Influence of Flow Rate Change on CO2 Levels During High Flow Nasal Ventilation (HFNV) in Preterm Infants.

November 26, 2025 updated by: Ori Hochwald , MD, Rambam Health Care Campus

Background Preterm infants often need respiratory support. HFNV is a non-invasive method with benefits over CPAP, such as reduced nasal trauma and improved feeding.

Aim Study the impact of low (2 LPM) vs. high (6 LPM) HFNV flow rates on CO2 levels in preterm infants.

Methods Design: Prospective, crossover observational study. Participants: Preterm newborns (24-33.6 weeks' gestation) on HFNV. Procedure: Randomized flow rate adjustments, monitoring tcCO2 and other respiratory parameters over three hours.

Outcomes Primary: Change in tcCO2. Secondary: Study terminations due to unsafe CO2 levels and changes in other respiratory metrics.

Statistical Analysis Sample size: 45 infants. Analysis: Paired and unpaired t-tests for comparison within and between groups.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Background:

Preterm Births: About 10% of births are preterm, with infants at risk for respiratory distress.

Respiratory Support: Endotracheal ventilation has improved survival but increased the risk of bronchopulmonary dysplasia.

Non-Invasive Support: Nasal CPAP minimizes complications. Heated, humidified high-flow nasal ventilation (HFNV) is an alternative, providing advantages like reduced nasal trauma and improved oral feeding.

Aim:

Primary Goal: Examine changes in transcutaneous CO2 (tcCO2) levels in preterm infants when using HFNV at low (2 LPM) versus high (6 LPM) flow rates.

Hypothesis: Different HFNV flow rates will show minimal change in tcCO2 (≤5 mmHg).

Methods:

Design: Prospective, crossover observational study in Rambam NICU. Participants: Preterm newborns (24-33.6 weeks' gestation) needing HFNV. Inclusion Criteria: Stabilized HFNP settings and tcCO2, parental consent. Exclusion Criteria: Specific flow and CO2 levels, unstable conditions, or congenital malformations.

Procedure: Randomize infants into two groups starting with 2 or 6 LPM flow rates, monitoring tcCO2 over three consecutive hours with alternating flow rates.

Measurements:

Primary Outcome: Change in tcCO2 levels. Secondary Outcomes: Number of study terminations due to pCO2/TcCO2 out of safety range, changes in respiratory parameters, and episodes of desaturation or bradycardia.

Statistical Analysis:

Sample Size: 45 infants needed to detect no difference with 90% power and 5% significance level.

Data Analysis: Use paired and unpaired Student's t-tests to compare results within and between groups.

Safety Protocol: The study will terminate if significant desaturation, bradycardia, or pCO2 levels outside the safety range occur.

Study Type

Interventional

Enrollment (Estimated)

45

Phase

  • Not Applicable

Contacts and Locations

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

Study Contact

Study Locations

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • Gestational age 240 to 336.
  • At least 6 hours of stabilized HFNP settings, i.e. minor changes in settings (FiO2 ≤0.10, no change in flow).
  • At least 6 hours of stabilized tcCO2, i.e. ≤5 mmHg variation.
  • At least 6 hours from surfactant administration.
  • Parental consent

Exclusion criteria:

  • If flow is <3 and tcCO2 related pCO2 is<40mmHg.
  • If Flow is ≥5 bpm and tcCO2 related pCO2 is>60mmHg.
  • Unstable infants due to acute conditions (sepsis. IVH), or congenital malformations.

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: start with 2LPM
Other: change flow from 6 to 2 LPM. Follow TcCO2 for 3 hours
change flow from 6 to 2 LPM. Follow TcCO2 for 3 hours
Other: change flow from 2 to 6 LPM. Follow TcCO2 for 3h
change flow from 2 to 6 LPM. Follow TcCO2 for 3h
Experimental: start with 6LPM0
start with 6LPM
Other: change flow from 6 to 2 LPM. Follow TcCO2 for 3 hours
change flow from 6 to 2 LPM. Follow TcCO2 for 3 hours
Other: change flow from 2 to 6 LPM. Follow TcCO2 for 3h
change flow from 2 to 6 LPM. Follow TcCO2 for 3h

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Delta CO2
Time Frame: 3 hours after flow change
the change in TcCO2
3 hours after flow change

Collaborators and Investigators

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

Sponsor

Rambam Health Care Campus

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)

August 16, 2023

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

June 26, 2024

First Submitted That Met QC Criteria

October 1, 2024

First Posted (Actual)

October 2, 2024

Study Record Updates

Last Update Posted (Actual)

November 28, 2025

Last Update Submitted That Met QC Criteria

November 26, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RMB059422

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

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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