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Biomedical subjects

V L Katz

Publications and source records attributed to V L Katz.

At least 19 recordsLinked to original sources

Meconium aspiration syndrome: reflections on a murky subject.

Meconium-stained amniotic fluid occurs in approximately 12% of live births. In approximately one third of these infants meconium is present below the vocal cords. However, meconium aspiration syndrome develops in only 2 of every 1000 live-born infants. Ninety-five percent of infants with inhaled meconium clear the lungs spontaneously. Recent investigations have suggested that a reexamination of our assumptions about the etiology of meconium aspiration syndrome is in order. Several authors have provided evidence that support the hypothesis that it is not the inhaled meconium which produces the primary pathologic condition of meconium aspiration syndrome but rather it is fetal asphyxia that is the etiologic agent. Asphyxia in utero produces pulmonary vasospasm and hyperreactivity of the pulmonary vessels. With severe asphyxia the fetal lungs undergo pulmonary vascular damage with pulmonary hypertension. The damaged lungs are then unable to clear the meconium. In the most severe cases there is right-to-left shunting and persistent fetal circulation with subsequent fetal death. The incidence of meconium aspiration may thus be essentially unaffected by current obstetric and pediatric interventions at birth. For the asphyxiated or distressed infant we recommend suctioning at birth and tracheal intubation. In the healthy fetus observation may be sufficient.

Asphyxia Neonatorum

Treatment of persistent postpartum HELLP syndrome with plasmapheresis.

Thrombocytopenia, associated with microangiopathic disease, is one characteristic of severe preeclampsia. Thrombocytopenia and intravascular hemolysis usually resolve by postpartum days 4 to 5. When thrombocytopenia secondary to microangiopathic disease persists, plasmapheresis may be used to arrest and reverse the process. Three patients over a 24-month period were successfully treated with plasma exchange with fresh frozen plasma. Several investigators who have cared for patients with persistent thrombocytopenia associated with preeclampsia have concluded that early plasmapheresis may be useful therapy. Plasma exchange should also be considered as a therapeutic option when clinical deterioration occurs due to microangiopathic disease.

Adult

Prenatal sonographic findings of massive lower extremity lymphangioma.

A massive lymphangioma was detected sonographically in the lower extremity of a fetus at 28 weeks' gestation. On ultrasound study, the mass had multiple cysts and extended from the left lower abdomen to the left knee. The differential diagnosis and obstetric management following prenatal diagnosis of a fetal lower extremity mass are presented.

Adult

Effect of daily immersion on the edema of pregnancy.

To evaluate whether pregnant women become refractory to the effects of immersion, we studied 11 healthy women from 26 to 38 weeks' gestation, immersed in 34 degrees C shoulder-deep water for 4 or 5 consecutive days. The daily immersion diuresis showed no change throughout the study (p = 0.98: mean, 145 ml, 159 ml, 159 ml, 173 ml, 184 ml, day 1 through day 5, respectively). The range of urine volumes was broad, 35 to 675 ml, depending on the subject's degree of edema. Immersion produced a significantly larger diuresis compared with preimmersion values, 162 ml versus 110 ml. Maternal blood pressure and heart rate consistently fell during immersion, and this effect was maintained for each day studied. The subjects' hematocrit, hemoglobin, and total protein were unchanged from a preimmersion sample on day 1 to a postimmersion sample on the last day of the study. The results of this study indicate that pregnant women do not become refractory to the hemodynamic and diuretic effects of immersion.

Adult

Emergency cerclages: a review of 40 consecutive procedures.

This report describes 40 consecutive emergency cerclages on dilated and effaced cervices prior to 26 weeks' gestation. These "emergency" cerclages were associated with a mean extension of gestational age of 12 weeks (range, 3 days to 20.5 weeks). Thirty-one of 40 pregnancies were carried to 28 weeks' gestation and 23 were carried to 34 weeks' gestation or greater. Twelve of 19 women with amniotic membranes bulging into the vagina carried pregnancies to 28 weeks' gestation, with seven of these 19 women carrying the gestation to 34 weeks' or beyond. There was no maternal morbidity. Thirty-four of 41 infants survived (83%). Two pregnancies delivered within 8 days of the procedure. Emergency cerclages should be considered as a management option in women with painless dilation of the cervix and previable gestation.

Anti-Bacterial Agents

The cisterna magna in second-trimester fetuses with abnormal karyotypes.

Six hundred thirty-eight gravidas at 14-21 weeks' gestation, who were at increased risk for an abnormal fetal karyotype, had sonographic measurement of the fetal cisterna magna at the level of the posterior fossa before genetic amniocentesis. The size of the fetal cisterna magna increased significantly with advancing gestational age in the normal fetus (P less than .001). Twenty-eight fetuses had abnormal karyotypes: 12 with trisomy, eight with translocation or structural rearrangements, seven with sex chromosome abnormalities, and one with triploidy. In each of these fetuses with abnormal karyotypes, the cisterna magna measurement was normal. We conclude that measurement of the fetal cisterna magna at 14-21 weeks' gestation is not useful as a screening test for abnormal fetal karyotype.

