Progression and variability of physiologic deterioration in an ovine model of lung infection sepsis

In this study, a lung infection model of pneumonia in sheep ( n = 12) that included smoke inhalation injury followed by methicillin-resistant Staphylococcus aureus placement into the lungs was used to investigate hemodynamic and pulmonary dysfunctions during the course of sepsis progression. To assess the variability in disease progression, animals were retrospectively divided into survivor ( n = 6) and nonsurvivor ( n = 6) groups, and a range of physiological indexes reflecting hemodynamic and pulmonary function were estimated and compared to evaluate variability in dynamics underlying sepsis development. Blood pressure and heart rate variability analyses were performed to assess whether they discriminated between the survivor and nonsurvivor groups early on and after intervention. Results showed hemodynamic deterioration in both survivor and nonsurvivor animals during sepsis along with a severe oxygenation disruption (decreased peripheral oxygen saturation) in nonsurvivors separating them from survivor animals of this model. Variability analysis of beat-to-beat heart rate and blood pressure reflected physiologic deterioration during infection for all animals, but these analyses did not discriminate the nonsurvivor animals from survivor animals. NEW & NOTEWORTHY Variable pulmonary response to injury results in varying outcomes in a previously reported animal model of lung injury and methicillin-resistant Staphylococcus aureus-induced sepsis. Heart rate and blood pressure variability analyses were investigated to track the varying levels of physiologic deterioration but did not discriminate early nonsurvivors from survivors.