Predicting High-Flow Nasal Oxygen Failure at 30 Minutes Using a Physiology-Informed Dual-Domain Model (EFI-HFNO)

June 16, 2026 updated by: Ruijin Hospital
This prospective, single-center, two-stage translational study develops and validates a physiology-informed dual-domain model for ultra-early (30-minute) prediction of high-flow nasal oxygen (HFNO) failure in patients with acute hypoxemic respiratory failure. The study includes a physiological validation cohort (n=24) to anchor the EIT-derived Flow Index (EFI) as a marker of inspiratory effort, followed by a temporally separated clinical derivation cohort (n=57) and independent validation cohort (n=58). Candidate predictors are screened from 1,328 clinical features. The final dual-domain model integrates persistent physiological burden (baseline PaCO₂ and 30-minute EFI) with short-term dynamic adaptation (ΔRR and ΔSpO₂ over 30 minutes). The model's discrimination is tested prospectively without refitting.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Detailed Description

This was a single-center, prospective, two-stage translational study conducted at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine. The study comprised three integrated components:

  1. Physiological validation cohort (n = 24) Mechanically ventilated patients with acute respiratory distress syndrome (ARDS) receiving pressure support ventilation underwent simultaneous electrical impedance tomography (EIT) and esophageal pressure monitoring. Measurements were performed at three sequentially adjusted pressure support levels: baseline clinical setting (PSbase), maximal tolerated level (PSmax), and minimal level (PSmin). The EIT-derived Flow Index (EFI) was calculated from the global impedance-time signal. Relationships between EFI and esophageal pressure swing (ΔPes) as well as pressure-time product per minute (PTP/min) were assessed using regression analysis. Changes in EFI across pressure support levels were evaluated by repeated within-subject comparisons.

  2. Clinical derivation cohort (n = 57) High-risk adult patients with acute hypoxemic respiratory failure (AHRF) initiated on high-flow nasal oxygen (HFNO) were prospectively enrolled between May 2025 and September 2025. Inclusion required at least one of the following high-risk criteria: PaO₂/FiO₂ ≤ 200 mmHg or FiO₂ ≥ 0.40 to maintain SpO₂ ≥ 92%; respiratory rate ≥ 25 breaths/min; APACHE II score ≥ 12; or bilateral infiltrates on chest imaging. EIT and bedside variables (heart rate, respiratory rate, arterial blood gases, ROX index) were recorded at baseline (HFNO initiation) and at 30 minutes. HFNO failure was defined a priori as clinically meaningful escalation to noninvasive ventilation (NIV) or endotracheal intubation due to sustained hypoxemia, progressive respiratory acidosis, respiratory muscle fatigue, or hemodynamic instability. Within-tier adjustments (increasing flow or FiO₂ without changing support modality) were not considered failure.

    Patient-level analyses were performed to identify two prespecified domains of early HFNO failure:

    Persistent abnormality (physiological burden that remained abnormal after accounting for baseline): evaluated by analysis of covariance (ANCOVA) for 30-minute variables adjusted for baseline values.

    Divergent short-term response trajectory (different evolution between success and failure groups): evaluated by generalized estimating equations (GEE) with time-by-group interactions across baseline and 30 minutes.

    A multivariable logistic regression model was constructed in the derivation cohort incorporating baseline PaCO₂, 30-minute EFI, ΔRR (change in respiratory rate), and ΔSpO₂ (change in peripheral oxygen saturation). An exploratory reference model using ΔPaO₂ instead of ΔSpO₂ was also evaluated.

  3. Prospective validation cohort (n = 58) An independent, temporally separate cohort of patients meeting the same inclusion/exclusion criteria was enrolled between October 2025 and March 2026 (after completion of the derivation cohort). The identical 30-minute reassessment protocol was applied. The prespecified logistic regression equation from the derivation cohort was applied directly without coefficient refitting. Discriminatory performance of the dual-domain model (baseline PaCO₂ + 30-min EFI + ΔRR + ΔSpO₂) was evaluated using area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity.

Total enrollment: 164 participants (24 physiological validation + 115 clinical HFNO participants [derivation 57 + validation 58] + 25 screened but excluded as detailed in the study flow diagram).

