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Biomedical subjects

R J Carpenter

Publications and source records attributed to R J Carpenter.

At least 55 records · Page 3Linked to original sources
PubMed1990

Flow velocity waveforms of the vascular system in the anemic fetus before and after intravascular transfusion for severe red blood cell alloimmunization.

Sixteen intravascular transfusions were performed in 16 anemic human fetuses. To investigate the status of the vascular system with Doppler ultrasonography before and after correction of anemia, pulsatility index values were obtained for the flow velocity waveforms of the middle cerebral artery, internal carotid artery, anterior cerebral artery, thoracic aorta, abdominal aorta, renal artery, femoral artery, and umbilical artery before and the day after the correction of anemia. The fetuses were divided into two groups: (1) fetuses with a hematocrit level between 2 and 4 SDs below the normal mean value for gestational age and (2) fetuses with a hematocrit value less than 4 SDs below the normal mean value for gestational age. No significant differences were observed in the pulsatility index values of the vessels studied before and after correction of anemia in both groups of fetuses. These data suggest that the pulsatility index cannot be used as an indicator of fetal anemia at the hematocrit values studied.

Anemia, Hemolytic, Autoimmune↗
PubMed1990

Cyanotic maternal heart disease in pregnancy.

Cyanotic heart disease has major implications for maternal and fetal well-being during pregnancy. This article reports six patients with cyanotic congenital heart disease recently managed at our institutions. Although the maternal condition deteriorated to some extent during each pregnancy, it was the fetal condition that ultimately dictated delivery in each case.

Adolescent↗
PubMed1990

Increased severity of fetal hemolytic disease with known rhesus alloimmunization after first-trimester transcervical chorionic villus biopsy.

Fetomaternal hemorrhage secondary to chorionic villus biopsy has the potential to accelerate fetal hemolytic disease in the pregnant patient previously sensitized to red cell antigens. A case of poor fetal outcome after first-trimester transcervical chorionic villus sampling in an alloimmunized patient is reported. An increase in antibody titers was associated with the demise of a hydropic fetus early in the second trimester. Maternal red cell alloimmunization is suggested as an absolute contraindication for chorionic villus sampling performed for genetic indications.

Adult↗
PubMed1990

Fetoplacental blood volume estimation in pregnancies with Rh alloimmunization.

Direct intravascular fetal transfusion under ultrasound guidance has become an important method of treating fetal anemia secondary to maternal red cell alloimmunization. An estimate of normal circulating volume would be useful in selecting the volume of donor blood to be transfused to achieve a desired final hematocrit. Thirty-five fetuses between 21 and 35 weeks of gestation underwent 67 direct intravascular transfusions. The fetoplacental volume relative to fetal weight estimated by ultrasound was found to be relatively constant throughout gestation at approximately 100 cm3/kg. The severity of fetal hemolytic disease and its treatment with intrauterine transfusions did not appear to alter the fetoplacental volume. A nomogram for fetoplacental blood volume versus gestational age is described.

Blood Transfusion, Intrauterine↗
PubMed1990

Flow velocity waveforms of the umbilical and cerebral arteries before and after intravascular transfusion.

Thirteen intravascular transfusions were performed in 13 human fetuses who were anemic because of severe red-cell alloimmunization. To investigate the status of the umbilical and cerebral circulations by pulsed Doppler ultrasound, we studied the fetal middle cerebral artery (N = 13), internal carotid artery (N = 11), anterior cerebral artery (N = 11), and umbilical artery (N = 13) before, within the first 2 hours after, and the day after intravascular transfusion. The gestational age at the time of transfusion was 21-31 weeks (mean +/- SD 25 +/- 3.1). The fetal hematocrits before transfusion ranged from 12-32% (23.4 +/- 6.1), whereas the hematocrit after transfusion was between 25-42% (35 +/- 5). The net blood volume transfused (volume infused--volume removed) ranged between 7.5-31.0 mL (16.0 +/- 7.4). The hematocrit of the transfused blood varied between 68-81% (74 +/- 4). Repeated-measures analysis of variance indicated significant differences in the pulsatility index values of the four vessels studied. The same analysis indicated significant differences in the pulsatility index values at the three time points. Multiple comparison tests showed that the pulsatility index was reduced significantly immediately after transfusion for each vessel studied, but returned to pretransfusion levels by the next day. These data suggest a change in vascular impedance soon after transfusion as a consequence of direct intravascular transfusion.

Anemia↗
PubMed1990

Serial maternal blood donations for intrauterine transfusion.

