Ventilator driving pressure correlates with neuroinflammation in healthy pigs ventilated for 50 hours

Abstract

<b>Introduction:</b> Total exposure to ventilator driving pressure (VDP) is associated with increased mortality in patients receiving mechanical ventilation (MV). An association has been established between MV and increased hippocampal inflammation (HI). This study investigates a potential correlation between HI and total exposure to VDP. <b>Methods:</b> Two groups of pigs with healthy lungs received volume control MV (PEEP 5cmH2O, tidal volume 8ml/kg) for 50 hours: MV (n=10), and MV with temporary transvenous diaphragm neurostimulation on every breath (MV+TTDN100%, n=7) delivered as previously published. The hippocampus was harvested and ionized calcium-binding adapter molecule-1 (IBA-1) and glial fibrillary acid protein (GFAP) assays were used to stain microglia and astrocytes, respectively. VDP was measured hourly and total exposure was calculated as the area under the curve. Spearman correlation was used for statistical analyses. <b>Results:</b> Total exposure to VDP and HI measures were significantly lower in the MV+TTDN100% group than in the MV group. Total exposure to VDP showed a moderate correlation with hippocampal IBA-1-positive cells r=0.67 (p=0.0059) and a strong correlation with GFAP-positive cells r=0.78 (p=0.0003, figure). <b>Conclusion:</b> Ventilator driving pressure is moderately to strongly correlated with HI in pigs with healthy lungs mechanically ventilated for 50 hours. TTDN reduces VDP and HI compared to MV alone.