The effect of porcine somatotropin supplementation in pigs on the lipid profile of subcutaneous and intermuscular adipose tissue and longissimus muscle

The effect of porcine somatotropin (pST) on the lipid profiles of adipose tissue and muscle was investigated. Sixteen crossbred barrows were injected daily with either 3 mg of pST or a placebo. After slaughter, total lipid and fatty acid composition of raw subcutaneous (SC) adipose and intermuscular (IM) adipose tissue and longissimus muscle were determined. The SC adipose tissue from pST-treated pigs had a 7.5% decrease in total lipid content; specific fatty acids 16:0, 18:0, and 18:1(n-9)c decreased most. The IM fat from pST-treated pigs had lower levels of 16:0 and 20:0. There was no effect of pST treatment on the lipid profile of the longissimus muscle. The data suggest that pST treatment produces small but significant changes in the saturated fatty acid content of adipose tissue in pigs.

Successful pregnancy outcomes after amniotic fluid embolism

Two patients who survived cardiorespiratory arrest occurring in association with amniotic fluid embolism syndrome were seen during the subsequent pregnancy. Both had uneventful pregnancies and delivered at term without complications. These are the only case reports of pregnancy after amniotic fluid embolism, and they support a model of amniotic fluid embolism involving chemically abnormal amniotic fluid rather than an unusual sensitivity to normal amniotic fluid.

Maternal respiration and blood gases during aerobic exercise performed at moderate altitude

We studied whether maternal acid-base status during aerobic exercise performed at moderate altitude is affected by pregnancy. Seven primiparus women were tested at 37 wk gestation and 12 wk postpartum. Subjects were studied at rest, and during two cycle (50 W, 75 W) and two treadmill (67 m.min-1; 2.5% grade, 67 m.min-1; 12% grade) protocols. Exercise bouts lasted 6 min with a 10-min rest between sessions. Minute (VE) and alveolar (VA) ventilation, tidal volume (VT), and ventilatory equivalent for carbon dioxide (VE/VCO2) were significantly (P less than 0.01) greater when exercise was performed during pregnancy. Physiological dead space (VD) was not affected by pregnancy status and did not differ between rest and exercise. Decreases (P less than 0.01) in arterial pH during exercise averaged 0.04 units in both pregnancy and postpartum. Despite similar change in maternal pH, carbon dioxide tension (PaCO2) remained unchanged during exercise at 37 wk gestation but decreased at 12 wk postpartum. Decreases in arterial bicarbonate [HCO3-] associated with exercise were smaller during pregnancy. Our findings indicate that pregnancy did not compromise maternal acid-base status during aerobic exercise.

Premature rupture of the membranes: management controversies

Preterm premature rupture of the membranes continues to be a leading cause of perinatal morbidity and mortality in the United States. In the absence of amnionitis or fetal compromise, expectant management is a reasonable alternative to permit fetal weight gain and to allow for fetal lung maturation. When embarking on an expectant management course, a variety of clinical approaches are available to the practicing clinician.

Recent developments in pregnancy-induced hypertension

Pregnancy-induced hypertension (PIH) still remains an area in obstetrics of active research and investigation. Despite widespread academic attention, the cause of this disorder still remains unknown. The purpose of this paper is to review the important contributions to the literature during the period of July, 1990 through June, 1991. Elucidation of the pathophysiology of PIH has been enhanced by investigations of altered platelet calcium metabolism, the renin-aldosterone-angiotensin system, and other potent vasopressors. Recent reports of clinical management for eclampsia, liver rupture, HELLP syndrome, severe PIH in the second trimester, severe hypertension, and magnesium toxicity are presented.

Cardiac disease in pregnancy

The pregnant patient with normal cardiac function can accommodate many significant alterations in the cardiovascular system without difficulty. Pregnancy in a patient with significant cardiac disease, however, can be extremely hazardous, resulting in decompensation and even death. these conditions account for up to 30% of maternal mortality. This article reviews the interaction between cardiac disease and pregnancy.

