Distribution of oxygenated blood flow at three different routes of extracorporeal membrane oxygenation in exteriorized fetal lambs

OBJECTIVE

The purpose of this study was to determine which extracorporeal membrane oxygenation (ECMO) route best approximates the normal physiologic pattern of oxygenated blood distribution in fetal lambs submerged in warm saline solution.

STUDY DESIGN

Six fetal lambs ranging from 113 to 129 days of gestation were delivered by cesarean section and oxygenated with ECMO in a warm saline solution bath. We compared the distribution of oxygenated blood flow during intact placental circulation with 3 routes of ECMO, from the right atrium to the carotid artery (V-A), from the right atrium to umbilical vein (V-UV), and from the right atrium with umbilical artery to umbilical vein [(V + UA)-UV], in exteriorized fetal lambs. Distribution of oxygenated blood flow was determined by nonradioactive colored microspheres.

RESULTS

The ECMO blood flow rate through the catheters during V-A, V-UV or (V + UA)-UV ECMO ranged at 150 to 300 ml/min. Among the 3 different routes of ECMO, the oxygenated blood distribution in (V + UA)-UV showed the best correlation with placental-fetal blood flow, particularly in the brain and heart.

CONCLUSION

This study indicated that (V + UA)-UV ECMO most closely approximates normal intact placental-fetal blood flow distribution in fetal lambs.

Obstetric emergencies precipitated by malignant brain tumors

OBJECTIVE

Our goal was to present a case series of pregnancy-associated malignant brain tumors.

STUDY DESIGN

A review was conducted from 1978-1998 at 5 hospitals.

RESULTS

Ten women were diagnosed with a malignant brain tumor during pregnancy (n = 8) or post partum (n = 2). Patients diagnosed antenatally exhibited severe symptoms, manifest between 27 and 32 weeks' gestation. Six were emergently delivered of their infants because of maternal deterioration, and 2 were delivered electively in the early third trimester after documentation of fetal pulmonary maturity. There were 4 maternal deaths and 1 neonatal death; all of the other infants maintained viability.

CONCLUSIONS

Malignant brain tumors rarely occur in pregnancy. In contrast to reports that describe an indolent course, each of the 8 antenatal patients experienced a neurologic crisis. If symptoms are amenable to pharmacologic control, we advocate delivery in the early third trimester after documentation of fetal pulmonary maturity. To minimize temporal lobe or cerebellar herniation in neurologically unstable patients, a consideration should be made for cesarean delivery with the patient under general anesthesia, followed by immediate neurosurgical decompression.

Histologic and biochemical study of the brain, heart, kidney, and liver in asphyxia caused by occlusion of the umbilical cord in near-term fetal lambs

OBJECTIVE

We sought to determine the relationship between the degree of histologic changes in the brain, heart, kidney, and liver in fetal lambs after severe asphyxia and to analyze the role of oxidative stress in the pathogenesis of fetal multiple organ failure.

STUDY DESIGN

Eight chronically instrumented near-term fetal lambs were asphyxiated by partial umbilical cord occlusion for approximately 60 minutes until the fetal arterial pH reached <6.9 and the base excess reached <-20 mEq/L. An additional 6 fetuses were used as sham-asphyxiated controls. Fetal heart rates, blood pressure, fetal breathing movements, and arterial blood gases and acid-base states were serially monitored. The brain, heart, kidney, and liver were collected 72 hours after asphyxia, processed, and histologically examined after hematoxylin and eosin staining. Fetal brain histologic features were classified into 5 grades, with 5 being the most severe damage. The other organs were examined histologically by pathologists who were blinded to the treatment. Each organ was assayed for tissue concentrations of thiobarbituric acid-reactive substances, superoxide dismutase, glutathione, lactate, and glucose.

RESULTS

Myocardial changes of necrosis, phagocytosis, and contraction bands occurred in only 2 of the most severely (grade 5) brain-damaged fetuses. The same 2 cases showed fatty changes and congestion in the liver. In the kidney all asphyxiated cases showed tubular necrosis, but glomeruli were generally spared. Of the measures of oxidative stress, only liver tissue levels of thiobarbituric acid-reactive substances and superoxide dismutase were significantly higher in the asphyxiated group than in the control group, but there was no correlation with the degree of damage. Lactate level was higher only in the heart in the asphyxiated fetuses.

CONCLUSION

Renal tubular damage was seen with all degrees of asphyxia, despite variable brain damage. Histologic changes in the myocardium and liver were seen only with the most severe brain damage. Oxidative stress appears to play a role in the pathogenesis of liver damage.

