Impact of PEEP Trials on Ventilation-Perfusion Matching in ARDS Patients

Shanghai Jiao Tong University

Status and phase: Invitation-only; Phase 3; Phase 2

Conditions: ARDS

Treatments: Drug: 10ml of 10% saline is injected centrally

Study type: Interventional

Funder types: Other

Identifiers

NCT06823804

2022325

Details and patient eligibility

About

In the treatment of critically ill patients, mechanical ventilation is a key link, and appropriate mechanical ventilation strategies can open the alveoli and improve oxygenation, while inappropriate mechanical ventilation can increase lung injury and seriously affect the prognosis. Ventilator-related lung injury is mainly concentrated in barotrauma, volumetric injury, shear injury, and biological injury, and the monitoring of respiratory ventilation to the level of local ventilation can help to better assess the state of alveolar opening and alveolar collapse, and help to understand the uniformity of gas distribution in the lungs, which is closely related to lung injury. However, how to achieve simple, bedside and real-time lung ventilation and lung volume assessment in clinical work has always been a difficult problem to be overcome. This study intends to explore the changes of local ventilation and blood flow in the lungs during PEEP trail in patients with ARDS monitored by EIT.

Full description

1. Background and Rationale ARDS is associated with heterogeneous lung collapse. The recruitment-to inflation (R/I) ratio has emerged as an index of recruitability, but is usually assessed globally. Electrical impedance tomography (EIT) enables regional assessment of ventilation and may provide more precise determinations of recruitable lung regions, particularly dorsal areas.
2. Objectives Primary objective: To compare the predictive value of regional (dorsal and ventral) versus global R/I for recruitment success in moderate-severe ARDS. Secondary objectives: To classify recruitment phenotypes and evaluate associations with oxygenation, compliance improvement, ventilator-free days, ICU length of stay, and 28-day mortality.
3. Study Design Prospective, single-centre observational cohort study in ICU patients with moderate-severe ARDS. All eligible patients undergo standardised recruitment maneuver and EIT monitoring.
4. Study Setting Ruijin Hospital, Shanghai Jiao Tong University School of Medicine ICU, December 2022 - December 2024.
5. Intervention Standardized PEEP step maneuver from 5 → 15 cmH₂O, maintained for 3 minutes. Continuous EIT monitoring of regional compliance, oxygenation, hemodynamics. Dynamic strain cutoff (>0.6) or adverse events terminate the maneuver. Ventilation mode: volume control, tidal volume 4-6 mL/kg predicted body weight, plateau ≤28-30 cmH₂O, FiO₂ titrated for SpO₂ 88-92%.
6. Measurements EIT-derived ΔEELI in dorsal and ventral regions Regional and global compliance (Crec and Crs) R/I calculated: Crec/Crs at baseline PEEP Airway opening pressure by low-flow inflation method Primary outcome: recruitment success (≥10% compliance improvement + ≥20 mmHg PaO₂/FiO₂ increase) Secondary: ventilator-free days, ICU LOS, 28-day mortality, dynamic strain
7. Statistical Analysis Plan Distribution check by Shapiro-Wilk. Paired tests for within-patient comparisons. ROC curves and Youden index for cut-off selection. Multivariate regression for mortality risk factors. Bonferroni correction for multiple comparisons.
8. Safety Monitoring Terminate RM if: MAP <65 mmHg, SpO₂ <88%, arrhythmia onset, dynamic strain >0.6.

Enrollment: 120 estimated patients

Sex: All

Ages: 18 to 90 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients who meet the Berlin definition of ARDS and have been treated with mechanical ventilation (clinical diagnosis of ARDS by the attending ICU physician)
• PaO₂/FiO₂ ≤150 mmHg

Exclusion criteria

• Age< 18 or >90 years
• Pneumothorax, pneumomediastinum
• Hemodynamic instability (rising vasopressor need in <6h)
• Contraindications to RM or EIT

Trial design

Primary purpose: Supportive Care

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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120 participants in 1 patient group

evaluate the feasibility of using EIT to calculate regional recruitment-to-inflation (R/I) ratios

Experimental group

Description:

Regional R/I ratios were computed for the global lung, dorsal (dependent), and ventral (non-dependent) regions of interest (ROIs), which were defined as 50% of the ventro-dorsal lung diameter based on EIT imaging.compare the predictive value of regional (dorsal and ventral) versus global R/I for recruitment success in moderate-severe ARDS.

Treatment:

Drug: 10ml of 10% saline is injected centrally