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Biomedical subjects

G A Dildy

Publications and source records attributed to G A Dildy.

At least 37 records · Page 2Linked to original sources
PubMed1996

Determination of fetal RhD status from uncultured amniocytes.

OBJECTIVE: To determine the accuracy of DNA analysis for fetal RhD status using polymerase chain reaction (PCR) on uncultured amniocytes. METHODS: Three hundred forty-seven amniotic fluid (AF) samples obtained for a variety of clinical indications were tested for fetal RhD status using PCR and primers specific for the genes coding for D and Cc/Ee. Fetal RhD status was confirmed by serologic methods on neonatal cord blood obtained at the time of delivery. RESULTS: In 346 of 347 cases (99.7%), the PCR results of AF were in agreement with the serologic RhD blood type. The single error was in an RhD-negative fetus (misidentified as RhD-positive) whose AF was contaminated with blood from an RhD-positive mother. The likelihood of an erroneous result was 0.3%. CONCLUSION: Polymerase chain reaction-based analysis of fetal RhD status using uncultured amniocytes and established primers appears to be highly accurate.

Amniotic Fluid↗
PubMed1996

Intrapartum fetal pulse oximetry: past, present, and future.

Oxygen saturation monitoring (pulse oximetry) has markedly improved medical care in many fields, including anesthesiology, critical care, and newborn intensive care. In obstetrics, fetal heart rate monitoring remains the standard for intrapartum assessment of fetal well-being. Fetal heart rate monitoring is sensitive but nonspecific for detecting fetal compromise. Additional clinical information is needed to discern those fetuses not at risk for development of intrapartum acidosis to avoid unnecessary intervention. Fetal oxygen saturation monitoring is a new technique currently under development. This article reviews the evolution of intrapartum fetal oxygen saturation monitoring and proposes directions for future investigation.

Acidosis↗
PubMed1996

Prospective evaluation of the antenatal incidence and postnatal significance of the fetal echogenic cardiac focus: a case-control study.

OBJECTIVE: We evaluated the antenatal incidence and postnatal significance of echogenic cardiac foci observed during antenatal ultrasonography. STUDY DESIGN: During a 4-month period, all women undergoing dating ultrasonography between 16.0 and 24.9 weeks' gestation at one referral center were prospectively evaluated for an echogenic cardiac focus during an apical four-chamber view of the heart. Referrals for maternal or fetal complications were excluded. Postnatal echocardiography was performed for those identified with positive findings. Controls were selected from among normal subjects in the general group for comparison with the study group. RESULTS: Five hundred six consecutive fetuses were evaluated at a mean +/- SD gestational age of 20.6 +/- 1.6 weeks. There were 25 (4.9%) fetuses found to have echogenic cardiac focus (left ventricle = 19, right ventricle = 6). Echocardiography was performed between 0.3 and 20.1 weeks postdelivery. After birth, 12 echogenic left ventricle papillary muscles and three echogenic left ventricle chordae were identified; there were no postnatal right ventricle findings. There were no cases of intracardiac tumor or myocardial dysfunction; one neonate had minor structural malformations. There were no significant differences in maternal age, gravidity, parity, gestational age at ultrasonography, gestational age at delivery, or 5-minute Apgar scores. A significant difference was observed in birth weight between the control (n = 50) and study (n = 25) groups (3465 +/- 501 gm vs 3124 +/- 589 gm; p = 0.002). This difference persisted after correcting for gestational age, although all infants in both groups born after 37.0 weeks weighed > 2500 gm. CONCLUSIONS: The incidence of echogenic cardiac foci during routine midtrimester ultrasonography is 4.9%. As an isolated finding, the echogenic cardiac focus may be associated with a statistically significant but clinically insignificant decrease in birth weight. Because of these findings, we consider an isolated echogenic cardiac focus in a patient at low risk for cardiac abnormalities a variant of normal, which does not warrant follow-up clinical evaluation.

Case-Control Studies↗
PubMed1996

Umbilical cord blood gas analysis at delivery.

