Connelly N R, Magee M, Kiessling B
Department of Anesthesiology, Baystate Medical Center, Tufts University School of Medicine, Springfield, MA 01199, USA.
J Clin Monit. 1996 Jul;12(4):311-5. doi: 10.1007/BF02221752.
To evaluate the utility of the iSTAT blood analyzer, a bedside device for hematocrit, sodium, potassium, and glucose measurement during cardiopulmonary bypass (CPB).
Forty patients scheduled for elective CPB were evaluated prospectively. In addition to using the iSTAT analyzer, blood samples were analyzed at four time points: following induction of anesthetic, 10 min. after initiation of CPB, 60 min. after initiation of CPB, and following heparin neutralization by protamine. Blood glucose concentration was measured by the hospital laboratory using a Kodak Analyzer and by a glucose meter, electrolytes were evaluated by the Kodak Analyzer and BGE (a device which is commonly used for "satellite laboratory" determinations of electrolyte and blood gas results), and hematocrit samples were measured by the hospital laboratory using an NE 8,000 and a centrifuge. The means and standard deviations of the differences between the methods were calculated.
The hematocrit values determined by the iSTAT machine, when adjusted for the level of total protein (according to manufacturer's directions), differed from the laboratory values by 0.53 +/- 1.46 percentage points. An alternative to measuring total protein and making the adjustment is simply adding 1% to the hematocrit in the pre-CPB period and 3% on-CPB or post-CPB, which we found to yield values that differed from the laboratory by 0.52 +/- 1.42 percentage points. For all four tests (hematocrit, sodium, potassium, and glucose) the iSTAT had a similar relationship to the laboratory values as did the other commonly used means (centrifuge, BGE, and glucose meter) of clinical evaluation.
In summary, we found that in patients undergoing CPB, the iSTAT values agreed sufficiently well with standard laboratory values and that the iSTAT instrument can be relied upon for bedside measurements.
评估iSTAT血液分析仪在体外循环（CPB）期间用于床边测定血细胞比容、钠、钾和葡萄糖的实用性。
对40例计划进行择期CPB的患者进行前瞻性评估。除使用iSTAT分析仪外，还在四个时间点对血样进行分析：麻醉诱导后、CPB开始后10分钟、CPB开始后60分钟以及鱼精蛋白中和肝素后。血糖浓度由医院实验室使用柯达分析仪和血糖仪进行测量，电解质由柯达分析仪和BGE（一种常用于“卫星实验室”测定电解质和血气结果的设备）进行评估，血细胞比容样本由医院实验室使用NE 8,000和离心机进行测量。计算各方法间差异的均值和标准差。
根据制造商说明，对总蛋白水平进行校正后，iSTAT机器测定的血细胞比容值与实验室值相差±0.53个百分点。另一种方法是不测量总蛋白也不进行校正，而是在CPB前将血细胞比容值增加1%，在CPB期间或CPB后增加3%，我们发现这样得到的值与实验室值相差±0.52个百分点。对于所有四项检测（血细胞比容、钠、钾和葡萄糖），iSTAT与实验室值的关系与其他常用的临床评估方法（离心机、BGE和血糖仪）相似。
总之，我们发现，在接受CPB的患者中，iSTAT测定值与标准实验室值足够吻合，iSTAT仪器可用于床边测量。
