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Biomedical subjects

C W Redman

Publications and source records attributed to C W Redman.

At least 127 records · Page 7Linked to original sources
PubMed1992

Antenatal cardiotocogram quality and interpretation using computers.

OBJECTIVE: To test the application in practice of computerized fetal heart rate (FHR) analysis in pregnancy. DESIGN: Randomized distribution of subjects with computerized analysis automatically revealed or concealed. SETTING: A district general hospital and a teaching hospital outside London. SUBJECTS: 2869 pregnant women studied within a year. OUTCOME MEASURES: Quality and duration of the cardiotocogram; quantitative measurement of FHR variation; number of stillbirths. RESULTS: With interactive advice to the operator, records were of improved quality (up to 28% without signal loss) with potentially much reduced recording time. The short-term FHR variation measured in the last records before intervention is reported for the first time. CONCLUSION: The benefits of using the computers include improvement in record quality and saving of time. In addition, where interpretation depended on estimation of FHR variation there was prima facie evidence of observer misinterpretation; visual analysis was unreliable. A larger trial is now required with more rigorous constraints on intervention.

Cardiotocography↗
PubMed1992

Spontaneous resolution of pre-eclampsia-related thrombocytopenia.

OBJECTIVE: To observe the spontaneous resolution of pre-eclampsia-related thrombocytopenia. DESIGN: A retrospective study. SETTING: High Risk Pregnancy Unit, John Radcliffe Maternity Hospital, Oxford. SUBJECTS: Thirty women with pre-eclampsia complicated by the HELLP/ELLP syndrome who did not receive any specific treatment for their thrombocytopenia. INTERVENTION: Serial platelet counts throughout labour and the puerperium until the platelet counts returned to levels above 100 x 10(9)/l. MAIN OUTCOME MEASURES: Time taken from delivery and platelet nadir for platelet counts to return to levels above 100 x 10(9)/l. The rate of recovery from the platelet nadir was measured by the slope of the serial platelet counts plotted against time. RESULTS: The mean time until platelet count exceeded 100 x 10(9)/l was 67 h (SD 25) after delivery and 44 h (SD 17) from the platelet nadir. All women had counts above 100 x 10(9)/l by 111 h after delivery, and by 88 h after the platelet nadir. Although the time to recovery appeared to depend on the degree of thrombocytopenia, the rate of resolution did not. CONCLUSION: These data can be used as a guide by clinicians as to the expected time course for postpartum resolution of pre-eclampsia-related thrombocytopenia.

Adolescent↗
PubMed1992

Short-term fetal heart rate variation, decelerations, and umbilical flow velocity waveforms before labor.

OBJECTIVE: To determine the value of computerized antepartum measurements of short-term fetal heart rate (FHR) variation and decelerations as a predictor of outcome, and to compare these with measurements of the umbilical artery flow velocity waveform. METHODS: Data were collected from 3563 high-risk patients for measurements of FHR variables (15,702 records) and outcome (intrauterine death or metabolic acidemia on delivery). Detailed analyses were made on 89 patients with one or more records in which short-term FHR variation was 3 milliseconds or less. Umbilical artery flow velocity waveforms were measured concurrently on 2441 occasions in 991 patients. RESULTS: More than half of the patients with FHR variation of 3 milliseconds or less were identified before 31 weeks. When short-term FHR variation exceeded 3 milliseconds, there were no intrauterine deaths and only one instance of metabolic acidemia on cesarean delivery. When FHR variation fell below 2.6 milliseconds, 34% of the subjects had metabolic acidemia on cesarean or intrauterine death. The appearance or absence of decelerations was an unreliable guide to outcome. The correlation between FHR variation and the umbilical artery flow velocity waveform was low (r = 0.32). The population studied contained some patients without placental vascular disease or, in five with pre-eclampsia, without abnormal umbilical artery velocity waveforms but with grossly reduced FHR variation. CONCLUSION: Reduction in short-term FHR variation, as measured by computer, reliably predicts fetal outcome and is a more general measure of fetal well-being than are umbilical artery flow velocities.

Blood Flow Velocity↗
PubMed1992

Approximate entropy, a statistic of regularity, applied to fetal heart rate data before and during labor.