Oxidative stress, brain white matter damage and intrauterine asphyxia in fetal lambs

In order to examine the role of oxidative stress in asphyxia-induced perinatal brain damage, near-term fetal lambs were subjected to umbilical cord occlusion for approximately 60min until fetal arterial pH diminished to less than 6.9 and base excess to less than -20 meq/l. The levels of superoxide, hydrogen peroxide, glutathione (GSH) and thiobarbiturate-reactive substances (TBARS) within brain grey and white matter were determined at 72h to correlate with morphological changes. Although the topography and extent of brain damage varied somewhat from case to case, ranging from focal infarction in grey or white matter to subtle and patchy alterations of white matter, the telencephalic white matter appeared to bear the brunt of damage as compared to other regions. The parietal white matter, in particular was often the seat of early pathological changes that could be seen in isolation. These white matter changes were accompanied by significant increases in hydrogen peroxide and TBARS levels as compared to those in grey matter. In another set of experiments, 8 different brain regions were assayed for TBARS, GSH and superoxide dismutase (SOD). A highly significant rise in the levels of TBARS was again noted in the parietal and frontal white matter. SOD levels were higher in the frontal and parietal white matter, basal ganglia and cerebellum. Cerebral cortical and hippocampal neurons were relatively unaffected until accompanied by more severe damage to grey and white matter at other sites. These results suggest that the developing telencephalic white matter appears to be most vulnerable to the effects of intrauterine fetal asphyxia and that oxidative stress may be a major contributing factor in the pathogenesis of perinatal hypoxic-ischemic encephalopathy.

Two sinusoidal heart rate patterns in fetal lambs undergoing extracorporeal membrane oxygenation

OBJECTIVES

The study analyzed the phase relationship between fetal heart rate and arterial blood pressure fluctuation during sinusoidal heart rate patterns in fetal lambs.

STUDY DESIGN

Thirty-two fetal lambs were placed on extracorporeal membrane oxygenation after cesarean delivery at ages ranging between 113 and 133 days' gestation. Sinusoidal heart rate patterns persisting for >10 minutes were analyzed. The relationships between the sinusoidal heart rate cycles and the arterial blood pressure cycles were quantitatively expressed in degrees by timing the zenith and the nadir of each and assigning a phase-angle index (with 0 [360] and 180 degrees being synchronized and reciprocal, respectively). Simultaneous blood samples were taken from the 4 different sites of the fetal circulation for blood gas and acid-base analysis when the sinusoidal heart rate pattern appeared. Regional cerebral blood flow was determined by means of the colored microsphere technique in 8 fetuses with sinusoidal patterns and 7 control fetuses.

RESULTS

Sinusoidal heart rate patterns were observed in 13 (40.6%) of the 32 fetal lambs. Two types of fetal heart rate and arterial blood pressure relationship could be recognized during sinusoidal pattern, the reciprocal type (n = 7) and the synchronized type (n = 9). A reciprocal type of sinusoidal pattern preceded a synchronized type pattern in 3 lambs that showed sinusoidal patterns at different stages of the experiment. The reciprocal type was associated with a higher baseline heart rate and amplitude of the sinusoidal heart rate pattern than was the synchronized type. The synchronized type was associated with a lower pH and base excess than was the reciprocal type. The cerebral blood flow in the medulla oblongata was significantly lower during the synchronized type pattern than during the reciprocal type pattern.

CONCLUSION

There are 2 types of sinusoidal heart rate pattern. A synchronized type sinusoidal heart rate pattern may indicate more advanced fetal compromise than is associated with a reciprocal type pattern.

Fetal heart rate patterns in postasphyxiated fetal lambs with brain damage

OBJECTIVE

We previously showed that in asphyxiated fetal lambs the duration of hypotension correlated well with the severity of histologic damage to the brain, whereas the duration of bradycardia did not. This study compares fetal heart rate patterns with the degree of histologic damage to the brain.

STUDY DESIGN

Twelve chronically instrumented near-term fetal lambs were subjected to asphyxia by umbilical cord occlusion until fetal arterial pH was <6. 9 and base excess was <-20 mEq/L. An additional 4 fetuses served as sham-asphyxia controls. Fetal heart rate (from electrocardiogram), arterial blood pressure, fetal breathing movements, and electrocorticogram were continuously monitored before, during, and for 72 hours after asphyxia. Fetal brain histologic features were categorized as mild (group 1, n = 5), moderate (group 2, n = 4), and severe (group 3, n = 3). Long-term fetal heart rate variability expressed as amplitude range was assessed visually every 5 minutes from 30 minutes before asphyxia until 2 hours of recovery and at 6, 12, 24, 48, and 72 hours of recovery.