Amniotic fluid embolism

Amniotic fluid embolism remains an enigmatic and often lethal condition. The pathophysiology is complex, however, from a clinical standpoint. Right or, more commonly, left heart failure is the dominant physiologic aberration. Disseminated intravascular coagulation is often present. The detection of squamous cells in the central circulation of living patients can no longer be considered pathognomonic for this condition.

Cardiac disease in pregnancy

Cardiac disease in pregnancy remains a major cause of indirect maternal death. An understanding of the impact of the physiologic changes associated with pregnancy upon structural cardiac disease is essential for proper counseling and management of these complex patients.

Position change and central hemodynamic profile during normal third-trimester pregnancy and post partum

Central hemodynamic response to position change was assessed in 10 normotensive primiparous patients between 36 and 38 weeks' gestation. Studies were repeated between 11 and 13 weeks post partum. Compared with the left lateral position, we observed a mean 9% fall in cardiac output in the supine position and an 18% fall when patients were standing. When standing, these patients had a 30% increase in pulse and a 21% fall in left ventricular stroke work index. The orthostatic response after pregnancy was much more labile than that during the third trimester. These findings have important descriptive implications for the understanding of the human response to orthostasis during pregnancy, as well as clinical implications for patients at risk of uteroplacental insufficiency and for working women during pregnancy.

Cardiac output responses of primigravid women during exercise determined by the direct Fick technique

We compared metabolic and cardiovascular responses to aerobic exercise with the direct Fick technique in women during and after pregnancy. Seven subjects were studied at 37 weeks' gestation and again 12 weeks postpartum. All were tested at rest and during four sequential exercise bouts consisting of 5 minutes at each of two cycle (50 and 75 W) and two treadmill (67 m x min-1 at 2.5 and 12% grade) protocols. Oxygen consumption (VO2) and heart rate were measured during the fifth minute of exercise. Arterial and mixed venous oxygen contents, obtained from catheters placed in the radial and pulmonary arteries, respectively, were used to calculate arterial-venous oxygen difference. Cardiac output and stroke volume were calculated from the Fick equation. Responses of VO2, cardiac output, and stroke volume were greater when exercise was performed at 37 weeks' gestation as compared with postpartum. In contrast, heart rate response (during cycling) and arterial-venous oxygen difference (during treadmill walking) were less when exercise was performed during pregnancy. Our results indicate that there is no compromise in maternal cardiac output during either cycle or treadmill exercise performed late in pregnancy as compared with postpartum conditions.

Central hemodynamic assessment of normal term pregnancy

Ten carefully screened primiparous patients between 36 and 38 weeks' gestation underwent pulmonary artery catheterization, arterial line placement, and central hemodynamic assessment in the left lateral recumbent position. Studies were repeated in the same patients between 11 and 13 weeks post partum. Compared with the nonpregnant state, there was a significant fall in systemic vascular resistance, pulmonary vascular resistance, colloid oncotic pressure, and colloid oncotic pressure-pulmonary capillary wedge pressure gradient by the late phase of the third trimester (p less than 0.05). Pregnancy was associated with a significant rise in cardiac output and pulse in all patients (p less than 0.05). There was no significant change in pulmonary capillary wedge pressure, central venous pressure, left ventricular stroke work index, or mean arterial pressure. Normally the late phase of the third trimester is not associated with hyperdynamic left ventricular function as assessed by the left ventricular stroke work index/pulmonary capillary wedge pressure ratio.

Fetal heart rate transmission with the facsimile telecopier in rural areas

Over a 30-month period, 24 portable facsimile telecopiers were placed in rural hospitals with delivery services, allowing 24-hour direct transmission of fetal heart rate tracings for consultation. An analysis of the first 209 intrapartum fetal heart rate strips is presented. Variable decelerations were the most frequent indication for consultation, but they were less commonly interpreted as indicating fetal distress. Such units have major advantages in terms of both cost and versatility over previously described systems and have proved extremely valuable to the rural practitioner of obstetrics.

