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Biomedical subjects

R K Tamura

Publications and source records attributed to R K Tamura.

At least 37 records · Page 2Linked to original sources
PubMed1987

Umbilical cord size and amniotic fluid volume in prolonged pregnancy.

Expectant management of prolonged pregnancy is predicated on reassuring biophysical testing. However, even the combination of a reactive nonstress test and normal amniotic fluid volume may not prevent subsequent morbidity. To test the hypothesis that diminished cord Wharton's jelly incurs risk of peripartum cord compression in addition to decreased amniotic fluid, 68 patients with confirmed gestational age greater than or equal to 41 weeks were evaluated prospectively with semiweekly nonstress tests and weekly ultrasound examinations. Amniotic fluid volume was assessed, and umbilical cord diameter was measured and then correlated with the quantity of Wharton's jelly at delivery, determined by cord circumference. A significant correlation between cord circumference and umbilical cord diameter was observed, even in those patients with decreased amniotic fluid volume. Either an amniotic fluid volume less than 3.8 cm or an umbilical cord diameter less than 1.6 cm was associated with significant cord compression patterns. Peripartum morbidity was greatest in the presence of a smaller cord and decreased fluid, suggesting a synergism between these two factors for the risk of cord compression in prolonged pregnancy.

Amniotic Fluid↗
PubMed1987

Percutaneous umbilical transfusion in severe rhesus isoimmunization: resolution of fetal hydrops.

The rhesus-sensitized fetus with the worst prognosis is one with early onset of hydropic changes. Percutaneous umbilical blood sampling now enables access to the fetal circulation and thereby allows more precise evaluation of fetal anemia and direct intravascular transfusion. A variation of this technique was used in three pregnancies complicated by fetal pericardial effusion, scalp edema, and abdominal ascites before 26 weeks' gestation. Twelve ultrasound-guided percutaneous transfusions of 30 to 85 ml packed red blood cells were administered into the umbilical cord at its placental insertion. In each fetus the hydropic changes completely resolved and pregnancy outcome was successful. Neither adjunctive therapy with digoxin or Lasix nor exchange transfusions were used. Percutaneous umbilical transfusions appear to have the potential to improve the prognosis for the severely isoimmunized fetus.

Adult↗
PubMed1987

Ultrasonic prediction of birth weight in preterm fetuses: which formula is best?

Data from previous studies have suggested that birth weight prediction was enhanced by using formulas specifically derived from preterm fetuses. However, no prospective comparison of different formulas was performed. We obtained ultrasonic data on 61 pregnancies at risk for preterm delivery with a gestational age of 29.0 +/- 3.0 weeks (mean +/- SD). In all women birth weight was predicted within 7 days of delivery. Of the 61 pregnancies, 49 (80%), 41 (67%), 30 (49%), and 17 (28%) weighed less than 1750, 1500, 1250, and 1000 gm, respectively; 14 published formulas were compared for accuracy in predicting birth weight in these four categories. The formulas with the smallest absolute mean percent errors incorporated head and abdominal circumferences and femur length. The formula of Weiner et al., derived from low birth weight infants, produced the smallest absolute mean percent error and SD, 10.9% +/- 7.9%; this error was further reduced to 7.7% +/- 6.5% in infants weighing less than 750 gm. These findings suggest that birth weight in the preterm fetus is best predicted by a formula targeted to such a population.

Birth Weight↗
PubMed1987

Underestimation of gestational age by conventional crown-rump length dating curves.

Inaccuracies in gestational age assignment based on published crown-rump length data were noted in patients with known ovulation dates. In this study, we tested the hypothesis that crown-rump length data derived from pregnancies with known ovulation dates differ from those of menstrually timed pregnancies. Seventy-two previously infertile women with known dates of ovulation had crown-rump length measurements from 35-79 days postovulation. We transformed the data to menstrual age (gestational age) by adding 14 days to the date of ovulation and compared our crown-rump length values with those of two previous reports. At corresponding crown-rump length values, the gestational ages from our data differed from those in the previous studies. We suggest using crown-rump length dating curves based on ovulation-timed pregnancies because crown-rump length data derived from menstrually dated pregnancies underestimate true gestational age.

Embryonic and Fetal Development↗
PubMed1986

Conservative treatment of ectopic pregnancy with methotrexate.

Six subjects with distal ampullary ectopic pregnancies were treated with four doses of intravenous methotrexate (1.0 mg/kg) followed by four doses of leucovorin (0.1 mg/kg, intramuscularly). The diagnosis was established in all cases by laparoscopy following sonography and radioimmunoassay for serum beta subunit of human chorionic gonadotropin. Subjects were followed with daily quantitative serum beta-human chorionic gonadotropin radioimmunoassay and sonography. Five of the six subjects experienced resolution of their ectopic pregnancy without additional surgical treatment. One subject underwent salpingectomy following treatment. Morbidity also included three patients with mild stomatitis or gastritis, and two patients had transient elevations of serum transaminase levels. Two patients had protracted courses and received blood transfusions. The most abrupt response and most uncomplicated courses were experienced in the three subjects with initial human chorionic gonadotropin levels below 1000 mIU/ml. This preliminary experience suggests that methotrexate may be an effective alternative for the treatment of early ectopic pregnancy.

