American journal of respiratory cell and molecular biology
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Am. J. Respir. Cell Mol. Biol. · Jun 2006
Comparative StudyBactericidal function of alveolar macrophages in mechanically ventilated rabbits.
Protective ventilation strategies have been universally embraced because of reduced mortality. We tested the hypothesis that tidal volume (VT) in an in vivo model of mechanical ventilation would modulate bactericidal function of alveolar macrophages (AMs). Adult New Zealand White rabbits were mechanically ventilated for 4 h with a VT of 6 ml/kg (low) or a VT of 12 ml/kg (traditional), with each group receiving 3 cm H2O positive end-expiratory pressure with and without intratracheal lipopolysaccharide (LPS) instillation (20 mg/kg). ⋯ Lung wet:dry weight ratio in the traditional VT group was increased when compared with the low VT group without LPS (7.3 +/- 0.4 versus 6.1 +/- 0.3, respectively; P < 0.05). Additionally, IL-8 expression was significantly greater under conditions of LPS treatment and mechanical ventilation at VT of 12 ml/kg. These results suggest that the traditional ventilator approach (12 ml/kg VT) in a model of in vivo mechanical ventilation results in lung pathology without affecting AM antibacterial function.