动态通气参数对急性呼吸窘迫综合征犬肺外炎症反应和肺外脏器功能的影响

目的 观察机械通气动态通气参数对急性呼吸窘迫综合征(ARDS)犬肺外炎症介质水平及肺外脏器功能的影响.方法 36条健康杂种犬,按照随机数字表法分为正常对照组(N组)、ARDS模型组(M组)及机械通气A-D组6组.采用气管内盐酸吸入法建立ARDS模型,按下述方案行机械通气.A组(LVLYHR):小潮气量、低吸气流速、高通气频率;B组(HVHFHR):大潮气量、高吸气流速、高通气频率;C组(HVHFLR):大潮气量、高吸气流速、低通气频率;D组(HVIYLR):大潮气量、低吸气流速、低通气频率.分组机械通气后4 h后处死动物,留取血清用放射性免疫吸附法行IL-8和TNF-α检测;留取肝肾组织行病理学检查.数据处理运用方差分析,以P<0.05为差异具有统计学意义.结果 B组、C组血中IL-8和TNF-α含量显著高于M组、A组、D组(P<0.05),A组、D组和M组差异无统计学意义(P>0.05).N组与其他相比差异具有统计学意义(P<0.05).B组肝肾组织病理学改变最为严重,C组较B组稍有减轻.A组和D组的病理学改变较B、C组明显减轻,A组和M组改变接近.结论 大潮气量、高吸气流速、高通气频率机械通气可以使血清炎症介质水平升高,加重肺外器官的炎症反应;降低通气频率及吸气流速,对防治多器官功能衰竭有重要意义.

Effects of dynamic ventilatory factors on extrapulmonary inflammatory response and function of extrapulmonary organs in a dog model of acute respiratory distress syndrome

Objective To investigate the effects of dynamic ventilatory factors on inflammatory response and function of extrapulmonary organs in acute respiratory distress syndrome (ARDS) dogs. Method Thirty-six healthy dogs were randomly divided into 6 groups: normal control group (N group), ARDS group ( M group) and ventilation groups (A～D groups)hased on a series of random number. The ARDS dog model was replicated by iutrawacheal instillation of hydrochloric acid and mechanical ventilation was carried out according to the following protocols. Group A:low VT, low inspiratory flow and high respiratory rate. Group B: large VT, high inspiratory flow and high respiratory rate. Group C: large VT, high inspiratory flow and low respiratory rate. Group D: large VT, low inspiratory flow and low respiratory rate. After 4 hours of mechanical ventilation, animals were sacrificed.Tumor necrosis factor (TNF)-α and intefleukin (IL)-8 levels in blood serum were measured by radioimmunoassay.Histopathological changes of liver and kidney were observed under light microscope. Results The level of IL-8 and TNF-u of group B and C were much higher than those of group D, A and M ( P<0.05), but there was no significant difference among group D, A and M ( P>0.05). The level of IL-8 and TNF-α of group N were much lower than other groups ( P<0.05). The change of histopathology was the most significant in group B and C while the change of histopathology on group C was better than group B. The change of histopathology on group A and D was better than group B and C. The change of group A was similar to group M. All the data were analyzed by statistical F test. There was statistical difference with P<0.05. Comclusions Large tidal volumes with high inspiratory flow and high respiratory rate may increase mediators of inflammation in blood sennn, and aggravate the irflamnnmtory response of extrapulmonary organs. Beducfion of inspiratory flow and respiratory rate ventilation may prevent the occurrence d multiple organ dysfunction syndrome.