Tao Guocai, Chen Yan, Wen Changyun, Bi Min
Department of Anesthesia, Southwest Hospital, The 3rd Military Medical University, Chongqing, China.
Blood Press Monit. 2011 Dec;16(6):285-90. doi: 10.1097/MBP.0b013e32834dc5bc.
Although a validated oscillometry sphygmomanometer satisfies the accuracy criteria of Advancement of Medical Instrumentation (AAMI), its long-term blood pressure (BP) measurement error during operations remains to be determined. We aim to (a) compare the error range throughout surgical operations with the accuracy criteria of AAMI, and (b) investigate the probabilities of occurrence of abnormal, large errors and clinically meaningful errors.
BP level were measured from 270 participants using oscillometry and arterial cannulation (invasive method) in the same BP monitor throughout surgeries. Mean deviation and SD (oscillometry vs. invasive method) were calculated from 6640 sets of data and presented in the Bland-Altman Plots. Also, the average, the largest, and the smallest measurement errors (errormean, errormax, and errormin) per patient were obtained. The probability distributions of the three types of errors were shown using histograms (percentage vs. SD). In addition, the clinically meaningful large errors (≥ 10 mmHg) of the adult patients when their systolic blood pressure (SBP) values were around 90 mmHg were investigated.
The mean deviation (1.98 mmHg for SBP and 4.31 mmHg for diastolic blood pressure (DBP) satisfies the AAMI criterion (≤ 5 mmHg), but the SD (14.87 mmHg for SBP and 11.21 mmHg for DBP) exceeds the AAMI criterion (≤ 8 mmHg). The probability of errormax more than 40 mmHg is 14% for SBP and 6% for DBP. The probability of errormean more than 24 mmHg (4.07% for SBP and 1.48% for DBP), and that of errormin more than 24 mmHg (0.37% for SBP and 0.37% for DBP) are all greater than the criterion of 0.26%. The clinically meaningful errors are found in 28.78% of the adult patients.
The SD of long-term BP measurement by our oscillometric method during operations exceeds AAMI accuracy criteria. And it is important to be aware of the abnormal large errors and clinically meaningful errors as their probabilities are rather significant. We analyze the possible cause of the major errors and deduce that similar errors may also happen with other oscillometric devices.
尽管经过验证的示波法血压计满足医学仪器促进协会（AAMI）的准确性标准，但其在手术过程中的长期血压（BP）测量误差仍有待确定。我们旨在（a）将整个手术过程中的误差范围与AAMI的准确性标准进行比较，以及（b）调查异常、大误差和具有临床意义的误差发生的概率。
在整个手术过程中，使用示波法和动脉插管法（侵入性方法）在同一血压监测仪上对270名参与者的血压水平进行测量。从6640组数据中计算平均偏差和标准差（示波法与侵入性方法），并绘制在布兰德-奥特曼图中。此外，还获得了每位患者的平均、最大和最小测量误差（误差均值、误差最大值和误差最小值）。使用直方图（百分比与标准差）展示三种误差类型的概率分布。此外，还对成年患者收缩压（SBP）值在90 mmHg左右时具有临床意义的大误差（≥10 mmHg）进行了研究。
平均偏差（SBP为1.98 mmHg，舒张压（DBP）为4.31 mmHg）满足AAMI标准（≤5 mmHg），但标准差（SBP为14.87 mmHg，DBP为11.21 mmHg）超过AAMI标准（≤8 mmHg）。SBP误差最大值超过40 mmHg的概率为14%，DBP为6%。误差均值超过24 mmHg的概率（SBP为4.07%，DBP为1.48%）以及误差最小值超过24 mmHg的概率（SBP为0.37%，DBP为0.37%）均大于0.26%的标准。在28.78%的成年患者中发现了具有临床意义的误差。
我们的示波法在手术期间长期血压测量的标准差超过了AAMI准确性标准。并且意识到异常大误差和具有临床意义的误差很重要，因为它们的概率相当显著。我们分析了主要误差的可能原因，并推断其他示波设备可能也会出现类似误差。