The study was approved by the Ruijin Hospital Ethics Committee (Reference Nos. [2025]30 and [2025]232). All participants provided written informed consent.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
164

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Shanghai Municipality
      • Shanghai, Shanghai Municipality, China, 200025
        • Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients with acute respiratory failure receiving HFNO

Description

Inclusion Criteria (must meet all):

  • Age ≥18 years
  • Acute hypoxemic respiratory failure (AHRF) requiring HFNO initiation
  • At least one of the following high-risk criteria: a) PaO₂/FiO₂ ≤200 mmHg or FiO₂ ≥0.40 to maintain SpO₂ ≥92%; b) Respiratory rate ≥25/min; c) APACHE II score ≥12; d) Bilateral infiltrates on chest imaging

Exclusion Criteria:

  • Neuromuscular disease affecting spontaneous breathing
  • Pregnancy
  • Contraindication to EIT (e.g., chest wall wounds, pacemaker)
  • Do-not-intubate order
  • Hypercapnic respiratory failure as primary diagnosis (PaCO₂ >50 mmHg with pH <7.30 at baseline, unless mixed mechanism)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Physiological Validation Cohort
Mechanically ventilated patients with acute respiratory distress syndrome (ARDS) receiving pressure support ventilation. Intervention: Simultaneous electrical impedance tomography (EIT) and esophageal pressure monitoring at three sequential pressure support levels (PSmin, PSbase, PSmax). Outcome measures: EIT-derived Flow Index (EFI), esophageal pressure swing (ΔPes), pressure-time product per minute (PTP/min). No HFNO administered.
Device: Mechanical Ventilation Support
Patients received pressure support ventilation at three sequentially adjusted levels (PSmin, PSbase, PSmax). Breathing parameters were continuously monitored using an electrical impedance tomography (EIT) device, and inspiratory effort was invasively measured via an esophageal pressure catheter.
Device: Electrical Impedance Tomography Monitoring
PulmoVista 500 EIT device (Dräger Medical, Lübeck, Germany) was used for continuous real-time monitoring of regional lung ventilation.
Derivation Cohort - HFNO Success
High-risk patients with acute hypoxemic respiratory failure (AHRF) initiated on high-flow nasal oxygen (HFNO) who achieved clinical stabilization without requiring escalation to noninvasive ventilation or endotracheal intubation within 72 hours. Intervention: EIT monitoring and bedside data collection (heart rate, respiratory rate, arterial blood gases, SpO₂, ROX index, EMOX index) at baseline (HFNO initiation) and at 30 minutes. No additional device intervention.
Other: High-Flow Nasal Oxygen Therapy
Patients received HFNO as part of standard clinical care for acute hypoxemic respiratory failure. The treatment was titrated by the clinical team based on physiological parameters (SpO₂, RR, ABG), aiming to maintain SpO₂ ≥ 92% and reduce signs of respiratory distress.
Device: High-Flow Nasal Oxygen Therapy With EIT Monitoring
Patients received standard-of-care HFNO for AHRF. Additionally, a PulmoVista 500 EIT device was used to monitor lung ventilation and derive the EFI at baseline and 30 minutes.
Derivation Cohort - HFNO Failure
High-risk patients with AHRF initiated on HFNO who required escalation to noninvasive ventilation or endotracheal intubation within 72 hours due to refractory hypoxemia, progressive respiratory acidosis, severe respiratory distress, or hemodynamic instability. Intervention: EIT monitoring and bedside data collection (same variables as success group) at baseline and 30 minutes. Escalation decision guided by predefined objective criteria, not by EIT data.
Other: High-Flow Nasal Oxygen Therapy
Patients received HFNO as part of standard clinical care for acute hypoxemic respiratory failure. The treatment was titrated by the clinical team based on physiological parameters (SpO₂, RR, ABG), aiming to maintain SpO₂ ≥ 92% and reduce signs of respiratory distress.
Device: High-Flow Nasal Oxygen Therapy With EIT Monitoring
Patients received standard-of-care HFNO for AHRF. Additionally, a PulmoVista 500 EIT device was used to monitor lung ventilation and derive the EFI at baseline and 30 minutes.
Validation Cohort - HFNO Success