Fetal acid-base status is the end point that all antepartum and intrapartum surveillance tools are designed to assess, either directly or indirectly. Umbilical arterial blood pH is normal in 80% of depressed newborns, thereby proving the absence of birth asphyxia both in the delivery room and in the courtroom. The technique, normal ranges, and risks, benefits and cost analysis of routine versus selected umbilical blood sampling are considered. The American College of Obstetricians and Gynecologists recommends performing umbilical blood sampling for acid-base analysis in selected deliveries. However, in our opinion routine umbilical blood sampling at all deliveries has merit.

Acid-Base Equilibrium↗
PubMed1996

Very advanced maternal age: pregnancy after age 45.

OBJECTIVE: Our purpose was to describe the maternal and fetal outcomes of pregnancies in women > or = 45 years old at delivery. STUDY DESIGN: A retrospective review of in-hospital deliveries after 20 weeks of gestation was performed in four Utah tertiary care hospitals for the 10-year period between 1985 and 1994. RESULTS: Seventy-nine cases were identified among 126,500 births, with an incidence of 0.63 per 1000 births. Maternal ages were 45 (n = 44), 46 (n = 21), and > or = 47 (n = 14) years. Three of the conceptions were assisted, including both twin gestations. Thirty-seven (46.8%) had obstetric complications during pregnancy; the most frequent complications were gestational diabetes (12.7%) and preeclampsia (10.1%). Median (range) gestational age at delivery was 39 (22.9 to 41.7) weeks; 12 (15.2%) deliveries occurred before 37 weeks. Eight (9.9%) karyotype abnormalities were diagnosed. The cesarean section rate was 31.7%; the most frequent indications were abnormal lie (n = 9), fetal distress (n = 5), and previous cesarean delivery (n = 5). There were no maternal deaths. Median (range) birth weight was 3466 (397 to 5085) gm; 14 (17.3%) were < 2500 gm and 16 (19.8%) were > 4000 gm. Twelve (14.8%) infants were admitted to the neonatal intensive care unit. The corrected perinatal mortality rate was 1.3% (1/78). CONCLUSIONS: In women > 45 years old at delivery maternal and fetal outcomes were generally good, but there was a high incidence of pregestational (chronic hypertension, hypothyroidism) and gestational (karyotype abnormalities, gestational diabetes, cesarean section, macrosomia) complications. This information may be helpful for counseling women between 45 and 50 years old who are considering pregnancy.

Apgar Score↗
PubMed1996

The relationship between oxygen saturation and pH in umbilical blood: implications for intrapartum fetal oxygen saturation monitoring.

OBJECTIVE: Our purpose was to evaluate the relationship between umbilical arterial blood oxygen saturation determined by hemoximetry (Sao2) and umbilical arterial blood pH and base excess determined by blood gas analysis to establish a "critical threshold" for fetal preductal arterial oxygen saturation determined by reflectance pulse oximetry (Spo2). STUDY DESIGN: Umbilical artery and vein blood specimens were obtained at delivery. Blood gas analysis and hemoximetry were performed. Polynomial regression analysis and receiver-operator characteristic curves were calculated for umbilical arterial blood Sao2 and theoretic preductal arterial blood Sao2 versus umbilical arterial blood pH and base excess. RESULTS: A total of 1101 paired umbilical artery and vein specimens were obtained. When the umbilical arterial blood Sao2 was > or = 30%, umbilical arterial blood pH was > or = 7.13 in 99.0% (388/392) of cases and < 7.13 in 1.0% (4/392) of cases. When umbilical arterial blood Sao2 was < 30%, umbilical arterial blood pH was > or = 7.13 in 91.4% (648/709) of cases and < 7.13 in 8.6% (61/709) of cases. CONCLUSIONS: From these analyses, it appears that an Spo2 cutoff value of 30% would be reasonable in clinical trials of intrapartum fetal pulse oximetry.

Acid-Base Imbalance↗
PubMed1996

Amniotic fluid index and perinatal morbidity.

Our purpose was: (1) to determine whether assessment of amniotic fluid index in high risk patients with a reactive nonstress test (NST) allowed improved recognition of the fetus at risk for perinatal morbidity than a reactive NST alone; and (2) to determine the optimal low amniotic fluid index (AFI) which should prompt clinical concern. The last NST performed within a week of delivery and amniotic fluid index were retro-spectively compared with various indices of perinatal morbidity. In fetuses with a reactive NST, decreasing AFI was directly correlated with a risk of 5-minute Apgar score of less than 7 and delivery for fetal distress. When various subgroupings of AFI were compared, 7 cm or greater appeared to have a better inverse correlation with the indices of morbidity than lower cut-off values. The addition of AFI assessment to the standard NST allows better prediction of perinatal morbidity than the NSTs alone. Seven centimeters appears to be a reasonable cut-off for clinical concern.