OBJECTIVE: To determine whether approximate entropy (ApEn), a new statistic of regularity, when applied to fetal heart rate (FHR) data antepartum or in labor, would offer an advantage over standard statistics of variation in predicting outcome. METHODS: A large data base of antepartum FHR records collected in clinical practice over 10 years was available. Two data sets in labor were stored on disk in small computers interfaced to fetal monitors on-line. Outcomes were assessed using blood gas values on delivery and Apgar scores. RESULTS: Antepartum, when the most favorable form of ApEn was used on 769 good-quality FHR records, the correlation with measurement of short-term variation was high. This was especially true when the fetal pulse interval variation fell below the normal range (less than 6 milliseconds short-term; r = 0.93) and in 20 other records with sinusoidal variation (r = 0.96). Approximate entropy varied with fetal sleep cycles and took longer to calculate than FHR variation. During the last hour of labor, in 319 records, there was no significant correlation between umbilical artery base deficit values on delivery and ApEn measurement. In 871 additional good-quality records of fetuses with normal outcome, the mean (+/- standard error [SE]) ApEn (0.95 +/- 0.005) was significantly greater than in 22 records (0.88 +/- 0.028) from fetuses with abnormal outcome (umbilical artery base deficit more than 12 mmol/L and Apgar score of 3 or less at 1 minute). However, consideration of the frequency distributions of these measurements showed that ApEn did not discriminate between normal and abnormal outcomes. The SD of fetal pulse intervals rose in labor whereas ApEn values fell, confirming that this new statistic of regularity differs from standard statistics of variation. CONCLUSION: Approximate entropy offered no advantage over measurement of short-term FHR variation antepartum, and neither measurement predicted outcome in labor.

Adult↗
PubMed1991

Congenital heart block with hydrops fetalis treated with high-dose dexamethasone; a case report.

A 32-year-old woman with systemic lupus erythematosus was found to have a fetus with heart block and fetal ascites at 23 weeks gestation. Treatment with high-dose corticosteroids ameliorated the early signs of heart failure, although the fetal heart rate gradually fell from 48 beats/min to 42 beats/min by 34 weeks. Sudden deterioration of the fetal state occurred at 35 weeks, and this only partially responded to digitalisation. Neonatal death occurred on Day 18 from the consequences of severe birth asphyxia. The relationship and pathogenesis of anti-Ro antibodies, congenital heart block and hydrops fetals are discussed, together with the in utero management of this condition.

Adult↗
PubMed1991

Detection of fetal cells in maternal blood.

We report the detection of fetal cells in the maternal circulation by enzymatic amplification of a single copy gene sequence that was fetal-specific. Fetal HLA-A2-positive cells were sorted from maternal HLA-A2-negative cells by flow cytometry and confirmed by demonstration of a fetal-specific HLA-DR4 sequence. However, this sequence could not be detected in unenriched maternal DNA prepared at 28 and 32 weeks' gestation. The sensitivity of detection was 1 HLA-DR4-positive cell in 10(5) HLA-DR4-negative cells. We conclude that prenatal diagnosis of paternally inherited autosomal-dominant genetic defects may be possible by selective gene amplification of maternal peripheral blood. However, preliminary enrichment for fetal cells may be necessary.

Female↗
PubMed1991

Short-term variation in abnormal antenatal fetal heart rate records.

In a retrospective study the relation of reduced fetal heart rate variation to fetal acidemia was analyzed with a computerized system for numeric analysis. Between 1983 and 1987, 78 pregnancies were identified in which at least one record of the fetal heart rate had very low long-term variation. The outcome was analyzed to determine the numeric criteria of fetal heart rate variation that most efficiently detect a fetus that will die (preterminal) or is dying (terminal). Because fetal compromise was found on occasion to be associated with a slow sinusoidal fetal heart rate rhythm that increased measures of long-term variation. It was necessary to define a new index of short-term fetal heart rate variation (the 1/16 minute epoch-epoch variation). This was closely related to long-term variation (r = 0.9) but provided better detection of preterminal records as judged by metabolic acidemia at delivery or intrauterine death.

Adult↗
PubMed1991

Computerized analysis of episodic changes in fetal heart rate variation in early labor.

Fetal heart rate variation in early labor was measured by computerized analysis in cyclic episodes of low or high variation in 136 women at 37 to 42 weeks' gestation. The amplitude (mean +/- SE) in episodes of low variation was 20.6 +/- 0.4 milliseconds; in high variation it was 57.3 +/- 1.1 milliseconds. The duration (mean +/- SE) of low episodes (24.3 +/- 1.3 minutes) was less than that of high episodes (45.1 +/- 2.7 minutes) but was sometimes greater than 1 hour. In episodes of low variation the amplitude was less than 5 beats/min long term in 11% and less than 2.5 milliseconds (pulse intervals) short term in 8%; these measures would be predictive of intrauterine death if persistent before birth. We conclude that the use of decreased fetal heart rate variation as a diagnostic sign of acute fetal hypoxemia in labor is incorrect, because changes of this size occur randomly as a consequence of fetal sleep states. There was no significant correlation between fetal heart rate variation over the last hour of labor and umbilical arterial base deficit on delivery.

