Abstract:

Objective To investigate the effects of mechanical ventilation with different tidal volumes(VT) and positive end-expiratory pressure(PEEPs) on the lung edema in acute lung injury rabbit(ALI) models.Methods Thirty-six New Zealand rabbits were randomized into 6 groups(6 in each group). ①normal control group(NC), ② ALI group(Lipopolysaccharides 50 μg/kg intravenously), ③CVLP group(ALI + ventilation with V_T 15 mL/kg and 5 cmH₂O PEEP), ④ CVHP group(ALI + ventilation with VT 15 mL/kg and 10 cmH₂O PEEP), ⑤ LVLP group(ALI + ventilation with V_T 8 mL/kg and 5 cmH₂O PEEP), ⑥ LVHP group(ALI + ventilation with V_T 8 mL/kg and 10 cmH₂O PEEP). The ALI models receiving ventilation with different tidal volumes and PEEPs were ventilated for 4 h. Lung wet-to-dry weight(W/D) ratio was used to assay the lung edema.Results The W/D ratios in CVLP group(5.47±0.28), CVHP group(5.25±0.12), LVLP group(5.24±0.12) and LVHP group(5.12±0.10) decreased significantly(P<0.05) as compared with that of the ALI group(5.84±0.20), but increased(P<0.05) as compared with the NC group(4.81±0.19). The W/D in LVHP group was lower than that in CVLP group(P<0.05).Conclusion Ventilation attenuates lung edema in ALI models. Ventilation with both low V_T and high PEEP is more beneficial for lung edema in ALI.

Key words: acute lung injury, ventilation, lung edema