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Biomedical subjects

N Wasserstrum

Publications and source records attributed to N Wasserstrum.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of acetaminophen on fetal acid-base balance in chorioamnionitis.

The effect of antipyretic treatment with acetaminophen on fetal status was examined in eight laboring women febrile with chorioamnionitis. After a fetal heart rate tracing and scalp blood gas level were obtained near maximum maternal fever, a 650-mg acetaminophen suppository was administered. If the temperature remained greater than 101 degrees F, the dose was repeated in one to two hours. The fetal heart rate tracing was analyzed again after the mother's fever was reduced by acetaminophen. All patients delivered within four hours of the first dose. Umbilical artery blood gases were obtained at delivery. Significant improvements in the bicarbonate concentration and base deficit were noted at the time of delivery as compared to the scalp gas at the height of the maternal fever. The fetal heart rate tracings at the height of the maternal fever, characterized by tachycardia, poor variability and late decelerations, changed to a normal heart rate pattern without decelerations when the mother's fever was reduced. Hence, in the laboring gravida with chorioamnionitis, reducing maternal fever with acetaminophen improves fetal status and thereby may reduce the probability of cesarean section for fetal distress.

Acetaminophen↗
PubMed1989

Betamethasone and the human fetal ductus arteriosus.

We used a sensitive Doppler echocardiographic technique to evaluate in utero the effects of betamethasone on the human ductus arteriosus. Transient, mild constriction of the ductus arteriosus 4-5 hours after the first injection of betamethasone occurred in two of 11 trials. The relatively mild and brief effects on the human ductus of betamethasone in usual doses are probably not clinically significant in most instances. Hence, they do not appear to contraindicate the use of glucocorticoids to promote fetal lung maturation.

Betamethasone↗
PubMed1989

Implications of sino-aortic baroreceptor reflex dysfunction in severe preeclampsia.

Loss of sino-aortic baroreceptor reflex sensitivity has been associated with various forms of hypertension. Baroreflexive dysfunction antedates elevation of blood pressure (BP) in some forms of hypertension, and may play a role in their pathogenesis. We studied baroreflex function in seven women with severe preeclampsia being treated with intravenous hydralazine. As indices of baroreflex sensitivity and hemodynamic competence, we measured the reflexive elevations in heart rate (HR) (delta HR/delta BP) and cardiac index (CI) (delta CI/delta BP) in response to hydralazine-induced falls in blood pressure. The change in cardiac index per unit change in systemic vascular resistance index (SVRI) (delta CI/delta SVRI) served as an additional measure of hemodynamic competence. The results indicated that a higher baseline blood pressure was associated with a dramatic reduction in baroreflex sensitivity (delta HR/delta BP) and baroreflex control of blood pressure (delta CI/delta BP and delta CI/delta SVRI). In patients with higher baseline blood pressures, the severe impairment of baroreflex function eliminated the normal circulatory buffer against vasodilator-induced hypotension. Abrupt and profound reductions in blood pressure and the development of fetal distress in response to hydralazine occurred in the patients with higher initial blood pressures. In addition, the present results suggest that phenomena such as the blood pressure lability and increased responsiveness to angiotensin that characterize preeclampsia are, at least in part, reflections of baroreflex dysfunction.

Adult↗
PubMed1989

Quantitative hemodynamic effects of acute volume expansion in severe preeclampsia.

In a study of eight patients with severe preeclampsia, cumulative rapid infusions of 500 mL (set of eight patients) and 1000 mL (subset of five patients) of 5% albumin in normal saline were followed with invasive hemodynamic measurements at 5 and 30 minutes. Pulmonary capillary wedge pressure and central venous pressure rose. Cardiac index rose 23 and 34% at 5 minutes after the 500-mL and 1000-mL infusions, respectively; at 30 minutes, it remained at 17 and 34%, respectively, above control. The systemic vascular resistance index fell 24 and 29% below control values at 5 minutes after the respective infusions; at 30 minutes, it remained at 15 and 25%, respectively, below control. Mean systemic arterial pressure was unchanged, except for a small reduction shortly after the initial 500-mL infusion. In contrast, mean pulmonary arterial pressure rose significantly. Hence, the dominant effects of acute volume expansion in severe preeclampsia include an unchanged (or slightly reduced) mean systemic arterial pressure, resulting from marked elevations in cardiac index and concomitant, proportionate declines in systemic vascular resistance index.