Amniotic Fluid↗
PubMed1995

Amniotic fluid embolism: analysis of the national registry.

OBJECTIVE: We analyzed the clinical course and investigated possible pathophysiologic mechanisms of amniotic fluid embolism. STUDY DESIGN: We carried out a retrospective review of medical records. Forty-six charts were analyzed for 121 separate clinical variables. RESULTS: Amniotic fluid embolism occurred during labor in 70% of the women, after vaginal delivery in 11%, and during cesarean section after delivery of the infant in 19%. No correlation was seen with prolonged labor or oxytocin use. A significant relation was seen between amniotic fluid embolism and male fetal sex. Forty-one percent of patients gave a history of allergy or atopy. Maternal mortality was 61%, with neurologically intact survival seen in 15% of women. Of fetuses in utero at the time of the event, only 39% survived. Clinical and hemodynamic manifestations were similar to those manifest in anaphylaxis and septic shock. CONCLUSIONS: Intact maternal or fetal survival with amniotic fluid embolism is rare. The striking similarities between clinical and hemodynamic findings in amniotic fluid embolism and both anaphylaxis and septic shock suggest a common pathophysiologic mechanism for all these conditions. Thus the term amniotic fluid embolism appears to be a misnomer.

Adolescent↗
PubMed1995

Cardiac arrest during pregnancy.

Cardiac arrest occurs rarely in pregnancy. Nevertheless, the practicing obstetrician stands a likely chance of encountering this acute condition at least once over the course of a busy career. A basic understanding of maternal-fetal physiology and the acute management of cardiac arrest are of key importance. ECC is not significantly changed from that administered to the nonpregnant patient. Factors unique to pregnancy, however, such as lateral uterine displacement, effects of drugs on the mother and the fetus, and the issues of perimortem cesarean section should be understood by the consulting obstetrician. The critical period in management of these patients is within the first several minutes of the event. In many situations, the obstetrician may be the first to arrive and initiate therapy before the arrival of multidisciplinary assistance. Prompt initial management will give the mother and fetus the best chances for survival.

Cardiopulmonary Resuscitation↗
PubMed1994

Intrapartum fetal pulse oximetry: the effects of maternal hyperoxia on fetal arterial oxygen saturation.

OBJECTIVE: Our purpose was to observe the effects of maternal oxygen administration on fetal arterial oxygen saturation in normal human fetuses during labor. STUDY DESIGN: Twenty healthy women with uncomplicated pregnancies were studied during active labor at term. Arterial oxygen saturation was measured by a noninvasive reflectance pulse oximeter designed for fetal application (Nellcor, Inc, Pleasanton, Calif.). The first group was studied during 20-minute intervals of inspired oxygen concentrations of 21%, 40%, and 100%. In a second group the effects of prolonged (45 minutes) supplemented 40% oxygen administration were evaluated. Differences between groups were analyzed by analysis of variance; significance was considered at p < 0.05. RESULTS: A significant increase in fetal arterial oxygen saturation (50% +/- 8% vs 64% +/- 6%, p < 0.0001) was detected in the group given 100% oxygen for 20 minutes but not in the groups that received 40% oxygen for 20 or 45 minutes. CONCLUSIONS: Prolonged maternal administration of 40% oxygen resulted in no significant demonstrable change in fetal arterial oxygen saturation determined by reflectance pulse oximetry in normal fetuses. Because the administration of oxygen by standard mask techniques rarely results in 40% inspired oxygen concentration, fetal benefits of such intrapartum maternal oxygen administration are questionable.

Adult↗
PubMed1994

Intrapartum fetal pulse oximetry: fetal oxygen saturation trends during labor and relation to delivery outcome.

