | Ventilator asynchrony is determined as the sum of the triggering and cycling-off delays per breath, expressed as a percentage of the total breath duration. The trigger delay is measured as the time difference between the onset of neural inspiration and the ventilator inspiratory flow, and the cycling delay as the time difference between the end of neural inspiration and the end of ventilator inspiratory flow. Breath-by-breath data are ensemble-averaged over the last 15 minutes of each study arm. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Transpulmonary pressure | average of last 15 minutes of each study arm | Transpulmonary pressure is determined as the difference between mouth pressure and esophageal pressure during inspiration. Breath-by-breath data are ensemble-averaged over the last 15 minutes of each study arm. |
| Transdiaphragmatic pressure | average of last 15 minutes of each study arm | Transdiaphragmatic pressure is determined as the difference between gastric pressure and esophageal pressure during inspiration. Breath-by-breath data are ensemble-averaged over the last 15 minutes of each study arm. |
| Oxygenation index | at the end of each study arm | Oxygenation index is determined as the ratio between arterial oxygen tension and fraction of inspired oxygen. Arterial oxygen tension is obtained at the end of each study arm. |
| Dead space ventilation | average of last 15 minutes of each study arm | Dead space ventilation is determined each breath using the Bohr equation: (PaCO2-PeCO2/PaCO2)\*Vt. Here Vt is tidal volume, PaCO2 is the partial pressure of carbon dioxide in the arterial blood, and PeCO2 is the end-tidal carbon dioxide tension in the expired air. Breath-by-breath data are ensemble-averaged over the last 15 minutes of each study arm. |
Countries
Netherlands
Outcome results
None listed