NCT06494215

Comparison of Different Methods to Calculate Pendelluft by Electrical Impedance Tomography in Mechanically Ventilated Patients

Comparison of Different Methods to Calculate Pendelluft by Electrical Impedance Tomography in Patients Undergoing Invasive Mechanical Ventilation Under Pressure Support Mode

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 15 (estimated)
• Sponsor: University of Sao Paulo General Hospital · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

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.

Conditions

• Asynchrony, Patient-Ventilator
• ARDS
• Respiratory Insufficiency
• Respiratory Effort-Related Arousal | Patient | Respiratory Measures and Ventilator Management

Interventions

Type	Name	Description
OTHER	Pressure Support Variation and Calculation of Respiratory Mechanics	Patients will be submitted to different levels of pressure support (PS) in a randomly assigned order. First 30 minutes shall be recorded at the clinical PS. Next, blood gas samples shall be collected. Subsequently, three inspiratory pauses of at least 2 seconds shall be performed with an interval of at least 8 respiratory cycles between them. The same shall be performed with three expiratory pauses. Next, the PS shall be varied to 50% less or 50% more than clinical PS (based on randomization) and the same procedures shall be performed after 30 minutes of data recording (blood gas sample collection, inspiratory and expiratory pauses). All data shall be analyzed offline using a software that will be able to compare three different methods to calculate Pendelluft magnitude based on the literature. After completion of the protocol, ventilatory parameters shall be returned to the original settings. If the patient becomes tachypneic during lower PS, the protocol shall be interrupted.

Timeline

• Start date: 2024-06-11
• Primary completion: 2025-06-11
• Completion: 2025-06-11
• First posted: 2024-07-10
• Last updated: 2024-07-10

Locations

1 site across 1 country: Brazil