Because of concern regarding viral disease transmission, 21 pregnant women who had been alloimmunized to various red-cell antigens donated 77 units of blood (range two to six donations) for intrauterine transfusion to their anemic fetuses. Patients received supplemental iron and vitamin therapy throughout the blood donation period. Before the first donation, the mean (+/- SD) maternal hematocrit was 34.4 +/- 2.8%, whereas at delivery it was 33.4 +/- 3.5%. Maternal hematocrit was noted to decline slightly between the first and second donations but returned to pre-donation values with subsequent donations. No adverse maternal or fetal effects occurred secondary to repeated donations. Use of maternal designated-donor red cells for intrauterine transfusion offers potential advantages over the use of random allogeneic red blood cell units.

Adult↗
PubMed1990

Doppler assessment of the renal blood flow velocity waveform during indomethacin therapy for preterm labor and polyhydramnios.

To investigate the effects of indomethacin on the human fetal renal blood flow velocity waveform, 17 fetuses whose mothers were treated for preterm labor (N = 8) or polyhydramnios (N = 9) were studied. There were five growth-retarded fetuses (all in the group with polyhydramnios), 11 normal fetuses, and one fetus with red-cell alloimmunization. The indomethacin dose in all patients was 25 mg orally every 6 hours. The gestational age of the fetuses studied varied between 24-35 weeks (mean +/- SD 29.6 +/- 2.8). The fetal renal artery was studied at its origin from the aorta before and during the first 24 hours of indomethacin therapy. Seven fetuses manifested ductal constriction. Three fetuses also manifested tricuspid regurgitation. All ductal constrictions and the tricuspid regurgitations resolved in utero after discontinuation of indomethacin. There were no significant differences in the pulsatility index values of the renal artery before and during indomethacin therapy. These results suggest that there is no change in fetal renovascular parameters detectable with pulsatility index measurements during the first 24 hours of maternal indomethacin therapy.

Ductus Arteriosus↗
PubMed1990

Outcome of twin-twin transfusion diagnosed before 28 weeks of gestation.

To develop prognostic indicators for those patients diagnosed with twin-twin transfusion before 28 weeks' gestation, we conducted a retrospective analysis of all cases diagnosed at Baylor College of Medicine from January 1985 through April 1989. Twenty-seven cases of twin-twin transfusion were diagnosed by ultrasound; the criteria for diagnosis were polyhydramnios in one amniotic cavity and oligohydramnios in the other cavity. The mean (+/- SD) age at diagnosis was 21.9 +/- 2.9 weeks and the mean age at delivery was 26.8 +/- 4.9 weeks. Gestational age at diagnosis was similar in survivors and non-survivors (21.7 +/- 3.7 versus 22.2 +/- 2.8 weeks; P = .35); however, surviving infants were delivered later in gestation (31.9 +/- 3.5 versus 25.9 +/- 3.4 weeks; P = .000008). The overall survival rate was 21%. Fetal hydrops correlated with poor survival. Amniocentesis for decompression and tocolysis failed to decrease perinatal mortality.

Adult↗
PubMed1989

Relationship between human development and disappearance of unusually large von Willebrand factor multimers from plasma.

von Willebrand factor (vWF) multimers were examined in fetal, umbilical cord, and neonatal platelet-poor plasma (PPP) specimens. Sixty-five of 65 (100%) fetal PPP samples aged less than 35 weeks and seven of ten (70%) fetal samples aged greater than 35 weeks had unusually large vWF (ULvWF) multimers. Thirty of 46 (65%) cord PPP samples from neonates ranging in gestational age from 34 to 41 weeks had ULvWF. There was no significant relationship between either gestational age at time of delivery or birth weight and likelihood of finding ULvWF multimers in cord PPP samples. No maternal PPP sample contained ULvWF multimers. Serial heelstick samples from 16 preterm and term neonates were analyzed for 8 weeks. ULvWF multimers disappeared from the PPP of ten of the neonates during this time. The PPP of four neonates had vWF patterns similar to those in normal adult PPP throughout the sampling period. The ULvWF multimeric forms of fetal and neonatal PPP samples were similar to those constitutively released from endothelial cells. They were not as slowly migrating in a very porous 0.5% agarose gel system as the ULvWF multimers released from Weibel-Palade bodies in response to the calcium ionophore A23187. A vWF protomer was present in 97% of fetal samples, 83% of cord blood specimens, and 11% of neonatal heelstick samples, but was not found in any maternal sample. These results indicate that control mechanisms operative in older children and adults to prevent circulation of ULvWF multimers and vWF protomeric forms are normally acquired late in uterine life or during the neonatal period. ULvWF multimers, which are normal components of fetal, most cord, and some neonatal plasma samples, may contribute to in utero and postnatal hemostasis.

