Acute normovolaemic haemodilution does not aggravate gastric mucosal acidosis during cardiac surgery

• Published in: Intensive care medicine Vol. 24; no. 4; pp. 313 - 321
• Main Authors: BACHER, A, MAYER, N, RAJEK, A. M, HAIDER, W
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-04-1998; Berlin Springer Nature B.V
• Subjects: Acidosis; Acidosis - etiology; Acidosis - metabolism; Aged; Analysis of Variance; Anesthesia; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Blood; Blood Gas Analysis; Blood transfusion; Blood transfusions; Cardiopulmonary Bypass; Emergency and intensive cardiocirculatory care. Cardiogenic shock. Coronary intensive care; Female; Gastric mucosa; Gastric Mucosa - chemistry; Heart; Heart surgery; Hematocrit; Hemodilution - adverse effects; Hemodilution - methods; Humans; Hydrogen-Ion Concentration; Hydroxyethyl starch; Intensive care; Intensive care medicine; Intraoperative Complications - etiology; Intraoperative Complications - metabolism; Male; Medical sciences; Middle Aged; Oxygen Consumption; Patients; Prospective Studies; Splanchnic Circulation; Standard error; Statistical analysis; Statistics, Nonparametric; Surgery; Transfusion; Variance analysis; Heart; Human; Postoperative; Intensive cardiocirculatory care; Intensive care; Mucosa; Normovolemia; Induced hemodilution; Surgery; pH; Complication; Biological effect; Gastric juice
• ISSN: 0342-4642; 1432-1238
• 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The patients were randomly assigned to one of two groups: In 10 patients (group 1), 500 ml of blood was withdrawn and stored after anaesthesia induction.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.