Independent temporally separate cohort of high-risk AHRF patients initiated on HFNO who achieved clinical stabilization without escalation. Same inclusion/exclusion criteria as derivation cohort. Intervention: Identical 30-minute reassessment protocol: EIT monitoring and bedside data collection at baseline and 30 minutes. Model tested prospectively without coefficient refitting.
Device: High-Flow Nasal Oxygen Therapy With EIT Monitoring
Patients received standard-of-care HFNO for AHRF. Additionally, a PulmoVista 500 EIT device was used to monitor lung ventilation and derive the EFI at baseline and 30 minutes.
Validation Cohort - HFNO Failure
Independent temporally separate cohort of high-risk AHRF patients initiated on HFNO who required escalation to noninvasive ventilation or endotracheal intubation. Same escalation criteria as derivation cohort. Intervention: EIT monitoring and bedside data collection at baseline and 30 minutes. The fixed dual-domain model (baseline PaCO₂, 30-min EFI, ΔRR, ΔSpO₂) derived from the derivation cohort was applied without refitting to assess discrimination.
Device: High-Flow Nasal Oxygen Therapy With EIT Monitoring
Patients received standard-of-care HFNO for AHRF. Additionally, a PulmoVista 500 EIT device was used to monitor lung ventilation and derive the EFI at baseline and 30 minutes.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
HFNC Failure Rate(Early Reassessment at 30 Minutes)
Time Frame: within 30 minutes after HFNO initiation (with monitoring of outcomes up to hospital discharge)
HFNO failure was defined as escalation to noninvasive ventilation (NIV) or endotracheal intubation due to refractory hypoxemia, progressive respiratory acidosis, severe respiratory distress, or hemodynamic instability. Within-tier adjustments (increasing flow or FiO₂ without changing support modality) were NOT considered failure.
within 30 minutes after HFNO initiation (with monitoring of outcomes up to hospital discharge)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Physiological Validation of EFI
Time Frame: During physiological measurements in mechanically ventilated patients (performed before the clinical HFNO cohort; within 48 hours of ICU admission)
EFI was compared with esophageal pressure swing (ΔPes) and pressure-time product per minute (PTP/min) across pressure support levels using regression analysis and repeated within-subject comparisons.Unit of Measure No unit for R² (dimensionless ratio); Arbitrary units (a.u.) for EFI; cm H₂O for ΔPes; cm H₂O·s/min for PTP/min.
During physiological measurements in mechanically ventilated patients (performed before the clinical HFNO cohort; within 48 hours of ICU admission)
Persistent Abnormality at 30 Minutes
Time Frame: within 30 minutes after HFNO initiation
ANCOVA-adjusted 30-minute values of EFI, PaCO₂, heart rate, respiratory rate, pH, PaO₂ were compared between HFNO success and failure groups to identify persistent physiological burden.Unit of Measure EFI: arbitrary units (a.u.); PaCO₂ and PaO₂: mmHg; Heart rate: beats/min; Respiratory rate: breaths/min; pH: dimensionless (pH units);
within 30 minutes after HFNO initiation
Divergent Short-Term Response Trajectories
Time Frame: Baseline to 30 minutes after HFNO initiation
Generalized estimating equations (GEE) evaluated time-by-group interactions for EFI, respiratory rate, PaO₂, PaCO₂, pH, heart rate, ROX, to identify divergent early response trajectories.Measure of Central Tendency / Measure of Dispersion Time-by-group interaction P values; Estimated marginal means at baseline and 30 minutes for each group; Within-patient change scores (Δ values) between the two time points for each variable Unit of Measure EFI: arbitrary units (a.u.); Heart rate: beats/min; Respiratory rate: breaths/min; pH: dimensionless (pH units); PaCO₂ and PaO₂: mm Hg; ROX: dimensionless index.
Baseline to 30 minutes after HFNO initiation

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ruijin Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Hongping Qu, Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 1, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 31, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 16, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 26, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 17, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 16, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • [2025]232 and [2025] 30

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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