Mohler J G, Mohler P A, Pallivathucal R G
University of Southern California Medical Center.
Scand J Clin Lab Invest Suppl. 1987;188:61-7.
In the daily care of pulmonary disease patients, we have often encountered large differences in the bicarbonate value calculated from blood gas determination pCO2 and pH, and the serum CO2 obtained from the Dupont Automatic Clinical Analyzer (ACA). Realizing that many clinicians utilize the automated measurement of serum CO2 ([CO2]s) in place of blood gas determinations, we felt it necessary to analyze paired sets of ACA [CO2]s and blood gas bicarbonate values ([HCO3-]p) for variations which might lead to clinically significant differences in interpretation. A study of 1,841 patient samples, matched by date and within +/- 2 hours of sampling, and supported by a thorough chart review of 100 randomly selected patients, indicates that a statistically significant difference, which is unrelated to apparent changes in the patient clinical status, does exist. Evaluation of pK changes due to temperature failed to correct these differences in serum CO2 and plasma bicarbonate. Based on the limited information available in the literature, as well as the strict quality control measures utilized in the measuring of [CO2]s using the ACA method and the measurement of bicarbonate by blood gas determination, we have concluded that the differences in the [CO2]s and [HCO3-]p can only be related to erroneous assumptions about the method of measuring [CO2]s by the ACA or other automated methods as well as manual techniques of back titration.
在肺部疾病患者的日常护理中，我们经常遇到通过血气测定pCO2和pH计算得出的碳酸氢盐值与使用杜邦自动临床分析仪（ACA）测得的血清CO2之间存在很大差异。由于意识到许多临床医生使用血清CO2（[CO2]s）的自动测量结果来代替血气测定，我们认为有必要分析配对的ACA [CO2]s和血气碳酸氢盐值（[HCO3-]p），以找出可能导致临床解释出现显著差异的变化。一项对1841份患者样本的研究表明，确实存在与患者临床状态的明显变化无关的统计学显著差异，这些样本按日期匹配，且采样时间在正负2小时内，同时对100名随机选择的患者进行了全面的病历审查作为支持。对温度引起的pK变化的评估未能纠正血清CO2和血浆碳酸氢盐之间的这些差异。基于文献中有限的可用信息，以及使用ACA方法测量[CO2]s和通过血气测定测量碳酸氢盐时所采用的严格质量控制措施，我们得出结论，[CO2]s和[HCO3-]p之间的差异只能与对ACA或其他自动方法测量[CO2]s的方法以及回滴定的手工技术的错误假设有关。
