不同类型的可变减速及其对新生儿结局的影响。

Kazandi Mert, Sendag Fatih, Akercan Fuat, Terek Mustafa Cosan, Gundem Gursen

Ege University, Faculty of Medicine, Department of Obstetrics and Gynecology, Bornova, Izmir 35100, Turkey.

Singapore Med J. 2003 May;44(5):243-7.

OBJECTIVE

Although the only objective finding of intrapartum fetal distress is obtained through the measurement the fetal scalp pH, this invasive procedure is not available in every institution. The careful examination of fetal heart rate tracings for abnormalities, especially of the most commonly seen one, variable decelerations gains great importance under these circumstances. The aim of the present study is to determine the prognostic significance of variable decelerations in intrapartum fetal heart rate monitoring.

METHODS

A total of 96 fetal heart rate tracings were analysed to assess the prognostic significance of variable decelerations. Sixty-six percent (64/96) of cases exhibited atypia characterised with (1) slow return of the fetal heart rate to the baseline; (2) loss of variability during the decelerations; (3) loss of initial and/or secondary accelerations; (4) persistence of secondary acceleration (overshoot); and (5) continuation of the baseline fetal heart rate at a lower level; (6) biphasic deceleration. One and five-minute Apgar scores and umbilical artery pH were used to assess the final fetal condition.

RESULTS

Adverse fetal outcome characterised by fetal acidosis and Apgar score lower than 7 at one and five minutes were uncommon with pure variable decelerations. Typical and atypical variable decelerations were associated with low Apgar scores (< 7) at one minute in 9.3% and 54.6% of cases (p < 0.001) and at five minutes in 6.25% and 25% of cases (p < 0.05), respectively. In addition umbilical artery pH found to be lower than 7.2 in these cases ( 18.75% - p < 0.05). There was no danger for the fetal haemodynamic conditions when typical uterus contraction/variable deceleration ratios were two or more than two. However, risk of fetal hypoxia damage was quite high when this ratio was lower than two in atypical variable 5th minute low Apgar scores and pH (81.8% and 36.6% respectively). Atypical features are helpful in the identification of distress characterised by low Apgar scores in fetuses with variable decelerations. Admission to the neonatal intensive care unit was more common in patients with atypical variable decelerations in comparison with typical variable decelerations (34.3% versus 3.1%).

CONCLUSION

While typical variable decelerations are frequently harmless, atypical variations pose a significant risk of fetal hypoxia.

目的

虽然产时胎儿窘迫的唯一客观诊断依据是通过测量胎儿头皮pH值获得，但这种侵入性操作并非在每个机构都可行。在这种情况下，仔细检查胎儿心率曲线以发现异常，尤其是最常见的变异减速，就显得尤为重要。本研究的目的是确定产时胎儿心率监测中变异减速的预后意义。

方法

共分析96份胎儿心率曲线，以评估变异减速的预后意义。66%（64/96）的病例表现出非典型特征，包括：（1）胎儿心率缓慢恢复至基线；（2）减速期间变异性丧失；（3）初始和/或继发性加速丧失；（4）继发性加速持续存在（过冲）；（5）胎儿心率基线持续处于较低水平；（6）双相减速。采用1分钟和5分钟Apgar评分以及脐动脉pH值来评估胎儿最终状况。

结果

单纯变异减速时，以胎儿酸中毒和1分钟及5分钟Apgar评分低于7分为特征的不良胎儿结局并不常见。典型和非典型变异减速分别在9.3%和54.6%的病例中与1分钟时低Apgar评分（<7分）相关（p<0.001），在6.25%和25%的病例中与5分钟时低Apgar评分相关（p<0.05）。此外，这些病例中脐动脉pH值低于7.2（18.75% - p<0.05）。当典型宫缩/变异减速比值为2或大于2时，胎儿血流动力学状况无危险。然而，当该比值低于2时，非典型变异在第5分钟时低Apgar评分和低pH值的胎儿缺氧损伤风险相当高（分别为81.8%和36.6%）。非典型特征有助于识别变异减速胎儿中以低Apgar评分为特征的窘迫。与典型变异减速相比，非典型变异减速患者入住新生儿重症监护病房更为常见（34.3%对3.1%）。