Chromosome Aberrations

Steroid therapy for hydrops associated with antibody-mediated congenital heart block.

Evaluation of fetal bradycardia noted during a routine prenatal visit at 24 weeks' gestation in a mother without symptoms showed an antibody-mediated heart block with anti-La (SSB) antibody present. The fetus had a pericardial effusion and ascites. After maternal steroid therapy, the ascites resolved and the pericardial effusion was substantially diminished. Steroid therapy may be a helpful adjunct for treatment of a premature infant with hydrops as a result of antibody-mediated heart block.

Adrenal Cortex Hormones

The clinical implications of subchorionic placental lucencies.

Forty-six patients were identified at a perinatal diagnostic referral center as having subchorionic placental lucencies. These lucencies varied from simple to multicystic and covered up to 50% of the subchorionic placental surface. Clinical follow-up of 40 patients demonstrated no increase in the incidence of adverse pregnancy outcome. We conclude that these pregnancies are not at higher risk when the subchorionic placental lucencies are not associated with other intraplacental or fetal anomalies.

Chorion

Role of ultrasound and informed consent in the evaluation of elevated maternal serum alpha-fetoprotein.

Informed consent of medical procedures should include a discussion of both the risk of the procedure and the probability of the malady in question. Many centers in the United States currently recommend amniocentesis for all women with elevated levels of maternal serum alpha-fetoprotein (MSAFP) unexplained by targeted ultrasound examination. Prospective clinical data from our unit support the use of an algorithm that provides for a 90% reduction of the predicted risk of neural tube defect from MSAFP alone. The predicted risk is revised only if the ultrasound shows normal fetal cranial size and shape, normal ventricular size, normal posterior fossa anatomy, and normal spinal anatomy. Preliminary results supported this approach with no reduction in sensitivity, while substantially reducing the need for invasive testing. The additional experience reported here of 20,211 patients resulted in 451 ultrasound examinations for an elevated MSAFP, but only 54 amniocenteses. During this period, nine open neural tube defects were detected among patients with elevated MSAFP using ultrasound; none was missed. All fetuses with defects had ultrasound findings of cranial and intracranial changes first reported by Campbell. These data support the premise that, prior to amniocentesis, informed consent should include discussion of the ultrasound evaluation.

Amniocentesis

Fetal death after normal biophysical profile.

Presented are three cases of fetal death, all of which occurred within 3 days of a normal biophysical profile. Despite the excellent record of this antepartum test in predicting fetal well-being, there is a low incidence of false-negative tests; increasing the frequency of testing will not prevent all false-negative tests.

Adult

The effect of lateral tilt on maternal and fetal hemodynamic variables.

We measured maternal blood pressure and heart rate, fetal heart rate, and umbilical artery velocity waveforms in 25 healthy women placed in the supine and in both right and left 5 degrees and 10 degrees lateral tilt positions. Although we found no significant difference among these variables in the various maternal positions, two of 25 women became hypotensive and symptomatic in the supine and 5 degrees tilt positions. Because we could not predict which women would become symptomatic, we recommend lateral tilt of all pregnant women during operative procedures beyond 20 weeks' gestation, including those in the lithotomy position for vaginal delivery.

Adolescent

Pregnancy-induced changes in the maximal physiological responses during swimming.

The effect of pregnancy on peak O2 uptake (VO2 peak) during tethered swimming was evaluated in 10 women during their 25th and 35th wk of pregnancy, as well as 9-11 wk postpartum. The swim results were compared with cycle ergometry results obtained at similar times. The results indicated that exercise-induced maximal heart rates remained the same and were similar for the swim and cycle trials, approximately 184 +/- 4 beats/min. Cycling VO2 peak was not affected by pregnancy, averaging 1.94 +/- 0.11 l/min. Postpartum swim VO2 peak was similar to the cycle results; however, during pregnancy it was significantly lower than cycling VO2 peak (P less than 0.05; postpartum, 1.78 +/- 0.14 l/min; 25th wk, 1.64 +/- 0.12; 35th wk, 1.48 +/- 0.11). Hemoglobin concentrations and hematocrits were lower during pregnancy; however, changes in plasma volume (based on hematocrit and hemoglobin) were found to be significantly greater during cycling than during swimming and also greater during pregnancy for both modes of exercise. It was concluded that, unlike cycling, the VO2 peak of pregnant women during swimming is reduced. This reduction in VO2 peak was associated with a decreased peak ventilation (r = 0.864) but was not correlated to exercise-induced hemoconcentration (r = -0.29). Furthermore, pregnancy results in a greater-than-normal exercise-induced hemoconcentration, which may be related to pregnancy-induced changes in capillary dynamics.