RESULTS

Long-term fetal heart rate variability amplitude decreased from 32 +/- 17 beats/min (mean +/- SEM) preocclusion to 4 +/- 13 beats/min at the end of occlusion (P <.001) without significant differences among the 3 groups. During 10 to 45 minutes of recovery, the long-term variability of group 1 was significantly greater than that of groups 2 and 3. At 24 to 72 hours of recovery, the long-term variability of groups 1 and 2 was significantly higher than that of group 3, which was almost 0. The "checkmark" and sinusoidal fetal heart rate patterns were observed during the recovery period in groups 2 and 3.

CONCLUSIONS

Decreased long-term fetal heart rate variability and the "checkmark" and sinusoidal fetal heart rate patterns were indicators of the severity of asphyxial histologic damage in the fetal brain.

Brain lipid peroxidation and antioxidant levels in fetal lambs 72 hours after asphyxia by partial umbilical cord occlusion

OBJECTIVES

The purpose of this study was to explain the role of oxidative stress in the pathogenesis of brain damage caused by intrauterine fetal asphyxia.

STUDY DESIGN

Six chronically instrumented near-term fetal lambs were subjected to asphyxia by partial umbilical cord occlusion for approximately 60 minutes until fetal arterial pH diminished to less than 6.9 and base excess to less than -20 mEq. Another six fetuses surgically prepared but not occluded were used as control. Fetuses were killed after 72 hours and eight different brain regions (frontal and parietal gray matter, frontal and parietal white matter, basal ganglia, thalamus, hippocampus, and cerebellum) were dissected and assayed for thiobarbituric acid reactive substances, glutathione, and superoxide dismutase.

RESULTS

Thiobarbituric acid reactive substance levels in asphyxiated animals were elevated in frontal and parietal white matter, basal ganglia, and thalamus compared with those in controls. The concentrations of superoxide dismutase in the asphyxiated group were also higher in frontal and parietal white matter, basal ganglia, and cerebellum compared with those in the control group. Between the two groups, however, glutathione concentrations did not differ significantly.

CONCLUSION

These results suggest that oxidative stress may be a major contributing factor to the development of brain damage in intrauterine fetal asphyxia.

Physiologic and histologic changes in near-term fetal lambs exposed to asphyxia by partial umbilical cord occlusion

OBJECTIVES

Our purpose was to characterize the histologic changes in the asphyxiated fetal lamb brain and to correlate the severity of these changes with fetal physiologic parameters during and after asphyxia.

STUDY DESIGN

Seventeen near-term fetuses were used for analysis: control group without manipulation (n = 4, 132 +/- 1.1 days of gestation at autopsy, mean +/- SEM), sham-asphyxia control group (n = 3, 132 +/- 1.3 days), and asphyxiated group, which successfully survived 72 hours after asphyxia (n = 10, 130 +/- 1.0 days). Asphyxia was produced by umbilical cord occlusion lasting for approximately 60 minutes until fetal arterial pH diminished to < 6.9 and base excess to < -20 mEq/L. Fetal heart rate, blood pressure, and electrocorticographic activity were continuously monitored. The fetuses were killed 72 hours after asphyxia, and the brains were fixed in formalin and processed for histologic and immunocytochemical studies.

RESULTS

Neuropathologic changes varied from case to case, ranging from almost total infarction of cortical and subcortical structures to extremely subtle and patchy white matter alterations characterized by slight vacuolization of the white matter or slight to moderate increases in cellularity confined to the junction of cerebral cortex and white matter. Even fetuses that showed full recovery of all physiologic parameters, including electrocorticographic activity, demonstrated subtle but distinct white matter lesions. The gray matter, including the hippocampal neurons, was generally spared in these cases. Electrocorticographic parameters, duration of hypotension during asphyxia, and delayed recovery of blood lactate concentrations correlated well with the histologic grading of brain damage.

CONCLUSIONS

Asphyxia by partial umbilical cord occlusion in near-term fetal lambs produces variable neuropathologic changes. The mildest change is a white matter lesion characterized by vacuolization and loss of myelin or by increased cellularity in the damaged regions.

Cardiac oxygenation by extracorporeal membrane oxygenation in exteriorized fetal lambs

OBJECTIVE

The purpose of this study was to determine the degree of cardiac oxygenation produced by different routes of extracorporeal membrane oxygenation in fetal lambs submerged in warm saline solution.

