ObjectiveTo investigate the effects of different tidal volume on lung injury in patients with acute respiratory distress syndrome(ARDS).
MethodsThe respiratory system compliance(C)=0.6 mL·cmH2O-1·kg-1 was set as the critic point, the patients were divided into the C≥0.6 group9 cases with (C)≥0.6 mL·cmH2O-1·kg-1 and C < 0.6 group(10 cases with C < 0.6 mL·cmH2O-1·kg-1).At different tidal volume (6 mL/kg.IBW, 8 mL/kg.IBW, 10 mL/kg.IBW, 12 mL/kg.IBW), the end-expiratory lung volume(EELV) was detected, the pulmonary strain was calculated, and the changes of peak pressure(Ppeak) and plateau pressure(Pplat) were observed.
ResultsWith the increasing of tidal volume, the Ppeak and Pplat increased, and the Pplat was ≤30 cmH2O.The differences of the Pplat between the tidal volume of 6 mL/kg.IBW and 8 mL/kg.IBW, 10 mL/kg.IBW, 12 mL/kg.IBW were statistically significant(P < 0.05).When the tidal volume increased gradually from 6 mL/kg.IBW to 12 mL/kg.IBW, the the pulmonary strain increased from (0.31±0.27) to (0.52±0.46), and the tidal volume was positively correlated with pulmonary strain(r=0.978, P < 0.01).Compared with 6 mL/kg.IBW, the pulmonary strain in C≥0.6 group significantly increased under 12 mL/kg.IBW tidal volume ventilation, and the difference of which was statistically significant(P < 0.05).Under 10 mL/kg.IBW and 12 mL/kg.IBW tidal volume ventilation, the pulmonary strain was more than 0.27.Compared with VT=6 mL/kg.IBW, the differences of the pulmonary strain in C < 0.6 group among 8 mL/kg·IBW, 10 mL/kg·IBW and 12 mL/kg.IBW tidal volume ventilation were not statistically significant(P>0.05), and the pulmonary strain under different tidal volumes was more than 0.27.
ConclusionsFor the ARDS patients with C≥0.6mL·cmH2O-1·kg-1, the tidal volume increasing to 8 mL/kg.IBW does not aggravate lung injury.For the ARDS patients with C < 0.6mL·cmH2O-1·kg-1, the ventilation with 6 mL/kg.IBW tidal volume can still aggravate lung injury.
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