University of Twente Student Theses


High Flow Nasal Cannula Therapy and Scaled Tidal Flow Volume Curves in Exercise Induced Bronchoconstriction of Children with Asthma

Beekman-Teeuw, M.M. (2023) High Flow Nasal Cannula Therapy and Scaled Tidal Flow Volume Curves in Exercise Induced Bronchoconstriction of Children with Asthma.

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Abstract:Rationale: High Flow Nasal Cannula (HFNC) therapy is increasingly used in acute severe asthma care. However, clinical evidence is low and evidence-based guidelines for the settings are lacking. Therefore, this research focused on the effect of HFNC-therapy on exercise provoked asthma of children in a prospective randomized cross-over trial. Moreover, the clinical use and feasibility of Scaled Tidal Flow Volume (STFV) curves is explored. These curves are derived from unobtrusive pressure measurements during tidal breathing and could aid in determining the best HFNC settings. They have not yet been determined in children with asthma or during HFNC therapy. Methods: Children with asthma, suspected to be severely uncontrolled, were approached to participate. They performed two Exercise Challenge Tests (ECTs), with either spontaneous recovery or recovery with HFNC therapy, in random order. When the bronchial lability was <30% participants were excluded. Prior to each ECT, baseline measurements were performed without HFNC therapy and with two different flowrates. After the ECT the measurements were repeated serially. Measurements consisted of spirometry, diaphragm electromyography and pressure in the HFNC device. The pressure measurements were converted to STFV curves. Results: Seven patients with asthma participated in this study. One of them met the bronchial lability criterium and performed 2 ECTs. This participant showed comparable recovery of lung function with HFNC therapy and during spontaneous recovery. The respiratory rate and parameters describing the shape of the STFV curves decreased. The electrical activity of the diaphragm increased. These results were in line with the baseline measurements in all 7 participants. In the measurements during spontaneous recovery STFV curves no relationship was found between the Ratio between Forced Expiratory Volume in 1 second and Forced Vital Capacity (FEV1/FVC-ratio) and the expected FEV1/FVC-ratio derived from the STFV curves (r = 0.006, p = 0.930). The feasibility of the STFV curves during HFNC therapy was 63% compared to 95% without HFNC therapy. Conclusion: The breathing pattern, and consequently the STFV curve, changes during HFNC therapy. Therefore, references for STFV-curves during HFNC therapy have to be made separately from references of STFV-curves that are measured without HFNC therapy. Furthermore, future research on HFNC therapy should focus on the effect of the change in breathing pattern and the clinical relevance of this effect.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:44 medicine
Programme:Technical Medicine MSc (60033)
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