Physiological Effects of External PEEP in Controlled Mechanical Ventiated Patients With autoPEEP

Effects of External PEEP in Controlled Mechanical Ventiated Patients With autoPEEP. A Physiological Study

This experimental physiologic study is conducted to determine the effect of different mechanical ventilation settings (in terms of positive end-expiratory pressure) on patients receiving mechanical ventilation with expiratory flow obstruction and autoPEEP. The main question it aims to answer In patients with autoPEEP, what is the effect of applying external PEEP on gas exchange and the lung emptying pattern in patients with total ventilatory support? Participants must comply:

- Age > 17 years.

• Invasive mechanical ventilation (endotracheal tube or tracheostomy) in controlled mode, with SpO2 > 90%, for more than 12 hours.
• No contraindications for abdominal compression.
• Presence of autoPEEP greater than 3 cmH2O measured in mechanical ventilation with total support and ZEEP.
• Total mechanical respiratory support, without respiratory muscle activity (inspiratory or expiratory).

Study Overview

• Status: Active, not recruiting
• Conditions: Obstructive Airway Diseases
• Intervention / Treatment: Other: PEEP titration

Detailed Description

The study includes patients with controlled mechanical ventilation and autoPEEP. By programming different levels of external PEEP, its effect on respiratory mechanics, gas exchange, and pulmonary emptying constants will be determined. Once included in the study, participants remain on the established mechanical ventilation schedule.Subsequently, they will remain for 5 minutes at each programmed PEEP level, during which the variables under study will be recorded. They will remain at 3 PEEP levels for 15 minutes before taking arterial blood gas samples. The variables under study will be recorded and stored in a respiratory monitor and an electrical impedance tomograph, and subsequently analyzed offline.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Argentina
  • Buenos Aires, Argentina
    • Hospital Santojanni

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Age > 17 years. Invasive mechanical ventilation (endotracheal tube or tracheostomy) in controlled mode, with SpO2 > 90%, for more than 12 hours.

No contraindications for abdominal compression. AutoPEEP greater than 3 cmH2O measured during mechanical ventilation with full support and ZEEP.

Full mechanical respiratory support, with no respiratory muscle activity (inspiratory or expiratory).

-

Exclusion Criteria:

Cardiovascular instability: Hypotension (MAP < 60 mmHg), hypertension (SBP > 180 mmHg), heart rate < 40 bpm or > 150 bpm.

Refusal to participate in the study by a family member (without signed informed consent).

Evidence of air leak: Pneumothorax, subcutaneous emphysema, pneumomediastinum. Intracranial hypertension (ICP > 20 mmHg). Pregnant patient. Body Mass Index greater than 40 kg/m².

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PEEP titration	Other: PEEP titration; External PEEP will be increased by 3 cmH₂O, from 0 to 15 cmH₂O.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To evaluate the expiratory time constant as a function of external PEEP.	Methodology: the expiratory pattern is defined through the expiratory time constant at different PEEP levels relative to the reference (ZEEP).	1 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To evaluate thel effect of external PEEP in gas exchange respect to reference (ZEEP)	Gas exchange: Methodology: Arterial blood gas samples (PaO2 and PaCO2 in mmHg) are taken after a 15-minute stability period at three time points: without external PEEP (reference), and 3 cmH2O below and 3 cmH2O above final PEEP.	1 hour

Collaborators and Investigators

• Sponsor: Hospital Donación Francisco Santojanni

Publications and helpful links

General Publications

• Pepe PE, Marini JJ. Occult positive end-expiratory pressure in mechanically ventilated patients with airflow obstruction: the auto-PEEP effect. Am Rev Respir Dis. 1982 Jul;126(1):166-70. doi: 10.1164/arrd.1982.126.1.166.
• Lourens MS, van den Berg B, Aerts JG, Verbraak AF, Hoogsteden HC, Bogaard JM. Expiratory time constants in mechanically ventilated patients with and without COPD. Intensive Care Med. 2000 Nov;26(11):1612-8. doi: 10.1007/s001340000632.
• Roesthuis LH, van der Hoeven JG, Guerin C, Doorduin J, Heunks LMA. Three bedside techniques to quantify dynamic pulmonary hyperinflation in mechanically ventilated patients with chronic obstructive pulmonary disease. Ann Intensive Care. 2021 Dec 4;11(1):167. doi: 10.1186/s13613-021-00948-9.
• Lemyze M, Favory R, Alves I, Perez T, Mathieu D. Manual compression of the abdomen to assess expiratory flow limitation during mechanical ventilation. J Crit Care. 2012 Feb;27(1):37-44. doi: 10.1016/j.jcrc.2011.05.011. Epub 2011 Jul 27.
• Dawson SV, Elliott EA. Wave-speed limitation on expiratory flow-a unifying concept. J Appl Physiol Respir Environ Exerc Physiol. 1977 Sep;43(3):498-515. doi: 10.1152/jappl.1977.43.3.498.
• Valta P, Corbeil C, Lavoie A, Campodonico R, Koulouris N, Chasse M, Braidy J, Milic-Emili J. Detection of expiratory flow limitation during mechanical ventilation. Am J Respir Crit Care Med. 1994 Nov;150(5 Pt 1):1311-7. doi: 10.1164/ajrccm.150.5.7952558.
• HYATT RE. The interrelationships of pressure, flow, and volume during various respiratory maneuvers in normal and emphysematous subjects. Am Rev Respir Dis. 1961 May;83:676-83. doi: 10.1164/arrd.1961.83.5.676. No abstract available.
• Kimball WR, Leith DE, Robins AG. Dynamic hyperinflation and ventilator dependence in chronic obstructive pulmonary disease. Am Rev Respir Dis. 1982 Dec;126(6):991-5. doi: 10.1164/arrd.1982.126.6.991.
• Jonson B, Nordstrom L, Olsson SG, Akerback D. Monitoring of ventilation and lung mechanics during automatic ventilation. A new device. Bull Physiopathol Respir (Nancy). 1975 Sep-Oct;11(5):729-43.
• Bergman NA. Intrapulmonary gas trapping during mechanical ventilation at rapid frequencies. Anesthesiology. 1972 Dec;37(6):626-33. doi: 10.1097/00000542-197212000-00011. No abstract available.

Study record dates

Study Major Dates

• Study Start (Actual): September 10, 2025
• Primary Completion (Estimated): December 20, 2026
• Study Completion (Estimated): April 10, 2027

Study Registration Dates

• First Submitted: January 25, 2026
• First Submitted That Met QC Criteria: May 20, 2026
• First Posted (Actual): May 28, 2026

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: intrinsic PEEP; External PEEP; controlled mechanical ventilation
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Respiratory Insufficiency; Positive-Pressure Respiration, Intrinsic
• Other Study ID Numbers: Hospitalsantojanni.2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No