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Biomedical subjects

A Huch

Publications and source records attributed to A Huch.

At least 19 recordsLinked to original sources
PubMed1992

[New aspects in the evaluation of Doppler blood flow curves: three- dimensional image and analysis of Doppler shift frequencies within the heart cycle].

Since the introduction of Doppler ultrasound to the area of medical diagnostics, there have been numerous improvements and important technical refinements. In obstetrics, Doppler examination allows a more accurate and encompassing evaluation of the foetal condition than was previously possible. Combined with today's sophisticated computer technology, it has a great potential in research and to expand our knowledge about the physiology and pathophysiology of foetal and maternal haemodynamics. This paper describes a new way of integrating another factor into the evaluation of Doppler blood flow waveforms, namely, the intensities of various frequencies. One result should be more detailed information about the given haemodynamic situation; another, a valuable tool for the quality control of Doppler blood flow measurements. Although our work was on applications in the field of obstetrics, the method we have developed can be used in all medical areas.

Blood Flow Velocity↗
PubMed1992

Umbilical artery blood flow velocity waveforms in twin pregnancies.

To detect discordant fetal growth in twin pregnancies and assess a possible role for Doppler ultrasound measurements of blood flow velocity waveforms in umbilical arteries in such cases, 32 twin pregnancies were examined on 125 occasions. The last examination was within 14 days of delivery. There was postpartum death of one pair of twins with the twin transfusion syndrome. Birthweight was appropriate for gestational age in 15 twin pairs, both infants were small for gestational age (SGA) in 5, and one of the infants was SGA in 12 twin pairs. The correlation coefficient of RI difference at the last examination and percentage birth weight difference in twin pairs was 0.68. Cutoff points for the delta RI and weight difference were established. The sensitivity of delta RI (0.1) was 77.8%; specificity, 95.8%; positive predictive value, 87.5%; and negative predictive value, 92.0%.

Blood Flow Velocity↗
PubMed1992

The variability of cardiopulmonary adaptation to pregnancy at rest and during exercise.

OBJECTIVE: To examine the cardiopulmonary adaptation to normal pregnancy in sitting women during rest and bicycle exercise. DESIGN: A longitudinal study beginning early in pregnancy and ending 8-12 months after delivery. SETTING: University Hospital, Zurich, Switzerland. SUBJECTS: 20 women were monitored every second week during pregnancy from 8 to 14 weeks gestation, twice in the puerperium and twice 6-8 weeks and twice 8-12 months after delivery. All the women finished the study, but not all of them participated in every visit. MEASUREMENTS AND MAIN RESULTS: The results obtained 8-12 months after delivery are considered the non-pregnant data and are presented first so that any change in pregnancy will be more obvious. Values given below refer to the median except when stated otherwise. At rest: 1. Oxygen consumption increased significantly from a median of 182 ml/min in the non-pregnant state to 256 ml/min by 8-11 weeks gestation, and peaked at 300 ml/min at 32 weeks. At 6-8 weeks after delivery the value was 225 ml/min. 2. Oxygen consumption per kg increased significantly from 3.0 ml/min in the non-pregnant state to 4.3 ml/min by 8-11 weeks gestation and peaked at 5.0 ml/min soon after delivery. At 6-8 weeks after delivery the value was 3.4 ml/min. 3. Carbon dioxide production generally showed changes similar to those of oxygen consumption. 4. Respiratory quotient did not show any significant changes. 5. Ventilation increased from a median of 9.4 l/min in the non-pregnant state to 10.5 l/min by 8-11 weeks and then slowly increased to 12.6 l/min in late pregnancy. 6. Respiratory rate did not change significantly. 7. Tidal volume showed a median of 563 ml in the non-pregnant women and rose significantly to 632 ml in early pregnancy, peaking at 715 ml in late pregnancy. 8. Alveolar ventilation increased significantly from a non-pregnant value of 3.4 l/min to 6.2 l/min in early pregnancy, peaking at 6.7 l/min at term; 6-8 weeks after delivery the value was 4.5 l/min. 9. Ventilation equivalent for oxygen fell significantly from the median non-pregnant value of 52 to 42 in early pregnancy and remained at that level until 6-8 weeks after delivery when it was 44. 10. Ventilation equivalent for carbon dioxide showed similar changes to those for oxygen. 11. Alveolar carbon dioxide tension fell significantly from a median non-pregnant level of 4.6 kPa (34 mmHg) to 4.0 kPa (30 mmHg) in early pregnancy. It began to increase in the puerperium and was 4.3 kPa (33 mmHg) 6-8 weeks after delivery. 12. Mixed venous carbon dioxide tension fell significantly from a median of 5.9 kPa (44 mmHg) to 5.2 kPa (39 mmHg) during pregnancy. 13. Transcutaneous carbon dioxide tension decreased significantly in early pregnancy from 8.8 kPa (66 mmHg) in the non-pregnant women, and from 20 weeks gestation remained at 6.9 kPa (52 mmHg). 14. Transcutaneous oxygen tension showed a non-significant increase from 10.0 kPa (75 mmHg) in the non-pregnant women to 11.1 kPa (83 mmHg) during pregnancy. 15. Cardiac frequency increased gradually from a non-pregnant median of 80 b.p.m. to about 90 b.p.m. in the last 2 months of pregnancy. In the puerperium the median was 75 b.p.m. 16. Cardiac output increased significantly by almost 50% from the non-pregnancy level to that at 8-11 weeks gestation. 17. Cardiac output per kg also increased significantly by 50% from the non-pregnant level to that at 8-11 weeks gestation. From mid-pregnancy there was a gradual fall until delivery. 18. Stroke volume increased significantly from a median of 31 ml in the non-pregnant state to 51 ml in early pregnancy, and remained at this level until delivery. In the puerperium the stroke volume was 63 ml. 19. Oxygen pulse increased significantly from a median of 2.2 ml in the non-pregnant women to 3.1 ml in early pregnancy and remained at that level. 20. Individual curves.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed1992

