Devoe L D, Castillo R, Saad S, McKenzie J, Searle N, Davis H
Obstet Gynecol. 1986 Feb;67(2):191-6.
The percent acceleration time (PAT) is a fetal heart rate parameter, which may be derived from the nonstress test (NST). It is based on measurement of the duration of individual movement-associated fetal heart rate accelerations (MAFAs), obtained during a nonstress test, and is calculated by the formula: (formula, see text) The authors studied 148 fetuses undergoing four or more serial nonstress tests who were delivered within one week of their last test. Percent acceleration time of fetuses with normal outcomes had a mean value of 15.5 +/- 10.0 (SD)%, correlated well with the frequency and amplitude of movement-associated fetal heart rate accelerations but was independent of gestational age and mean baseline fetal heart rate. No normal fetus had a percent acceleration time of less than 5% on its last nonstress test, while only one abnormal fetus had a percent acceleration time that exceeded the mean percent acceleration time of the normal group. All abnormal fetuses had a significant progressive decline in percent acceleration time (mean: 50.6%). Percent acceleration time values were more sensitive in identifying fetuses with perinatal compromise than were conventional criteria for nonstress test reactivity, and may provide a useful alternative to assessment of fetal status when other quantitative methods are unavailable (continuous ultrasound visualization) or less reliable (maternal perception, tokodynamometry, palpation).
加速时间百分比（PAT）是一种胎儿心率参数，可从无应激试验（NST）中得出。它基于对无应激试验期间获得的与胎动相关的胎儿心率加速（MAFA）持续时间的测量，并通过以下公式计算：（公式见正文）作者研究了148例接受四次或更多次连续无应激试验且在最后一次试验后一周内分娩的胎儿。结局正常的胎儿的加速时间百分比平均值为15.5±10.0（标准差）%，与与胎动相关的胎儿心率加速的频率和幅度相关性良好，但与胎龄和胎儿平均基线心率无关。在最后一次无应激试验中，没有正常胎儿的加速时间百分比低于5%，而只有一例异常胎儿的加速时间百分比超过了正常组的平均加速时间百分比。所有异常胎儿的加速时间百分比均有显著的逐渐下降（平均值：50.6%）。与无应激试验反应性的传统标准相比，加速时间百分比值在识别有围产期损害的胎儿方面更敏感，并且在其他定量方法不可用（连续超声可视化）或不太可靠（母亲感知、宫缩力描记法、触诊）时，可能为评估胎儿状况提供一种有用的替代方法。
