Asymmetrical High Flow Nasal Cannula and End-Expiratory Lung Impedance (EELI and AHFNC)

June 27, 2025 updated by: Gustavo Plotnikow, Argentinian Intensive Care Society

Effects of an Asymmetrical High Flow Nasal Cannula Interface on End-Expiratory Lung Impedance

Objective: The primary aim is to assess end-expiratory lung impedance (EELI) changes during the application of high-flow oxygen therapy using asymmetric nasal cannulae, comparing conditions with the mouth closed and open in healthy volunteers in various positions. The secondary objective includes evaluating respiratory rate, shortening fraction, and diaphragm excursion via ultrasound.

Study Design: This is a prospective observational cohort study conducted in the Critical Care Unit of Sanatorio Parque Rosario from November 5 to December 31, 2024. It will involve 20 healthy adult volunteers without respiratory conditions, with informed consent obtained from all participants. Volunteers with contraindications for electrical impedance tomography (EIT) will be excluded.

Methods: Equipment Used: PulmoVista 500 Dräger (EIT), AIRVO 2 (high-flow oxygen generator), asymmetric nasal cannula (Optiflow OPT 966), Toshiba iStyle ultrasound machine.

Procedures: The study includes EELI measurements in different positions (semi-seated, supine Fowler, prone, and prone Fowler) with various high-flow oxygen settings (40 and 60 L/min). Diaphragm excursion and thickening will be assessed using ultrasound.

Scenarios and Measurements: 17 different testing scenarios will be conducted, with 16 intervals for washout breathing at room air between scenarios. Data on EELI, respiratory rate, and diaphragm measurements will be collected.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Methodology:

Procedures: EELI, respiratory rate, and diaphragm measurements will be taken in various body positions while using high-flow oxygen therapy (HFNC) set at 40 and 60 L/min. Diaphragm excursion and thickening will be evaluated with ultrasound.

Data Collection and Analysis: Volunteers will participate in 17 different testing scenarios, with intervals of 5-minute washout periods breathing room air in a semi-seated position between each measurement. Continuous variables will be expressed as mean ± standard deviation or median and interquartile range. Repeated measures ANOVA will be used for statistical comparisons, with significance set at p < 0.05.

17 Testing Scenarios:

Semi-seated at 45° breathing room air. Semi-seated at 45° with asymmetric HFNC at 40 L/min, mouth closed for 5 minutes.

Semi-seated at 45° with asymmetric HFNC at 40 L/min, mouth open for 5 minutes. Semi-seated at 45° with asymmetric HFNC at 60 L/min, mouth closed for 5 minutes.

Semi-seated at 45° with asymmetric HFNC at 60 L/min, mouth open for 5 minutes. Supine in Fowler position (60°) with asymmetric HFNC at 40 L/min, mouth open for 5 minutes.

Supine in Fowler position (60°) with asymmetric HFNC at 40 L/min, mouth closed for 5 minutes.

Supine in Fowler position (60°) with asymmetric HFNC at 60 L/min, mouth open for 5 minutes.

Supine in Fowler position (60°) with asymmetric HFNC at 60 L/min, mouth closed for 5 minutes.

Prone at 180° with asymmetric HFNC at 40 L/min, mouth open for 5 minutes. Prone at 180° with asymmetric HFNC at 40 L/min, mouth closed for 5 minutes. Prone at 180° with asymmetric HFNC at 60 L/min, mouth open for 5 minutes. Prone at 180° with asymmetric HFNC at 60 L/min, mouth closed for 5 minutes. Prone Fowler position with asymmetric HFNC at 40 L/min, mouth open for 5 minutes.

Prone Fowler position with asymmetric HFNC at 40 L/min, mouth closed for 5 minutes.

Prone Fowler position with asymmetric HFNC at 60 L/min, mouth open for 5 minutes.

Prone Fowler position with asymmetric HFNC at 60 L/min, mouth closed for 5 minutes.

Duration per Participant: Approximately 2 hours and 15 minutes.

Ethical Considerations: All data will be anonymized and kept confidential. Participants' rights to withdraw at any time will be respected, and no personal identifying information will be disclosed.

This comprehensive approach aims to elucidate the physiological impacts of using asymmetric HFOT on end-expiratory lung volume and related respiratory parameters in various positions and conditions.

Study Type

Observational

Enrollment (Actual)

17

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

  • Argentina
      • Buenos Aires, Argentina, 1425
        • Hospital Britanico de Buenos Aires

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Probability Sample

Study Population

healthy volunteers healthcare professionals working at Sanatorio Parque in Rosario, aged between 18 and 50 years, who sign the informed consent form and have no history of respiratory pathology (who are non-smokers and do not have a history of any type of respiratory disease).

Description

Inclusion Criteria:

  • healthy volunteers between 18 and 50 years of age who sign the informed consent form, without respiratory pathology.

Exclusion Criteria:

  • contraindication to implement electrical impedance tomography or high flow oxygen therapy

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
Intervention / Treatment
Healthy Adult Volunteers
Healthy adult volunteers, all above 18 years of age, who provide informed consent.
Device: High flow oxygen therapy
Application of high flow oxygen therapy through asymmetric cannula at 40 and 60 L/m

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
End-Expiratory Lung Impedance
Time Frame: From enrollment to the end of treatment at 2.30hours
Variation of end-expiratory lung impedance in different positions and with different flows.
From enrollment to the end of treatment at 2.30hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Respiratory Rate
Time Frame: From enrollment to the end of treatment at 2.30hours
Number of respiratory cycles per minute while breathing in a quiet manner at rest.
From enrollment to the end of treatment at 2.30hours
Diaphragm Thickness Fraction
Time Frame: From enrollment to the end of treatment at 2.30hours
Diaphragm Thickness Fraction (DTF) is a measure used to assess diaphragm function by comparing the change in diaphragm thickness from end-expiration to end-inspiration expressed as a percentage
From enrollment to the end of treatment at 2.30hours
Diaphragm excursion
Time Frame: From enrollment to the end of treatment at 2.30hours
Diaphragm excursion refers to the movement or displacement of the diaphragm during the respiratory cycle, measured from its lowest position at end-expiration to its highest position at end-inspiration. This parameter is assessed using ultrasound and reflects the diaphragm's ability to contract effectively, with greater excursion indicating stronger respiratory muscle function.
From enrollment to the end of treatment at 2.30hours

Collaborators and Investigators

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

Sponsor

Argentinian Intensive Care Society

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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)

November 5, 2024

Primary Completion (Actual)

December 31, 2024

Study Completion (Actual)

January 31, 2025

Study Registration Dates

First Submitted

November 4, 2024

First Submitted That Met QC Criteria

November 4, 2024

First Posted (Actual)

November 5, 2024

Study Record Updates

Last Update Posted (Actual)

July 2, 2025

Last Update Submitted That Met QC Criteria

June 27, 2025

Last Verified

June 1, 2025

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • #30102024

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

all IPD on which the results of the publication are based will be in the publication or shared through direct links after consultation with the PI via e-mail

IPD Sharing Time Frame

January 2025-January 2026

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • CSR

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

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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