Nonstress testing with acoustic stimulation and amniotic fluid volume assessment: 5973 tests without unexpected fetal death

In a 36-month period antepartum testing was performed 5973 times in 2628 women with singleton high-risk pregnancies. The testing scheme involved a modified nonstress test with sound stimulation. Testing was performed twice weekly for patients with diabetes (classes B through R), gestational age exceeding 42 weeks, and documented intrauterine growth retardation, and weekly for other indications. If no spontaneous acceleration was observed within 5 minutes, a single 1- to 2-second sound stimulus was applied to the lower maternal abdomen with an artificial larynx. If necessary, a second sound stimulation was applied within 10 minutes. In addition all patients received ultrasonographic four-quadrant assessment of amniotic fluid volume. The mean testing time was 10 minutes. Only 2% of tests were nonreactive with sound stimulation. Seventeen percent of nonstress tests that were nonreactive with sound stimulation were followed by positive results of a contraction stress test or a biophysical profile score less than or equal to 4. The overall intervention rate was 3%. All fetuses with a single acceleration only eventually met criteria for negative results to a contraction stress test or had a biophysical profile score greater than or equal to 8. There were no unexpected antepartum fetal deaths. Sound-induced accelerations appear to be valid in the prediction of fetal well being, and the use of sound stimulation results in a significant shortening of testing time. Simultaneous assessment of amniotic fluid volume may reduce the risk of fetal death to a negligible level.

Reliability of intrapartum fetal heart rate monitoring in the postterm fetus with meconium passage

Fifty-six postterm fetuses with intrapartum meconium passage underwent routine scalp stimulation and scalp blood sampling. Fetal heart rate (FHR) patterns were compared with blood pH. Nine fetuses (16%) had a scalp pH less than 7.20. Twenty-nine fetuses (54%) demonstrated spontaneous or induced FHR accelerations; none were acidemic. Acidemia with normal variability was found only in conjunction with severe variable decelerations, and may represent respiratory acidosis. In this group, two of nine acidemic fetuses demonstrated no decelerations (pH 7.04) or mild variable decelerations only (pH 7.19). The absence of late decelerations was not as reliable as the presence of accelerations in the prediction of fetal well-being. Thirty-three percent of the fetuses who failed to exhibit spontaneous or provoked FHR accelerations were acidemic. These findings suggest that in this high-risk group of fetuses, the absence of spontaneous FHR accelerations should be followed by an attempt to induce accelerations, scalp pH assessment, or cesarean section.

Rupture of the scarred uterus

Although theoretically important, the bulk of obstetric literature indicates that scar separation following a lower transverse uterine incision is not a significant problem in clinical obstetrics. The need for emergency intervention for such scar separation is not increased over that in any laboring patient for a number of other causes. Ideally, the capability of emergency intervention should be available for any laboring patient. In reality, however, such a situation will not commonly be present in all hospitals in the United States. The absence of in-house anesthesia coverage does not appear to be a valid reason to exclude the carefully informed patient from a trial of labor following a previous low transverse uterine incision. Not only is scar separation infrequent, but maternal and perinatal morbidity should be negligible when such scar separation does occur. The use of oxytocin and epidural anesthesia appears to be appropriate. The latter does not mask signs or symptoms of scar separation. Because most scar separation will be heralded by the appearance of variable decelerations, extremely careful fetal heart-rate monitoring is mandatory for any patient laboring with a previous uterine incision. Finally, the detection of an asymptomatic scar separation after successful vaginal delivery in a nonbleeding patient does not appear to mandate repair. However, the uncertainties regarding the method of delivery for future pregnancies should be carefully explained to such patients if nonrepair is elected.

Prenatal diagnosis of cysts of the fetal choroid plexus

Over a two-year period, cysts of the fetal choroid plexus were diagnosed prospectively by routine second-trimester ultrasonography in five patients, representing 0.18% of the population scanned for standard obstetric indications. Gestational age at the time of diagnosis ranged from 16-22 weeks. The cysts were located in the posterior portion of the choroid plexus within the lateral ventricle. The maximum diameter ranged from 3-14 mm. In two cases, the cyst was noted to be bilocular. No additional anomalies were detected in any fetus. Follow-up sonography two to five weeks after the initial scan documented disappearance of the cysts in all cases. The course of pregnancy in these patients was otherwise uneventful, and all infants were normal physically and neurologically both at the time of birth and between four and 24 months of follow-up.