Adolescent↗
PubMed1986

Ultrasonic fetal abdominal circumference: comparison of direct versus calculated measurement.

The ultrasonically derived fetal abdominal circumference is one of the essential parameters used to predict birth weight, assess fetal growth, and follow the evolution of fetal ascites. Growth curves relating abdominal circumference to gestational age have been reported for directly measured abdominal circumferences. However, none have been reported for abdominal circumferences calculated from measurements of fetal abdominal diameters. In this report, 197 normal fetuses ranging from 18 to 41 weeks' gestation are studied. The validity of 468 abdominal circumferences calculated from fetal abdominal diameters is tested by comparing the data with a similar number of direct abdominal circumference measurements obtained by a digitizer. From 18 to 41 weeks' gestation, directly measured fetal abdominal circumferences are significantly larger than fetal abdominal circumferences calculated from abdominal diameters (P less than .0001). The authors conclude that clinical management decisions based on abdominal circumference data are predicated on the use of appropriate abdominal circumference and/or abdominal diameter growth curves.

Abdomen↗
PubMed1986

Diabetic macrosomia: accuracy of third trimester ultrasound.

Sonar biparietal diameter, head circumference, and abdominal circumference percentile values obtained late in the third trimester were compared with birth weight percentile (relative to dates) in 147 diabetic mothers and 40 control fetuses of nondiabetics. Estimates of fetal weight by the method of Shepard et al were also calculated from these sonar data and compared with birth weight percentile. Abdominal circumference values greater than the 90th percentile correctly predicted macrosomia (defined as birth weight greater than 90th percentile) in 78% of cases. Biparietal diameter and head circumference percentiles were significantly less predictive of macrosomia. When analyzed in a similar manner, estimated fetal weights greater than the 90th percentile correctly predicted macrosomia at birth in 74% of cases. However, when both the abdominal circumference and the estimated fetal weight exceeded the 90th percentile, macrosomia was correctly diagnosed in 88.8% of pregnant women with diabetes mellitus.

Abdomen↗
PubMed1985

Meconium below the vocal cords at delivery: correlation with intrapartum events.

Intrapartum events were studied in 272 patients with meconium-stained amniotic fluid. All infants underwent DeLee suction followed by intubation and 58 of 272 had meconium present below the vocal cords at delivery. Neither the total duration of variable fetal heart rate decelerations or a continuous saltatory pattern nor the presence or absence of late decelerations could be related to an increased risk of meconium below the vocal cords. When a rising baseline fetal heart rate and decreased variability were present as well, a significantly greater proportion of patients had meconium below the vocal cords. Routine obstetric and pediatric suctioning did not prevent the single death that occurred in a fetus who had deep meconium aspiration in utero.

Amniotic Fluid↗
PubMed1985

Real-time ultrasound estimations of weight in fetuses of diabetic gravid women.

To test the applicability of equations for fetal weight estimations in a group of fetuses suspected of being large for gestational age, real-time ultrasound measurements of fetal biparietal diameters and abdominal circumferences were obtained for 34 fetuses of diabetic mothers. In the first phase of the study the accuracy in the prediction of weight was assessed with use of two known equations. In the second phase, biparietal diameter, abdominal circumference, and actual birth weight data of the 34 study fetuses were used as independent variables to determine the best-fitting equation for relating estimated fetal weight (EFW) to biparietal diameter (BPD) and abdominal circumference (AC); this equation is log (EFW) = 0.02597 AC + 0.2161 BPD - 0.1999 (AC X BPD2)/1000 + 1.2659. The standard deviation of differences is 322.26 gm and multiple R = 0.781. In the final phase the reliability of this equation was compared to those of Thurnau and Shepard in 34 additional fetuses of diabetic gravid women. The data suggest that in these fetuses suspected of being large for gestational age the weight estimates calculated at or near term may be enhanced if predictive equations are formulated specifically from the data for such fetuses.

Abdomen↗
PubMed1985

Predictive value, sensitivity, and specificity of ultrasonic targeted imaging for fetal anomalies in gravid women at high risk for birth defects.

In this report the predictive value of ultrasonic targeted imaging for fetal anomalies (TIFFA) is defined. Six hundred fifteen pregnant women at high risk for birth defects were scanned from January, 1980, to December, 1983. Follow-up evaluation was available on 569 fetuses. The pregnancies were classified into five groups according to the indications used for ultrasonic targeted imaging studies. The largest number of women were placed in group 1 and were referred because of a variety of abnormalities in previous or ongoing pregnancies. The women classified in the other four groups were examined because of maternal or fetal reasons related to specific craniospinal (29%), urinary (7.9%), gastrointestinal (6.7%), and skeletal (3.7%) defects. In our series the predictive values of abnormal and normal ultrasonic targeted imaging studies were 95% and 99%, respectively. A detailed breakdown of the accuracy of ultrasonic targeted imaging in relation to each anatomic category is presented; these data are useful in counseling gravid women with anomalous fetuses.