STUDY DESIGN

Seven fetal lambs ranging in age from 113 to 133 days of gestation were delivered by cesarean section and oxygenated with extracorporeal membrane oxygenation. To maintain the patency of the ductus arteriosus, prostaglandin E1 was continuously infused intravenously to the fetus. Initially the extracorporeal membrane oxygenation route was from the right atrium to the carotid artery. Then the extracorporeal membrane oxygenation route was changed to flow from the right atrium to the umbilical vein. The fetus was kept in a warm saline solution bath, and the fetal circulation was maintained. Extracorporeal membrane oxygenation flow ranged between 100 and 200 ml/min throughout the experiment. Simultaneous blood samples were taken during both types of extracorporeal membrane oxygenation from the following points in the fetal circulation: premembrane (least oxygenated blood leaving the fetus from the right atrium), postmembrane (oxygenated blood returning to the fetus), the carotid artery, and the left ventricle. The respiratory gases and pH of each sample were measured. Six fetuses received nonradioactive colored microspheres injected into the oxygenated blood returning to the fetus flow before returning to the fetuses during both types of extracorporeal membrane oxygenation. After the animals were killed, microspheres were counted in the myocardium separately taken from the right and left atria and the right and left ventricles to determine cardiac blood flow.

RESULTS

During right atrium to carotid artery extracorporeal membrane oxygenation, left ventricle PO2 remained low as postmembrane PO2 increased; these values were not significantly correlated (r = 0.234, p = 0.61). During right atrium to umbilical vein extracorporeal membrane oxygenation, left ventricle and postmembrane PO2 exhibited a significant positive correlation (r = 0.855, p = 0.014). When the extracorporeal membrane oxygenation route was switched from the right atrium to carotid artery to the right atrium to umbilical vein, there was a significant increase in left ventricle PO2 and a decrease in left ventricle PCO2, whereas the respiratory gases and pH remained unchanged at other sites in the circulation. Microsphere counts were consistently higher during right atrium to umbilical vein extracorporeal membrane oxygenation than during right atrium to carotid artery extracorporeal membrane oxygenation in all four samples from different parts of myocardium (p < 0.001 by paired t test).

CONCLUSION

More effective cardiac oxygenation is provided by right atrium to umbilical vein extracorporeal membrane oxygenation than by right atrium to carotid artery extracorporeal membrane oxygenation.

Oxygenation in fetal lambs supported by extrauterine right atrium to artery extracorporeal membrane oxygenation

OBJECTIVE

Our purpose was to determine the adequacy of oxygenation, particularly cranial and cardiac oxygenation, in exteriorized fetal lambs on right atrium to artery extracorporeal membrane oxygenation.

STUDY DESIGN

Thirteen fetal lambs were placed on right atrium to artery extracorporeal membrane oxygenation between the gestational ages of 113 and 133 days. Various PO2 and oxygen saturation (SO2) values were obtained by varying the oxygen concentrations at the oxygenator membrane. Blood gases, pH, and SO2 were observed on samples taken before and after membrane oxygenation from the left ventricle and through the cranial carotid arterial catheter. These were compared with control values obtained before the cessation of umbilical circulation. Fetal coronary oxygenation was represented by left ventricle PO2 and SO2 and cranial oxygen by carotid artery PO2 and SO2.

RESULTS

We classified oxygen saturation as low, medium, and high on the basis of the level of postmembrane SO2. Carotid artery cranial oxygenation in the low SO2 group was equivalent to control values, but that in the medium and high SO2 groups was significantly higher than in the control group. Left ventricle oxygenation was consistently lower than cranial oxygenation in any SO2 group. In the low group left ventricle oxygenation was significantly lower than the control values.

CONCLUSIONS

Right atrium to artery extracorporeal membrane oxygenation appears sufficient to oxygenate the fetal cranial circulation but may be inadequate for the efficient distribution of oxygenated blood into the left ventricle and thus the coronary circulation.

Obstetrics and gynecology

Treating HIV-infected pregnant patients and the newborn with zidovudine reduced the percentage of HIV-infected infants. Uterine myomas are being treated effectively with gonadotropin-releasing hormone analogues. Nonoperative therapy is being used in the patient with an ectopic pregnancy.

Term early-onset neonatal seizures: obstetric characteristics, etiologic classifications, and perinatal care

OBJECTIVE

To describe obstetric characteristics and etiologic classifications and assess perinatal care in term neonates with early-onset seizures.

METHODS

We performed a retrospective review of neonatal and obstetric records of neonates delivered at term with a diagnosis of early-onset seizures between January 1981 and December 1992 at Long Beach Memorial Medical Center. Data regarding obstetric characteristics and etiologic classifications of the seizures were abstracted from the medical records. Lack of antepartum testing in high-risk patients, delayed intervention with nonreassuring antepartum or intrapartum fetal heart rate patterns, birth trauma, and failure to use prophylactic antibiotics or treat infection were the criteria used for identifying seizures that were potentially preventable.