Septic shock during pregnancy

A multiinstitutional review of 10 pregnancies complicated by septic shock was undertaken to identify the clinical characteristics and hemodynamic alterations associated with this condition. Prolonged rupture of membranes with the subsequent development of chorioamnionitis or postpartum endometritis were risk factors that commonly preceded the diagnosis of septic shock. The majority of septic shock cases occurred during the puerperium. There were two maternal deaths in this selected series. Associated complications included pulmonary edema, adult respiratory distress syndrome, disseminated intravascular coagulation, pulmonary emboli, and cardiac arrest. The primary hemodynamic derangements were reduced systemic vascular resistance with depressed myocardial function. The mean initial systemic vascular resistance index in eight surviving women was 885 +/- 253 dyne.sec/cm5.m2. Despite an overall presenting cardiac index of 4.20 +/- 2.01 L/min/m2, five patients (50%) had evidence of myocardial depression based on analysis of their left ventricular function curves. Mean arterial pressure, systemic vascular resistance, and left ventricular stroke work index all showed significant improvement after therapy. A hemodynamic algorithm based on volume therapy, inotropic agents, and peripheral vasoconstrictors is offered. This therapeutic approach is designed to optimize cardiac performance and maintenance of organ perfusion in the critically ill patient with septic hypotension during pregnancy.

In utero ischemic injury: sonographic diagnosis and medicolegal implications

The antenatal diagnosis of fetal neurologic injury has profound medical and legal implications. We report a case of antenatally diagnosed intracranial lesions including parenchymal hemorrhage in an otherwise physically normal infant. Computerized tomography in the newborn period demonstrated diffused ischemic damage with secondary cystic changes in addition to intracranial hemorrhage.

Central hemodynamic alterations in amniotic fluid embolism

Amniotic fluid embolism is an uncommon but devastating obstetric emergency. We report hemodynamic data derived from pulmonary artery catheterization in four previously unpublished cases of amniotic fluid embolism syndrome. These findings confirm a recently published reinterpretation of the central hemodynamics of this condition.

Clinical indications for pulmonary artery catheterization in the patient with severe preeclampsia

The obstetric literature reflects an increased interest in invasive hemodynamic monitoring during the past decade. While much of this interest has focused on research applications, the patient with severe preeclampsia may benefit clinically from pulmonary artery catheterization under several circumstances. These conditions include severe hypertension unresponsive to conventional antihypertensive therapy, pulmonary edema, persistent oliguria unresponsive to fluid challenge, and in induction of conduction anesthesia in select patients. Theoretical and clinical evidence to support this contention is presented.

Vaginal birth after cesarean

Allowing a woman with a previous cesarean birth a trial of labor rather than performing an elective repeat cesarean section continues to be a controversial area in obstetrics today. In an effort to evaluate the risks associated with a trial of labor, a prospective investigation was undertaken from July 1, 1982, through June 30, 1984. During the first year of the study, patients with a known vertical scar or more than one prior cesarean birth were excluded from an attempted trial of labor. Beginning July 1, 1983, patients with two prior cesarean births were no longer excluded and were studied prospectively. During this 2-year period, 32,854 patients were delivered of their infants at the Los Angeles County/University of Southern California Medical Center. Of these patients, 2708 (8.2%) had undergone a prior cesarean birth, and 1796 women (66%) underwent a trial of labor. A total of 1465 (81%) of them achieved a vaginal delivery. Successful vaginal delivery by the number of prior cesarean sections was as follows: one, 82%; two, 72%; three, 90%. When contrasted with the group without a trial of labor, the group with a trial of labor had significantly less maternal morbidity. In a comparison of the groups with and without a trial of labor, the incidence of uterine dehiscence (1.9% versus 1.9%) and rupture (0.3% versus 0.5%) was similar. With the application of attempted vaginal delivery in our patients with a previous cesarean birth, we were able to reduce our cesarean delivery rate for this population alone by 54%. In summary, the benefits associated with a trial of labor in the patient with a prior cesarean birth far outweigh the risks. The policy of "once a cesarean section, always a cesarean section" should be abandoned.