OBJECTIVES: Our purpose was to study fetal arterial oxygen saturation trends by continuous pulse oximetry during labor in subjects with normal and abnormal delivery outcomes. STUDY DESIGN: Continuous fetal arterial oxygen saturation was measured during labor with a noninvasive reflectance pulse oximeter designed for fetal application. Averaged arterial oxygen saturation values were compared between stage 1 and stage 2 of labor, with stage 1 further subdivided into early (< or = 4 cm), middle (5 to 7 cm), and late (8 to 10 cm) phases. Delivery outcome was considered to be abnormal for any of the following conditions: gestational age < 37 weeks, maternal oxygen administration, delivery by cesarean section, 5-minute Apgar score < 7, umbilical artery pH < 7.10, birth weight < 2500 gm, or newborn intensive care unit admission. RESULTS: A total of 291 subjects were studied: 142 in Provo, 90 in Nijmegen and 59 in San Francisco. Subjects with delivery complications (n = 125) were evaluated separately from those with normal delivery outcomes (n = 160). Fetal arterial oxygen saturation was 58% +/- 10% (mean +/- SD) during the cumulative period of study for the normal-outcome group. A significant decrease (paired t test, p < 0.001) in fetal arterial oxygen saturation occurred from stage 1 (59% +/- 10%) to stage 2 (53% +/- 10%) labor. When stage 1 was subdivided into early (< or = 4 cm), middle (5 to 7 cm), and late (8 to 10 cm) phases, a gradual decreasing trend in fetal arterial oxygen saturation was observed: 62% +/- 9%, 60% +/- 11%, and 58% +/- 10%. CONCLUSIONS: With the use of reflectance pulse oximetry, a statistically significant decrease in fetal arterial oxygen saturation was observed during labor in women with normal and abnormal delivery outcomes.

Adult↗
PubMed1994

Effects of chronic exercise on blood volume expansion and hematologic indices during pregnancy.

OBJECTIVE: To compare blood volumes and hematologic indices between nine aerobically trained, physically active pregnant women who continued to exercise throughout gestation and five healthy yet sedentary gravidas. METHODS: Subjects were tested on three occasions: 25 and 36 weeks of pregnancy and 12 weeks postpartum. Plasma volumes were estimated by dye dilution with Evans blue. Blood samples were taken from the antecubital vein with the subjects resting in a seated, semirecumbent position. In addition to plasma volume estimations, blood samples were analyzed for hematocrit ratio, hemoglobin concentration, red cell count, and plasma protein concentration. Blood volumes and red cell volumes were calculated from plasma volume estimates and hematocrit ratios. RESULTS: Average birth weight and length of gestation did not differ between the subject groups. Analysis of variance indicated that absolute blood volume measures were significantly greater (P < .01) in the physically active compared to sedentary subjects at all three test times. Similar results were found for plasma and red cell volumes (P < .01). Blood volumes relative to body weight were significantly higher in physically active subjects (P < .01) than in their sedentary counterparts at 25 weeks (88.5 versus 75.5 mL/kg) and at 36 weeks (88.4 versus 70.9 mL/kg), as well as at 12 weeks postpartum (72.2 versus 57.6 mL/kg). All vascular volumes were significantly (P < .001) lower at 12 weeks postpartum compared to those seen during pregnancy in both subject groups. Hematologic indices of hematocrit ratio, hemoglobin concentration, red cell count, and plasma protein concentration were all greater (P < .001) at 12 weeks postpartum than during pregnancy. CONCLUSIONS: Physically active women possessed significantly greater vascular volumes than their sedentary counterparts. Although this difference was maintained throughout gestation as the active gravidas continued to exercise, there was no apparent effect on pregnancy outcome.

Adult↗
PubMed1993

The effects of a long-acting progestin on the hypothalamic-pituitary-ovarian axis in women with normal menstrual cycles.

