Identification of passive respiratory mechanics using Rapid Expiratory Occlusions (REOs)

Feasible methods to assess respiratory compliance and airway resistance without requiring clinical effort or interrupting normal breathing patterns would decrease the high burden of respiratory testing on healthcare systems. This study aims to provide proof of concept of a novel rapid expiratory occlusion (REO) test in a healthy adult population. REO test data was collected for unassisted spontaneous breaths and a PEEP challenge in N=80 healthy adults. Model-identified compliance and resistance values are compared to physiological expectations and literature. Median [min, max] compliance was 0.506 [0.199, 1.562] cmH 2 O −1 L, and resistance was 1.777 [0.811 2.478] cmH 2 OL −1 s in initial spontaneous breathing, matching expectations. When PEEP was applied compliance decreased (independent of PEEP level) and resistance increased (proportional to set PEEP). This study established proof-of-concept efficacy for a model-based REO method identifying compliance and resistance, and informs device development and testing for clinical populations. • Identifiability of pulmonary mechanics parameters is a key issue in modelling spontaneous breathing from non-invasive test data. • Rapid Expiratory Occlusion (REO) allows per-breath and intra-breath passive mechanics to be identified. • REO thus allows active mechanics to be identified from the un-occluded breath profile and minimisation of parameter trade off.