Characterization of pulmonary function and mechanics in a novel model of pneumococcal pneumonia

Introduction: We characterized pulmonary function and mechanics in a novel model of severe pneumococcal pneumonia. Methods: Six pigs (33.5 ± 1.9 Kg) were anesthetized, intubated and on MV. Following surgical preparation, and 4 hours thereafter, 15 mL of 10 8 cfu/mL of S. pneumonia 19A was instilled into each pulmonary lobe. Every 24 hours, pulmonary function/mechanics and arterial pressure were assessed. Upon autopsy, 72 hours after bacterial challenge, pneumonia was confirmed if lung tissue S. pneumoniae was ≥ 3 log cfu/gram tissue. Results: Severe pneumonia was confirmed in 5 out of 6 pigs. S. pneumoniae concentration of the right upper, medium, lower lobe and the left upper and lower lobe was 4.6±2.1, 4.5±3.0, 3.3±2.7, 3.8±2.2 and 3.1±2.9 CFU/gram, respectively (p=0.796). Pulmonary function and mechanics significantly worsened throughout the study time. Conclusions: In a new model of severe invasive pneumococcal pneumonia, lung function and mechanics severely worsen. This model could be used to study pathophysiology and novel therapeutic/preventive strategies.