This study was performed to determine how a long-acting, slow-release preparation of norethindrone (NET) affects the hypothalamic-pituitary-ovarian axis of normal ovulatory women. Ten women were studied during the luteal phase of their menstrual cycle, and again at six and twelve weeks following intramuscular administration of 100 mg NET microencapsulated in poly-D,L-lactide-co-glycolide. Serial LH samples, serum E, P, and NET were followed by a GnRH stimulation test. Compared to luteal phase values, six and twelve weeks of treatment with NET inhibited serum E2 and P while mean serum LH remained unchanged and mean serum FSH increased significantly (p < 0.05). LH pulse frequency after NET treatment was twice the rate (p < 0.01) as that of the luteal phase, whereas LH pulse amplitude was decreased significantly (p < 0.05). Finally, although there was no significant change in pituitary LH secretion in response to GnRH, NET treatment augmented FSH responsiveness to GnRH at the times studied. Preserved pituitary responsiveness to GnRH in NET-treated patients suggests that inhibited ovarian function results in an increase in GnRH pulse frequency but not GnRH pulse amplitude. Since the progestational milieu is maintained in these patients by NET treatment, the decrease in serum E2 may be responsible for the increase in GnRH pulse frequency. The presence of a critical level of E2 may be necessary for progestins to affect the hypothalamic GnRH pulse generator.

Adult↗
PubMed1993

Effects of maternal aerobic fitness on cardiorespiratory responses to exercise.

We hypothesized that aerobically fit women who continued to exercise throughout pregnancy would have enhanced cardiorespiratory responses to exercise. Physically active (N = 10) and sedentary (N = 6) subjects were compared during steady-state (15 min) semi-recumbent cycle exercise performed at a given heart rate (HR; 140 b.min-1) twice during pregnancy (25 wk, 36 wk) and 12 wk postpartum. Indirect calorimetry was used to measure volumes and fractional concentrations of expired gases. Cardiac output was estimated via CO2 rebreathing. Data were analyzed with repeated measures ANOVA. Caloric expenditure during exercise was significantly (P < 0.001) greater in the physically active (7.2 kcal.min-1) compared with sedentary (4.7 kcal.min-1) subjects. Alveolar ventilation and cardiac output responses to exercise were proportionally greater (P < 0.001) in the aerobically fit subjects. Ventilatory equivalents for O2 and physiological dead space/tidal volume ratios were significantly (P < 0.01) lower in the physically active subjects during exercise. In contrast, ratings of perceived exertion during exercise did not differ between subject groups. It appears that a physically active woman's enhanced cardiorespiratory responses to acute exercise are maintained during pregnancy if she continues her aerobic fitness program throughout gestation.

Adult↗
PubMed1993

Severe pulmonary hypertension in pregnancy following successful repair of ventricular septal defect in childhood.

BACKGROUND: Because of advances in surgical repair, an increasing number of women born with structural cardiac disease now live to reproductive age. Patients treated successfully in childhood are followed for varying periods of time, then may be lost to follow-up or told that no follow-up is necessary because their condition is stable. However, the hemodynamic changes that accompany pregnancy may result in cardiovascular decompensation, even after years of apparently good health. CASES: We have recently cared for two women who had undergone repair of congenital heart disease in childhood. Although they thought that their repair was complete and they had been asymptomatic until the pregnancy, both presented with symptoms and signs of severe pulmonary hypertension, subsequently confirmed on cardiac catheterization. One patient elected to terminate her pregnancy, and the other died in the immediate puerperium. CONCLUSION: Despite normal physical function and an absence of abnormal physical findings, a thorough cardiac evaluation including echocardiography should be considered for pregnant patients with a history of repaired congenital heart disease, especially if the original defect is known to lead to pulmonary hypertension.

Adult↗
PubMed1993

Preliminary experience with intrapartum fetal pulse oximetry in humans.

Electronic fetal heart rate (FHR) monitoring is commonly used to assess fetal well-being during labor. Nonreassuring patterns in many cases are associated with normal fetal acid-base condition, leading to unnecessary operative intervention. Fetal pulse oximetry has several potential advantages over FHR monitoring because it assesses not only pulse, but also arterial oxygen saturation and tissue perfusion. We describe our preliminary experience with the Nellcor N-400 Fetal Oxygen Saturation Monitor and FS-10 Oxisensor in 73 subjects during active labor at term. The mean (+/- standard deviation) duration of monitoring was 161.4 +/- 106.0 minutes, with sensor contact achieved 67.3 +/- 22.5% of the time during labor. Data were successfully recorded in all patients, with a reliable signal obtained 50.1 +/- 21.6% of the time during labor. The mean fetal oxygen saturation was 57.9 +/- 10.0%. The potential for research and clinical applications appears promising with further sensor and monitor development.

Adult↗