羟乙基淀粉和林格液对感染性休克犬内脏器官灌注的影响

目的 探讨感染性休克时复苏液体对内脏器官灌注的影响。方法 用指多糖(LPS)静脉注射复 制犬感染性休克模型,随机分为羟乙基淀粉(HES)组和林格液(RS)复苏组。模型成功后稳定1 h记为0 min, 分别予以HES和RS复苏60 min(1 ml·kg-1·min-1),然后以同等速度输入生理盐水维持180 min。经肺动 脉漂浮导管和脉搏指示持续心排血量(PiCCO)导管监测心排血量(CO)、中心静脉压(CVP)、肺动脉楔压 (PAWP),胸腔内血管容量(ITBVI),平均动脉压(MAP)等血流动力学指标并计算心排血指数(CI);行动脉 血气分析,记录乳酸水平,并计算氧输送指数(DO2)、氧耗指数(VO2);用电磁流量计记录肠系膜血流量;用胃 肠张力计监测肠黏膜二氧化碳分压(PgCO2),计算肠黏膜-动脉二氧化碳分压差(Pg-aCO2)和肠黏膜pH值 (pHi)。记录制模前及复苏0、30、60、120、180和240 min两组血流动力学、氧代谢、内脏器官灌注等指标的变 化。结果 ①血流动力学改变:与制模前比较,0 min两组MAP和CI均明显降低(P均<0．05)。与0 min比 较,HES组30 min后MAP明显升高,60 min后恢复到制模前水平,而RS组MAP也明显升高,120 min后恢 复至制模前水平(P均<0．05);液体复苏30 min后,两组CI和ITBVI均明显升高(P均<0．05),240 min仍 明显高于0 min,但两组间差异无显著性。②全身氧代谢改变:制模后两组动物DO2和动脉血pH均明显降低, 动脉乳酸水平明显升高。液体复苏30 min后,两组DO2均明显升高,HES组DO2显著高于同时期RS组 (P<0．05)。与0 min比较,两组动物液体复苏180 min后动脉乳酸水平明显降低,但两组间差异无显著性。 ③内脏器官灌注改变:与制模前比较,0 min两组肠系膜血流量均显著降低。与0 min比较,HES组在液体复 苏60 min后肠系膜血流量升高,RS组无增加,且显著低于同时期HES组(P<0．05)。HES组在液体复苏后 肠系膜血流量明显升高的同时伴有Pg-aCO2降低和pHi明显上升(P均<0．05);而RS组复苏后Pg-aCO2 明显升高,pHi呈下降趋势,显著低于同时期HES组(P<0．05)。结论 RS和HES液体复苏均有利于升高血 压,提高氧输送,改善感染性休克时的血流动力学状态;但在改善内脏器官灌注上HES可能优于RS。

Effect of hydroxyethyl starch and Ringer's solution on splanchnic perfusion in dogs with septic shock

OBJECTIVE: To investigate the effect of 6% hydroxyethyl starch (HES) and Ringer's solution (RS) on splanchnic perfusion in dogs with septic shock. METHODS: Twenty-four mongrel dogs with septic shock induced by lipopolysaccharides (LPS) were randomly divided into two groups: HES group and RS group. Dogs of each group received an intravenous infusion of HES or RS (1 mlxkg(-1)xmin(-1)) for 60 minutes, followed by normal saline for 180 minutes with same infusion speed. Parameters of hemodynamics, oxygen dynamic, and splanchnic perfusion were monitored at 0, 30, 60, 120, 180, 240 minutes after basic measurements (pre-LPS). RESULTS: (1) After LPS infusion, mean arterial pressure (MAP) and cardiac index (CI) lowered significantly (P<0.05). Compared to that of 0 minutes, MAP and CI were elevated by fluid therapy in both groups, but there was no difference between HES and RS group. (2) Compared with pre-LPS, oxygen delivery (DO(2)) was reduced, arterial blood pH lowered and arterial lactate level increased markedly at 0 minutes (P<0.05). DO(2) increased by fluid therapy in both groups, but DO(2) was higher in HES group at the same time points (P<0.05). Compared to 0 minutes, arterial lactate levels were lowered at 180 minutes in both groups. (3) Mesenteric blood flow decreased after LPS infusion in all animals (P<0.05). Mesenteric blood flow increased after HES infusion, at the same time intramucosal pH (pHi) was elevated and Pg-aCO(2) decreased significantly (all P<0.05), but they showed no difference in RS group. At the same time, mesenteric blood flow and pHi was higher in HES group than that in RS group. CONCLUSION: Both HES and RS could improve MAP and DO(2) in dogs with septic shock, but the effect of HES was better than RS on splanchnic perfusion.