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.
Age ≥18 years
Weaning from mechanical ventilation with tracheostomy
Longstanding tracheostomy, defined as tracheostomy being present prior to current hospital admission
Tracheostomy primarily indicated for chronic upper airway obstruction or to secure airway patency due to persistent stupor/coma
Chronic positive pressure respiratory support at home (excluding night-time continuous positive airway pressure for sleep apnea)
Mucociliary disease in medical history (e.g. cystic fibrosis, pulmonary ciliary dyskinesia)
Crossover
Oxygen therapy
DeviceAll 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.
Sputum viscoelasticity
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.
Sputum visco-elasiticity
The difference between COT and HFTO in change in sputum viscoelasticity from baseline to the end (after 10-90 min) of the early disconnection session
Dyspnea presence
The presence of self-reported dyspnea sensation during early (\<90 min) and late (12 hour) disconnection sessions. Presence of self-reported dyspnea and discomfort is evaluated by asking patients.
Respiratory effort
The difference in respiratory effort between conventional oxygen therapy and high-flow oxygen therapy during early disconnection sessions measured by median esophageal pressure swing and pressure time product during the early disconnection session.
Dyspnea severity
The severity of self-reported dyspnea sensation during early (\<90 min) and late (12 hour) disconnection sessions. Severity of self-reported dyspnea is evaluated using a dyspnea visual-analog scale (D-VAS)
Click on the lead sponsor to view all of their trials.
Henrik Endeman
Lead sponsor
Erasmus Medical Center
Sponsor institution
Fisher and Paykel Healthcare
Collaborator
