Cunningham S, Symon A G, McIntosh N
Department of Child Life and Health, University of Edinburgh, United Kingdom.
Int J Clin Monit Comput. 1994 Nov;11(4):211-6. doi: 10.1007/BF01139872.
Computerised physiological data contains artifact that needs to be identified and possibly removed. Whilst computers may eventually satisfactorily perform this function, at present only manual removal is possible for the majority of intensive care computer groups. We assessed the effects of artifact and its removal on the physiological data of 3 patients. Artifact was manually removed from 7 days of data in 4 parameters (heart rate, respiratory rate, systolic blood pressure [sbp] and transcutaneous oxygen [tcpO2]) by 3 independent observers. Six hour time periods were analysed. Median and mean values before and after the manual removal of artifact were compared. Overall 6.5% of data was removed as artifact. This was greatest for tcpO2 (9.9%) and sbp (10.6%), with smaller amounts for respiratory rate (2.8%) and heart rate (2.4%). Sbp showed a marked difference in the amount of data removed between patients, whereas tcpO2 data contained quite large volumes of artifact, but this was fairly consistent between patients. Removal of artifact affected mean values more than median values. One observer considered that both physiological and non-physiological artifact should be removed, whereas the other two observers removed only non-physiological artifact. Agreement in results between the latter was good. Our results suggest that inter-observer variability should have a minimal effect on values, once rules identifying the type of artifact to be removed are agreed. Removal of artifact did not have a clinically significant effect on results, but may be an important consideration in the statistical analysis of computerised physiological data.
计算机化的生理数据包含需要识别并可能去除的伪迹。虽然计算机最终可能会令人满意地执行此功能，但目前对于大多数重症监护计算机组来说，只能进行人工去除。我们评估了伪迹及其去除对3例患者生理数据的影响。3名独立观察者从7天的数据中人工去除了4个参数（心率、呼吸频率、收缩压[sbp]和经皮氧分压[tcpO2]）中的伪迹。分析了6小时的时间段。比较了人工去除伪迹前后的中位数和平均值。总体而言，6.5%的数据作为伪迹被去除。这在tcpO2（9.9%）和sbp（10.6%）中最为明显，呼吸频率（2.8%）和心率（2.4%）的去除量较小。Sbp在不同患者之间去除的数据量存在显著差异，而tcpO2数据包含相当大量的伪迹，但在不同患者之间相当一致。去除伪迹对平均值的影响大于中位数。一名观察者认为应同时去除生理和非生理伪迹，而另外两名观察者只去除非生理伪迹。后两者之间的结果一致性良好。我们的结果表明，一旦确定了去除伪迹类型的规则，观察者间的变异性对数值的影响应最小。去除伪迹对结果没有临床显著影响，但在计算机化生理数据的统计分析中可能是一个重要的考虑因素。