Adult↗
PubMed1988

Indomethacin in the treatment of premature labor. Effects on the fetal ductus arteriosus.

Indomethacin is a potent agent in the treatment of premature labor, but its use has been limited because of concern about its constrictive effects on the fetal ductus arteriosus. To study these effects we used serial fetal echocardiography in 13 pregnant women in premature labor who received indomethacin according to three different dose schedules, ranging from 100 to 175 mg per day, for a maximum of 72 hours. The gestational ages of the fetuses ranged from 26.5 to 31.0 weeks. The detection of ductal constriction in 7 of the 14 fetuses by echocardiography led to the discontinuation of indomethacin. Three fetuses also had tricuspid regurgitation. There was no statistically significant difference between the mean (+/- SEM) gestational age of the fetuses with ductal constriction and that of those without constriction (29.3 +/- 0.59 and 28.4 +/- 0.52, respectively). There was no relation between serum indomethacin levels in the mothers and ductal constriction. In all seven fetuses affected, ductal constriction had resolved by the time they were restudied 24 hours after the discontinuation of indomethacin. Persistent fetal circulation was not detected in any of the 11 neonates studied after delivery. Indomethacin used to treat premature labor appears to cause transient constriction of the ductus arteriosus in some fetuses, even after short-term use.

Adolescent↗
PubMed1988

Mathematical modeling of fetal growth: V. Fetal weight changes at term.

Fetal growth after 37 weeks menstrual age was investigated by comparing ultrasound estimates of fetal weight with corresponding weights of newborns. Using a weight estimation equation with minimal systematic error, evidence was found that fetuses delivered at term do not increase in weight the last two weeks before delivery. This change in fetal growth is regarded as a biological process that is needed to prepare the fetus for its life after birth. Only one of three subsets, that of estimated weights below 3000 g, showed significant weight increase after 37 weeks. This subset had, however, on average the longest scan-delivery interval. We conclude that conventional birthweight standards are influenced both by a cessation of fetal growth approximately two weeks before delivery and by an association between fetal size and the duration of gestation.

Birth Weight↗
PubMed1988

Teratogenic effects of first-trimester cyclophosphamide therapy.

Intravenous cyclophosphamide was administered for severe exacerbation of systemic lupus erythematosus to a patient not known to be in the first trimester of pregnancy. The patient received no other medication except prednisone. Her neonate was born with multiple anomalies, including absent thumbs, cleft palate, low-set ears, and multiple eye abnormalities. These anomalies probably reflect teratogenic effects of cyclophosphamide, and indicate that judgment is required before its use in the first trimester. Furthermore, this case illustrates the need for effective contraception and repetitive pregnancy testing when potentially teratogenic agents are administered to presumably nonpregnant women in the reproductive age group.

Abnormalities, Drug-Induced↗
PubMed1988

Influence of short-term indomethacin therapy on fetal urine output.

Eight pregnancies ranging from 27-32 weeks' gestation were treated for preterm labor with oral indomethacin. The dosage regimen was 25 mg every four hours in four patients and 25 mg every six hours in the other four patients. The maximum duration of indomethacin therapy was 72 hours. In three patients, fetal ductus arteriosus constriction mandated discontinuation of indomethacin at 24 hours. Sonographic assessment of hourly fetal urine output was performed before therapy, at multiple regular intervals during therapy, and 24 hours after the last dose of indomethacin. A dramatic decline was noted from the mean baseline fetal urine output of 11.2 mL/hour. The mean fetal urine output at five, 12, and 24 hours during therapy was 2.2, 1.8, and 1.8 mL/hour, respectively (P less than .05). Twenty-four hours after completion of indomethacin therapy, the mean fetal urine output was 13.5 mL/hour. Poor correlation (r = 0.14, P less than .05) was noted between maternal serum indomethacin levels and hourly fetal urine output. This significant decline in urine output is consistent with other results in neonatal and adult animals and humans. Furthermore, it implies a role for prostaglandins in controlling urine output during fetal life.

