Electrical Impedance Tomography-derived Flow Index During Spontaneous Breathing Trial Stratifies the Risk of Reintubation Within 48 h After Extubation (EIT-FI Weaning)

Accurate prediction of readiness to liberate patients from mechanical ventilation remains challenging. Conventional indices such as the rapid shallow breathing index (RSBI) and maximal inspiratory pressure (MIP) often miss early signs of injurious breathing patterns or regional ventilation asynchrony that can lead to extubation failure. Electrical impedance tomography (EIT) provides continuous, non-invasive imaging of regional lung ventilation. We developed a novel EIT-derived Flow Index (FI) which integrates the magnitude of inspiratory effort with the temporal synchrony of lung filling. This prospective, multicenter observational study aimed to (1) validate the predictive value of FI during spontaneous breathing trials (SBT) compared with conventional weaning indices, and (2) compare the predictive ability of EFI with traditional weaning indices(RSBI,MIP,P0.1).

Study Overview

• Status: Completed
• Conditions: Acute Respiratory Failure; Ventilator Weaning Assessment
• Intervention / Treatment: Device: electrical impedance tomography

Detailed Description

This multicenter observational study was conducted in three tertiary ICUs in China. Adult patients (≥18 years) receiving invasive mechanical ventilation for ≥48 hours and meeting readiness criteria underwent a standardized 30-minute pressure support SBT (PS 8 cmH₂O, PEEP 5 cmH₂O, FiO₂ ≤0.5) with continuous EIT monitoring. EFI was calculated breath by breath from the global impedance-time signal. Conventional weaning indices (RSBI, MIP, P0.1) and physiological variables were recorded.

Primary endpoint: SBT success (completion of 30-minute SBT without predefined failure criteria).

Key secondary endpoint: reintubation within 48 hours after extubation. Other secondary endpoints: ventilator-free days at day 7 (VFD-7), ICU mortality. Predictive performance was assessed using ROC analysis. The EFI cutoff value was derived from the primary endpoint analysis and carried forward for post-extubation risk stratification.

• Study Type: Observational
• Enrollment (Actual): 150

Contacts and Locations

Study Locations

• China
  • Shanghai, China, 200025
    • Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine，Shanghai，China.
  • Beijing Municipality
    • Beijing, Beijing Municipality, China
      • Peking Union Medical College Hospital
  • Fujian
    • Fuzhou, Fujian, China, 200025
      • Fujian Provincial Hospital

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

1. 150 critically ill patients requiring respiratory support were planned for inclusion
2. Age ≥18 years
3. Gender is not limited
4. Patients with expected duration of respiratory support >24 hours

Description

Inclusion Criteria:

• Age ≥18 years
• Acute respiratory failure requiring intubation and mechanical ventilation ≥48 hours
• Hemodynamic stability (no escalation of vasoactive agents)
• Oxygenation: FiO₂ ≤0.5, PEEP ≤8 cmH₂O
• Meeting standard ICU criteria for SBT readiness

Exclusion Criteria:

• Neuromuscular diseases impairing spontaneous breathing
• High cervical spinal cord injury
• Deep sedation (RASS ≤-3)
• Inadequate EIT signal quality
• Contraindications to EIT
• Pregnancy
• Expected survival <24 h

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Conventional method Respiratory Drive group; Conventional method Respiratory Drive group（Methods include: esophageal pressure monitoring, airway obstruction pressure (P0.1) )	Device: electrical impedance tomography; Respiratory drive assessed by flow index measured by electrical impedance tomography.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Spontaneous Breathing Trial (SBT) Success Rate	Proportion of patients who complete the 30-minute Spontaneous Breathing Trial (SBT) without signs of respiratory distress, hypoxemia, or hemodynamic instability.	Within 30 minutes of Spontaneous Breathing Trial (SBT)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Reintubation Rate within 48 hours	Proportion of patients requiring reintubation within 48 hours following successful extubation.	Within 48 hours after extubation.
Ventilator-Free Days by Day 7	Number of days free from mechanical ventilation within 7 days after extubation.	Within 7 days after extubation.
ICU Mortality	Mortality rate of patients during their ICU stay in this study.	during the ICU stay or within 24 hours following transfer out of the ICU
Reintubation rate within 48 hours after extubation	Proportion of patients who successfully completed the spontaneous breathing trial (SBT) and underwent planned extubation who required reintubation within 48 hours after extubation.	within the 48 hours after extubation
Ventilator-Free Days at Day 7 (VFD-7)	Number of days alive and free from invasive mechanical ventilation within 7 days after extubation. Days after reintubation are not counted as ventilator-free days.	Within 7 days after extubation
ICU Mortality	Proportion of patients who died during ICU hospitalization or within 24 hours after transfer out of the ICU.	During ICU stay or within 24 hours after ICU discharge

Collaborators and Investigators

• Sponsor: Ruijin Hospital
• Collaborators: Peking Union Medical College Hospital; Fujian Provincial Hospital
• Investigators: Study Chair: Hongping Qu, Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine; Study Director: Jialin Liu, Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine; Principal Investigator: rui zhang, Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2024
• Primary Completion (Actual): December 31, 2025
• Study Completion (Actual): December 31, 2025

Study Registration Dates

• First Submitted: March 10, 2025
• First Submitted That Met QC Criteria: March 10, 2025
• First Posted (Actual): March 14, 2025

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 20, 2026
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: acute respiratory failure; Respiratory drive; Electrical Impedance Tomography (EIT)
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Respiratory Insufficiency
• Other Study ID Numbers: 202530

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation

Drug and device information, study documents

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