Expected-value bias in routine third-trimester growth scans
Expected-value bias in routine third-trimester growth scans
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DOI：
10.1002/uog.21929
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发表时间：
2020-03-01
影响因子：
7.1
通讯作者：
Papageorghiou, A. T.
中科院分区：
文献类型：
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作者：
Drukker, L.;Droste, R.;Papageorghiou, A. T.
目的进行胎儿生长扫描的操作人员通常知道妊娠的孕周，这可能导致在进行生物测量时的期望值偏差。我们的目的是评估常规胎儿生长扫描中期望值偏差的发生率，并评估其对标准生物测量的影响。方法我们收集了常规超声生长扫描结合操作员眼球跟踪的前瞻性全长视频记录。期望值被定义为扫描时的孕周，基于在测年扫描中确定的估计预产期。期望值偏差定义为操作员在保存测量之前，在卡尺调整过程中查看屏幕上的测量框时发生的偏差。我们研究了三个标准生物测量平面，在这三个平面上测量头围(HC)、腹围(AC)和股骨长度(FL)。结果我们分析了由16家运营商进行的272次妊娠晚期扫描，在此期间共获得1409次测量(包括354次HC、703次AC和352次FL；包括重复测量)。在保存的标准生物特征平面测量中，91.4%存在期望值偏差(HC为85.0%，AC为92.9%，FL为94.9%)。操作员更倾向于将测量结果调整为接近期望值，而不是偏离期望值(47.7%比19.7%；P
Objectives Operators performing fetal growth scans are usually aware of the gestational age of the pregnancy, which may lead to expected-value bias when performing biometric measurements. We aimed to evaluate the incidence of expected-value bias in routine fetal growth scans and assess its impact on standard biometric measurements.Methods We collected prospectively full-length video recordings of routine ultrasound growth scans coupled with operator eye tracking. Expected value was defined as the gestational age at the time of the scan, based on the estimated due date that was established at the dating scan. Expected-value bias was defined as occurring when the operator looked at the measurement box on the screen during the process of caliper adjustment before saving a measurement. We studied the three standard biometric planes on which measurements of head circumference (HC), abdominal circumference (AC) and femur length (FL) are obtained. We evaluated the incidence of expected-value bias and quantified the impact of biased measurements.Results We analyzed 272 third-trimester growth scans, performed by 16 operators, during which a total of 1409 measurements (354 HC, 703 AC and 352 FL; including repeat measurements) were obtained. Expected-value bias occurred in 91.4% of the saved standard biometric plane measurements (85.0% for HC, 92.9% for AC and 94.9% for FL). The operators were more likely to adjust the measurements towards the expected value than away from it (47.7% vs 19.7% of measurements; P