Successful fetal therapy for cystic adenomatoid malformation associated with second-trimester hydrops

Fetal hydrops secondary to cystic adenomatoid malformation was detected in a second-trimester fetus. In utero thoraco-amniotic shunt placement resulted in resolution of the hydrops. At term, there was no evidence of pulmonary hypoplasia.

Ultrasound-guided paracentesis in the diagnosis of postpartum hemoperitoneum. A report of three cases

Real-time ultrasound and ultrasound-guided paracentesis were used in the diagnosis of hemoperitoneum in three patients. In all three, who had decreasing hematocrits, the possibility of intraperitoneal bleeding was confirmed or excluded with the two techniques.

Amniotic fluid embolism

A critical review of animal and human data leads to a reassessment of traditional concepts of amniotic fluid embolism. Left ventricular failure, rather than pulmonary hypertension, is the major hemodynamic derangement consistently seen in humans. The detection of squamous cells in the pulmonary artery blood of pregnant women is not pathognomonic for amniotic fluid embolism.

Labor and delivery in the patient with structural cardiac disease

The clinical management of labor and delivery in patients with serious structural cardiac defects is challenging. In this article, peripartum pathophysiology is discussed and management recommendations based on recent clinical data are presented.

Peripartum colloid osmotic pressures: correlation with serum proteins

Colloid osmotic pressure is a principal regulator of capillary fluid exchange. Alterations in colloid osmotic pressure in preeclamptic patients, as well as significant peripartum changes in colloid osmotic pressure in normotensive patients, are reported. In a study of 72 normotensive and preeclamptic patients, peripartum colloid osmotic pressure, serum albumin, and total serum protein were compared. Both groups exhibited significantly lower colloid osmotic pressure in the postpartum period than that measured antepartum. The mean antepartum colloid osmotic pressure in preeclamptic patients was significantly lower than in normotensive subjects. Regression equations were calculated [colloid osmotic pressure = 5.21 (total serum protein) -11.4 (r2 = 0.851)] and [colloid osmotic pressure = 8.1 (serum albumin) -8.2 (r2 = 0.891)]. Within the physiologic ranges most commonly reported for normotensive and preeclamptic patients, the use of these equations allowed calculation of colloid osmotic pressure to within 10% of measured values in 75 and 80% of the cases, respectively. Where direct measurement of colloid osmotic pressure is not readily available, calculated values may be helpful in patient management.

The nonlaboring transverse lie. A management dilemma

During a one-year period, 29 patients at 37 weeks' gestation or later were referred to the breech version clinic at Los Angeles County/University of Southern California Medical Center and found to have sonographic evidence of a transverse lie. Because of the relative instability of the lie and the high probability of spontaneous conversion, the patients were not considered candidates for version and were returned to their referral agencies for subsequent prenatal care. The subsequent outcomes in these patients were reviewed. Twenty-four (83%) spontaneously converted to a longitudinal lie and presented in labor with either a vertex (15 [52%]) or breech (9 [31%]) presentation. The five (17%) remaining patients presented in labor with a persistent transverse lie. Overall, the cesarean section rate was 13 of 29, or 45%. The indications for cesarean section were breech presentation, eight (62%), and transverse lie, five (38%). Major complications included two prolapsed cords, one spontaneous uterine rupture and one neonatal death. Based on a review of our experience, it appears reasonable to consider external version in any patient with a persistent transverse lie around 39 weeks. The high rate of subsequent cesarean section and major morbidity associated with expectant management of these patients suggests that if version is unsuccessful, strong consideration should be given to elective cesarean section.

