Screening Expiratory Flow Limitation by Flow-time Curve (FLOWLY)

Expiratory flow limitation (EFL) is defined as a dynamic condition that expiratory flow cannot be further increased with higher expiratory driving pressure. Under mechanical ventilation, it can cause intrinsic positive end-expiratory pressure (PEEP) and dynamic hyperinflation, and be associated with worse clinical outcome. The detection of EFL however needs special maneuvers and offline analysis of flow-volume curves, which are infeasible in routine practice and cannot be used during real-time monitoring. The investigators propose a new and simple approach using flow derived parameters to detect EFL in real time without needing any intervention.

Study Overview

• Status: Completed
• Conditions: ARDS, Human

• Study Type: Observational
• Enrollment (Actual): 45

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5B 1W8
      • St. Michael's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Intubated patients in the intensive care unit (ICU) receiving mechanical ventilation.

Description

Inclusion Criteria:

1. Age ≥18 years, intubated or tracheostomized
2. Receiving invasive mechanical ventilation in assist/control mode with PEEP ≥ 5 cmH2O
3. Receiving continuous intravenous sedation
4. Displaying a monotonous regular breathing pattern with no obvious asynchrony

Exclusion Criteria:

1. Severe hypoxemia in baseline clinical ventilator settings (SpO2 < 90%)
2. Hemodynamic instability (mABP <60 mmHg, systolic arterial pressure >180 mmHg, heart rate <40/min or >150/min)

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Outcome (Presence / absence of EFL) will be determined by off-line analysis of recorded flow-volume loops during PEEP reduction.	2 years

Secondary Outcome Measures

Outcome Measure	Time Frame
Percentage of intrinsic PEEP caused by the EFL.	2 years

Collaborators and Investigators

• Sponsor: Unity Health Toronto

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2017
• Primary Completion (Actual): August 12, 2024
• Study Completion (Actual): August 12, 2024

Study Registration Dates

• First Submitted: July 11, 2017
• First Submitted That Met QC Criteria: July 11, 2017
• First Posted (Actual): July 12, 2017

Study Record Updates

• Last Update Posted (Estimated): May 20, 2025
• Last Update Submitted That Met QC Criteria: May 15, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Respiration Disorders; Respiratory Distress Syndrome
• Other Study ID Numbers: 17-098

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No