RESULTS

Forty term neonates had early-onset seizures out of 60,712 live births (0.07%). These seizures were attributed to hypoxic events in 15 neonates (37.5%), cerebral malformations in seven (17.5%), cerebral infarcts in seven (17.5%), intracranial hemorrhage in five (12.5%), infection in three, and an unknown etiology in three. Twenty-three neonates had 5-minute Apgar scores of 7 or greater (cerebral malformations excluded). Seven of these neonates (30%) had cerebral infarcts. A review of all records identified nine cases (22.5%) of the early-onset seizures as potentially preventable.

CONCLUSION

The majority of the term early-onset neonatal seizures identified did not appear to be preventable. Many of the neonates with 5-minute Apgar scores of 7 or greater had cerebral infarcts.

Abruptio placentae: perinatal outcome in normotensive and hypertensive patients

OBJECTIVE

The objective of this study was to compare perinatal outcomes of hypertensive and normotensive women experiencing abruptio placentae. Our hypothesis is that hypertensive women have a less favorable perinatal outcome than do normotensive women.

STUDY DESIGN

Women with the diagnosis of abruptio placentae delivered between July 1, 1988, and May 31, 1992, composed the study group (n = 226) in this case-control study. The incidence of abruptio placentae was 0.7% during this time. Those women with either multifetal gestations (n = 4) or delivery before 20 weeks' gestation (n = 2) were excluded from data analysis. The remaining 220 patients were divided according to their hypertensive (n = 29) or normotensive (n = 191) status. Maternal and neonatal medical records were reviewed and abstracted for demographic variables, antepartum complications, delivery route, abruptio placentae grade, neonatal gender, birth weight, Apgar score, cord pH, and perinatal mortality. These perinatal outcome variables were compared between the hypertensive and normotensive patient groups.

RESULTS

Black women with abruptio placentae were significantly more likely to be hypertensive (p = 0.0078). Hypertensive women with abruptio placentae had the antepartum complication diabetes mellitus significantly more often than did normotensive women (p = 0.032). However, they were similar to normotensive women with regard to the frequency of positive urine drug screen and trauma. Hypertensive women were no more likely to be delivered before 32 or 37 weeks' gestation, have neonates weighing < 1500 or 2500 gm, or to be delivered by cesarean section. Abruptio placentae grades 2 and 3 occurred more often in hypertensive women (p = 0.053), as did significantly lower umbilical cord artery (p = 0.005) and venous (p = 0.003) pH values. Neonates from hypertensive women were no more likely to have low 5-minute Apgar scores or to die than those from normotensive women.

CONCLUSION

Although hypertensive women experiencing abruptio placentae are more likely to have higher-grade abruptio placentae and lower umbilical cord pH values, the overall perinatal outcome was not significantly different from that of normotensive women experiencing abruptio placentae.

Variable fetal heart rate decelerations and electrocortical activities

OBJECTIVE

The purpose of this study was to examine the influence of fetal behavioral states on baroreflex-mediated, variable fetal heart rate decelerations caused by umbilical cord occlusion.

STUDY DESIGN

Five chronically instrumented fetal lambs were subjected to intermittent partial umbilical cord occlusion for 1 minute every 3 minutes, lasting 2 hours. Fetal behavioral states determined by electrocorticogram and heart rates by electrocardiogram were monitored continuously during these experiments.

RESULTS

The fetuses exhibited an alteration between low- and high-voltage electrocorticogram states. Both the depth and width of the variable fetal heart rate decelerations were greater during high-voltage than during low-voltage electrocorticogram.

CONCLUSION

Amplitude and duration of variable fetal heart rate decelerations are affected by fetal behavioral states.

Cesarean section, 1988--to have or have not!

Images

Neonatal seizures after cesarean delivery: higher risk with labor

A study was done on the occurrence of neonatal seizures in 14,367 infants delivered by cesarean section in a perinatal region in 4 years. Although seizures occurred in 1% of all of these infants, small infants weighing less than 2500 gm at birth had the highest frequency (greater than 4%). Term infants delivered before labor (repeat cesarean section) had the lowest seizure rate (less than 0.2%), and this was a significantly lower (four times) frequency than that seen in term infants delivered by primary cesarean section. These data suggest that brain function as indexed by neonatal seizures can be adversely affected during labor.

Ultrasound needle guidance for amniocentesis in pregnancies with low amniotic fluid

In six pregnancies accompanied by oligohydramnios (three cases) or decreased amniotic fluid and maternal obesity (three cases), needles specifically designed for use with ultrasound were successfully utilized in combination with real-time ultrasound guidance for amniocentesis. There was successful fluid retrieval in all six, with two requiring more than one needle pass. All three cases accompanied by oligohydramnios later resulted in fetal death. In the three cases accompanied by decreased amniotic fluid and maternal obesity, the amniocentesis results were helpful in ensuring the existence of a normal pregnancy. A specially designed ultrasound needle used in combination with a real-time guidance system is helpful in the performance of difficult amniocentesis.

