控制性低中心静脉压对肝叶切除术患者小肠氧代谢的影响

目的 评价控制性低中心静脉压(CVP)对肝叶切除术患者小肠氧代谢的影响.方法 全麻下择期行肝叶切除术患者30例,ASA Ⅰ或Ⅱ级,随机分为3组(n=10):正常CVP常规输液组(Ⅰ组)、低CVP限制输液组(Ⅱ组)和低CVP常规输液组(Ⅲ组).Ⅰ组及Ⅲ组麻醉诱导前静脉输注乳酸钠林格氏液8～10 ml/kg,麻醉诱导期间开始静脉输注乳酸钠林格氏液和6%羟乙基淀粉130/0.4(1:1)10～15 ml·kg-1h-1.Ⅱ组麻醉诱导前静脉输注乳酸钠林格氏液1 ml/kg,麻醉诱导期间开始静脉输注乳酸钠林格氏液1 ml·kg-1·h-1,至肝实质完全离断前.Ⅱ组和Ⅲ组开腹前静脉注射呋塞咪10 mg,开腹后静脉输注硝酸甘油0.05～0.8μg·kg-1·min-1,在肝实质开始离断前降低CVP至0～5 cm H2O并维持到肝实质完全离断,肝实质完全离断后停用硝酸甘油并快速静脉输注乳酸钠林格氏液和6%羟乙基淀粉130/0.4,使CVP>6 Cm H2O.分别于开腹后降CVP前(T1)及肝实质完全离断后升高CVP前(T2)取桡动脉血样和肠系膜上静脉血样,进行血气分析,测定乳酸盐浓度,计算动脉血氧含量(CaO2)、静脉血氧含量(CsmvO2)、氧摄取率(ERO2)和肠系膜上静脉-动脉乳酸盐浓度差(Dsmv-aBL).结果 与T1时比较,三组T2时CaO2和CsmvO2均下降(P<0.05),但都在正常范围内,ERO2和Dsmv-aBL差异无统计学意义(P>0.05).三组各时点PaO2、SaO2、CaO2、CsmvO2、ERO2和Dsmv-aBL比较差异无统计学意义(P>0.05).结论 控制性低CVP对肝叶切除术患者小肠氧代谢无不良影响,提示机体的氧供需仍能保持平衡.

Effect of controlled low central venous pressure on small intestinal oxygen metabolism in patients undergoing hepatic lobectomy

Objective To investigate the effect of controlled low central venous pressure (CVP) on intestinal oxygen metabohsm in patients undergoing hepatic lobectomy.Methods Thirty ASA Ⅰ or Ⅱ patients with fight liver tumor aged 27-60 yr weighing 48-85 kg undergoing elective hepatic lohectomy under general anesthesia were randomly divided into 3 groups (n=10 each) : group Ⅰ normal CVP + conventional fluid administration; group Ⅱ low CVP + restricted fluid administration and group Ⅲ low CVP + conventional fluid administration.The patients were premedicated with intransuscular diazepam 10 mg and atropine 0.5 mg. Anesthesia was induced with midazolam, fentanyl, propofol and vecuronium and maintained with isoflurane inhalation, propofol infusion and intermittent iv boluses of fentanyl and vecuronium. The patients were mechanically ventilated (VT=10 ml/kg,RR= 10-13 bpm). Group Ⅰ and Ⅱ received lactated Ringer's solution (LRS) 8-10 ml/kg before induction of anesthesia and LRS and 6% hydroxyethyl starch (HES) 130/0.4 (in a ratio of 1 : 1) were infused at 10-15 ml·kg-1·h-1 during operation. Group Ⅱ received LRS 1 ml/kg before induction of anesthesia and LRS infused was continued at 1 ml·kg-1·h-1 during the course of operation until the diseased liver parenchyma was removed. In group Ⅱ and Ⅲ CVP was controlled at 0-5 cm H2O by intravenous nitroglycerin infusion after abdomen was opened until the diseased liver parenchyma was removed. Blood samples were obtained from radial artery and superior mesentefic vein (SMV) for blood gas analysis and determination of lactate concentration before CVP was lowered (T1) and at the end of low CVP (T2). Arterial O2 content (CaO2),O2 content of SMV blood (CsmvO2), oxygen extraction ratio (ERO2) and difference in blood lactate between artery and SMV (Dsmv-aBL)were calculated. Results CaO2 and CsmvO2 were significantly decreased at T2 as compared with the baseline before CVP was lowered at T1 in all 3 groups (P < 0.05) but were still within normal range. There was no significant diference in ERO2, Dsmv-aBL, PaO2, SaO2, CaO2 and CsmvO2 at both T, and T2 among the 3 groups. Conclusion Low CVP has no significant adverse effect on intestinal oxygen metabolism in patients undergoing hepatie lobectomy.