Abstract
<jats:p>Mechanical ventilation may induce extrapulmonary responses shaped by the host inflammatory-metabolic background. This exploratory study characterized renal functional changes during 1 h of reduced-tidal-volume mechanical ventilation in male Wistar rats with diet-induced obesity or lipopolysaccharide (LPS)-induced endotoxemia, together with concurrent respiratory, acid–base, metabolic, and hemodynamic alterations. Arterial blood gas, biochemical, hemodynamic, and urinary variables were assessed at the pre-MV and post-MV time points. Renal protein expression was evaluated only at the post-MV time point. The arterial partial pressure of carbon dioxide (PaCO₂) decreased significantly in both groups. In the Obese group, metabolic acid–base abnormalities persisted and were accompanied by increases in serum urea and the urinary protein-to-creatinine ratio. In the LPS group, lactate increased, bicarbonate decreased, and mean arterial pressure and serum creatinine increased. At the post-MV time point, renal interleukin-6 expression was higher in the Obese group than in the LPS group, whereas renal tumor necrosis factor-alpha expression was higher in the LPS group than in the Obese group. These findings indicate that a shared reduction in PaCO₂ may coexist with phenotype-associated renal and systemic patterns. The results support the interpretation that physiological and renal changes observed during mechanical ventilation should be considered in relation to the underlying pathophysiology and inflammatory-metabolic context of the host.</jats:p>