Obstetric characteristics and fetal heart rate patterns of infants who convulse during the newborn period

Seizure activity in the immediate neonatal period has been shown to correlate with long-term neurological handicap. The perinatal course of 34 term and 32 preterm infants who developed seizure activity in the neonatal period was compared to that of 66 matched control infants without neonatal seizure activity. The incidence of antenatal complications and abnormal fetal heart rate patterns and the percentages of abnormal labor, operative delivery, and low Apgar scores were significantly greater in the study infants than in the control infants. Earlier onset of seizure activity was seen in term versus preterm infants and term infants with abnormal versus normal fetal heart rate patterns. Management decisions regarding intervention or nonintervention based on fetal heart rate patterns were deemed appropriate in 31 of 34 term infants, yet short- and long-term neurological sequelae were significant.

Nurse-midwifery in a large teaching hospital

The role of the nurse-midwife in a busy obstetric hospital is explored. This report reviews the role and development of this service and teaching program in a high volume obstetric service. The relationship among the nurse-midwives, residents, and faculty demonstrates the ability of these services to work effectively with a high-risk population. The occasional complication in the obstetric patient as seen in this study dictates a close working relationship within the hospital environment. With the ever increasing demands being placed on obstetric care, a strong working relationship among health care professionals is essential.

Interferon responses in maternal and fetal mice

The kinetics of maternal-fetal interferon and a chemical interferon inducer were studied in Swiss-Webster white mice at 8, 15, and 19 days of gestation. Crude interferon was administered by maternal tail vein injection to one group. There was no transfer of interferon to the fetus despite high maternal levels. A chemical interferon inducer (10-carboxymethyl-9-acridanone) was given intramuscularly to a second group. Both maternal and fetal interferon responses rapidly reached significant levels, although the fetal response was less than that of the mother. Presence of the inducer was demonstrated in both maternal and fetal samples, indicating placental transport of the chemical to the fetus. The implications of these findings for the fetal immune response are discussed.

Vaginal delivery following cesarean section: use of oxytocin augmentation and epidural anesthesia with internal tocodynamic and internal fetal monitoring

The cesarean section rate continues to rise, and, as new indications for the operation continue to be proposed, a method for safely decreasing the rate is truly needed. Less than 1% of patients in the United States are allowed a trial of labor after a cesarean section, in spite of the thousands of (safe) vaginal deliveries after cesarean section now reported in the literature. Few reports in the literature mention the use of oxytocin or regional anesthesia in these patients. We present our experience with 230 trials of labor after primary low transverse cesarean section. One hundred eighty-one patients (79%) were delivered vaginally, 73 patients (32%) received epidural anesthesia, and 94 patients (41%) received oxytocin augmentation of labor. Internal tocodynamic and fetal heart monitoring was used in all patients. Our rationale for this controversial management is discussed.

Amniotic fluid catecholamines and metabolites in intrauterine growth retardation

Simultaneous determinations of amniotic fluid levels of the catecholamines dopamine (DA), norepinephrine (NE), and epinephrine (E), and the intraneuronal metabolites of DA, 3,4-dihydroxyphenylacetic acid (DOPAC) and NE, 3,4-dihydroxyphenylglycol (DOPEG), were made, by radioenzymatic assay, in pregnancies resulting in growth-retarded (n = 14) and normal (n = 63) infants. Significant elevations in the mean concentration of NE (p less than 0.000005), E (p less than 0.005), and DOPEG (p less than 0.000001) as well as a significant decrease in the mean concentration of DOPAC (p less than 0.000001) were found in pregnancies resulting in growth-retarded infants as compared to pregnancies resulting in normal infants. Amniotic fluid DOPEG levels were found to be the most discriminative. As amniotic fluid catecholamines are predominantly of fetal origin, these findings suggest that an increase in adrenergic activity and a decrease in dopaminergic activity occur in intrauterine growth retardation as a response to chronic stress.

Double-blind comparison of intravenously injected butorphanol and meperidine in parturients

One hundred women with moderate-to-very-severe prepartum pain participated in a double-blind study of intravenously injected butorphanol and meperidine that compared the analgesic properties, effect on the process of labor, condition of the newborn and the incidence of side effects associated with the two drugs. Cervical dilation, infant birth weight and Apgar scores were not significantly different between the test groups. The mean fetal heart rate for the butorphanol group was significantly faster than that of the meperidine group. Butorphanol provided significantly more analgesia than meperidine at 30 minutes and one hour after administration, based on pain intensity and pain relief scores. Some side effects, including sedation, dizziness, lightheadedness, nausea, vomiting and pain at the injection site, were reported for both drugs.

