Trans-pulmonary Pressure in ARDS (T3P)

Trans-Pulmonary Pressure and Prone Position in Ards Patients

Adequate PEEP selection in ARDS is still a matter of research. The main objectives of using PEEP in ARDS are improvement in oxygenation, lung recruitment at the end of expiration, prevention of opening and closing of terminal respiratory units at minimal hemodynamic compromise. The challenge is to carry out these objectives in a patient-centered approach based on individual characteristic of lung pathophysiology. Recently, it has been proposed to set PEEP from the trans-pulmonary end-expiratory pressure. Trans-pulmonary pressure (Ptp) is obtained from the difference between airway pressure and measured esophageal pressure (Pes). Measured Pes values have been found positive in the supine position in ARDS patients, leading to negative values of Ptp. The strategy proposed by Talmor and coworkers is to adjust PEEP up to get Ptp between 0 and 10 cm H2O. Whether this strategy improves survival is under investigation. Prone position ventilation significantly improves survival in severe ARDS as demonstrated by meta-analyses and a recent multicenter randomized controlled trial.

The purpose of present project is to investigate Ptp at end-expiration in the prone position in severe ARDS. The project is centered on the question about what are the values of measured Pes in prone position. The hypothesis is that they are lower than in the supine position due to the relief of the weight of heart, mediastinum and lung and also to recruitment of dorsal lung regions. To investigate this hypothesis, measured Pes, Ptp, end-expiratory lung volume, overall lung recruitment (pressure-volume curve), and regional recruitment by using electrical impedance tomography. will be assessed in supine then in the prone position across two different strategies of PEEP selection, PEEP/FIO2 table and Talmor proposal.

Study Overview

• Status: Completed
• Conditions: Acute Respiratory Distress Syndrome
• Intervention / Treatment: Device: level of positive end expiratory pressure (Prone Proseva); Device: level of positive end expiratory pressure (Prone Talmor)

• Study Type: Interventional
• Enrollment (Actual): 32
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Lyon, France, 69004
    • Hôpital de la Croix Rousse
  • Lyon, France, 69004
    • Hopital De La Croix-Rousse

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• ARDS
• intubated
• indication of proning
• no contra-indication of proning

Exclusion Criteria:

• contra-indication to proning
• contra-indication to esophageal balloon
• proning before
• end of life decision
• legal protection
• pregnancy
• ECMO

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Prone Proseva	Device: level of positive end expiratory pressure (Prone Proseva); PEEP based on PEEP/FIO2 table vs PEEP based on the value of oesophageal pressure
Active Comparator: Prone Talmor	Device: level of positive end expiratory pressure (Prone Talmor); PEEP based on PEEP/FIO2 table vs PEEP based on the value of oesophageal pressure

