Batchelder Paul B, Raley Dena M
From the Clinimark Laboratories, Golden, Colorado.
Anesth Analg. 2007 Dec;105(6 Suppl):S85-S94. doi: 10.1213/01.ane.0000268495.35207.ab.
Maximizing the laboratory setting for testing baseline pulse oximetry accuracy in an arterial desaturation study requires a study design that considers management of several aspects in the physiology of the test subject, special attention to the device under test, and great care in the preanalytical (sample handling) and analytical (Co-oximeter) phases. Statistics used to describe the resulting SpO2 performance include Precision (size of the data cloud), Bias (offset of the data cloud), and A(rms) (accuracy root mean square), which combines the size and offset of the data cloud in one number. The A(rms) is the primary statistic required by regulatory organizations to describe general performance over the entire saturation range. It does not describe any one point, but is a compilation of all points over the range tested. Most pulse oximeters in use today specify an A(rms) of 2%. To meet this specification, two-thirds of the readings will be within 2% of the Co-oximeter reference; however, some individual readings can be as inaccurate as 6% or more. The A(rms) statistic does not have the capacity to represent all pulse oximeter behavior. Saturation pop-ups, drop-downs, frozen readings, and periods of no reading are not portrayed by the A(rms). The next steps in the advancement of regulatory validation testing would be to develop standards that include an expanded analysis of pulse oximeter performance by assessment of pop-ups, dropouts, frozen readings, and periods of no reading through assessment of sensitivity/specificity and possibly a "Performance Index" similar to the approach taken by Barker.
在一项动脉血氧饱和度降低研究中，要最大限度地利用实验室环境来测试基线脉搏血氧饱和度的准确性，需要一种研究设计，该设计要考虑测试对象生理学中几个方面的管理、对被测设备给予特别关注，以及在分析前（样本处理）和分析（共血氧计）阶段要格外小心。用于描述所得SpO2性能的统计数据包括精密度（数据云的大小）、偏差（数据云的偏移）和A(rms)（均方根误差），后者将数据云的大小和偏移合并为一个数值。A(rms)是监管机构要求用来描述整个饱和度范围内总体性能的主要统计数据。它不是描述任何一个点，而是测试范围内所有点的汇总。当今使用的大多数脉搏血氧仪规定的A(rms)为2%。为满足这一规格，三分之二的读数将在共血氧计参考值的2%以内；然而，一些个别读数可能不准确达6%或更高。A(rms)统计数据无法代表所有脉搏血氧仪的行为。饱和度弹出、下降、读数冻结和无读数时段都无法通过A(rms)体现出来。监管验证测试进一步发展的下一步将是制定标准，通过评估弹出、中断、读数冻结和无读数时段，包括通过评估敏感度/特异性以及可能类似于巴克采用的方法的“性能指数”，对脉搏血氧仪性能进行扩展分析。
