Department of Anesthesiology, Regensburg University Medical Center, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
Clin Chim Acta. 2017 Oct;473:14-20. doi: 10.1016/j.cca.2017.08.012. Epub 2017 Aug 12.
A common characteristic of all blood gas analyzers on the market is that measurements are processed at 37°C, not at the real patients´ temperature. Subsequently temperature-sensitive parameters can be mathematically corrected (alpha-stat method) or used directly (pH-stat method). National rules in Germany (Rili-BAEK) demand defined accuracy and precision without any restriction to samples´ temperatures or corrections. As consequence in the investigation at hand we tried to find out whether blood gas analyzers can fulfill the regulations for pCO and pO when normothermia of the matrix is not given.
Five matrices (blood from intensive care unit (ICU) patients, blood from healthy donors and 3 levels of bovine based quality control material) were tonometered at "high" and "low" partial pressures of O and CO within the RiLi-BAEK controlled range at 32, 37 and 40°C. One mL material was aspired into each blood gas (BG) syringe and analysis was accomplished immediately after. The procedure was repeated 10-fold for "high" and "low" gas concentrations and run on 4 different analyzers. At 18°C instead to the "high" one a "median" gas (n=10 as well) was employed. Every condition which constitutes of temperature (4), matrix (5), analyzer (4) and level of the partial pressure (2) led to a total of 1600 measurements.
At 32°C or 37°C matrix temperature 7.5% to 27.5% of the pCO(T) and between 14.5% and 28.1% of the pO(T) results were outside the borders required by the RiLi-BAEK. At 18°C or 40°C the number of results beyond the allowed borders grows up to 82.5% for pCO(T) and 73% for pO(T) depending on the partial pressure (PP) level.
High precision in automated quality control (at a constant matrix temperature) is given in modern BGAnalyzers but is counteracted in practice by non normothermic patient's temperature and unavoidable sample handling effects.
市场上所有血气分析仪的一个共同特点是，测量是在 37°C 下进行的，而不是在患者的实际体温下进行的。随后，可以对热敏参数进行数学校正（alpha-stat 方法）或直接使用（pH-stat 方法）。德国的国家法规（Rili-BAEK）要求在不限制样本温度或校正的情况下，具有明确的准确性和精密度。因此，在本研究中，我们试图确定在基质未达到正常体温的情况下，血气分析仪是否能够满足 pCO 和 pO 的规定。
将五种基质（来自重症监护病房（ICU）患者的血液、来自健康供体的血液和三个水平的牛基质量控制材料）在 RiLi-BAEK 控制范围内的 32、37 和 40°C 下用“高”和“低”氧分压和二氧化碳分压进行平衡。将 1 毫升材料吸入每个血气（BG）注射器中，并在完成后立即进行分析。该过程在四个不同的分析仪上重复了 10 次，用于“高”和“低”气体浓度，并在 18°C 下用“中位数”气体（也为 10 次）代替“高”气体。每个条件（温度（4）、基质（5）、分析仪（4）和分压（2））总共产生了 1600 个测量值。
在 32°C 或 37°C 基质温度下，7.5%至 27.5%的 pCO(T)和 14.5%至 28.1%的 pO(T)结果超出了 Rili-BAEK 要求的边界。在 18°C 或 40°C 下，取决于分压（PP）水平，超出允许边界的结果数量增加到 pCO(T)的 82.5%和 pO(T)的 73%。
在现代 BGAnalyzers 中，自动化质量控制（在恒定基质温度下）具有高精度，但在实践中，患者的非正常体温和不可避免的样本处理效应会抵消这一精度。
