Ventilator-Associated Pneumonia: The Role of Kidney–Lung Crosstalk and Renal Replacement Therapy, a Narrative Review

Background/Objectives: Multiple organ dysfunction syndrome (MODS) results from dynamic inter-organ interactions rather than isolated organ failures. Among these, kidney–lung crosstalk is a key determinant of outcomes in critically ill patients. Acute kidney injury (AKI) promotes pulmonary dysfunction through hemodynamic, inflammatory, endothelial, and metabolic mechanisms, while acute respiratory failure and mechanical ventilation may aggravate renal injury. Ventilator-associated pneumonia (VAP) may represent a clinical consequence of these interactions, although causality remains uncertain. Renal replacement therapy (RRT) may further influence kidney–lung crosstalk through several physiological mechanisms. To summarize current evidence on kidney–lung crosstalk, evaluate its potential contribution to VAP susceptibility, and examine the role of RRT in modulating these interactions.