Teloh Johanna Katharina, Dohle Daniel-Sebastian, Sönmez Serhat, Tsagakis Konstantinos, Verhaegh Rabea, Petersen Miriam, Jakob Heinz, de Groot Herbert
Institute of Physiological Chemistry, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
Department of Thoracic and Cardiovascular Surgery, University Hospital Essen, Essen, Germany.
Arch Med Sci. 2017 Apr 1;13(3):585-590. doi: 10.5114/aoms.2016.58144. Epub 2016 Apr 7.
Dilutional acidosis may result from the introduction of a large fluid volume into the patients' systemic circulation, resulting in a considerable dilution of endogenous bicarbonate in the presence of a constant carbon dioxide partial pressure. Its significance or even existence, however, has been strongly questioned. Blood gas samples of patients operated on with standard cardiopulmonary bypass (CPB) were analyzed in order to provide further evidence for the existence of dilutional acidosis.
Between 07/2014 and 10/2014, a total of 25 consecutive patients scheduled for elective isolated coronary artery bypass grafting with CPB were enrolled in this prospective observational study. Blood gas samples taken regularly after CPB initiation were analyzed for dilutional effects and acid-base changes.
After CPB initiation, hemoglobin concentration dropped from an average initial value of 12.8 g/dl to 8.8 g/dl. Before the beginning of CPB, the mean value of the patients' pH and base excess (BE) value averaged 7.41 and 0.5 mEq/l, respectively. After the onset of CPB, pH and BE values significantly dropped to a mean value of 7.33 ( < 0.0001) and -3.3 mEq/l ( < 0.0001), respectively, within the first 20 min. In the following period during CPB they recovered to 7.38 and -0.5 mEq/l, respectively, on average. Patients did not show overt lactic acidosis.
The present data underline the general existence of dilutional acidosis, albeit very limited in its duration. In patients undergoing coronary artery bypass grafting it seems to be the only obvious disturbance in acid-base homeostasis during CPB.
稀释性酸中毒可能是由于大量液体进入患者体循环，在二氧化碳分压恒定的情况下导致内源性碳酸氢盐被显著稀释。然而，其重要性甚至是否存在一直受到强烈质疑。对接受标准体外循环（CPB）手术的患者的血气样本进行分析，以进一步证明稀释性酸中毒的存在。
在2014年7月至2014年10月期间，本前瞻性观察研究共纳入了25例连续计划接受择期单纯冠状动脉旁路移植术并使用CPB的患者。对CPB开始后定期采集的血气样本进行稀释效应和酸碱变化分析。
CPB开始后，血红蛋白浓度从平均初始值12.8 g/dl降至8.8 g/dl。在CPB开始前，患者的pH值和碱剩余（BE）值的平均值分别为7.41和0.5 mEq/l。CPB开始后，pH值和BE值在最初20分钟内显著下降，分别降至平均值7.33（<0.0001）和-3.3 mEq/l（<0.0001）。在CPB后续期间，它们分别平均恢复到7.38和-0.5 mEq/l。患者未出现明显的乳酸酸中毒。
目前的数据强调了稀释性酸中毒的普遍存在，尽管其持续时间非常有限。在接受冠状动脉旁路移植术患者中，它似乎是CPB期间酸碱平衡中唯一明显的紊乱。
