Comparison of acid-induced inflammatory responses in the rat lung during high frequency oscillatory and conventional mechanical ventilation.

ABSTRACT

BACKGROUND: The present study was performed to compare the effects of high frequency oscillatory ventilation (HFOV) with conventional mechanical ventilation (CMV) on pulmonary inflammatory responses in a rat acid-induced lung injury model. METHODS: Anesthetized rats were instilled intratracheally with HCl (0.1 N, 2 mL/kg) and then randomly divided into three mechanical ventilation settings HFOV (an oscillatory frequency of 15 Hz, mean airway pressure (MAP) of 9 cmH(2)O), CMV at tidal volume of 12 and 6 mL/kg for 5 h. RESULTS: After HCl instillation, HFOV significantly attenuated the increases in neutrophil infiltration and TNF-α concentration in bronchoalveolar lavage fluid compared with the CMV groups. During HFOV, there was an inhibition of an increase in TNF-α mRNA expression and a decrease in SP-A mRNA expression induced by acid instillation. CONCLUSION: This animal study demonstrates that HFOV is a suitable form of mechanical ventilation to prevent inflammatory responses in acid-induced lung injury.