The conservative aggressive management of placenta previa

One hundred and seventy-three cases of placenta previa managed at the Women's Hospital of Los Angeles County-University of Southern California Medical Center from July, 1975, through June, 1978, were reviewed and compared to a similar series of cases studied in the same institution in 1969. The perinatal mortality of 12.6% was roughly one half of that in the earlier study. The fetal death rate did not change significantly, but the neonatal mortality was markedly less, especially in the 27-to-32-week range. Expectant management was employed in 65.8% of patients, as compared to 42.6% in 1969. The higher rate of expectant management was characterized by the aggressive use of antepartum transfusions in the face of moderate-to-severe bleeding in lieu of delivery, as well as the occasional use of tocolytic agents for inhibition of premature labor in the presence of vaginal bleeding. Elective termination of pregnancy utilizing the lecithin/sphingomyelin (L/S) ratio for determination of pulmonary maturation also resulted in significantly less overall neonatal morbidity and mortality. These multiple factors appear to have contributed to a dramatic reduction in the perinatal mortality associated with placenta previa.

The randomized management of term frank breech presentation: a study of 208 cases

A prospective study of 208 women in labor at term with singleton fetuses in a frank breech presentation was carried out. One hundred fifteen patients were randomized to a vaginal delivery group and 93 to an elective cesarean section group. Of the 93 women scheduled for cesarean section, 88 were delivered according to protocol. Five women progressed rapidly in labor and were delivered vaginally without complications. Of the 115 women scheduled for vaginal delivery, x-ray pelvimetry was obtained on 112. Three women were delivered vaginally without incident before x-ray pelvimetry could be obtained. One of these women was delivered of an infant who died shortly after birth of lethal congenital anomalies. Of the 112 women with x-ray pelvimetry, 52 had one or more inadequate pelvic measurements and were scheduled for indicated cesarean section. Three women, however, were delivered vaginally without incident before operation could be performed. Of the remaining 60 patients in this group, 49 were delivered vaginally without a perinatal death. Eleven women required cesarean section for difficulties during labor. There were no maternal deaths, but 73 (49.3%) of the 148 women who were delivered by cesarean section in this study experienced postpartum morbidity. Only four (6.7%) of the 60 women delivered vaginally had postpartum complications. Based on the data, it seems resonable to allow vaginal delivery in carefully selected cases of term frank breech presentation.

Clinical fetal monitoring. The usage and relationship to trends in cesarean delivery and perinatal mortality

During the six years 1970--1975, 62,266 deliveries occurred at Women's Hospital, Los Angeles Country--University of Southern California Medical Center. Of these patients, 18,106 (29 per cent) were monitored, with an incidence of 18 per cent in 1970 which rose to 35 per cent in 1975. The patients were divided into monitored and unmonitored groups for comparison of cesarean section rates and various aspects of perinatal mortality. The overall cesarean section rate was 9.6 per cent with 2,830 cesareans performed in monitored patients (16 per cent) and 3,124 in those unmonitored, a 7 per cent incidence including repeat cesarean. The cesarean rate remained remarkably stable over the 6-year study period even though the monitoring incidence nearly doubled. From 1970 to 1975, the intrapartum death rate fell progressively in contrast to the incidence of antepartum fetal deaths, which remained unchanged. Overall, 50 per cent survival rate was achieved in the birth weight range of 1,200 grams. A particular group of perinatal patients who apparently benefited from intrapartum monitoring were those liveborns with birth weights of 1,500 grams or less. Over the study period, the neonatal mortality in monitored patients declined, whereas mortality in the neonates which were not monitored during labor remained high.

The influence of scalp sampling on the cesarean section rate for fetal distress

One year's obstetric experience at Los Angeles County-University of Southern California Medical Center was reviewed and compared with previous years. The incidence of cesarean section for fetal distress is low and has remained constant over the past 7 years. Periodic changes and decreased baseline variability of the fetal heart rate accounted for 39% of the diagnoses of fetal distress in this group. Scalp sampling clarified the diagnosis of fetal distress and prevented unnecessary cesarean section. Compromised perinatal outcome in the greater than 2,500 gram weight group was confined to those who were monitored, had indications for monitoring, or had identifiable prospective risk factors, with rare exceptions.