Congenital Abnormalities↗
PubMed1985

Is amniotic fluid material in the central circulation of peripartum patients pathologic?

Cytologic findings of amniotic fluid material (AFM) in pulmonary arterial blood (PAB) of survivors of amniotic fluid embolism (AFE) are assumed to be pathologic. However, no cytologic studies of central blood from patients without clinical AFE have been reported. To address this question PAB samples from peripartum patients without clinical AFE were examined for the presence and extent of AFM (including squames, mucin, and lanugo hair). Ten samples were obtained from five patients. All patients had at least one sample postpartum. Peripheral blood from a nonpregnant adult female control was processed similarly. Results were compared to a PAB sample from a patient with clinical AFE. The patient with clinical AFE had many squames, clumps of lanugo hair, and mucin in one sample. In six of ten study samples, there were squames, accompanied in two cases by lanugo hair or trophoblast. In nine of ten samples there was mucin. There appeared to be no difference in cytologic findings in patients according to mode of delivery or sampling time. The control blood sample was negative for amniotic fluid-like material. AFM may be found in peripartum patients without clinical amniotic fluid embolism. A quantitative difference was seen between the index patient and each of our five study patients. These findings suggest that there is a quantitative continuum of AFM transported to the central circulation in peripartum patients which may, in part, explain the varied clinical presentations and severity of AFE.

Adult↗
PubMed1985

Intraoperative ultrasound for gynecologic procedures.

Recent technological advances in portable dynamic imaging equipment allow for the performance of intraoperative ultrasound examinations during certain gynecologic procedures. Reported is the authors' technique for such an examination and outlined are specific vaginal and abdominal gynecologic procedures wherein adjunctive ultrasound may facilitate performance of the operative procedure, enhance safety, and decrease the possibility of complications.

Abortion, Induced↗
PubMed1984

Perinatal outcome following prior delivery in the late second or early third trimester.

Forty pregnancies in 37 women who were previously delivered of a live-born fetus between 20 and 32 weeks' gestation are reported here. Fourteen pregnancies were treated with cervical cerclage between 14 and 16 weeks. Twenty-six pregnancies were initially managed conservatively, but three of these patients had a McDonald cerclage placed between 18 and 23 weeks because of significant change in cervical effacement or dilatation. The risk of preterm delivery was 36% (5 of 14) in the cerclage group and 38% (10 of 26) in those patients managed conservatively. The perinatal survival rates were 93% (13 of 14) and 88% (23 of 26), respectively. These results are encouraging when it is considered that only 14% (9 of 64) of prior gestations (exclusive of spontaneous abortions and elective terminations) were carried to term and the perinatal survival rate was 28% (18 of 64). Although this study was nonrandom, these results also support the selective use of cervical cerclage on the basis of past history and physical examination.

Birth Weight↗
PubMed1984

Placenta previa: aggressive expectant management.

We report the outcomes of 95 expectantly managed cases of placenta previa; all were diagnosed after 21 weeks' gestation. Patients at risk for preterm delivery because of hemorrhage or preterm labor received aggressive care, including multiple transfusions, volume expansion and tocolytic therapy, and amniotic fluid surfactant determinations, to achieve the goal of delivery at 37 weeks' gestation with mature fetal lung function. We present guidelines for outpatient management and double setup examination prior to delivery. The role of ultrasound in diagnosis (three asymptomatic cases; 13 cases with preterm labor) and serial placental localization to determine the timing, route, and place of delivery is presented. Eighty-six percent of 19 infants born weighing less than 2500 gm were managed expectantly. Hemorrhage was the determinant in delivery timing in 50 cases. All four deaths were neonatal with birth weights less than 2200 gm. This is the lowest perinatal mortality rate (4.2%) published to date. Use of this aggressive approach is particularly suitable for patients cared for in a teritary center.

Adolescent↗
PubMed1984

Diminished growth in fetuses born preterm after spontaneous labor or rupture of membranes.

We examined biparietal diameter, abdominal circumference, and birth weight in 148 preterm infants to assess fetal growth. A statistically significant proportion of preterm fetuses had biparietal diameter and abdominal circumference values below the fiftieth and tenth percentile levels as compared with that expected in normal fetuses. Similarly, birth weight of infants in the study fell significantly below the fiftieth and tenth percentiles relative to Brenner's curve. We conclude that diminished fetal growth is associated with early delivery secondary to preterm labor or preterm premature rupture of membranes or both. Additionally, since biparietal diameters in preterm fetuses are smaller than those of normal fetuses the prediction of gestational age by cephalometry should be advanced by 7 to 10 days.

Birth Weight↗