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Biomedical subjects

L D Platt

Publications and source records attributed to L D Platt.

225 records · Page 13Linked to original sources
PubMed1978

Real-time B-scan-directed amniocentesis.

Utilizing real-time B scan, 150 amniocenteses, 14 in the second trimester and 136 in the third trimester, were carried out in 143 patients. In 146 procedures, amniotic fluid was obtained with a single attempt. In four other procedures, two attempts were required, and oligohydramnios was present in two. In one, both taps were dry, while in the other a second tap yielded a slight amount of meconium fluid. One patient was tapped in a site other than that suggested by real-time scanning, and a bloody tap (Apt negative) was obtained. Clear fluid was obtained when the real-time-indicated site was used. The remaining patient had premature rupture of membranes, and two attempts yielded bloody fluid (Apt negative) and the procedure was abandoned. Amniocenteses in eight patients had failed previously (one to three attempts). With the subsequent aid of real-time B scan, fluid was obtained in a single attempt. These data suggest that real-time B scanning prior to and/or during amniocentesis is as reliable as the static B scan method and, in some cases, may have a clear advantage.

Amniocentesis↗
PubMedDate not supplied

Amniotic fluid alpha fetoprotein (AFAFP) and maternal serum alpha fetoprotein (MSAFP) in abdominal pregnancies: correlation with extent and site of placental implantation and clinical implications.

The hypotheses are evaluated that in abdominal pregnancies 1) elevated MSAFP is due to an altered maternal-placental interface, and 2) differences in MSAFP levels may reflect placental location within the peritoneal cavity. A review of 1,193 ectopic pregnancies from 1983-1993 identified three cases of advanced abdominal pregnancy. All three had undergone second trimester genetic amniocentesis for amniotic fluid alpha fetoprotein (AFAFP) and karyotype. The clinical course was reviewed (including presentation and surgical findings). MSAFP was elevated in two of the three cases (3.63 and 4.88 MoM). AFAFP and fetal karyotype were normal in all three cases. Elevated MSAFP values were associated with more extensive visceral implantation, longer surgical operative time, greater blood loss and transfusion requirements. Abdominal pregnancies with elevated MSAFP appear to have more extensive placental involvement of the abdominal viscera; this would, in fact, account for the elevated MSAFP values given the normal AFAFP.

Adult↗
PubMedDate not supplied

Doppler ultrasound in the fetus: a review of current applications.

With the recent introduction of Doppler pulsed and continuous wave as well as color-flow mapping, assessment of blood velocity in the human fetus has added a new dimension to fetal assessment. Although investigators initially examined blood flow in the descending aorta and umbilical vein, there was a wide variation in normal values because of the difficulty of accurately measuring the area of the vessels, a requirement for computation of blood volume. Using duplex sector scanners, velocity and blood flow have been obtained from the right and left ventricular chambers and aortic and pulmonic outflow tracts. At the present time the clinical application of the latter measurements is still under investigation. Doppler color-flow mapping appears to be promising for elucidation of abnormal flow in fetuses suspected of having structural and/or functional cardiovascular disease. Because of the difficulty in computing volume flow due to the above mentioned factors, more recently investigators have examined angle independent parameters of blood velocity from the aorta, carotid and umbilical arteries in an attempt to quantify peripheral resistance. This latter technique appears to be promising for elucidation of placental pathology as is found in a number of fetal and placental diseases.

Blood Flow Velocity↗
PubMedDate not supplied

Use of femur length as a means of assessing M-mode ventricular dimensions during second and third trimesters of pregnancy in normal fetus.

Eighty-two normal fetuses were scanned from 18 to 41 weeks of gestation. The following M-mode measurements were correlated with the femur length: end-diastolic right ventricular (r = 0.93), left ventricular (r = 0.92), biventricular outer (r = 0.94), and biventricular inner (r = 0.94) dimensions; tricuspid (r = 0.93) and mitral (r = 0.92) valve opening excursion; right (r = 0.76) and left (r = 0.70) ventricular wall thickness; and interventricular septal thickness (r = 0.75). Polynomial regression demonstrated that linear regression best described the data from which the mean and 5% and 95% confidence limits for predicted M-mode measurements were computed for the femur length.

Diastole↗