Autoradiography↗
PubMed1989

Development of individual growth standards for estimated fetal weight: II. Weight prediction during the third trimester and at birth.

Using a weight estimation procedure based of the Rossavik growth model, we have evaluated the possibility of establishing individual growth curve standards for fetal weight estimates and of predicting birth weights in the second trimester. In 20 normal fetuses delivered at term, 95% of the weight estimates obtained after 26 weeks' menstrual age (MA) were within +/- 22% of the predicted weight estimates. In these same fetuses the mean difference between birth weight estimates based on growth patterns before 26 weeks, MA, and actual birth weights was 1.2%, with 95% of the percent deviations being between 13.3% and - 8.8%. In a similar prospective study, the mean percent difference was -1.7%, with a range of 9.6% to -13.6%. Direct comparison of weight estimates obtained during the last week before delivery with birth weight projections indicated that birth weight estimates obtained 14 weeks before delivery had smaller systematic and random errors than those obtained within a week of delivery. These results indicate that individual growth curve standards for fetal weight estimates and the growth potential of individual fetuses can be determined from growth patterns in the second trimester.

Birth Weight↗
PubMed1989

Integration of the transabdominal technique into an ongoing chorionic villus sampling program.

Data are presented on 869 patients undergoing chorionic villus sampling procedures by one of two sampling techniques: 544 by a transcervical catheter aspiration method and 325 by a transabdominal two-needle aspiration method. The transcervical approach was the only procedure used in the first 330 cases, at which time the transabdominal technique was incorporated into our program. After an initial learning curve in the first 100 procedures the transcervical fetal loss rate stabilized at 2.7%, the number of patients requiring more than one catheter insertion decreased to 11%, and tissue weights greater than or equal to 10 mg were obtained in 88% of cases. The fetal loss rate for transabdominal chorionic villus sampling was 2.6%, indicating the addition of this new method did not significantly alter the fetal loss rate. Transabdominal chorionic villus sampling had an overall success rate of 99%, with only one insertion of the guide needle required for 98% of patients. Tissue weights of greater than or equal to 10 mg were obtained in 99% of cases. These results demonstrate that the transabdominal procedure can be rapidly and effectively incorporated by an operator already experienced with transcervical chorionic villus sampling. Since several contraindications exist for either chorionic villus sampling method, the availability of both techniques at a single center greatly enhances the ability to offer first-trimester fetal diagnosis to a majority of patients.

Abdomen↗
PubMed1989

Doppler assessment of the pulsatility index of the middle cerebral artery during constriction of the fetal ductus arteriosus after indomethacin therapy.

To investigate the effects of constriction of the ductus arteriosus on the pulsatility index of the middle cerebral artery, maximum velocity waveforms were obtained in 13 fetuses (one set of twins) whose mothers were treated with indomethacin for preterm labor (n = 9) or polyhydramnios (n = 3). Eleven of the fetuses manifested ductal constriction within 48 hours of therapy, whereas two fetuses had constriction after 1 week of therapy. Six of the 13 fetuses also manifested tricuspid insufficiency in association with constriction of the ductus arteriosus. All abnormal cardiac changes resolved in utero after discontinuation of indomethacin. No difference in the pulsatility index values of the middle cerebral artery was observed in the fetuses with ductal constriction but without tricuspid regurgitation (n = 7) when the values were compared with those obtained in absence of ductal constriction (1.87 +/- 0.37 vs. 1.88 +/- 0.33). In the fetuses that manifested both ductal constriction and tricuspid insufficiency (n = 6), the pulsatility index values in the middle cerebral artery were significantly lower in the presence of ductal constriction when compared with the values obtained in the absence of ductal constriction (2.22 +/- 0.26 vs. 1.57 +/- 0.34). These results indicate that a response to indomethacin sufficient to cause both ductal constriction and tricuspid insufficiency decreases the pulsatility index of the middle cerebral artery.

Blood Circulation↗
PubMed1989

Doppler assessment of the pulsatility index in the cerebral circulation of the human fetus.

