不同潮气量对急性呼吸窘迫综合征病人肺损伤的影响

Effect of different tidal volume on lung injury in patients with acute respiratory distress syndrome

目的:探讨不同潮气量对急性呼吸窘迫综合征(ARDS)病人肺损伤的影响。方法:以呼吸系统顺应性(C)=0.6 mL·cmH2O^-1·kg^-1为界将ARDS病人分为2组,其中C≥0.6 mL·cmH2O^-1·kg^-1者9例,C<0.6 mL·cmH2O^-1·kg^-1者10例,分别记为C≥0.6组和C<0.6组。测定不同潮气量6 mL/kg.IBW、8 mL/kg.IBW、10 mL/kg.IBW、12 mL/kg.IBW)下的呼气末肺容积(EELV),计算肺应变,观察不同潮气量下气道峰压(Ppeak)、气道平台压(Pplat)等的变化。结果:纳入行机械通气的ARDS病人19例,C≥0.6组9例,C<0.6组10例。随着潮气量的增加,Ppeak和Pplat均逐渐增加,且Pplat均≤30 cmH2O。与6 mL/kg.IBW潮气量相比,8 mL/kg.IBW、10 mL/kg.IBW和12 mL/kg.IBW潮气量的Pplat差异均有统计学意义(P<0.05)。在所有病人中,潮气量由6 mL/kg.IBW逐渐增加至12 mL/kg.IBW时,肺应变由(0.31±0.27)逐渐增加至(0.52±0.46),且潮气量和肺应变呈显著正相关关系(r=0.978,P<0.01)。对于C≥0.6组的病人,与6 mL/kg.IBW潮气量相比,仅12 mL/kg.IBW潮气量的肺应变明显增加,差异有统计学意义(P<0.05),且10 mL/kg.IBW、12 mL/kg.IBW潮气量通气时肺应变>0.27。C<0.6组的病人中,与6 mL/kg.IBW潮气量相比,8 mL/kg.IBW、10 mL/kg.IBW和12 mL/kg.IBW潮气量的肺应变差异无统计学意义(P>0.05),且不同潮气量时肺应变均>0.27。结论:C≥0.6 mL·cmH2O^-1·kg^-1的ARDS病人,在机械通气时潮气量适当增加至8 mL/kg.IBW并不明显加重肺损伤;而C<0.6 mL·cmH2O^-1·kg^-1的病人即使采用6 mL/kg.IBW潮气量通气仍可致严重肺损伤。

Objective:To investigate the effects of different tidal volume on lung injury in patients with acute respiratory distress syndrome(ARDS).Methods:The 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 group[9 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.Results:With 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.Conclusions:For the ARDS patients with C≥0.6 mL·cmH2O^-1·kg^-1,the tidal volume increasing to 8 mL/kg.IBW does not aggravate lung injury.For the ARDS patients with C<0.6 mL·cmH2O^-1·kg^-1,the ventilation with 6 mL/kg.IBW tidal volume can still aggravate lung injury.