Abstract #0823

Effect of Pulmonary Hysteresis on Airspace Dimensions During Positive End Expiratory Pressure Trials in Mechanically Ventilated Rats Using Hyperpolarized Gas Diffusion MRI

Maurizio Cereda¹, Yi Xin², Kiarash Emami², Jessie Huang², Jennia Rajaei², Harrilla Profka², Biao Han², Puttisarn Mongkolwisetwara², Stephen J. Kadlececk², Nicholas N. Kuzma², Stephen B. Pickup², Brian Kavanagh³, Clifford Deutschman¹, Rahim Rizi²

¹Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, United States; ²Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; ³Departments of Critical Care Medicine and Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada

Using hyperpolarized gas MRI, we provide evidence supporting the role of airspace recruitment, rather than expansion, in ventilated healthy rats without atelectasis. Our results showed that hysteresis was associated with a decrease in the size of ventilated airspaces. These results, obtained through imaging, are relevant because they contribute to the clarification of a controversial physiological mechanism. Furthermore, this study provides an additional rationale for investigating strategies that may minimize pulmonary stress.