Physiological Effect High-flow Tracheal Oxygen on Viscosity of Airway Mucus and Respiratory Effort in Patients Weaning From Invasive Mechanical Ventilation

Condition(s) studied

Investigational drug(s) / intervention(s)

Oxygen therapy: All patients are subject to both oxygen therapy groups in this randomized cross-over study. Study measurements are performed during several different disconnection sessions. Disconnection sessions can either be short (\<90 min) or long (12 hours). Both short and long disconnection sessions are performed twice; once with conventional oxygen, and once with high-flow tracheal oxygen as respiratory support.

Study summary

Rationale: Tracheostomized patients weaning from mechanical ventilation are at risk for dryness of airway mucosa and sputum accumulation during disconnection from mechanical ventilation. High-flow tracheal oxygen (HFTO) is being used as supportive therapy during disconnection sessions in tracheostomized patients weaning from invasive mechanical ventilation (IMV) to limit dryness while maintaining oxygenation. We recently summarized the studies comparing physiological effects HFTO as compared to other interfaces, collectively referred to as conventional oxygen therapy (COT), in a systematic review and identified areas of lacking knowledge: effect on sputum viscoelasticity, respiratory effort early in the weaning process and dyspnea sensation. We hypothesize that HFTO, compared to COT, decreases viscoelasticity of the sputum and provides respiratory support during weaning. This may improve weaning by facilitating clearance of airway mucus, preventing respiratory failure, and providing comfort by decreasing dyspnea.

Objective: To determine the physiological effect of HFTO compared to COT on sputum viscoelasticity, respiratory effort and dyspnoea.

Study design: Pilot study with randomized crossover design, single-center. Study population: Twenty adult patients weaning from mechanical ventilation with tracheostomy.

Intervention (if applicable): Crossover with COT and HFTO during two days in the weaning phase.

Main study parameters/endpoints: Primary endpoint: sputum viscoelasticity measured by rheology during long disconnection sessions in the final phase of weaning. Secondary endpoints: respiratory effect measured by swings in esophageal pressure (PES) and prevalence and severity of dyspnoea sensation by visual analogue scale (VAS).

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The study compares two therapeutic modalities both used in clinical care without side-effects or complications. Study procedures and measurements consist of standard clinical procedures that are performed daily in clinical setting with negligible risk of deterioration for the patient. During weaning with HFTO sputum clearance might be more easy for the patient and respiratory effort might decrease, both are assumed to be beneficial for the weaning process of the patient.

Eligibility

Primary outcome measure(s)

• Sputum viscoelasticity — The 12-hour disconnection session
  During disconnection from the ventilator patients do not breathe actively heated and humidified gas mixtures. During disconnection from the ventilator the airway mucus thickens. This thickening can be quantified by measuring visco-elasticity and at the end of the disconnection sessions. The change in visco-elasticity between the start and end of the disconnection session will be compared within patients between disconnection sessions with HME and HFTO. Hence, the primary end-point is the change in sputum viscoelasticity from baseline to the end of the long disconnection sessions (≥12 hours). Viscoelastic (G\*) is made up of elasticity (G') and viscosity (G'') of mucus at a 5% strain rate (or linear viscoelastic region, which reflects the small deformation regime) and the critical stress (σ critical)· and strain (y critical) of mucus, which reflect the behavior of mucus under high amounts of shear stress and thus the large deformation regime.

Trial sites (1)

Other trials for the same condition