Objective To investigate the effect of intra-abdominal hypertension(IAH) on respiratory function in pigs.Methods Twelve pigs were randomly divided into two groups (n=6 in each group),ie.IAH20 group(intra-abdominal pressure=20 mm Hg) and IAH30 group(intra-abdominal pressure=30 mm Hg).Pig model of IAH was established by intraperitoneally injection of carbon dioxide.The changes in respiratory function parameters including pulmonary dynamic compliance（Cdyn），peak inspiratory pressure(PIP) ,SpO2 and PaCO2 were recorded at different time points.Results Cdyn was significantly decreased at different time points compared with baseline in group IAH30 and group IAH20.PIP significantly increased at different time points compared with baseline in both IAH groups，but group IAH30 was more severe than group IAH20. No significant changes of SpO2 and PaCO2 were found in two IAH groups.Conclusion IAH can impair respiratory function by decreasing lung compliance and increasing inspiratory pressure.
【摘要】 目的 探讨腹水引起的腹内高压对肝硬化小鼠肺组织水通道蛋白1（AQP1）和水通道蛋白5（AQP5）表达的影响。 方法 雄性美国癌症研究所（Institudo of Cancer Reseach，ICR）小鼠50只，随机取10只作正常对照组（腹压0 cm H2O，1 cm H2O=0.098 kPa），其余40只用四氯化碳建立肝硬化小鼠模型，并随机分为4组:肝硬化（腹压0 cm H2O）组、肝硬化（腹压5 cm H2O）组、肝硬化（腹压10 cm H2O）组、肝硬化（腹压20 cm H2O）组，通过腹腔注射不同量的白蛋白生理盐水形成不同的腹压，并维持腹压24 h后取肺组织行病理、免疫组织化学、肺湿/干比值及实时荧光定量PCR检测AQP1和AQP5 mRNA表达量。 结果 与正常对照小鼠相比，肝硬化小鼠肺AQP5、AQP1表达明显下降（Plt;0.05）；肝硬化小鼠随着腹内压的升高，肺湿/干比值升高，AQP5、AQP1表达相应增加（Plt;0.05）。 结论 肝硬化可以影响肺AQP1、AQP5的表达；肝硬化小鼠随着腹内压的升高，AQP1、AQP5表达相应增加，并与肺水肿的严重程度密切相关。【Abstract】 Objective To investigate the role of intra-abdominal hypertension caused by ascites on the expression of Aquaporin (AQP) 1 and AQP 5 in the lung of cirrhotic mice. Methods We randomly chose 10 from 50 male Institude of Cancer Research (ICR) mice to form the control group [intra-abdominal pressure (IAP)=0 cm H2O, 1 cm H2O=0.098 kPa]. The model of cirrhosis were prepared by subcutaneous injection of carbon tetrachloride for the rest 40 mice which were then randomly divided into 4 groups: cirrhosis (IAP=0 cm H2O) group, cirrhosis (IAP=5 cm H2O) group, cirrhosis (IAP=10 cm H2O) group, and cirrhosis (IAP=20 cm H2O) group. Saline with different volume of albumin was injected into the peritoneum of each mouse in order to form different IAP. After 24 hours, analysis of pathology, immunochemistry and wet/dry ratio was done for the lungs of these mice; and the expression of AQP1 and AQP5 at the protein and mRNA levels were analyzed by IHC and qRT-PCR. Results Compared with the normal mice, the expression of AQP1 and AQP5 in lungs of cirrhotic mice were significantly lower (Plt;0.05). Both the lung wet/dry ratio and the expression of AQP1 and AQP5 raised with the increase of IAP. Conclusion Cirrhosis can affect the expression of AQP1 and AQP5 in lungs. The expression of AQP5 and AQP1 in lungs of cirrhotic mice increases with the increase of IAP, which is also closely correlated with the severity of pulmonary edema.
ObjectiveTo evaluate the effect of positive end-expiratory pressure (PEEP) on respiratory function and hemodynamics in acute lung injury (ALI) with intra-abdominal hypertension (IAH). MethodsSix pigs were anesthetized and received mechanical ventilation (MV). Volume controlled ventilation was set with tidal volumn(VT) of 8 mL/kg,respiratory rate(RR) of 16 bpm,inspired oxygen concentration (FiO2) of 0.40,and PEEP of 5 cm H2O. ALI was induced by repeated lung lavage with diluted hydrochloric acid (pH<2.5) until PaO2/FiO2 declined to 150 mm Hg or less to established ALI model. Intra-abdominal hypertension was induced by an nitrogen inflator to reach intra-abdominal pressure of 20 mm Hg. Respiratory parameters and hemodynamics were continuously recorded at different PEEP levels(5,10,15,and 20 cm H2O). Every level was maintained for one hour. ResultsPaO2/FiO2 in PEEP5,10,15 and 20 were 90±11,102±10,172±23 and 200±34 mm Hg respectively. PaO2/FiO2 in PEEP15 and 20 were significantly higher than those in PEEP5 and 10 (P<0.05). Chest wall compliance (Ccw) in PEEP5,15 and 20 were 26±3,76±15 and 85±14 mL/cm H2O respectively. Ccw in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in lung compliance (CL) in different PEEP levels (P>0.05). Plateau pressure(Pplat) in PEEP5,10,15 and 20 were 30±3,31±2,36±2 and 38±4 cm H2O respectively. Pplat in PEEP15 and 20 were significantly higher than those in PEEP5 and 10 (P<0.05). There was no significant difference in Pplat between PEEP15 and 20 (P>0.05). Heart rate (HR) in PEEP5,15 and 20 were 113±17,147±30,and 160±30 beat/min respectively. HR in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in HR between PEEP15 and 20 (P>0.05).Cardiac index (CI) in PEEP5 and 20 were 4.5±0.6 and 3.5±0.6 L·min-1·m-2 respectively. CI in PEEP20 was significantly lower than that in PEEP5 (P<0.05). There was no significant difference in CI in PEEP5,10 or 15(P>0.05). Central venous pressure(CVP) in PEEP5,15 and 20 were 12±2,17±2,and 18±3 mm Hg respectively. CVP in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in CVP between PEEP15 and 20 (P>0.05). There were no significant differences in MAP,SVRI,ITBVI,GEDI,PVPI,or EVLWI between different PEEP levels. ConclusionConcomitant ALI and IAH can induce great impairments in respiratory physiology. When PEEP is gradually increased,oxygenation and the respiratory function are improved without significant secondary hemodynamic disturbances.