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Biomedical subjects

N Wasserstrum

Publications and source records attributed to N Wasserstrum.

17 recordsLinked to original sources
PubMed1992

Hereditary factor VII deficiency in pregnancy: peripartum treatment with factor VII concentrate.

This report describes pregnant sisters with severe factor VII deficiency and peripartum management with factor VII concentrate. In this family, two affected members had previously developed severe postpartum hemorrhage when managed with fresh frozen plasma. Therapy-related complications owing to plasma infusion included viral disease transmission and pulmonary edema. Therefore, to lessen the risks of complications, specific factor therapy was initiated shortly before parturition in both patients. Factor VII concentrate was administered prior to delivery and every 6 hr for the next 72 hr to keep trough levels at approximately 10%. Based on peak and trough levels, the mean factor VII half-lives were determined to be 3.6 and 5.7 hr. Use of the concentrate was associated with uncomplicated delivery and minimal postpartum bleeding.

Factor VII↗
PubMed1992

Successful treatment with the Smith-Hodge pessary of cervical incompetence due to defective connective tissue in Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders with at least ten distinct types. We report a case of EDS complicated by cervical incompetence. Treatment was undertaken after confirmation that the patient's EDS was not type IV, hence not associated with potentially serious vascular complications. Because of concern about stretching or tearing of the hyperextensible connective tissue associated with EDS, cerclage was not performed. The cervical incompetence due to defective connective tissue was treated with a Smith-Hodge pessary.

Adult↗
PubMed1991

Baroreflex function in normal pregnancy.

The sinoaortic baroreflex is one of the primary mechanisms that regulates blood pressure. Decreased baroreflex sensitivity has been reported in preeclampsia. We sought to determine whether pregnancy altered baroreflex sensitivity. From a radial artery catheter, heart rate and mean arterial pressure were recorded continuously onto a polygraph. The ratio of change in heart rate produced per unit of change in mean arterial pressure was calculated as an index of baroreflex sensitivity. Mean arterial pressure responses to incremental infusions of phenylephrine (0.4 to 2.0 micrograms/kg/min) were measured in the same patients at term (n = 9, 38.0 +/- 0.3 weeks) and again 6 to 8 weeks postpartum (n = 7). The results indicated (1) higher baroreflex sensitivity in pregnancy than in the postpartum period (0.9 vs 0.5 beats/min/mm Hg) (p less than 0.007); (2) attenuated vascular responsiveness to alpha-adrenergic stimulation in pregnancy (p less than 0.05); (3) a relationship between vascular responsiveness and baroreflex sensitivity. We conclude that pregnancy is associated with an increase in baroreflex sensitivity and that the attenuated response to phenylephrine is, at least in part, a result of increased baroreflex sensitivity.

Adolescent↗
PubMed1991

Flow velocity waveforms of the fetal circulation preceding fetal death in a case of lupus anticoagulant.

Flow velocity waveforms of the vascular system were evaluated at 25 weeks 2 days and 27 weeks 5 days of gestation in the case of a severely growth-retarded fetus. At the first scan, the cerebral vessels displayed low pulsatility indexes, reflecting the brain-sparing pattern that characterizes fetal stress. This compensatory reduction was lost at the time of the second, "preterminal" scan.

Adult↗
PubMed1991

Should continuous hydralazine infusions be utilized in severe pregnancy-induced hypertension?

Intravenous hydralazine therapy in severe preeclampsia-eclampsia may be administered by either continuous intravenous infusion or intermittent bolus therapy. We studied the hemodynamic effects of continuous intravenous hydralazine infusion in seven patients with severe pregnancy-induced hypertension. The starting infusion dose was 5 mg/hr and was increased every 15 to 20 minutes by 1 to 2 mg/hr to obtain a 20% reduction in mean arterial blood pressure. The initial mean systolic and diastolic blood pressures were 208.3 +/- 24.8 and 124.3 +/- 11.6 mmHg, respectively. The comparable mean levels following hydralazine therapy was 144 +/- 13.6 and 87 +/- 11.6 mmHg. This decline was obtained at a mean hydralazine dose of 16.04 +/- 3.65 mg/hr. Despite an increase in cardiac output, the rapid uncontrolled decline in blood pressure resulted in five of the seven patients developing fetal distress requiring cesarean delivery. If hydralazine therapy is to be used in severe preeclampsia-eclampsia, we advocate avoidance of continuous intravenous therapy.

