None listed
Conditions
Brief summary
Nasal high flow (NHF) therapy is an intervention used when managing a broad range of patients in acute and chronic care, both in hospital and at home. NHF provides breathing support through a nasal cannula that directs airflow into the nostrils, making ventilation more efficient and helping to relieve shortness of breath. While this treatment is effective, research to optimise this treatment is ongoing. For example, we previously compared the effects of different Duet cannula designs (symmetrical vs asymmetrical prongs) on ventilation in healthy participants, finding additional benefits when using the asymmetrical pronged cannula (ACTRN12623000235606). We are investigating whether different prong designs of asymmetrical cannulas influence ventilation during nasal high flow therapy in healthy volunteers. The study will compare any differences in ventilation between cannulas with curved and straight prongs (Duet [currently available] and Duet 2 [unreleased], Fisher & Paykel Healthcare). Additionally, we are comparing the physiological effects of standard NHF therapy to NHF therapy that incorporates dynamic flow reduction during the expiratory phase. These findings may help refine and improve the efficiency of nasal high flow therapy. We hypothesise that the curved cannula will be the most beneficial design and that further benefits are seen when dynamic flow reduction is used.
Interventions
Participants will undertake a single, 150-minute trial that will be completed continuously on one day. For Part A of the trial, the effects of two asymmetrical cannulas (one with curved prongs (Duet) and one with straight prongs (Duet 2)) will be investigated and compared during nasal high flow (NHF) therapy. The cannula will be fitted around the participants head by the researchers, so that the cannula prongs sit comfortably inside their nostrils. The cannula is held in place by an elastic band
Participants will undertake a single, 150-minute trial that will be completed continuously on one day. For Part A of the trial, the effects of two asymmetrical cannulas (one with curved prongs (Duet) and one with straight prongs (Duet 2)) will be investigated and compared during nasal high flow (NHF) therapy. The cannula will be fitted around the participants head by the researchers, so that the cannula prongs sit comfortably inside their nostrils. The cannula is held in place by an elastic band. Participants will use both cannulas during the trial, separated by a short washout period; order will be allocated randomly. During Part A, baseline measures will be made for 15-minutes while participants sit at rest, after which the first 45-minute NHF therapy intervention, using one of the two cannulas, will be applied using an Airvo 3 unit (Fisher & Paykel Healthcare, New Zealand). For NHF therapy, participants will sit at rest while humidified, 37°C air is pumped through the prongs at 50 L/min to provide positive airway pressure (standard NHF). After the first intervention period, a 10-minute washout will be provided before participants complete a second 45-minute intervention period of NHF therapy, using the other cannula. At the end of this period, they will be asked to rate the comfort of each cannula and which they preferred. For Part B, the effects of standard NHF, as outlined above, will be compared with NHF therapy that incorporates dynamic flow reduction during exhalation. The cannula used in the second intervention will remain in place and participants will immediately complete a further 45-minutes of NHF therapy. For this, the settings on the Airvo 3 unit will be changed to activate expiratory relief mode. Air flow from the Airvo 3 unit will be reduced by 30% (35L/min, 37°C). Expiratory relief will be applied for an additional 45-minutes so that any changes in ventilation resulting from the different mode can be measured and compared to the standard high flow mode. NHF therapy will be administered and supervised throughout the trial by the researchers in the laboratory. Adherence will be monitored by continuous, direct observation by the researchers.
Sponsors
School of Sport, Exercise & Nutrition, Massey University
Study design
Allocation
Randomised controlled trial
Intervention model
Other
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject)
Eligibility
Sex/Gender
All
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
Participants must be healthy, aged between 18 and 60 years and free of nasal/upper airway pathophysiology.
Exclusion criteria
To ensure quality of data collected and participant safety and comfort, participants will be excluded from the study if they meet any of these exclusion criteria: • They smoke or vape. • They have a long-term (greater than 12-months) breathing (those with well controlled asthma may participate), heart, or muscle conditions. • They have a blocked nose or a nose shape that prevents the study equipment (Nasal cannula) from fitting properly. • They have skin problems (such as rashes, open wounds, or burns) where ECG stickers or EIT belt would be placed. • They have an implanted electronic device, such as a pacemaker or defibrillator. • They are unable to stay still during the measurements (~ 45 min each tested condition). • They find nasal high flow (NHF) therapy uncomfortable or cannot tolerate it. • For cultural/personal reasons, they do not give permission to have equipment placed on their head and face. • They have had a cold or any respiratory infection symptoms within the last two weeks. • They are currently pregnant or think they may be pregnant.
Outcome results
None listed