Constriction, Pathologic↗
PubMed1988

Percutaneous umbilical cord blood sampling in the evaluation of fetal platelet counts in pregnant patients with autoimmune thrombocytopenia purpura.

Autoimmune thrombocytopenia purpura in pregnancy is associated with fetal thrombocytopenia. Twenty-one patients with autoimmune thrombocytopenia purpura (22 fetuses) underwent 26 umbilical cord punctures to assess the fetal platelet count. Blood could not be obtained from one fetus. Thrombocytopenia (less than 150,000/microL) was found in five cases, but in none was it of sufficient degree to preclude vaginal delivery. Persistent fetal bradycardia necessitating emergency cesarean delivery occurred in two cases. Umbilical cord puncture was found to be technically more difficult in the term fetus than in the second-trimester fetus studied in previous investigations.

Adolescent↗
PubMed1987

Detection and quantitation of constriction of the fetal ductus arteriosus by Doppler echocardiography.

Pulmonary hypertension may occur in the fetus in the presence of constriction of the ductus arteriosus. The feasibility of detection and quantitation of fetal ductal constriction by Doppler echocardiography was assessed in an animal preparation in which ductal constriction was created in the fetal lamb with a variable ligature causing varying degrees of fetal pulmonary hypertension (fetal pulmonary arterial systolic pressure 57 to 97 mm Hg and ductal gradient 9 to 42 mm Hg). Comparison of blinded, continuous-wave peak Doppler velocity (V) measurements of the ductal gradient with the modified Bernoulli assumption (gradient = 4V2) compared well with direct catheter measurements of instantaneous peak systolic gradient (r = .99, catheter = 0.95 X Doppler + 0.6), peak-to-peak gradient (r = .97), and mid-diastolic gradient (r = .85). Ductal constriction was characterized by an increase in the peak systolic and diastolic velocities. The normal human fetal ductus arteriosus blood flow velocity pattern was assessed by pulsed Doppler techniques in 25 normal human fetuses after 20 weeks gestation. The peak systolic flow velocity in the ductus arteriosus measured by image-directed pulsed Doppler echocardiography ranged from 50 to 141 cm/sec (mean 80 cm/sec) and increased with gestational age (r = .50). Diastolic velocity in the ductus arteriosus was consistently directed toward the descending aorta and ranged from 6 to 30 cm/sec. The ductal systolic velocities were the highest blood flow velocities in the fetal cardiovascular system. Application of these techniques to fetuses whose mothers were receiving indomethacin for treatment of premature labor at 30 to 31 weeks gestation confirmed this method to be sensitive for detection of fetal ductal constriction, which developed in three fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Experimental hypertension in pregnant sheep. III. Central hemodynamic alterations in the one-kidney model.

Experimental renal hypertension, with use of the one-kidney, one-clip model, was produced in nine pregnant ewes who were then studied during the last one third of gestation. The animals were chronically instrumented for the recording of arterial pressure, heart rate, and cardiac output; blood volume was determined weekly. The studies were carried out in four phases; a control period of 2 weeks, a surgery period of 1 week, a constriction or hypertensive period, and a postpartum period of 2 weeks. We detected no significant changes in heart rate or cardiac output during any phase of the study. The arterial pressure significantly increased during the constriction and postpartum phases (p less than 0.05). Blood volume remained relatively stable during the three pregnancy phases but significantly decreased in the postpartum phase (p less than 0.05). Systemic vascular resistance followed a pattern similar to that of the arterial pressure.

Animals↗
PubMed1983

Transplacental transmission of pemphigus.

In a pregnancy complicated by maternal pemphigus vulgaris (PV), pemphigus IgG was found both in the fetal circulation and fixed to fetal epidermis in the characteristic intercellular distribution. Light microscopic examination of fetal skin was diagnostic of PV. These findings indicated transplacental transmission of PV. They also strongly support the pathogenic role of PV antibodies and the concept of PV as a tissue-specific autoimmune disease. The occurrence of intrauterine death despite careful antepartum surveillance underscores the management problems encountered when pemphigus coexists with pregnancy.

Adult↗
PubMed1977

Baroreflexive depression of oxygen consumption in the squirrel monkey at 10 degrees C.