To determine whether the pulsatility index was similar in all cerebral vessels, 30 fetuses at 23 to 37 weeks' gestation were studied. There were 12 normal fetuses, 14 growth-retarded fetuses, and 4 fetuses that were transfused in utero because of Rh isoimmunization. The middle cerebral artery and the internal carotid artery were studied in all fetuses. The proximal anterior cerebral artery was also studied in addition to the other two vessels in 12 fetuses from the three groups. The pulsatility index was significantly higher in the middle cerebral artery than in the internal carotid artery in all three groups. The pulsatility index of the proximal anterior cerebral artery was between the values shown for the middle cerebral artery and the internal carotid artery. The pulsatility index of the proximal anterior cerebral artery was significantly different from the index for the middle cerebral artery and not significantly different from the index for the internal carotid artery. These data indicate the importance of knowing exactly which cerebral vessel is being insonated, so that the Doppler waveform can be interpreted correctly.

Carotid Artery, Internal↗
PubMed1989

Maternal malignancy metastatic to the products of conception: a review.

Documented reports of maternal malignancy metastatic to the placenta and fetus are rare. From 1866 until the present there have been 52 cases reported in the Western literature. We report a case of maternal large-cell carcinoma of the lung metastatic to the maternal brain and the placenta without fetal involvement.

Adult↗
PubMed1989

Comparison of four types of intrauterine transfusion: effect on fetal hematocrit.

The advent of cordocentesis has made it possible to treat fetuses affected by severe red cell alloimmunization by infusing red cells into umbilical vessels. In addition, serial hematocrits can be followed between transfusions. Twenty fetuses underwent a total of 118 intrauterine procedures. Four transfusion techniques were compared to assess the effect of each method on the stability of the fetal hematocrit between procedures. The change in hematocrit per day for direct intravascular transfusion was -1.06 +/- 0.68%, for intraperitoneal transfusion: +0.03 +/- 0.6%, for combined exchange intravascular and intraperitoneal transfusion: +0.02 +/- 0.3% and for combined direct intravascular and intraperitoneal technique: -0.01 +/- 0.4%. The greatest fall in hematocrit was noted with the use of the direct intravascular technique alone (p less than 0.001). The combined direct intravascular/intraperitoneal approach produces a stable hematocrit between procedures and offers the possibility of performing intrauterine transfusions at less frequent intervals.

Blood Transfusion, Intrauterine↗
PubMed1989

Intravenous pancuronium bromide for fetal neuromuscular blockade during intrauterine transfusion for red-cell alloimmunization.

Intravenous pancuronium bromide was administered into the umbilical cord by funipuncture to effect temporary fetal paralysis. Neuromuscular blockade was achieved in 12 fetuses undergoing a total of 34 intrauterine procedures for the treatment of severe red-cell alloimmunization. The same initial dose of 0.2 mg/kg fetal weight estimated by ultrasound was used in all cases, but anemic fetuses did not resume movement for prolonged periods. A relationship among fetal hematocrit, adjusted dose, and duration of paralysis was described by the equation: Duration (hours) = 5.24 + 10.30 adjusted dose (mg/kg) - 0.16 hematocrit (%) (R2 = 0.49; P less than .001). Intravenous pancuronium was found to be a safe and effective method for cessation of fetal movement during intrauterine procedures.

Blood Transfusion, Intrauterine↗
PubMed1988

Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus.

Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus is a promising strategy for the prevention of perinatal infections caused by group B streptococci. To explore the feasibility of this strategy, we vaccinated 40 pregnant women at a mean gestation of 31 weeks with a single 50-microgram dose of the Type III capsular polysaccharide of group B streptococcus. The only adverse effect detected was a mild local reaction in nine women (22 percent). Of the 35 women with low or unprotective antibody levels before immunization (less than 2 micrograms per milliliter), 20 (57 percent) responded to the vaccine. The geometric mean antibody level rose from 1.3 to 7.1 micrograms per milliliter four weeks after vaccination (P less than 0.02), and these levels persisted at delivery and three months post partum. Sixty-two percent of the vaccine-induced immunoglobulin in the mothers was IgG, which readily crosses the placenta. Infant antibody levels in cord serum correlated directly with maternal antibody levels at delivery (r = 0.913, P less than 0.001). Of the 25 infants born to women who responded to the vaccine, 80 percent continued to have protective levels of antibody at one month of age and 64 percent had protective levels at three months. Serum samples from infants with greater than or equal to 2 micrograms of antibody to Type III group B streptococcus per milliliter uniformly promoted efficient opsonization, phagocytosis, and bacterial killing in vitro of Type III strains. This effect could be mediated exclusively by the alternative complement pathway. Although this vaccine with an overall response rate of 63 percent is not optimally immunogenic, we conclude that maternal immunization is feasible and can provide passive immunity against systemic infection with Type III group B streptococcus in the majority of newborns. Larger trials with better vaccines will be required to evaluate the safety and clinical effectiveness of this strategy.

Adult↗