COMPARISON OF LUNG RECRUITABILITY ASSESSMENT BY HYSTERESIS RATIO AND RECRUITMENT-TO-INFLATION RATIO, AND PEEP TITRATION IN ARDS.

NCT07713420 | Not Yet Recruiting

• 1 other identifier: PRNA018/25
• Study Type: interventional
• Target: 30
• Locations: 0 countries
• Sites: N/A

Brief Summary

This multicenter, single-blind physiological study aims to compare two bedside methods for assessing lung recruitability in mechanically ventilated patients with acute respiratory distress syndrome (ARDS): the recruitment-to-inflation (R/I) ratio and the pressure-volume (PV) loop hysteresis ratio. Lung recruitability will be defined according to the reduction in lung collapse measured by electrical impedance tomography (EIT) during a standardized lung recruitment maneuver. Following baseline measurements, participants will undergo sequential physiological assessments, including lung recruitability evaluation using both the R/I ratio and a low-flow PV loop, a standardized lung recruitment maneuver with a decremental PEEP trial, and a second PV loop performed at a lower maximum inflation pressure. The order of the R/I ratio assessment and the PV loop maneuver will be randomized. In a final crossover phase, four different PEEP titration strategies will be evaluated in randomized order. Each strategy will be applied for 15 minutes and separated by a washout period at the patient's baseline clinical PEEP. Respiratory mechanics, gas exchange, ventilation/perfusion distribution, and hemodynamic variables will be assessed throughout the protocol. The primary objective is to determine the agreement between the hysteresis ratio and the R/I ratio for identifying lung recruitability. Secondary objectives include evaluating whether a PV loop performed with a lower maximum pressure provides similar information on recruitability and comparing the physiological effects of different PEEP titration strategies. Approximately 30 patients with moderate-to-severe ARDS receiving invasive mechanical ventilation will be enrolled.

Conditions

Acute Respiratory Distress Syndrome (ARDS)

Keywords

Mechanical ventilation; Lung recruitability; PEEP titration; Hysteresis Ratio; Recruitment-to-Inflation Ratio; Pressure-Volume Loop; Electrical Impedance Tomography (EIT); Esophageal Pressure; Acute Respiratory Distress Syndrome

Outcome Measures

Primary Outcomes (1)

• Agreement between the hysteresis ratio and the recruitment-to-inflation (R/I) ratio for assessing lung recruitability

  Agreement between lung recruitability assessed by the hysteresis ratio obtained from the pressure-volume loop and the recruitment-to-inflation (R/I) ratio, using the reduction in lung collapse measured by electrical impedance tomography (EIT) during the recruitment maneuver as the reference standard.

  During the study procedure (approximately within 2-3 hours after enrollment).

Secondary Outcomes (2)

• Agreement between PVloop30 and PVloop40 for the assessment of lung recruitability

  During the study procedure.

• Respiratory mechanics and ventilation/perfusion (V/Q) changes according to different PEEP titration methods

  During the study procedure, after 15 minutes of each randomized PEEP titration strategy

Study Arms (1)

Physiological study protocol

EXPERIMENTAL

Participants undergo the complete physiological study protocol, including assessment of lung recruitability, standardized lung recruitment, decremental PEEP trial, and randomized crossover evaluation of four PEEP titration strategies. All participants receive every study intervention; only the order of selected procedures is randomized.

Procedure: Physiological lung recruitability assessment and PEEP titration protocol

Interventions

Physiological lung recruitability assessment and PEEP titration protocol PROCEDURE

Participants undergo a standardized physiological protocol including lung recruitability assessment using the recruitment-to-inflation ratio and pressure-volume loop hysteresis ratio, a standardized lung recruitment maneuver, a decremental PEEP trial, and crossover evaluation of four PEEP titration strategies based on transpulmonary pressure, electrical impedance tomography, respiratory system compliance, and the recruitment-to-inflation ratio. The order of the recruitability assessments and PEEP titration strategies is randomized.

