Bacher A, Mayer N, Rajek A M, Haider W
Department of Anaesthesiology and General Intensive Care, University of Vienna, Austria.
Intensive Care Med. 1998 Apr;24(4):313-21. doi: 10.1007/s001340050573.
Acute normovolaemic haemodilution with subsequent autologous blood transfusion after surgery is widely used to reduce homologous blood requirements during cardiac surgery. The hypothesis tested was whether a low intraoperative haematocrit (Hct) resulting from haemodilution decreases gastric mucosal pH (pHi).
Prospective clinical investigation.
University Hospital of Vienna, Austria.
16 consecutive patients scheduled for elective cardiac surgery.
The patients were randomly assigned to one of two groups: In 10 patients (group 1), 500 ml of blood was withdrawn and stored after anaesthesia induction. An equal amount of 6% hydroxyethyl starch was simultaneously infused. After discontinuation of cardiopulmonary bypass (CPB), the autologous blood unit was transfused. Six patients (group 2), who were not subjected to haemodilution and autologous blood transfusion served as controls. In all patients, a gastric tonometry probe was inserted.
Measurements of pHi and Hct were performed before and after acute normovolaemic haemodilution, during pulsatile hypothermic (30-32 degrees C) CPB, after rewarming, and 30 min after autologous blood transfusion in group 1, and at corresponding time intervals in group 2. Repeated measures analysis of variance and the Mann-Whitney U test were used for statistical analysis. Data are presented as means +/- standard error of the mean. Haemodilution in group 1 caused a significant and persistent decrease in Hct (after haemodilution in group 1 34 +/- 1 vs 40 +/- 1% in group 2). In both groups, pHi decreased during rewarming and after termination of CPB. However, in group 1, pHi was better preserved than in group 2 (rewarming: 7.44 +/- 0.02 vs 7.34 +/- 0.04; after CPB: 7.38 +/- 0.03 vs 7.28 +/- 0.02; p < 0.05).
Acute normovolaemic haemodilution does not aggravate gastric mucosal acidosis during cardiac surgery.
急性等容性血液稀释并在术后进行自体输血，被广泛应用于减少心脏手术中对异体血的需求。本研究检验的假设是，血液稀释导致的术中低血细胞比容（Hct）是否会降低胃黏膜pH值（pHi）。
前瞻性临床研究。
奥地利维也纳大学医院。
16例择期心脏手术患者。
患者被随机分为两组：10例患者（第1组）在麻醉诱导后抽取500ml血液并储存，同时输注等量的6%羟乙基淀粉。体外循环（CPB）停止后，回输自体血。6例患者（第2组）未进行血液稀释和自体输血，作为对照组。所有患者均插入胃张力测定探头。
在第1组中，于急性等容性血液稀释前后、搏动性低温（30 - 32摄氏度）CPB期间、复温后以及自体输血后30分钟测量pHi和Hct，在第2组中于相应时间间隔进行测量。采用重复测量方差分析和曼-惠特尼U检验进行统计学分析。数据以平均值±平均标准误差表示。第1组的血液稀释导致Hct显著且持续下降（第1组血液稀释后为34±1%，第2组为40±1%）。两组中，pHi在复温期间和CPB结束后均下降。然而，第1组的pHi比第2组保存得更好（复温时：7.44±0.02对7.34±0.04；CPB后：7.38±0.03对7.28±0.02；p<0.05）。
急性等容性血液稀释在心脏手术期间不会加重胃黏膜酸中毒。
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