Unanesthetized squirrel monkeys exposed to an ambient temperature of 10 degrees C showed elevations in total body oxygen consumption (VO2), arterial blood pressure (BP), and heart rate (HR) above values recorded at 28 degrees C. Further elevation of BP in the cold by intravenous infusion of phenylephrine was accompanied by immediate reduction in VO2, inhibition of shivering, and decrease in rectal temperature, as well as immediate reduction in HR. The magnitude of reduction in VO2 correlated with the magnitude of the concomitant baroreflexive bradycardia. When the pressor effects of phenylephrine were opposed by administration of diazoxide or phentolamine, the inhibitory effects of phenylephrine on both HR and VO2 were abolished. In animals previously subjected to bilateral sinoaortic denervation, both the bradycardia and depression in oxygen consumption normally associated with BP elevation were markedly reduced. These results suggest that elevation of blood pressuere can inhibit the thermoregulatory increase in total body oxygen consumption normally produced by cold exposure, and that this inhibition, like the concomitant bradycardia, is probably mediated via the sinoaortic baroreceptors.

Animals↗
PubMed1977

Elevation of arterial blood pressure in the squirrel monkey at 10 degrees C.

Systemic arterial blood pressure, heart rate, and total body oxygen consumption were measured in seven unanesthetized squirrel monkeys exposed to ambient temperatures of 28 degrees C and 10 degrees C. At 28 degrees C, subjects sat quietly, the average mean arterial blood pressure was 116 +/- 16 (mean +/- SD, n - 7) mmHg, heart rate was 274 +/- 31 beats/min, and oxygen consumption was 14 +/- 1.4 ml/kg-min. At 10 degrees C, the animals shivered vigorously, the average mean arterial blood pressure was 139 +/- 16 mmHg, heart rate was 328 +/- 18 beats/min, and oxygen consumption was 31.6 +/- 3.9 ml/kg-min. Thus, the oxygen consumption more than doubled, the blood pressure rose by approximately 21%, and the heart rate by approximately 20%. Elevations in heart rate as well as systemic mean arterial blood pressure during exposure to low ambient temperature were probably mediated by sympathetic-adrenal discharges as well as by activity of skeletal muscles.

Animals↗
PubMed1977

Heart rate and oxygen uptake response to angiotensin in the squirrel monkey at 10 degrees C.

Unanesthetized squirrel monkeys exposed to an ambient temperature of 10 degrees C showed elevations in total body oxygen consumption (VO2), systemic arterial blood pressure (BP), and heart rate (hr) above values recorded at 28 degrees C. Further elevation of BP in the cold by intravenous infusion of phenylephrine (5-50 microgram/kg-min) was accompanied by reduction in both VO2 and HR, and the changes in VO2 were proportional to those in HR. When BP was raised by intravenous infusion of angiotensin (0.05-1.0 microgram/kg-min), large elevations in BP were again accompanied by reductions in HR and VO2. However, for equivalent elevations in BP, the depressions in both HR and VO2 were much smaller with angiotensin than they were with phenylephrine. Previous studies in this laboratory have demonstrated that in response to experimental elevation of BP, reflexes originating at the sinoaortic baroreceptors depress not only HR but also VO2. The present results suggest that angiotensin modulates baro-reflexive responses to elevation in BP. The reductions in HR and VO2 that ordinarily occur in response to baroreceptor stimulation may be modified by an action of angiotensin on the central nervous system.

Angiotensin II↗
PubMedDate not supplied

Fetal heart rate influence on the pulsatility index in the middle cerebral artery.

In 1300 Doppler assessments performed on the fetal cerebral arteries, 5 cases of heart rate deceleration were recorded while studying the middle cerebral artery. There were 3 normal fetuses (mean menstrual age +/- standard deviation: 28.6 +/- 2.1 weeks), one growth-retarded fetus (34 weeks, menstrual age) and 1 fetus with red cell alloimmunization (27 weeks, menstrual age). The magnitude of decline in the heart rate during the deceleration ranged from 44 to 93 bpm (67 +/- 18 bpm). Pulsatility index values were calculated on 44 waveforms and correlated with the heart rate. Linear regression analysis showed a statistically significant inverse correlation between the heart rate and the pulsatility index in the middle cerebral artery of 4 fetuses. These results indicate that heart rate will affect the pulsatility index of the middle cerebral artery.

Cerebral Arteries↗