Apgar Score↗
PubMed1991

Nitroprusside in preeclampsia. Circulatory distress and paradoxical bradycardia.

In severe preeclampsia, short-term peripartum management of hypertension with hydralazine is complicated by relatively prolonged hypotensive episodes, resulting in fetal distress. We hypothesized that nitroprusside's rapid onset and brief antihypertensive action would permit more controlled blood pressure reduction. Nitroprusside was infused into 10 invasively monitored subjects until mean arterial pressure either 1) was gradually reduced 10-20% or 2) fell abruptly. Subjects fell into two groups, defined by whether the hypotensive effect of nitroprusside was accompanied by a fall in heart rate (group A, n = 8) or a rise (group B, n = 2). Group B showed the expected sinoaortic baroreceptor reflex elevations in heart rate (+17 +/- 6 beats/min) in response to moderate falls in mean arterial pressure (-32 +/- 9 mm Hg) elicited by moderate doses (1.03 +/- 0.23 micrograms/kg/min). However in group A, steep reductions in mean arterial pressure (-75 +/- 22 mm Hg, p less than 0.0001), significantly greater than in group B (p less than 0.05), occurred at much lower doses (0.35 +/- 0.23 micrograms/kg/min; p less than 0.05) and were accompanied by falls in heart rate (-21 +/- 7 beats/min). The apparently paradoxical falls in heart rate and extreme hypotensive responses in group A indicate severe circulatory compromise, corresponding to the cardiac and vasomotor depression that characterizes severe hemorrhage and other forms of acute/severe hypovolemic hypotension. This hemodynamic pattern represents a cardiopulmonary baroreceptor reflex presumably related to the Bezold-Jarisch reflex. The appearance of this pattern in the present study probably reflects the imposition of nitroprusside's prominent venous dilator action on the relatively reduced blood volume that generally characterizes severe preeclampsia.

Adolescent↗
PubMed1990

In utero resolution of hydrops fetalis following the death of one twin in twin-twin transfusion.

A case of massive hydramnios involving a twin-twin transfusion syndrome is presented with death of the larger twin and the development of hydrops fetalis in the surviving smaller twin. The amniotic fluid volume of the surviving twin became normal and the hydrops fetalis resolved spontaneously in utero. Concomitant with the resolution of the hydrops fetalis, the umbilical cord systolic to diastolic ratio improved. At the time of delivery, the hydrops had resolved. The liveborn infant died 11 days later secondary to pulmonary hypertension and cardiorespiratory failure. Although the fetal status improved in utero, the pulmonary hypertension postdelivery resulted in neonatal death.

Adult↗
PubMed1990

Heparin therapy for pregnant women with lupus anticoagulant or anticardiolipin antibodies.

Maternal lupus anticoagulants and anticardiolipin antibodies are associated with a syndrome of recurrent pregnancy loss or preterm birth in live-borns, fetal growth retardation, and placental infarction. Fourteen women with one or more abnormal pregnancy outcomes (total 28 losses, one severely growth-retarded premature live-born) and no normal outcomes were treated with full-dose, subcutaneous, twice-daily heparin therapy in subsequent pregnancies. Treatment was started at an estimated gestational age of 10.3 +/- 4.0 (mean +/- SD) weeks (range 6-18), in a mean total daily dosage of 24,700 +/- 7400 units (range 10,000-36,000). Fourteen of 15 pregnancies resulted in live births at 36.1 +/- 1.7 weeks (range 33-39). The mean birth weight percentile was 57 +/- 21 (range 10-90), and Apgar scores were good to excellent. The number of placental infarcts was fewer in treated cases than in previous deliveries. Five fetuses had third-trimester or perinatal problems with no sequelae, four discovered by close maternal-fetal monitoring. There was an increased rate of preterm and cesarean deliveries. Maternal complications of treatment were few and minor, with no hypertension, preeclampsia, or serious drug-related complications. Heparin appears suitable for further investigation in the treatment of this obstetric syndrome.

