Comparison of Different Methods to Calculate Pendelluft by Electrical Impedance Tomography in Patients Undergoing Invasive Mechanical Ventilation Under Pressure Support Mode
Trial Snapshot
- Phase
- Not Applicable
- Status
- Recruiting
- Enrollment
- 15
- Locations
- 1
- Primary Endpoint
- 3. Magnitude of respiratory effort
Study Overview
Brief Summary
The Pendelluft phenomenon is an important cause of lung damage in spontaneously breathing mechanically ventilated patients since it considerably increases the stress on the lung parenchyma in the dependent areas. It can result in a local driving pressure up to three times higher than the global driving pressure. The measurement of Pendelluft is still uncertain in the literature, and although various methods have been proposed, not all have the same meaning in terms of pulmonary overstress and overstrain. This study proposes a comparative analysis of different ways to calculate and estimate the stress imposed on the lung parenchyma by Pendelluft in terms of regional volume and local driving pressure through electrical impedance tomography.
Detailed Description
Respiratory mechanics and regional ventilation will be monitored by electrical impedance tomography (Enlight 1800 and 2100, Timpel). Esophageal and gastric pressures will be obtained by placing an esophageal/gastric balloon cathether (Nutrivent ®), validation concerning position will be done through modified Baydur maneuver (delta esophageal/delta airway pressure = 0.8-1.2). The hardware Pneumodrive will be used to inflate the balloon and store the airway, gastric and esophageal pressures.
Initially the patients will be monitored with EIT for aproximately 30 minutes after pletismography stabilization. Then, an arterial blood-gas sample shall be collected for analysis. Next, three expiratory and three inspiratory pauses of at least two seconds will be realized with intervals of eight respiratory cycles between them, allowing plateau pressure to be recorded and global and regional driving pressure to be estimated. All this data will be stored for later analysis. The same procedures and measurements shall be made sequentially with a 50% higher pressure support and with a 50% lower pressure support.
Study Design
- Study Type
- Interventional
- Allocation
- Na
- Intervention Model
- Single Group
- Primary Purpose
- Diagnostic
- Masking
- None
Masking Description
None (Open Label)
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Patients under invasive mechanical ventilation intubated due to respiratory failure in pressure support mode (weaning phase)
Exclusion Criteria
- •Age less than 18 years; sedation or neuromuscular blockade; absence of respiratory effort; contraindications to esophageal balloon cathether positioning or electrical impedance tomography belt positioning; presence of pneumothorax or active air leaks; hemodynamic instability; absence of informed consent.
Arms & Interventions
Pressure Support Variation
Patients shall be submitted to pressure support variation in a randomly assigned manner. First 30 minutes after plethysmogram stabilization shall be recorded at clinical pressure support. Next, a blood gas sample shall be collected by a nurse or a physician, and three inspiratory pauses of at least 2 seconds shall be performed in between eight respiratory cycles. Next three expiratory pauses shall be performed in between eight respiratory cycles. All data shall be recorded and analysed offline. Subsequently the same sequence of events shall be performed at a 50% higher pressure support and at a 50% lower pressure support. The sequence in which this will happen shall be randomly assigned (first lower PS vs higher PS or first higher PS vs lower PS).
Intervention: Pressure Support Variation and Calculation of Respiratory Mechanics (Other)
Outcomes
Primary Outcomes
3. Magnitude of respiratory effort
Time Frame: During 30 minutes after plethysmogram stabilization at clinical PS, during 30 minutes at 50% lower PS, and during 30 minutes at 50% higher PS
Respiratory effort shall be estimated through expiratory pauses and though recording of esophageal pressure at different pressure support levels. These data shall be compared to Pendelluft magnitude according to the different methods of calculation
1. Magnitude of Pendelluft
Time Frame: During 30 minutes after plethysmogram stabilization at clinical PS, during 30 minutes at 50% lower PS, and during 30 minutes at 50% higher PS
Three differents methods of estimating magnitude of Pendelluft shall be compared using a software based on electrical impedance tomography monitoring (Enlight 2100, Timpel Medical®, Brazil)
2. Magnitude of Pendelluft during inspiratory pause
Time Frame: During 30 minutes after plethysmogram stabilization at clinical PS, during 30 minutes at 50% lower PS, and during 30 minutes at 50% higher PS
One of the methods of Pendelluft measurement shall be performed during an inspiratory pause for comparison with a normal cycle (without pause).
Secondary Outcomes
No secondary outcomes reported