This monocentric, randomized crossover study aims to assess the impact of high-flow tracheal therapy (HFT) on the rheological properties of tracheobronchopulmonary secretions in tracheostomized patients. The primary objective is to compare the viscoelastic characteristics of secretions collected with and without HFT. Secondary objectives include evaluating the effects of HFT on dyspnea, patient comfort, and secretion appearance. The study will take place at Cliniques Universitaires Saint-Luc, with adult tracheostomized patients undergoing standard care.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
SINGLE
Enrollment
15
Device: Airvo 2 (Fisher \& Paykel Healthcare) Settings: Flow rate start at 40L/min and will be adapted according to tolerance; temperature aimed at 37°C or 34°C according to tolerance, FiO₂ set (if needed) according to SpO2 target values.
Cliniques universitaires Saint-Luc
Brussels, Belgium
Critical stress (σc)
The rheological properties measured using Rheomuco (Rheonova) will be sampled during a suctioning procedure. The critical stress σc = G\*(γc).γc, where G\*(γc) is the viscoelastic modulus measured at the critical strain, is the measured stress at which this transition occurs. See the description of the other rheological outcomes in the secondary outcomes.
Time frame: Measured three times: at baseline, after one hour, after 4 hours
Dyspnea (modified Borg scale)
The modified Borg Scale (from 0 : no dyspnea; to 10 : maximal dyspnea) will be used
Time frame: Measured two times: at baseline and after 4 hours
Patient Comfort (Visual Analog Scale - VAS)
The VAS (from 0 : extremely comfortable; to 10 : extremely uncomfortable) will be used
Time frame: Measured two times: at baseline and after 4 hours
Secretion Appearance (Murray Scale)
The Murray scale define the following secretion appearance: * Mucoid * Mucopurulent * Purulent
Time frame: Measured two times: at baseline and after 4 hours
Viscoelastic modulus (G*)
The rheological properties measured using Rheomuco (Rheonova) will be sampled during a suctioning procedure. The ratio of the stress to the strain, the viscoelastic modulus G\* , describes the molecular network force in response to shear. In viscoelastic materials, the viscous dissipation shifts in time the stress response to the imposed strain, which is quantified by the damping ratio tan δ. Both G\* and tan δ provide the viscous and elastic moduli, G' and G''. See the description of the other rheological outcomes in the secondary outcomes.
Time frame: Measured three times: at baseline, after one hour, after 4 hours
Damping ratio (tan δ)
The rheological properties measured using Rheomuco (Rheonova) will be sampled during a suctioning procedure. At given deformation, a damping ratio above 1 would describe a predominantly viscous material (G'' \> G'), i.e. that behaves like a liquid, whereas a damping ratio below 1 denotes a predominantly elastic material (G' \> G''), that exhibits a solid-like behavior.
Time frame: Measured three times: at baseline, after one hour, after 4 hours
Critical strain (γc)
The rheological properties measured using Rheomuco (Rheonova) will be sampled during a suctioning procedure. The viscoelastic characteristics are measured at increasing strains, ranging from about 1 % to about 10000 %. At a critical strain value, γc, typically around or above 1000 % for sputa, the G' and G'' curves cross over (the damping ratio overcomes 1). Beyond this critical point, the sample becomes predominantly viscous over elastic (fluid-like) under strain and starts to flow. See the description of the other rheological outcomes in the secondary outcomes.
Time frame: Measured three times: at baseline, after one hour, after 4 hours
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