Abortion, Spontaneous↗
PubMed1990

Effect of indomethacin on the fetal ductus arteriosus during treatment of symptomatic polyhydramnios.

Ten pregnancies with 13 fetuses complicated by symptomatic polyhydramnios were treated with indomethacin. A baseline fetal echocardiogram was obtained before therapy, repeated 24 hours after the initiation of indomethacin and then performed weekly provided that the ductus arteriosus remained patent. The mean duration of indomethacin therapy was 28.3 +/- 18.9 days. The starting dose in all patients was 25 mg orally every six hours. The ductus arteriosus was noted to constrict in four patients, with the development of tricuspid regurgitation in one. One of the constrictions occurred after 23 days of therapy. In one patient with constriction a reduction of the indomethacin dosage was not associated with constriction, while in the other three, constriction was still evident at a reduced dosage. All constrictions and the tricuspid regurgitation resolved in utero within 24 hours after discontinuation of the indomethacin. We recommend careful monitoring of the fetal ductus arteriosus when treating symptomatic polyhydramnios with indomethacin.

Ductus Arteriosus↗
PubMed1990

Uterine blood flow velocity waveforms in pregnant women during indomethacin therapy.

Continuous-wave Doppler ultrasound was used to assess blood flow velocities and determine the pulsatility index of the uterine arteries in ten pregnant women at 23-33 weeks' gestation during indomethacin therapy for preterm labor or polyhydramnios. There was no statistically significant difference in the pulsatility index of the uterine arteries during maternal indomethacin treatment (mean +/- SD 0.85 +/- 0.29) compared with pre-treatment values (0.85 +/- 0.23). Although studies in animals have reported that indomethacin increases uterine impedance to flow, it appears that it does not affect the uterine impedance in humans.

Blood Flow Velocity↗
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↗
PubMedDate not supplied

Reduction in the middle cerebral artery pulsatility index after decompression of polyhydramnios in twin gestation.

Amniotic fluid decompression was performed for symptomatic polyhydramnios complicating four sets of discordant twin gestations. Doppler ultrasound waveforms of the middle cerebral artery were determined before and after the procedure in seven of the eight fetuses. After amniocentesis, the pulsatility index of the middle cerebral artery (PIMCA) was reduced in all fetuses (p < 0.01). When one considers only the larger twin in each set, the magnitude of the change in PIMCA was relatively consistent among the different sets (-0.60 +/- 0.14; p < 0.01; range, -0.45 to -0.79). The smaller twins showed a much more variable response (-0.82 +/- 0.70; range, -0.05 to -1.75). The pulsatility index of the umbilical artery (PIUA) showed no consistent trend in the five subjects in which it was determined. In principle, the cerebrovascular dilation indicated by the PIMCA measurements may in part be due to acute increases in maternal and fetal carbon dioxide tensions following relief of maternal restrictive lung dysfunction. More importantly, the acute fall in amniotic fluid pressure--the external pressure to which the fetoplacental unit is exposed--leads to pooling of blood in fetal and placental veins, and thereby reduces the effective blood volume of the fetoplacental unit. This effective hypovolemia, functionally analogous to that produced by fetal hemorrhage, elicits changes in regional vascular resistances that favor cerebrovascular perfusion. The impact of acute amniotic fluid decompression on the fetal circulation reflected in the marked changes in PIMCA suggests a role for monitoring to avoid large acute changes in pressure during therapeutic amniocentesis.

Amniocentesis↗