Biomedical subjects
Publications and source records attributed to T H Strong.
Eighteen of 901 women (2%) attempting vaginal birth after cesarean delivery (VBAC) received amnioinfusion. No untoward effects occurred in the subjects or their fetuses. We conclude that, though amnioinfusion in the setting of a VBAC attempt is needed only infrequently, it appears to be a reasonable intrapartum management option. The usual safeguards for a VBAC attempt should be followed.
Excluding labor, the greatest risks to the fetus from preterm PROM are umbilical cord accidents and infection. Heretofore, the clinical options for the PROM patient have been limited. With the advent and refinement of amnioinfusion, the utility of expectant management may be greatly increased. Through the use of amnioinfusion or its permutations, a number of diagnostic and therapeutic procedures previously unavailable to the PROM patient may become routine, including amniotic fluid volume expansion and direct in utero prophylaxis/treatment of amnionitis.
This study was undertaken to determine the incidence and associations of uterine rupture and dehiscence with an attempted vaginal birth after cesarean section. The charts from 137 patients who had uterine scar separation after a previous cesarean section from 1983 to 1989 were examined. Approximately 9.3% of the 119,395 women who were delivered in that interval had a prior cesarean section. Of those, 68.8% underwent a trial of labor with a 79.2% success rate. The uterine rupture rate in this latter group was 0.8%, while an additional 0.7% had a bloodless dehiscence. Bleeding and pain were unlikely findings with a uterine scar separation (3.4% and 7.6%, respectively). The most common manifestation of a scar separation was a prolonged fetal heart rate deceleration leading to operative intervention (70.3%). We conclude that, although the incidence of uterine rupture was low, the event is most often seen as an acute emergency. Prevention should be directed toward timely diagnosis and prompt management of labor dystocias. Staff and facilities for safe management of a uterine scar separation are a requisite for the conduct of a vaginal birth after previous cesarean section.
An intrauterine probe electrode was inserted into 100 laboring women and 366 bipolar electrode combinations were tested. A noise-cancelling technique was used with the final 28 subjects to remove competing maternal cardiac signals. Twenty-four (86%) had fetal heart rate tracings with sufficient technical quality to allow determination of the baseline fetal heart rate.
Electronic fetal heart rate and uterine activity monitoring during labor requires expensive equipment and a source of electricity. However, it is not available to most of the women in the world. Intrauterine manometry provides a method which can be employed in underdeveloped settings to assess uterine contractions and to time auscultation. The vertical column of fluid in a standard intrauterine pressure catheter (IUPC) correlated well (R = 0.93) with the intrauterine pressure measurements obtained by a standard IUPC/pressure transducer system. Intrauterine manometry provides an alternative measure of uterine tone which may be employed in underdeveloped areas.
Amnioinfusion was performed in a prospective, randomized trial of 60 women in the latent phase of labor with oligohydramnios, as defined by an amniotic fluid index less than or equal to 5.0 cm. All fetuses were at least 37 weeks' gestational age, had normal baseline fetal heart rate variability, and no clinically significant fetal heart rate decelerations at the outset. Subjects in the amnioinfusion group (n = 30) were titrated to and maintained at an amniotic fluid index level greater than or equal to 8.0 cm throughout labor. In the group receiving amnioinfusion, significantly lower rates of meconium passage (p = 0.04), severe variable decelerations (p = 0.04), end-stage bradycardia (p = 0.05), and operative delivery for fetal distress (p = 0.002) occurred. Significantly higher umbilical arterial blood pH values were also noted in the infusion group (p = 0.02). We conclude that prophylactic intrapartum amnioinfusion is an important technique for the reduction of intrapartum morbidity.
Amnioinfusion of 250 ml of normal saline solution was performed in 30 laboring women at greater than or equal to 37 weeks' gestation with oligohydramnios as defined by an amniotic fluid index of less than or equal to 5 cm. A total of 50 amnioinfusions were performed. Amniotic fluid volumes, as assessed by the amniotic fluid index, increased by a mean of 4.3 +/- 1.5 cm after infusion. We conclude that in women with oligohydramnios, 250 ml of amnioinfusate will increase the amniotic fluid index by approximately 4 cm.
One hundred forty-seven cases of congenital skull depression are analyzed, including two presented by the authors, and a review of the literature follows. A management plan emphasizing a conservative approach is outlined.
