Gerald P. Marquette

Diastolic circulatory dynamics in the presence of elevated placental resistance and retrograde diastolic flow in the umbilical artery a doppler echographic study in lambs

To evaluate the effects of elevated placental resistance on the diastolic blood flow in the main arteries of the fetus, placental resistance was mechanically increased in six exteriorized lambs. A string was inserted into the exposed section of the umbilical cord and placed around the veins isolating them from the arteries. Doppler flow velocities waveforms were measured by placing a lightweight acoustic bag on the umbilical cord. Placental resistance was increased by tightening the string until retrograde diastolic flow was observed in the umbilical artery. All measurements were obtained within 10 minutes. Heart rate, PO2, PCO2, and pH before umbilical vein compression were 177 +/- 24 beats/min, 16.4 +/- 1.8 mm Hg, 42.5 +/- 4 mm Hg, and 7.3 +/- 0.05, respectively, and 112 +/- 38 beats/min, 5.9 +/- 1.5 mm Hg, 56.6 +/- 7.0 mm Hg, and 7.2 +/- 0.05, respectively, after umbilical vein compression. The patterns of diastolic flow observed after compression were descending aorta, retrograde; aortic arch, retrograde; ascending aorta, bidirectional; cephalic aorta, forward, which were quite different from their respective baseline patterns. It is concluded that the appearance of reverse diastolic flow in the umbilical artery indicates that (1) the lowest vascular resistance in the fetal circulatory network is no longer at the placental but at the cerebral level, and (2) preplacental blood with low oxygen content from the descending aorta and pulmonary artery is being shifted toward the brain.

Myocardial ischemia: A complication of r ritodrine tocolysis

Demonstration of leakage of fetal blood into the maternal circulation secondary to damage in the placental barrier, as demonstrated in the above case reports, may have additional importance in the Rh-negative woman. Further studies will show if Rh-negative women with similar conditions should receive Rho (D antigen) immune globulin as is presently done in Rh-negative women undergoing ilmniocentesis.

Fetomaternal Hemorrhage During External Cephalic Version

OBJECTIVE: To estimate the frequency and volume of fetomaternal hemorrhage during external cephalic version for term breech singleton fetuses and to identify risk factors involved with this complication. METHODS: A prospective observational study was performed including all patients undergoing a trial of external cephalic version for a breech presentation of at least 36 weeks of gestation between 1987 and 2001 in our center. A search for fetal erythrocytes using the standard Kleihauer-Betke test was obtained before and after each external cephalic version. The frequency and volume of fetomaternal hemorrhage were calculated. Putative risk factors for fetomaternal hemorrhage were evaluated by &khgr;2 test and Mann-Whitney U test. RESULTS: A Kleihauer-Betke test result was available before and after 1,311 trials of external cephalic version. The Kleihauer-Betke test was positive in 67 (5.1%) before the procedure. Of the 1,244 women with a negative Kleihauer-Betke test before external cephalic version, 30 (2.4%) had a positive Kleihauer-Betke test after the procedure. Ten (0.8%) had an estimated fetomaternal hemorrhage greater than 1 mL, and one (0.08%) had an estimated fetomaternal hemorrhage greater than 30 mL. The risk of fetomaternal hemorrhage was not influenced by parity, gestational age, body mass index, number of attempts at version, placental location, or amniotic fluid index. CONCLUSION: The risk of detectable fetomaternal hemorrhage during external cephalic version was 2.4%, with fetomaternal hemorrhage more than 30 mL in less than 0.1% of cases. These data suggest that the performance of a Kleihauer-Betke test is unwarranted in uneventful external cephalic version and that in Rh-negative women, no further Rh immune globulin is necessary other than the routine 300-microgram dose at 28 weeks of gestation and postpartum. LEVEL OF EVIDENCE: II

The validity of the leukocyte esterase reagent test strip in detecting significant leukocyturia

This prospective trial demonstrated that the best possible definition for a positive leukocyte esterase test (Chemstrip 9) is + or ++. With use of this definition, the sensitivity in detecting significant leukocyturia is 83% and the specificity is 70%. The use of this test strip could reduce screening costs in registering obstetric patients.

The accuracy of visual and meter determinations of blood glucose with the use of Chemstrip bG.

The 95% confidence intervals for the blood glucose determinations with use of the Chemstrip bG were +/- 28 mg/dl by visual reading and +/- 18 mg/dl by means of the Accu-Chek photometer. These rapid methods continue to be an important aid in the home care of pregnant diabetic women.

The Bland-White-Garland syndrome in pregnancy

both cases on initial study. Later, the lateral ventricle width/hemispheric width ratio was greater than the normal range even for 15 to 17 weeks (Fig. 2). Early in development of the fetal brain, the aqueduct which separates the third and fourth ventricles is relatively short and broad. With growth and differentiation of the caudal mesencephalon, the aqueduct becomes greatly elongated and narrowed. This normal constriction of the aqueduct occurs rapidly between the fifteenth week and the seventeenth week after conception. This corresponds to the seventeenth to nineteenth week after the last normal menstrual period, the time at which hydrocephalus apparently developed in these two fetuses. Therefore, it is reasonable to suggest that congenital hydrocephalus due to X-linked aqueductal stenosis may develop as an exaggeration of the normal process of narrowing of the aqueduct of Sylvius which occurs during growth of the caudal mesencephalon 15 to 17 weeks after conception.