A Customised Mechanical Ventilator for Combined Oscillometry and X-ray CT Ventilation Imaging

Combining dedicated X-ray imaging methods, such as K-edge subtraction (KES) or spectral photon-counting CT (SPCCT) imaging, with respiratory oscillometry offers a unique opportunity to investigate the relationship between regional heterogeneity and global lung mechanics with high precision in in vivo models of respiratory pathologies. However, with current technology, these techniques cannot be performed simultaneously during mechanical ventilation without disconnecting the subject from the ventilator. We developed and in vitro validated a mechanical ventilator capable of delivering common pressure-supported modes, estimating respiratory mechanics via oscillometry, and performing rapid gas-mixing switches for SPCCT ventilation imaging, while minimizing tracer (Xenon) gas waste. The system consists of a blower-based ventilator able to switch between open and closed-circuit architecture, enabling fast switching between configurations for Xenon wash-in and wash-out. Bench testing confirmed accurate pressure waveform delivery, precise FiO₂ control, and reliable measurement of respiratory mechanics. The rapid switch between open- and closed-circuit modes minimized Xenon consumption. in vitro tests in a ventilated rabbit model confirmed the capability of enabling oscillometry and clinical SPCCT during mechanical ventilation. This ventilator provides a powerful tool for studying the correlation between regional ventilation defects and global respiratory mechanics, advancing our understanding of pulmonary pathophysiology and supporting the development of personalized, physiology-driven ventilation strategies.