Brackley K J, Ramsay M M, Broughton Pipkin F, Rubin P C
Department of Obstetrics and Gynaecology, University of Nottingham Medical School.
Br J Obstet Gynaecol. 1998 Jan;105(1):68-77. doi: 10.1111/j.1471-0528.1998.tb09353.x.
To describe changes in the maternal cerebral circulation and the external iliac arteries throughout pregnancy and the puerperium using the Laplace transform analysis of Doppler waveforms.
A prospective longitudinal study.
Department of Obstetrics and Gynaecology, Nottingham University Hospital.
A cohort of 17 healthy women studied every four weeks from early pregnancy until term and up to three months postpartum. Pre-conception data were available for 10 subjects.
Doppler signals were recorded from the internal carotid, middle cerebral and external iliac arteries. The waveforms were analysed using two different techniques: standard indices (systolic:diastolic ratio, pulsatility and resistance indices) and Laplace transform analysis, an alternative method of waveform shape analysis which may provide additional haemodynamic information.
Vessel wall tone decreased at an early stage in pregnancy in the cerebral circulation and in the external iliac artery, but this rose again following delivery. The Laplace transform analysis techniques suggest dramatic eight-fold increases in downstream resistance within the external iliac artery in the second half of pregnancy. An increase in downstream resistance to flow also occurred in the internal carotid artery whereas more stable conditions were noted in the middle cerebral artery.
Having a preliminary idea of the normal ranges for the Laplace transform analysis variables during pregnancy in a variety of maternal vessels, haemodynamic changes in pregnancies complicated by conditions, such as pre-eclampsia, can now be studied.
运用多普勒波形的拉普拉斯变换分析，描述整个孕期及产褥期母体脑循环和髂外动脉的变化。
一项前瞻性纵向研究。
诺丁汉大学医院妇产科。
选取17名健康女性组成队列，从妊娠早期至足月每四周进行一次研究，直至产后三个月。10名受试者有孕前数据。
记录颈内动脉、大脑中动脉和髂外动脉的多普勒信号。使用两种不同技术分析波形：标准指标（收缩压：舒张压比值、搏动指数和阻力指数）和拉普拉斯变换分析，这是一种波形形状分析的替代方法，可能提供额外的血流动力学信息。
孕期早期脑循环和髂外动脉的血管壁张力下降，但产后又再次上升。拉普拉斯变换分析技术表明，妊娠后半期髂外动脉下游阻力急剧增加了八倍。颈内动脉也出现了下游血流阻力增加的情况，而大脑中动脉的情况则较为稳定。
了解了孕期各种母体血管中拉普拉斯变换分析变量的正常范围后，现在可以研究患有子痫前期等疾病的妊娠中的血流动力学变化。