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Value of the esophageal pressure measured at the end of expiration	Oesophageal pressure is measured from a balloon inserted into the mid oesophagus at the end of expiration. Its value is subtracted to the airway pressure at the end of expiration leading to trans-pulmonary pressure at the end of expiration (Ptp,ee). The measurements are done first in the supine position. In the standardized condition PEEP is set from a PEEP/FIO2 table and Ptp,ee is measured. In the Talmor approach PEEP is set to obtain Ptp,ee between 0 and 10 cm H2O. The patient is then turned to the prone position. The measurements are repeated in the same way. Then for the rest of the proning session the patient receive either level of PEEP from each strategy. Measurements are repeated at the end of the session.	6.5 hours after inclusion
Value of the esophageal pressure measured at the end of expiration	Oesophageal pressure is measured from a balloon inserted into the mid oesophagus at the end of expiration. Its value is subtracted to the airway pressure at the end of expiration leading to trans-pulmonary pressure at the end of expiration (Ptp,ee). The measurements are done first in the supine position. In the standardized condition PEEP is set from a PEEP/FIO2 table and Ptp,ee is measured. In the Talmor approach PEEP is set to obtain Ptp,ee between 0 and 10 cm H2O. The patient is then turned to the prone position. The measurements are repeated in the same way. Then for the rest of the proning session the patient receive either level of PEEP from each strategy. Measurements are repeated at the end of the session.	8.0 hours after inclusion
Value of the esophageal pressure measured at the end of expiration	Oesophageal pressure is measured from a balloon inserted into the mid oesophagus at the end of expiration. Its value is subtracted to the airway pressure at the end of expiration leading to trans-pulmonary pressure at the end of expiration (Ptp,ee). The measurements are done first in the supine position. In the standardized condition PEEP is set from a PEEP/FIO2 table and Ptp,ee is measured. In the Talmor approach PEEP is set to obtain Ptp,ee between 0 and 10 cm H2O. The patient is then turned to the prone position. The measurements are repeated in the same way. Then for the rest of the proning session the patient receive either level of PEEP from each strategy. Measurements are repeated at the end of the session.	10 hours after inclusion
Value of the esophageal pressure measured at the end of expiration	Oesophageal pressure is measured from a balloon inserted into the mid oesophagus at the end of expiration. Its value is subtracted to the airway pressure at the end of expiration leading to trans-pulmonary pressure at the end of expiration (Ptp,ee). The measurements are done first in the supine position. In the standardized condition PEEP is set from a PEEP/FIO2 table and Ptp,ee is measured. In the Talmor approach PEEP is set to obtain Ptp,ee between 0 and 10 cm H2O. The patient is then turned to the prone position. The measurements are repeated in the same way. Then for the rest of the proning session the patient receive either level of PEEP from each strategy. Measurements are repeated at the end of the session.	11.5 hours after inclusion
Value of the esophageal pressure measured at the end of expiration	Oesophageal pressure is measured from a balloon inserted into the mid oesophagus at the end of expiration. Its value is subtracted to the airway pressure at the end of expiration leading to trans-pulmonary pressure at the end of expiration (Ptp,ee). The measurements are done first in the supine position. In the standardized condition PEEP is set from a PEEP/FIO2 table and Ptp,ee is measured. In the Talmor approach PEEP is set to obtain Ptp,ee between 0 and 10 cm H2O. The patient is then turned to the prone position. The measurements are repeated in the same way. Then for the rest of the proning session the patient receive either level of PEEP from each strategy. Measurements are repeated at the end of the session.	up to 26.5 hours after inclusion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Elastance of the chest wall	The elastance of the chest wall is the change in esophageal pressure between expiration and inspiration in response to a change in lung volume. It is not substantially changed by PEEP but it is by the change in position.	6.5 hours after inclusion
Elastance of the chest wall	The elastance of the chest wall is the change in esophageal pressure between expiration and inspiration in response to a change in lung volume. It is not substantially changed by PEEP but it is by the change in position.	8.0 hours after inclusion
Elastance of the chest wall	The elastance of the chest wall is the change in esophageal pressure between expiration and inspiration in response to a change in lung volume. It is not substantially changed by PEEP but it is by the change in position.	10 hours after inclusion
Elastance of the chest wall	The elastance of the chest wall is the change in esophageal pressure between expiration and inspiration in response to a change in lung volume. It is not substantially changed by PEEP but it is by the change in position.	11.5 hours after inclusion
Elastance of the chest wall	The elastance of the chest wall is the change in esophageal pressure between expiration and inspiration in response to a change in lung volume. It is not substantially changed by PEEP but it is by the change in position.	up to 26.5 hours after inclusion
Transpulmonary pressure at the end of expiration (Ptp,ee)	In the standardized condition, either in supine or prone, the transpulmonary pressure is the difference between airway pressure and esophageal pressure at the end of expiration. In the standardized approach, PEEP is set according to a PEEP/FIO2 table and Ptp,ee is dependent on the PEEP/FIO2 table. With the Talmor approach, Ptp,ee is directly set from measurement of esophageal pressure and PEEP set according to the PEEP/FIO2 table.	6.5 hours after inclusion
Transpulmonary pressure at the end of expiration (Ptp,ee)	In the standardized condition, either in supine or prone, the transpulmonary pressure is the difference between airway pressure and esophageal pressure at the end of expiration. In the standardized approach, PEEP is set according to a PEEP/FIO2 table and Ptp,ee is dependent on the PEEP/FIO2 table. With the Talmor approach, Ptp,ee is directly set from measurement of esophageal pressure and PEEP set according to the PEEP/FIO2 table.	8.0 hours after inclusion