Pre-ejection period of cardiac cycles in fetal lamb

The pre-ejection period (PEP) of the fetal cardiac cycle was studied on 22 chronically instrumented pregnant ewes. The PEP was measured from the onset of the Q wave on fetal electrocardiogram to the onset of the upstroke on the fetal arterial blood pressure curve. Lengthening of the PEP was observed in association with an increase in gestational age, fetal body weight, fetal brow-rump length, and fetal heart weight. Consequently, the PEP values were calculated to those at fetal heart weight of 10 grams. The PEPc (calculated) was prolonged by acidosis but no significant relationship was found between the PEPc and arterial blood pO2. An increase in coronary blood flow was associated with a shortening of the PEPc in the fetuses under normal physiologic conditions. Fetal hypoxemia and respiratory acidosis created by administration of 10 per cent O2 and 20 per cent CO2 with 20 per cent O2 to the mother increased fetal coronary flow and was in general associated with a prolonged pre-ejection period.

Extraabdominal uterine exteriorization at cesarean section

A series of 386 consecutive cesarean sections is presented in which postpartum uteri were randomly exteriorized or left in situ for suturing the hysterotomy incision in an attempt to evaluate differences in morbidity. Both groups were shown to be similar with respect to overall morbidity, although a high-morbidity subgroup exhibiting increased blood loss was defined and included significantly more patients in the noneventrated group. Emesis occurred in 4 (3.4%) patients in the eventrated group and was directly related to fundal traction under regional anesthesia. Although a larger prospective series is needed to evaluate more serious morbidity, the data presented suggest that uterine eventration at cesarean section is not to be condemned.

The randomized management of term frank breech presentation: vaginal delivery vs. cesarean section

A prospective study of the management of term frank breech presentation is currently ongoing at LAC-USC Medical Center. To date, 57 patients have been randomized to an elective cesarean section group and 70 to a vaginal delivery group. Of the 70 patients selected for vaginal delivery, 35 had one or more inadequate pelvic measurements by x-ray pelvimetry and were scheduled for indicated cesarean section. Of the remaining 35 patients in this group, 30 delivered vaginally without perinatal death. Two of the infants, however sustained brachial plexus injuries. Of the 57 patients scheduled, 55 underwent elective cesarean section. There were no maternal deaths, but 20 (36.4%) patients experienced morbidity and 5(9.1 per cent) patients experienced intraoperative complications. Based on the data accumulated to date, it seems reasonable to allow vaginal delivery in carefully selected cases of term frank breech presentation.

Management and outcome of pregnancy in diabetes mellitus, classes B to R

During the period 1971 to 1975, 260 women with diabetes mellitus, Classes B through R, were delivered of their infants at Los Angeles County Women's Hospital. The plan of patient management included frequent clinic visits and hospitalization to assure good control. A program of intensive antepartum fetal surveillance was begun at 34 weeks' gestation, with the use of daily 24 hour urinary estriol determinations and a weekly contraction stress test (CST). A lecithin/sphingomyelin ratio was evaluated for all patients before elective delivery. The perinatal mortality rate in these diabetic pregnant women was 46 per 1,000 as compared to 24 per 1,000 in the general population. Only three stillbirths occurred in the diabetic group, none within one week of a negative CST. Congenital malformations were responsible for almost half of the neonatal deaths. There were no deaths due to iatrogenic prematurity or trauma. Mean gestational age at delivery was 37.9 weeks and vaginal delivery was the mode for approximately half of the women. Two thirds of the infants did experience some morbidity.

Fetal carbohydrate metabolism: its clinical importance

A basic understanding of fetal nutrition and metabolism is essential in the clinical management of the obstetric patient. The fetus depends upon a constant infusion of glucose for energy production and growth. Maternal glucose is the prime source of this nutrient. Alterations in maternal carbohydrate homeostasis will lead to changes in fetal metabolism. In diabetes mellitus, hyperglycemia may produce hyperinsulinemia and macrosomia. The growth-retarded fetus may have a decreased supply of maternal glucose and reduced amounts of hepatic glycogen and adipose tissue. The fetus must depend upon these stores for survival during periods of intrauterine hypoxia. In the newborn period, hypothermia and hypoxia may rapidly deplete energy reserves. With this information, the clinician may more knowledgeably manage dietary demands in the antepartum patient, fetal distress during labor, and the immediate newborn period.

Circulatory response to atropine in sheep fetus

Atropine was given to the semichronic sheep fetus intravenously. Fetal heart rate, fetal perfusion pressure, and carotid blood flow increased. Cerebral blood flow was measured with the radioactive microsphere technique. Atropine was capable of increasing the cerebral blood flow. Elevation of carbon dioxide also caused an increase in cerebral blood flow, adding to the effect of atropine.