Laser Doppler technique for the measurement of digital and segmental systolic blood pressure.

A technique is described for measuring digital and segmental systolic blood pressure by laser Doppler fluxmetry. A transparent plastic capsule contains the small sphygmomanometer cuff connected to a Statham manometer. It has a hole for positioning the probe at the very tips of fingers or toes. An advantage of this method over the conventional strain-gauge technique is that it is better suited for determinations at short digits where it is difficult to fix a strain-gauge. Moreover, it allows consecutive pressure and flux measurements at almost identical distal sites without moving the probe. The correlation between the values obtained by the conventional and laser Doppler procedures are excellent. Systolic pressures were determined on 14 extremities of 7 healthy controls and on 20 extremities of 14 patients with intermittent claudication due to peripheral arterial occlusive disease. Measuring sites were the upper arm, forearm, index finger, ankle and big toe. The values agree well with those obtained earlier by the strain-gauge technique.

Aged↗
PubMed1992

Recombinant human erythropoietin in the treatment of postpartum anemia.

Postpartum maternal anemia (hemoglobin concentration below 10 g/dL) is a common problem in obstetrics. Human recombinant erythropoietin, which has been shown to correct the anemia of end-stage renal disease and eliminate the need for transfusions, was used in a comparative study of women with postpartum hemoglobin concentrations below 10 g/dL. Five daily doses of 4000 IU were given. Hematologic and clinical data were compared on days 5, 14, and 42 after therapy in the treated women and in untreated women. Both groups received the same iron and folic acid supplements. Significantly greater increases in reticulocytes, hemoglobin, and hematocrit were seen by day 5 for the treated subjects compared with controls. Ferritin levels were significantly lower in the therapy group than in controls. No differences were seen between the groups in the platelet counts or clinical characteristics. No negative side effects were observed. As in other studies in populations without renal disease, recombinant human erythropoietin enhanced endogenous erythropoiesis over and above the normal physiologic recovery rate.

Anemia↗
PubMed1991

[Are Doppler methods suitable for the study of adaptive maternal central circulatory regulation in pregnancy? II. Assessment of time parameters and determination of minute distance, conclusions].

Echocardiographic Doppler measurements of blood flow velocity are a noninvasive way of studying maternal central haemodynamics. Part 2 reports on additive and derived physiological parameters using different Doppler ultrasound techniques. This paper shows that quantitative assessment of adaptive maternal central circulatory regulation must be interpreted in respect of methods and machines. Technical requirements to be met by the Doppler equipment to avoid present limitations are discussed as are various aspects involved in such studies.

Blood Flow Velocity↗
PubMed1990

[Are Doppler methods appropriate for the study of adaptive maternal central circulation regulation in pregnancy?].