The pregnancy outcomes of 56 women with a twin gestation and a prior cesarean birth were analyzed to determine whether a trial of labor was a reasonable consideration. Of these patients, 31 (55%) underwent an elective repeat cesarean delivery and 25 (45%) attempted vaginal delivery. Of those who attempted vaginal delivery, 18 (72%) were vaginally delivered of both infants. The dehiscence rate among women with twin pregnancies who attempted a trial of labor was 4% compared with 2% in women with singleton pregnancies. There were no significant differences in maternal or neonatal morbidity or mortality rates in trial of labor versus no trial of labor groups. We conclude in this limited population that a trial of labor in a twin gestation after a previous cesarean delivery appears to be a reasonable consideration. The usual safeguards for attempted vaginal delivery in the twin gestation should be followed.
Perimortem cesarean section probably represents an underemphasized procedure on the skills list of the emergency physician. Although fraught with emotional and medicolegal overtones, the procedure can yield viable infants in at least 15% of cases and occasionally alters maternal hemodynamics so as to restore the pulse in a clinically dead woman. This article reviews the physiology and hemodynamics of the maternal-fetal unit and discusses prognostic factors for the survival of healthy mother and infant, leading to recommendations for when to perform a perimortem cesarean section. The article then describes the technical aspects of the procedure.
The incidence of placenta previa in twin gestations was compared to that found in singleton pregnancies over a ten-year period. During this period, eight placenta previas occurred in 1,464 twin pregnancies, for an incidence of 0.55%, which was significantly higher (P less than .05) than the incidence of 0.31% in singleton pregnancies (458 placenta previas in 148,197 singleton pregnancies). We conclude that a twin gestation confers an added risk of placenta previa.
An intrapartum fetal death within 20 minutes of a reassuring acoustically stimulated fetal heart rate acceleration is reported. The cause of death in this instance was congenital pneumonia, gram-negative sepsis, and meconium aspiration. Umbilical cord pH values obtained at delivery did not demonstrate asphyxia (ie, low pO2, high pCO2, and low pH), but suggested a metabolic acidosis typical of sepsis.
Vaginal birth after cesarean delivery in a woman with breech presentation is a controversial issue. In this prospective study, 137 patients had a breech presentation. Of them, 27 (19.7%) met the protocol criteria for attempted vaginal delivery and desired a trial of labor. Thirteen (48%) achieved vaginal delivery, with no increase in fetal or maternal morbidity. Our data suggest that in selected patients, a trial of labor after a cesarean delivery with a breech presentation is a reasonable consideration.
A newly available intrauterine pressure transducer was evaluated clinically in 100 patients. Successful insertion was accomplished in 95%. There were no significant intrapartum maternal or fetal complications. Partial dehiscence of a surgically scarred uterus did occur in one patient who received the device, but a clear relationship between its attempted insertion and the dehiscence was not apparent. Early in the clinical trial, a number of devices malfunctioned; the manufacturer defined and remedied the problem. The intrauterine transducer required no maintenance and appeared to be practical in laboring women. We suggest that the utility of the intrauterine pressure transducer might be enhanced with several modifications, including the addition of a re-zeroing mechanism and a reduction in the device's length.
We have frequently observed that fetuses born with nuchal cords have umbilical cords that contain less vascular coiling. To study the association between umbilical vascular coiling and nuchal entanglement, the density of umbilical coiling was objectively assessed in relationship to nuchal entanglement of the umbilical cord using the "umbilical coiling index" in 200 consecutive liveborn neonates. The umbilical coiling index of each cord was determined by dividing the number of complete vascular coils by the total length of the cord in centimeters. The mean umbilical coiling index among those with nuchal cords (0.18 +/- 0.09 coils/cm) was significantly less than that among the group without nuchal entanglement (0.21 +/- 0.07 coils/cm), P = 0.01. Among those with umbilical coiling indices < or = 0.10 coils/cm, 42% had nuchal cords, while only 4.8% of cords with indices > or = 0.30 coil/cm had nuchal cords (P = 0.007). It is concluded that a relationship exists between the density of umbilical vascular coiling and nuchal entanglement of the cord.
Electrical shock in pregnancy is associated with significant perinatal morbidity and mortality. A case of such an electrical shock in pregnancy is reported. A review of the literature follows. The severity of maternal injury does not correlate with the injury sustained by the fetus. Close fetal surveillance following electrical injury is necessary.