Physiological study protocol

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Intubated patients with acute respiratory distress syndrome (ARDS): PaO2/FiO2 ratio \<200, with bilateral infiltrates of non-cardiogenic origin, with a PEEP of at least 5 cmH2O.
• The patient is receiving mechanical ventilation and continuous sedation.
• The patient has an esophageal balloon.
• Written informed consent signed and dated by the patient or one relative in case the patient is unable to consent, after a full explanation of the study by the investigator and prior to study participation

You may not qualify if:

• Patients with\< 18 years old
• Pregnant woman
• Lung recruitment maneuvers are deemed unsafe by the medical team
• Unable to fit EIT belt due to patient size
• Contraindications to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode placement)
• Hemodynamic instability (Systolic BP \< 75 mmHg or MAP \< 60 mmHg despite vasopressors and/or heart rate \< 55 bpm)
• Hypernatremia (Na+ \>145mEq/L)
• The formalized ethical decision to withhold or withdraw life support
• Patient under guardianship
• Patients deprived of liberties
• Impossibility to give informed consent by both patient and family (i.e. language barrier)
• Patient was already enrolled in the present study in a previous episode of acute respiratory failure.

Sponsors & Collaborators

• Oriol Roca: lead

Related Publications (5)

• Mauri T, Eronia N, Turrini C, Battistini M, Grasselli G, Rona R, Volta CA, Bellani G, Pesenti A. Bedside assessment of the effects of positive end-expiratory pressure on lung inflation and recruitment by the helium dilution technique and electrical impedance tomography. Intensive Care Med. 2016 Oct;42(10):1576-1587. doi: 10.1007/s00134-016-4467-4. Epub 2016 Aug 12.

  PMID: 27518321 BACKGROUND

• Scaramuzzo G, Spadaro S, Dalla Corte F, Waldmann AD, Bohm SH, Ragazzi R, Marangoni E, Grasselli G, Pesenti A, Volta CA, Mauri T. Personalized Positive End-Expiratory Pressure in Acute Respiratory Distress Syndrome: Comparison Between Optimal Distribution of Regional Ventilation and Positive Transpulmonary Pressure. Crit Care Med. 2020 Aug;48(8):1148-1156. doi: 10.1097/CCM.0000000000004439.

  PMID: 32697485 BACKGROUND

• Millington SJ, Cardinal P, Brochard L. Setting and Titrating Positive End-Expiratory Pressure. Chest. 2022 Jun;161(6):1566-1575. doi: 10.1016/j.chest.2022.01.052. Epub 2022 Feb 5.

  PMID: 35131298 BACKGROUND

• Chiumello D, Arnal JM, Umbrello M, Cammaroto A, Formenti P, Mistraletti G, Bolgiaghi L, Gotti M, Novotni D, Reidt S, Froio S, Coppola S. Hysteresis and Lung Recruitment in Acute Respiratory Distress Syndrome Patients: A CT Scan Study. Crit Care Med. 2020 Oct;48(10):1494-1502. doi: 10.1097/CCM.0000000000004518.

  PMID: 32897667 BACKGROUND

• Chen L, Del Sorbo L, Grieco DL, Junhasavasdikul D, Rittayamai N, Soliman I, Sklar MC, Rauseo M, Ferguson ND, Fan E, Richard JM, Brochard L. Potential for Lung Recruitment Estimated by the Recruitment-to-Inflation Ratio in Acute Respiratory Distress Syndrome. A Clinical Trial. Am J Respir Crit Care Med. 2020 Jan 15;201(2):178-187. doi: 10.1164/rccm.201902-0334OC.

  PMID: 31577153 BACKGROUND

MeSH Terms

Conditions

Respiratory Distress Syndrome

Condition Hierarchy (Ancestors)

Lung Diseases; Respiratory Tract Diseases; Respiration Disorders

Central Study Contacts

Oriol Roca, MD, PhD

CONTACT

+34 932607500; oriol.roca@bellvitgehospital.cat

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SEQUENTIAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Head of the Intensive Care Unit

Study Record Dates

• First Submitted: July 14, 2026
• First Posted: July 20, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): January 1, 2029
• Last Updated: July 20, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share