不同程度的非气性腹腔内加压对大鼠血流动力学及代谢的影响

目的 评价不同压力梯度的非气性腹腔内压对大鼠血流动力学及代谢的影响,明确麻醉状态下大鼠的安全腹腔内压力范围.方法 Wistar大鼠24只,随机分配进入0、5、10、15mmHg 4个不同程度的腹腔加压组,分别以IAP0、IAP5、IAP10、IAP15表示,每组6只.腹腔内加压采用非扩张性气囊,依据分组不同进行不同程度的腹腔加压,时间30mmin.分别于基础状态(S1)、腹腔内加压末期(S2)、去除腹压后20min(S3)、去除腹压后40min(S4)4个时间点,自大鼠股动脉抽取动脉血气标本,测定血pH、PaO2、PaCO2、HCO3-、碱剩余(BE)及乳酸(LAC)水平.实验结束前,留取血液用于测定血清谷丙转氨酶(ALT)及血肌酐(Cr)水平.整个实验过程中通过右侧颈动脉插管,监测动物平均动脉压(MAP)及心率(HR)变化.结果 实验期间各组动物均无死亡.S2期IAP15组大鼠MAP较IAP0组下降42％(P＜0.01),而IAP5、IAP10组MAP未见明显下降(P＞0.05).各组动物在S1、S2、S3、S4期HR变化均不明显(P＞0.05).动脉血气方面,IAp15组动物于S2、S3期时pH值较其他各组明显下降(p＜0.01),S4期时PH仍末完全恢复正常(P=0.045).各组间不同时点PaO2、PaCO2均未发生明显改变(P＞0.05).S2、S3、S4期,IAP15组大鼠LAC值均明显高于IAP0、IAP5、IAP 10组(P＜0.01),而HCO3-、BE值明显低于其他3组(P＜0.01).与其他3组比较,IAP15 ALT值明显升高(P＜0.01),各组之间血Cr未见明显变化(p＞0.05).结论 麻醉状态下大鼠可耐受10mmHg下的安全非气性腹腔内压,应避免采用15mmHg的腹腔内加压.

Hemodynamic and metabolic changes as a result of application of different degrees of nonpneumatic intra-abdominal compression in rats

Objective To assess effects of different degrees of non-pneumatic intra-abdominal high pressure on metabolism and hemodynamics for the purpose of selecting the safe range of intra-abdominal pressure in anesthetized rats.Methods Twenty four male Wistar rats were anesthetized and randomly distributed into four groups (IAP0, IAP5, IAP10, IAP15) (n=6). All the rats underwent 30 minutes of intra-abdominal distension resulting in 0, 5, 10 or 15mmHg of intra-abdominal pressure with a non-pneumatic device.Arterial blood were collected at following 4 time points: baseline,end of insufflation,20 and 40min after desufflation respectively for assaying arterial blood pH,PaO2,PaCO2,HCO3-,base excess(BE),lactic acid(LAC).At the end of experiment,serum alanine aminotransferase(ALT) and creatinine(Cr) were determined.Mean artery pressure(MAP) and heart rate(HR) were monitored via right carotid catheter throughout the experiment.Results No death occurred in each group.MAP in IAP15 group decreased by 42 percent when compared with that in IAP0 group(P<0.01),while MAP in groups of IAP0,IAP5 and IAP10 remained stable in the period of insufflation.There was no HR changes in the four groups(P>0.05).The pH values at the period of insufflation and at 20min after desufflation in IAP15 group were significantly lower than those in other groups(P<0.01). The pH value did not return to a normal level 40min after desufflation(P=0.045).There were no significant changes in PaO2 and PaCO2 at different time points in all the groups(P>0.05).Significantly higher LAC level and significantly lower HCO3-and BE level were seen in IAP15 group compared with those of IAP0,IAP5,IAP10 groups at the end of the insufflation and at 20 and 40min after desufflation(P<0.01).The value of ALT was twice higher in IAP15 group than in IAP0,IAP5,IAP10 groups(P<0.01),while serum Cr showed no change in the four groups(P>0.05).Conclusion Safe limit of intra-abdominal pressures is less than 10mmHg,and intra-abdominal pressure of 15mmHg should be avoided in spontaneously breathing anesthetized rats.