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Completed

NCT Number: NCT06228703

The Effects of Different Flow Settings on Lung Impedance

This prospective, randomized crossover trial will enroll adult healthy volunteers. Initially, the subject's peak inspiratory flow will be measured using a mask connected with a respiratory monitor. Subsequently, the volunteers will undergo HFNC treatment at different flow settings while their peak inspiratory flow will be continuously monitored. The primary outcome of this study is the lung aeration with different flow settings. Secondary outcomes include the lung aeration with different devices, subject's comfort at different flow settings, and the correlation between the subject's peak inspiratory flow measured by HFNC and by a mask connected with a respiratory monitor.

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Key information

Conditions

Healthy

Age range

21 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Rush University

Forest Park, Illinois, 60612, United States

About this study

Background: High-flow nasal cannula (HFNC) is a device that can reduce the work of breathing (WOB) and improve oxygenation by providing a flow that matches or exceeds patient's peak inspiratory flow during tidal breathing. Despite its widespread use, there remains a lack of consensus regarding the optimal flow settings. Two new HFNC devices that can provide information regarding patient's peak tidal inspiratory flow breath by breath are recently available, which might help guide set and titrate the flow settings. This study aims to investigate the effects of different flow settings on lung impedance in a cohort of healthy volunteers by using the two new HFNC devices.

Methods: This prospective, randomized crossover trial will enroll adult healthy volunteers. Initially, the subject's peak inspiratory flow will be measured using a mask connected with a respiratory monitor. Subsequently, the volunteers will undergo HFNC treatment at different flow settings while their peak inspiratory flow will be continuously monitored. The primary outcome of this study is the lung aeration with different flow settings. Secondary outcomes include the lung aeration with different devices, subject's comfort at different flow settings, and the correlation between the subject's peak inspiratory flow measured by HFNC and by a mask connected with a respiratory monitor.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy volunteers between 21-65 years old

Exclusion criteria

  • Chronic pulmonary diseases, including COPD, interstitial lung disease, cystic fibrosis, etc.
  • Uncontrolled asthma;
  • Pregnancy
  • Subjects who have cold/flu symptoms (sore throat, runny nose, fever, chills, coughing)
  • Nose abnormalities that can affect the functionality of the nasal prongs

Treatment and study plan

High-flow nasal cannula device with flow setting at 40 L/min or higher

Device

Eligible participants will use the high-flow nasal cannula device (Airvo3 or HFT 750) with flow set at 40 L/min or higher

Other names: HFNC flow at 40 L/min or higher

Primary outcomes

  1. Change in End-expiratory Lung Impedance From Baseline Measured by Electrical Impedance Tomography (EIT)

    Time frame: Up to 4 hours

    End-expiratory lung impedance (EELI) was measured continuously using electrical impedance tomography (EIT). For each flow-setting condition, EELI values were averaged over a stable 1-minute period. The outcome represents the change in EELI (in arbitrary impedance units) from each participant's baseline measurement prior to intervention. Positive values indicate an increase in end-expiratory lung volume compared to baseline, while negative values indicate a decrease. EIT impedance units are dimensionless and device-specific and are used to represent relative changes in ventilation and lung volume.

Secondary outcomes

  1. Changes in Respiratory Rates Compared to Baseline

    Time frame: Up to 4 hours

    Respiratory rate was measured as breaths per minute. Change was calculated as the value during each HFNC flow condition minus the baseline respiratory rate. Positive values indicate an increase in respiratory rate, and negative values indicate a decrease.

  2. Subject's Comfort Level

    Time frame: Up to 4 hours

    Comfort level reported by participants using a visual numerical scale ranging between 0 (extreme discomfort) and 10 (very comfortable) at the end of each flow setting

Sponsors and collaborators

Lead sponsor

Rush University Medical Center

Other

Registry information

Official study title

The Effects of Different Flow Settings on Lung Impedance Using Two New HFNC Devices: A Randomized Crossover Study on Healthy Volunteers

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Jan 29, 2024
Registry last updated
Dec 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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