Transpulmonary pressure at the end of expiration (Ptp,ee)	In the standardized condition, either in supine or prone, the transpulmonary pressure is the difference between airway pressure and esophageal pressure at the end of expiration. In the standardized approach, PEEP is set according to a PEEP/FIO2 table and Ptp,ee is dependent on the PEEP/FIO2 table. With the Talmor approach, Ptp,ee is directly set from measurement of esophageal pressure and PEEP set according to the PEEP/FIO2 table.	10 hours after inclusion
Transpulmonary pressure at the end of expiration (Ptp,ee)	In the standardized condition, either in supine or prone, the transpulmonary pressure is the difference between airway pressure and esophageal pressure at the end of expiration. In the standardized approach, PEEP is set according to a PEEP/FIO2 table and Ptp,ee is dependent on the PEEP/FIO2 table. With the Talmor approach, Ptp,ee is directly set from measurement of esophageal pressure and PEEP set according to the PEEP/FIO2 table.	11.5 hours after inclusion
Transpulmonary pressure at the end of expiration (Ptp,ee)	In the standardized condition, either in supine or prone, the transpulmonary pressure is the difference between airway pressure and esophageal pressure at the end of expiration. In the standardized approach, PEEP is set according to a PEEP/FIO2 table and Ptp,ee is dependent on the PEEP/FIO2 table. With the Talmor approach, Ptp,ee is directly set from measurement of esophageal pressure and PEEP set according to the PEEP/FIO2 table.	up to 26.5 hours after inclusion
End expiratory lung volume (EELV)	EELV is the volume of gas at the end of expiration. It is measured from the ventilator by using the washout-washin technique after a small change in the FIO2. An increase in EELV can indicate recruitment (reopening of non aerated lung tissue) but some overinflation may also contribute to this increase. PEEP and prone position can increase EELV.	6.5 hours after inclusion
End expiratory lung volume (EELV)	EELV is the volume of gas at the end of expiration. It is measured from the ventilator by using the washout-washin technique after a small change in the FIO2. An increase in EELV can indicate recruitment (reopening of non aerated lung tissue) but some overinflation may also contribute to this increase. PEEP and prone position can increase EELV.	8.0 hours after inclusion
End expiratory lung volume (EELV)	EELV is the volume of gas at the end of expiration. It is measured from the ventilator by using the washout-washin technique after a small change in the FIO2. An increase in EELV can indicate recruitment (reopening of non aerated lung tissue) but some overinflation may also contribute to this increase. PEEP and prone position can increase EELV.	10 hours after inclusion
End expiratory lung volume (EELV)	EELV is the volume of gas at the end of expiration. It is measured from the ventilator by using the washout-washin technique after a small change in the FIO2. An increase in EELV can indicate recruitment (reopening of non aerated lung tissue) but some overinflation may also contribute to this increase. PEEP and prone position can increase EELV.	11.5 hours after inclusion
End expiratory lung volume (EELV)	EELV is the volume of gas at the end of expiration. It is measured from the ventilator by using the washout-washin technique after a small change in the FIO2. An increase in EELV can indicate recruitment (reopening of non aerated lung tissue) but some overinflation may also contribute to this increase. PEEP and prone position can increase EELV.	up to 26.5 hours after inclusion
Regional lung ventilation	regional ventilation is measured by using electrical impedance tomography. The change in thoracic impedance in response to electric current of small amplitude (50 ms) is proportional to amount of air among other factors, which are less important in magnitude as compared to air. The lung is sampled into anterior and posterior regions. The location of better aeration with PEEP and position will be mapped.	6.5 hours after inclusion
Regional lung ventilation	regional ventilation is measured by using electrical impedance tomography. The change in thoracic impedance in response to electric current of small amplitude (50 ms) is proportional to amount of air among other factors, which are less important in magnitude as compared to air. The lung is sampled into anterior and posterior regions. The location of better aeration with PEEP and position will be mapped.	8.0 hours after inclusion
Regional lung ventilation	regional ventilation is measured by using electrical impedance tomography. The change in thoracic impedance in response to electric current of small amplitude (50 ms) is proportional to amount of air among other factors, which are less important in magnitude as compared to air. The lung is sampled into anterior and posterior regions. The location of better aeration with PEEP and position will be mapped.	10 hours after inclusion
Regional lung ventilation	regional ventilation is measured by using electrical impedance tomography. The change in thoracic impedance in response to electric current of small amplitude (50 ms) is proportional to amount of air among other factors, which are less important in magnitude as compared to air. The lung is sampled into anterior and posterior regions. The location of better aeration with PEEP and position will be mapped.	11.5 hours after inclusion
Regional lung ventilation	regional ventilation is measured by using electrical impedance tomography. The change in thoracic impedance in response to electric current of small amplitude (50 ms) is proportional to amount of air among other factors, which are less important in magnitude as compared to air. The lung is sampled into anterior and posterior regions. The location of better aeration with PEEP and position will be mapped.	up to 26.5 hours after inclusion

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon

Publications and helpful links

General Publications

• Mezidi M, Parrilla FJ, Yonis H, Riad Z, Bohm SH, Waldmann AD, Richard JC, Lissonde F, Tapponnier R, Baboi L, Mancebo J, Guerin C. Effects of positive end-expiratory pressure strategy in supine and prone position on lung and chest wall mechanics in acute respiratory distress syndrome. Ann Intensive Care. 2018 Sep 10;8(1):86. doi: 10.1186/s13613-018-0434-2.

Study record dates

Study Major Dates

• Study Start: January 1, 2016
• Primary Completion (Actual): April 13, 2017
• Study Completion (Actual): April 13, 2017

Study Registration Dates

• First Submitted: April 3, 2015
• First Submitted That Met QC Criteria: April 13, 2015
• First Posted (Estimated): April 14, 2015

Study Record Updates

• Last Update Posted (Estimated): September 11, 2025
• Last Update Submitted That Met QC Criteria: September 5, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: mechanical ventilation; ARDS; prone position; PEEP
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Respiration Disorders; Respiratory Distress Syndrome
• Other Study ID Numbers: 69HCL14-0333