Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology
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Ultrasound Obstet Gynecol · Feb 1995
Comparative StudyFetal echocardiography during indomethacin treatment.
Fetal echocardiograms were evaluated in 315 studies performed in 107 fetuses exposed to indomethacin. In the majority of cases, the results of the fetal echocardiography study were within normal limits (74%). The most common abnormal phenomena were tricuspid valve regurgitation (10%), ductal constriction (6%), tricuspid valve regurgitation and ductal constriction (5%), an increased ductal velocity (2%), and other (3%). ⋯ We conclude that indomethacin treatment is relatively safe for the fetal heart. The most common side-effects are tricuspid valve regurgitation and ductal constriction. Tricuspid valve regurgitation may be detected before ductal constriction, but by itself it is not a contraindication for the continued use of indomethacin.
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Ultrasound Obstet Gynecol · May 1991
Interpretation of pulsatility index in feeder arteries to low-impedance vascular beds.
A simple electrical circuit is proposed as a model for peripheral vascular beds of low impedance. The model consists of a flow and pressure source, i.e. the 'feeder' artery, with the vascular bed represented by a Zener diode Z giving rise to a 'back pressure' P(z) and a pure resistance R. By applying Ohm's law to the definition of pulsatility index PI(flow) of flow in the feeder artery, it is shown that PI(flow) is dependent only on the mean blood pressure (input), the pulse pressure and P(z), and is independent of R. For those vascular beds where the impedance is largely resistive, e.g. the brain, the kidney and the uterine-placental complex, it is suggested that P(z) may be a more useful characterizing parameter than the value of PI(flow) as at present used by some workers.
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Ultrasound Obstet Gynecol · Jan 1991
Ethics, an emerging subdiscipline of obstetric ultrasound, and its relevance to the routine obstetric scan.
Ethics is an emerging subdiscipline of obstetric ultrasound because there are clinical dimensions of obstetric ultrasound that only ethics can identify and address. These dimensions concern the ethical obligations of physicians to their patients. ⋯ How ethics can bring to light clinical dimensions of obstetric ultrasound that are insufficiently appreciated is illustrated with the example of the routine use of obstetric ultrasound in the second trimester. The authors conclude that prenatal informed consent for sonogram should be an integral part of obstetric care in countries, such as the United States, in which routine ultrasound is not endorsed.