Adult↗
PubMed1991

Cytotoxic activity against trophoblast and choriocarcinoma cells of large granular lymphocytes from human early pregnancy decidua.

Large granular lymphocytes (LGL) are the most abundant cell type in first trimester human pregnancy decidua. We have shown previously that CD56-positive decidual LGL have cytotoxic activity against the natural killer (NK) target K562, and that this cytotoxicity is augmented by pretreatment with interleukin-2 (IL-2). We now report that flow cytometrically purified populations of CD56-positive decidual LGL have no cytotoxic activity against either the BeWo choriocarcinoma cell line or freshly isolated term trophoblast. Incubation of unfractionated decidual cells with IL-2 induced cytotoxicity against BeWo, but term trophoblast remained resistant to lysis. Both BeWo and trophoblast showed much lower binding frequencies to decidual or peripheral blood cells than K56 targets, and excess trophoblast did not inhibit cytotoxic activity against K562. This suggests that the resistance of trophoblast to lysis by either decidual or peripheral blood LGL is due to the lack of accessible NK target structures on the surface of trophoblast.

Choriocarcinoma↗
PubMed1991

Controlled trials of antihypertensive drugs in pregnancy.

It is taken for granted that severe hypertension in pregnancy should be treated, although the principle has not been formally tested by properly controlled trials. There is less certainty about treating mild to moderate hypertension (140/90 to 169/109 mm Hg). The risk of chronic hypertension in pregnancy depends on that of superimposed preeclampsia, which must be prevented by control of the blood pressure if antihypertensive treatment is to be beneficial. There is not a priori reason why lowering the blood pressure should have this effect. Most of the trials of treatment have been too small to provide conclusive answers. Usually treatment has been started too late to give a realistic expectation of influencing the evolution of superimposed preeclampsia. However, the largest trial of the early use of methyldopa in women with mild chronic hypertension, showed clearly that treatment does not prevent the superimposition of preeclampsia. beta-Adrenergic blocking agents, if used from the second start of the trimester, are associated with a major risk of severe growth retardation and are therefore contraindicated. Methyldopa has the best safety record, which includes long-term follow-up to assess the development of children exposed to methyldopa in utero. The ineffectiveness of antihypertensive drugs in preventing or ameliorating preeclampsia needs to be contrasted with the consistent evidence for the effectiveness of antiplatelet therapy. This is consistent with the increasing evidence that preeclampsia is not primarily, or even necessarily, a hypertensive disease.

Female↗
PubMed1991

Out-patient peritoneal lavage cytology in the detection of residual epithelial ovarian cancer.

Peritoneal lavage fluid cytology was performed in 87 out-patients with histologically proven epithelial ovarian cancer undergoing primary management. A total of 246 peritoneal lavages were attempted, usually with temporary cannulae (n = 229). From these, 184 samples were obtained, of which 156 (85%) were suitable for cytological analysis. The sensitivity of peritoneal lavage fluid cytology in 67 patients with known residual disease was 57% whereas serum CA 125 levels were elevated in 58 (87%). Pre- and post-treatment peritoneal lavage fluid cytology had prognostic value, but this was less than that of serum CA 125 measurements.

Adult↗
PubMed1991

The effect of maternal anaemia and iron deficiency on the ratio of fetal weight to placental weight.

OBJECTIVE: To examine the maternal influences which determine large placental weight and a high ratio of placental weight to birthweight. These are known predictors of adult blood pressure. DESIGN: Retrospective analysis of routine obstetric and haematology department records for a large cohort of pregnant women. SETTING: John Radcliffe Hospital, Oxford. SUBJECTS: 8684 pregnant women who were delivered between January 1987 and January 1989 and whose records could be linked to the results of two or more pregnancy blood counts. MAIN OUTCOME MEASURES: Placental weight and the ratio of placental weight to birthweight. RESULTS: Large placental weight was associated with a low maternal haemoglobin and a fall in maternal mean cell volume during pregnancy. The highest ratio of placental weight to birthweight occurred in the most anaemic women with the largest falls in mean cell volume. Large placental weight and a high ratio of placental weight to birthweight were also independently associated with a high maternal body mass index. Maternal smoking reduced placental weight, but increased the ratio of placental weight to birthweight. CONCLUSIONS: Anaemia and iron deficiency during pregnancy are associated with large placental weight and a high ratio of placental weight to birthweight. This points to maternal nutritional deficiency as a cause for discordance between placental and fetal growth. This may have important implications for the prevention of adult hypertension, which appears to have its origin in fetal life.

Anemia↗