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CompletedNCT05384275Updated Nov 28, 2023

High-Flow Aerosol Generation Study

An interventional study of High Flow Nasal Therapy in Oxygen Therapy; Heart Surgery, sponsored by Papworth Hospital NHS Foundation Trust. Completed at 1 site in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2023-11-28.

Sponsored by Papworth Hospital NHS Foundation Trust · Not applicable, Interventional, and Basic science

From the registry’s dates

  • Registered 1 year after the study started (first participant enrolled May 2021, registered May 2022).
Phase
Not applicable
Study type
Interventional
Enrollment
61
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

The study will be measuring aerosol generated from the point of tracheal extubation after cardiac surgery in patients who then receive either high-flow nasal oxygen therapy (HFNT) or standard low-flow oxygen therapy, who have been consented to participate within another randomised controlled trial (The NOTACS Study, IRAS ID 278290). Aerosol generation will be compared at various sizes of particles \< 10 microns in size and sampled in different locations in the standardised patient care rooms in the ICU. The rate of change of aerosol generation, maximum aerosol generation and duration of aerosol production greater than background will be investigated. The aim is to compare high-flow and standard low-flow oxygen therapy to determine if there is a difference in aerosol generation between the therapies.

02

Conditions studied

  • Oxygen Therapy; Heart Surgery
03

In context

Lead sponsor

Papworth Hospital NHS Foundation Trust is the lead sponsor of 62 studies on the registry; 8 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  1. Aged 18 years or over.
  2. Undergoing elective or urgent first-time or redo cardiac surgery (CABG, valve surgery, surgery on the aorta or any combination).
  3. Have one or more clinical patient-related risk factor for postoperative pulmonary complications (COPD, asthma, lower respiratory tract infection in last 4 weeks as defined by use of antibiotics, body mass index ≥35 kg/m2, current (within the last 6 weeks) heavy smokers (> 10 pack years))(26, 27).

For the purposes of the study, the following definitions apply:

Asthma is a disease characterized by recurrent attacks of breathlessness and wheezing, and patients will have been prescribed medication by inhalers or nebulisers (either bronchodilators or steroids).

Chronic Obstructive Pulmonary Disease (COPD) is an umbrella term used to describe chronic lung diseases that cause limitations in lung airflow. The more familiar terms 'chronic bronchitis' and 'emphysema' are no longer used but are now included within the COPD diagnosis. The most common symptoms of COPD are breathlessness, or a 'need for air', excessive sputum production, and a chronic cough. Patients suitable for the NOTACS study will have been prescribed medication by inhalers or nebulisers (either bronchodilators or steroids).

Exclusion criteria

Exclusion Criteria:

  1. Requiring home oxygen therapy.
  2. Deep hypothermic circulatory arrest planned.
  3. Contraindication to HFNT, e.g. nasal septal defect.
  4. Requirement for home respiratory support (including: CPAP, BiPAP).
  5. Requiring emergency cardiac surgery defined as surgery required within 24 hours of the decision to operate.
  6. Patient's not fluent in English.
05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
61 participants (actual)

Study arms

  • No intervention
    No intervention: Standard Oxygen Therapy

    Standard oxygen therapy arm patients will be given 30-40% inspired O2 and flow 2-6 l/min via nasal prongs or non-rebreathing mask (not humidified and not heated) post extubation. Monitoring of saturations, respiratory rate and arterial gases will happen 15 minutes post extubation and then as per local policy thereafter. If saturations \< 93% then FiO2 will be increased as per respiratory escalation protocol. Standard oxygen therapy will be given for a minimum of 16 hours post extubation.

  • Active comparator
    High-Flow Nasal Therapy

    High-flow nasal therapy arm patients will be given AIVRO 2 high flow oxygen therapy machines post extubation, start at 30-40% inspired O2 and flow 30 l/min then up to 50 l/min over 5-10 min. Monitoring of saturations, respiratory rate and arterial gases will happen after 15 minutes post extubation and then as per local policy thereafter. If saturations \< 93% then increase FiO2 as per respiratory escalation protocol. High flow nasal therapy will be given for a minimum of 16 hours post extubation.

    Device: High Flow Nasal Therapy

Interventions

  • DeviceHigh Flow Nasal Therapy

    High Flow Nasal Oxygen (Airvo2 Device)

06

What researchers measure

Primary outcomes

  1. To assess aerosol generation as measured by total exposure level of 0.3 micron particles during tracheal extubation and for 1 hour afterwards (study period) at 50 cm to the side of the patient's head.

    This will be measured by the total particle count using area under the curve (AUC) over the 1 hour timeframe.

    Time frame: 1 hour

Secondary outcomes

  1. To assess the time needed for particle counts to return to baseline level, measuring particles size 0.3, 0.5, 1.0, 2.5, 5.0 and 10.0 microns during tracheal extubation and for 1 hour afterwards.

    Measured at 50 cm to the side of the patient's head, at 50 cm from the top of the patient's head and by the patient's feet.

    Time frame: 1 hour

  2. To assess total aerosol generation measuring particles size 0.5, 1.0, 2.5, 5.0 and 10.0 microns during tracheal extubation and for 1 hour afterwards.

    Measured at 50 cm to the side of the patient's head, at 50 cm from the top of the patient's head and by the patient's feet.

    Time frame: 1 hour

  3. To assess total aerosol generation measuring particle size 0.3 microns during tracheal extubation and for 1 hour afterwards at 50 cm from the top of the patient's head and by the patient's feet.

    Time frame: 1 hour

  4. To assess the peak particle count of 0.3, 0.5, 1.0, 2.5, 5.0 and 10.0 micron during tracheal extubation and for 1 hour afterwards at 50 cm to the side of the patient's head, 50 cm from the top of the patient's head and by the patient's feet.

    Time frame: 1 hour

  5. To measure CO2 levels during tracheal extubation and for 1 hour afterwards.

    Measured at 50 cm to the side of the patient's head, at 50 cm from the top of the patient's head and by the patient's feet. A CO2 counter will be placed next to each of the particle counter devices.

    Time frame: 1 hour

07

Study locations

1 site
  • Royal Papworth Hospital NHS Foundation Trust
    Cambridge, Cambridgeshire CB20AY, United Kingdom
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Nov 28, 2023, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05384275
Lead sponsor
Papworth Hospital NHS Foundation Trust
Responsible party
Sponsor
First posted
May 20, 2022
Start date
May 17, 2021
Primary completion
Jan 31, 2023
Completion
Jan 31, 2023
Last update
Nov 28, 2023

Study contacts

Andrew Klein
principal investigator · Royal Papworth Hospital

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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