Adult

The role of ultrasound in evaluation of patients with elevated maternal serum alpha-fetoprotein: a review.

Accumulated experience with the sonographic detection of spina bifida and its associated fetal cranial changes indicates that nearly all these fetuses may be identified by ultrasound examination alone. A review of data from multiple centers shows that a complete and detailed, normal ultrasound is an appropriate basis for a reduction of at least 95% in the maternal serum alpha-fetoprotein (MSAFP)-based risk for neural tube defects. The use of this adjusted risk in patient counseling before amniocentesis may lower the rate of the procedure with no significant loss of diagnostic sensitivity. Among patients with elevated MSAFP, the rate of abnormal cytogenetic findings in fetuses with no abnormalities detected at ultrasound appears to be near 0.61%. Furthermore, the spectrum of abnormal cytogenetic results appears to differ from that associated with increased maternal age, in that the incidence of sex chromosome abnormalities is higher and that of Down syndrome is lower.

Amniocentesis

Physiologic changes during normal pregnancy.

Investigators in the past year have turned their efforts to several age-old obstetric questions. Using modern experimental tools, questions were raised about the validity of Nägele's rule of 280 days as a mean gestational length. One large study agreed with the 280-day mean length, while two other studies disputed it. Current guidelines for appropriate weight gain in pregnancy range from 9 to 14 kg. Several studies found that mean weight gain in healthy pregnant women was greater than these guidelines, with a mean of 15 kg and a normal range from 8 to 25 kg. Women who exercise strenuously throughout gestation were found to have smaller babies than control subjects, with a very mild asymmetric growth retardation. Their labors came on earlier, were shorter in duration, and involved less obstetric and surgical intervention. In an interesting study of maternal hemodynamics, standing was found to be associated with a decrease of more than 15% in cardiac output compared with output in the lateral supine position in the third trimester. Investigators studied exercise in the water and found it to have less effect on fetal cardiovascular parameters than exercise of similar intensity on land.

Birth Weight

Streptococcal toxic shock associated with septic abortion.

The group A streptococcus is capable of producing exotoxins that have been linked to a toxic shock-like syndrome. Streptococcal toxic shock is a rapidly progressive disease associated with injury to multiple organ systems and a 30-60% mortality rate. We present a case of a 40-year-old woman who developed group A streptococcal toxic shock following a spontaneous abortion. She required surgical debridement, pulmonary artery catheterization, mechanical ventilation, and massive transfusions. Clinicians must be aware of the presentation of this disease, as its incidence appears to be increasing.

Abortion, Septic

Spontaneous resolution of fetal nuchal cystic hygroma.

Complete resolution of the hygroma occurred in two fetuses with the mid-trimester ultrasound diagnosis of a nuchal cystic hygroma. Cytogenetic studies showed a normal 46,XX karyotype in one fetus, and a 47,XX, +18 in the other. Complete regression of cystic hygroma has been reported in fetuses with normal chromosomes, as well as in those with trisomy 21, and with Turner's syndrome. The incidence of spontaneous in utero resolution of fetal nuchal cystic hygroma is unknown. The natural history of cystic hygroma in utero cannot be correlated with the chromosome complement. An antenatal karyotype determination should be offered to any patient whose fetus has cystic hygroma, even to those with spontaneous resolution.

Adult

Immune thrombocytopenic purpura in pregnancy: a reappraisal of management.

Management and, particularly, mode of delivery of the pregnant patient with immune thrombocytopenic purpura (ITP) are controversial. We reviewed our experience with 31 pregnancies in 25 women with ITP over a 10-year period. Fourteen infants were born vaginally and 18 by cesarean. Six major complications occurred among mothers delivered by cesarean, whereas none occurred among those born vaginally (P = .028). Three of 32 infants were born with moderate thrombocytopenia (platelet count 51-100 x 10(9)/L) and two with severe thrombocytopenia (platelet count 50 x 10(9)/L or less); there were no clinically significant complications in these infants. No maternal characteristic could be used to predict the neonatal platelet count. In an analysis of 474 infants of mothers with ITP reported in the literature and including the present series, 10% were born with moderate thrombocytopenia and 15% with severe thrombocytopenia. The overall rate of intracranial hemorrhage in newborns with moderate or severe thrombocytopenia was 3%. No significant association was found between the rate of intracranial hemorrhage and delivery mode for moderately and severely thrombocytopenic neonates together (weighted odds ratio 1.69, 95% confidence interval 0.14-44.6) or for those with severe thrombocytopenia (crude odds ratio 1.38, 95% confidence interval 0.07-84.67). We conclude that the mode of delivery may not affect the rate of intracranial hemorrhage in thrombocytopenic newborns.

Delivery, Obstetric