Severe preeclampsia with persistent oliguria: management of hemodynamic subsets

Nine patients with severe preeclampsia or eclampsia complicated by persistent oliguria failed to respond to fluid challenge and underwent pulmonary artery catheterization to guide further fluid and hemodynamic management. Three hemodynamic subsets of patients were defined. Patients in category I had low pulmonary capillary wedge pressure, hyperdynamic ventricular function, and moderate elevation of systemic vascular resistance. These patients responded to volume infusion with a decline in systemic vascular resistance, a rise in wedge pressure and cardiac output, resolution of oliguria, and no change in blood pressure. Patients in category II had normal or elevated pulmonary capillary wedge pressure and cardiac output and normal systemic vascular resistance; they responded to pharmacologic preload and/or afterload reduction. A single patient (category III) exhibited markedly elevated wedge pressure and systemic vascular resistance and depressed ventricular function. Oliguria in this patient responded to volume restriction and aggressive afterload reduction. Hemodynamic observations in patients in category II imply the presence of selective vasodilator responsive renal arteriospasm in some preeclamptic patients with oliguria.

Antepartum reversal of hematologic abnormalities associated with the HELLP syndrome. A report of three cases

The "HELLP syndrome" refers to the occurrence of thrombocytopenia, elevated liver enzymes and, at times, hemolysis in patients with preeclampsia. Although uncontrolled series have reported a reversal of thrombocytopenia and elevated liver enzymes with aspirin and colloid infusion, most authors recommend that delivery be done soon after the diagnosis is made. The abnormal laboratory parameters of the HELLP syndrome may be reversed completely with bed rest alone, and with preterm gestations, conservative management may be possible.

Squamous cells in the maternal pulmonary circulation

Identification of squamous cells in the maternal pulmonary arterial circulation, either at autopsy or in blood aspirated from a pulmonary artery catheter, is currently regarded as pathognomonic for amniotic fluid embolism. Sixteen pregnant women underwent pulmonary arterial catheterization for a variety of medical indications. Examination of the buffy coat fraction of the distal lumen aspirate resulted in the identification of squamous cells in all cases. Squamous cells were similarly identified in control specimens from 17 nonpregnant patients; however, the difference in cell count between the pregnant and nonpregnant patients was significant. Such cells presumably reflect, in part, bloodstream contamination from sites of venous access. Reliable differentiation of adult from fetal squamous cells is not possible; however, the significant increase in cell count documented in pregnant patients suggests a possible fetal origin for some squamous cells detected during pregnancy. The detection of squamous cells in the pulmonary arterial circulation of pregnant women is not pathognomonic for amniotic fluid embolism. In a critically ill obstetric patient, such a finding should not deter the clinician from a thorough search for other causes of hemodynamic instability.

Intrapartum fetal surveillance: the role of fetal scalp blood sampling

Continuous electronic fetal heart rate monitoring and fetal scalp blood sampling have traditionally played a complementary role in intrapartum fetal surveillance. Nevertheless, biochemical assessment of fetal blood pH, with the use of scalp or umbilical cord blood, is often viewed as the "gold standard" against which biophysical indicators of fetal distress must be judged. In actual clinical practice, however, fetal scalp blood sampling is only rarely used. In addition, there is a growing body of evidence to suggest that, when properly interpreted, fetal heart rate assessment may be equal or superior to measurement of fetal blood pH in the prediction of both good and bad fetal outcomes. Under certain circumstances, fetal scalp blood sampling remains a valuable clinical tool; however, we recommend a deemphasis of fetal scalp blood sampling in general clinical practice. Both theoretical and practical considerations suggest that the properly trained clinician may pursue an approach for the detection of fetal distress that does not include scalp blood sampling without either compromising his ability to detect fetal distress or significantly increasing the cesarean section rate.

Hypogastric artery ligation for obstetric hemorrhage

Ligation of the hypogastric arteries has been recommended for control of obstetric hemorrhage. However, specific information regarding its effectiveness is lacking. The hospital charts of 19 patients undergoing bilateral hypogastric artery ligation for the control of otherwise intractable obstetric hemorrhage were reviewed. Indications included uterine atony (15), lateral extension of a low-transverse uterine incision (three), and placenta accreta (one). This procedure was effective in controlling bleeding in eight of 19 patients (42%). Hysterectomy was necessary in the remaining 11 patients. In these patients, blood loss, operating time, and intraoperative morbidity was increased when compared with a group of 59 patients undergoing emergency hysterectomy for obstetric hemorrhage without prior ligation of the hypogastric arteries. Surgical approaches to hypogastric artery ligation are discussed.