Quantification of Regional Lung Microstructure Response to Positive End-Expiratory Pressure by Hyperpolarized Gas MRI in Surfactant-Deficient Rats

Maurizio F. Cereda¹, Kiarash Emami², Stephen J. Kadlecek², Yi Xin², Puttisarn Mongkolwisetwara², Harilla Profka², Amy Barulic², Stephen Pickup², Nicholas N. Kuzma², Masaru Ishii³, Hooman Hamedani², Benjamin M. Pullinger², Rajat Ghosh², Jennia Rajaei², Clifford S. Deutschman¹, Rahim R. Rizi²

Positive end expiratory pressure (PEEP) protects surfactant deficient lungs from lung injury during mechanical ventilation. The mechanisms of this effect have not been established at the alveolar level. We used hyperpolarized gas MRI to quantify the effects of PEEP on lung microstructure on the alveolar and distal airspace level in surfactant deficient lungs. We show that, in spite of the increase in inspiratory pressures, PEEP alleviates airspace overdistension caused by surfactant deficiency. This technique can provide unique pathophysiological insight in the mechanisms of ventilator-associated lung injury.