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Biomedical subjects

M de Swiet

Publications and source records attributed to M de Swiet.

At least 19 recordsLinked to original sources
PubMed1992

Blood pressure in first 10 years of life: the Brompton study.

OBJECTIVES: To determine the normal range of blood pressure and its pattern of change in the first 10 years of life. To estimate at what age (if any) children consistently appear in one part of the blood pressure distribution and at what age familial correlations in blood pressure become significant. DESIGN: Longitudinal cohort study. SETTING: South east England. SUBJECTS: 2088 children of both sexes born consecutively in Farnborough Hospital, Kent, and their parents. MAIN OUTCOME MEASURE: Blood pressure measured by Doppler ultrasonography and sphygmomanometry. RESULTS: Systolic blood pressure rose from a mean of 88.5 mm Hg at age 6 months to 96.2 mm Hg at 8 years measured with a 8 cm cuff and from 89.1 mm Hg at age 5 years to 94.3 mm Hg at age 10 years measured with a 12 cm cuff. The larger cuff gave blood pressure readings about 6 mm Hg lower. This effect was independent of body weight and arm circumference. Diastolic blood pressure rose from 57.8 mm Hg at 5 years to 61.8 mm Hg at 10 years (12 cm cuff). There was only about 1 mm Hg difference between sexes. Blood pressure was correlated with weight, weight adjusted for height, height, and arm circumference at all ages studied. The correlation coefficient of repeated yearly measurements increased steadily with age from 0.28 at 2 years to 0.59 at 10 years. The correlation coefficients between child's blood pressure and mother's average blood pressure increased from 0.1 at age 1 year to 0.23 at age 10. CONCLUSIONS: Blood pressure changes relatively little between the ages of 6 months and 10 years. Yet because of the increasing strength of between occasion and family correlations, children are more consistently occupying a specific part of the blood pressure distribution as they grow older. Studies in children should help determine why some adults have hypertension and others do not.

Aging↗
PubMed1992

Thyroxine dosage during pregnancy in women with primary hypothyroidism.

OBJECTIVE: To assess whether pregnancy changes the thyroxine requirements of hypothyroid women. DESIGN: A retrospective, longitudinal study. SETTING: Queen Charlotte's and Chelsea Hospital for Women. SUBJECTS: 32 women referred for antenatal care during 35 pregnancies. MAIN OUTCOME MEASURES: Changes in thyroid stimulating hormone (TSH) and free thyroxine (fT4) levels as pregnancy progresses. RESULTS: In most of the pregnancies (80%), no change in thyroxine dose was required (mean dose 129 micrograms). The mean TSH levels in early (1.8 mU/l) and in late pregnancy (1.5 mU/l) were unchanged (P greater than 0.5). In the remaining pregnancies, thyroxine dose was increased after the first antenatal clinic appointment, on the basis of thyroid function test results, from a mean of 104 micrograms to a mean of 172 micrograms (P less than 0.01). These women had a mean early pregnancy TSH of 12.3 mU/l, which decreased by 95% to 1.3 mU/l (P less than 0.01). CONCLUSIONS: Most of the hypothyroid patients presenting to an antental booking clinic are well controlled in early pregnancy and will remain so throughout pregnancy. The dose of thyroxine does not need to be changed, and further assessments of thyroid function should not be necessary. It is unlikely that the patients were all 'overtreated' before conception, since they were referred to us by a large number of independent doctors. Women who are under-treated before the pregnancy are likely to require both increased thyroxine dose and further thyroid function assays. They can generally be easily detected, biochemically, at the first hospital visit.

Adult↗
PubMed1992

Medical disorders in pregnancy.

Progress in medical disorders in pregnancy has inevitably occurred over a wide front. Highlights of the past year include the use of real-time ultrasound rather than venography to diagnose deep vein thrombosis in pregnancy, the establishment of Doppler ultrasound for noninvasive measurement of cardiac output, better awareness of the risk to the fetus if the mother has immune thrombocytopenic purpura, the description of the maturation of fetal thyroid function, the problems of in utero treatment of congenital adrenal hyperplasia in the fetus, and an appreciation of the fetal risk if maternal phenylketonuria is not managed by strict dieting in pregnancy.

Clinical Protocols↗
PubMed1990

The British Hypertension Society protocol for the evaluation of automated and semi-automated blood pressure measuring devices with special reference to ambulatory systems.

With the increasing manufacture of expensive systems for the measurement of ambulatory blood pressure there is a need for potential purchasers to be able to satisfy themselves that the systems have been evaluated according to agreed criteria. The British Hypertension Society has, therefore, drawn up a protocol of requirements for the evaluation of these devices. This protocol incorporates many features of the American National Standard for Non-Automated Sphygmomanometers but includes many additional features, such as strict criteria for observer training, interdevice variability testing before and after a month of ambulatory use, and a new system of analysis which permits the test system to be graded. It is recommended that manufacturers of ambulatory blood pressure measuring devices should obtain an unbiased evaluation according to a recognized standard before a device is marketed.

Blood Pressure Monitors↗
PubMed1987

Anticoagulants.

Explore the source record for details and available documents.

Abnormalities, Drug-Induced↗
PubMed1986

Blood pressure in the puerperium.

Blood pressure was measured by random zero sphygmomanometer in the morning and afternoon for 5 days after normal delivery in a group of 136 previously normotensive women. The number of women studied each day varied from 32 to 125. The afternoon blood pressure was higher than the morning blood pressure (differences: 1.7 mmHg systolic, 2.6 mmHg diastolic; P less than 0.05). Both systolic and diastolic blood pressures rose for the first 4 days after delivery. The average rise over the whole period was about 6 mmHg systolic and 4 mmHg diastolic (P less than 0.05). A considerable number of previously normotensive women displayed elevations of blood pressure in the puerperium. Twelve per cent of all patients exceeded a diastolic blood pressure of 100 mmHg.

Adolescent↗
PubMed1986

The measurement of cardiac output by electrical impedance plethysmography in pregnancy. Are the assumptions valid?

The assumptions of the Kubicek technique for measurement of cardiac output by detection of changes in the chest wall electrical impedance have been re-examined. The fall in cardiac output in the latter half of pregnancy which Crawford's group calculated using the Kubicek technique can be almost entirely accounted for by a fall in the term dZ/dT of the Kubicek equation, as pregnancy progress. One key assumption of the Kubicek technique is a constant ejection flow rate equal to the initial flow as the pulmonary valve opens, which is multiplied by the estimated ejection time to obtain stroke volume. Initial flow rate is represented by the term dZ/dT in the Kubicek equation. Although this assumption has been shown to give a reasonable correlation with other techniques for measurement of cardiac output in the non-pregnant state, this may not be so for longitudinal studies in pregnancy because of the changes in lung mechanics and in the circulation which occur in this state. Crawford's data emphasizes the necessity for validating the Kubicek technique very critically during pregnancy.

Cardiac Output↗