WS03.06A novel use of electrical impedance tomography in children with cystic fibrosis

Objectives

Around 40% of children with cystic fibrosis (CF) have tracheobronchomalacia (TBM), an increased airway collapsibility. TBM is associated with increased respiratory symptoms and hospitalisations requiring regular airway clearance (AWC). Electrical impedance tomography (EIT) is a novel technology that may assist the titration of positive expiratory pressure (PEP) to optimise AWC through ventilation visualisation. Our aim is to establish if EIT is a feasible, useful clinical outcome measure in non-sedated typically developing children with CF and TBM to titrate PEP therapy for AWC.

Methods

Ten children aged between one and fifteen years with CF and a previous TBM diagnosis were invited to participate in a feasibility study. Whilst monitored by EIT, participants performed two-minutes of PEP breathing at 5, 10, 15 and 20 cmH₂O, each followed by one minute breathing at no resistance. Outcome measures were determined for tolerability of the monitoring; ease of administration; interpretation by the clinician; and clinical feasibility. A score of 70% or above was deemed successful for each criterion to determine the overall feasibility of EIT in titrating PEP therapy for AWC.

Results

All criteria met success in domains of tolerability (mean 98%; range 86-100) and intervention completion (mean 95%; range 90-100). The EIT regions of interest display (mean 96%; range 80-100) and software data analysis (mean 96%; range 90-100) allowed differences in regional lung ventilation to be observed with different PEP resistances. Ease of clinical use criteria highlighted difficulties with automated software functionality and impact on clinician time (mean 66%; range 10-100 and 75%; 0-100 respectively). In 50% of children, recommendations for airway clearance routine changes were made.

Conclusion

In children with CF and TBM, EIT maybe a feasible tool for examining, titrating and optimising PEP for airway clearance.