Echocardiographic Doppler measurements of blood flow velocity are a noninvasive way of studying maternal central haemodynamics. Part 1 reports on conditions as well as on practical and theoretical problems recognized as contributing significantly to the use and interpretation of Doppler ultrasound techniques in the assessment of adaptive central circulatory regulation in pregnancy. The significance of different techniques is shown by assessments of the peak velocity and the velocity time integral.

Aorta, Thoracic↗
PubMed1990

Uteroplacental blood flow velocity waveforms as a predictor of adverse fetal outcome and pregnancy-induced hypertension.

The resistance index (RI) of uteroplacental blood flow velocity waveforms (VWF) was investigated by continuous Doppler ultrasound in 286 nonselected pregnant women with singleton pregnancies at 18-21 weeks (n = 129) and at 31-33 weeks (n = 157) of gestation to evaluate the validity of this method as a screening procedure for abnormal pregnancy outcome (intrauterine growth retardation, pregnancy-induced hypertension and fetal asphyxia). The sensitivity of predicting pregnancy outcome was 26.6% at 18-21 weeks and 17.6% at 31-33 weeks of gestation. It was concluded that this method is too insensitive as a screening tool for the prediction of intrauterine growth retardation and pregnancy-induced hypertension in a low-risk nonselected pregnant population.

Blood Flow Velocity↗
PubMed1990

Peripheral skin temperature and microcirculatory reactivity during pregnancy. A study with thermography.

The aim of the study was to compare gradients of skin surface temperature on the arm and hand and to evaluate differences in the skin microcirculation reactivity between pregnant and non-pregnant women. We used the prototype of a highly sensitive thermograph system for the measurements. Eight healthy, non-pregnant women (mean age 27.9 years) and eleven pregnant women in the 14th-40th gestational week with normal pregnancies (mean age 28.7 years) were examined. Compared with the control collective, there were the following differences found in the pregnant group: --Skin temperature (ST) difference from the hand to the forearm was 2.6 +/- 0.8 degrees C instead of 0.6 +/- 1.2 degrees C (p less than or equal to 0.01). --There was a higher ST in the hand (p less than or equal to 0.01), but not in the proximal forearm. --An increase of the ST in the hand and the occurrence of a temperature difference compared with the forearm could be seen even in the early stages of pregnancy. --The skin temperature decrease was less marked in pregnant than in non-pregnant women after application of a cold stimulus (p less than or equal to 0.01) and after venous occlusion (not significant). The results obtained by telethermography indicate that during pregnancy there is a greater increase in the arteriovenous shunt blood flow (represented especially in the skin of the acral regions) than in capillary perfusion (represented mainly in the skin of the trunk and proximal extremities).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Hydrops fetalis in tachycardia: diagnostic and therapeutic procedures].

We report on a 33-year-old para II who was admitted to our hospital in her 29th gestational week with extensive fetal hydrops. Examinations showed a fetal supraventricular tachycardia with biventrical cardiac insufficiency. Digoxin was given both to the mother and to the fetus. At first, this treatment seemed to have no effect. Over a period of several weeks, however, oral therapy with digoxin and verapamil resulted in a stabilized fetal heart rate (175-180 beats/min). Signs of fetal cardiac insufficiency disappeared almost completely. In the 39th week the child was born spontaneously. Clinical examination revealed only a slight cardiac insufficiency. New possibilities of intrauterine therapy are discussed in the light of this case and other reports in the literature.

Adult↗
PubMed1990

Effect of epidural anesthesia for cesarean delivery on maternal femoral arterial and venous, uteroplacental, and umbilical blood flow velocities and waveforms.

The effect of epidural anesthesia on the maternal femoral arterial and venous, uteroplacental, and umbilical circulations was studied by the pulsed Doppler technique in 13 women undergoing elective cesarean delivery. Resistance and pulsatility indices of umbilical arterial velocity waveforms did not change with the use of epidural anesthesia. In the uteroplacental circulation, these indices increased in 11 patients, suggesting an increase in resistance. Reduction of sympathetic tone in resistance and capacitance vessels was reflected in the femoral artery by an increase in systolic and end-diastolic velocities, a reversal of the post-systolic backward flow, and an increase in mean velocity. The latter also occurred in the femoral vein. The diameters of these large maternal vessels did not change. This study suggests an impairment in uteroplacental circulation associated with a drop in peripheral vascular resistance and an increase in leg blood flow after epidural anesthesia.

Anesthesia, Epidural↗
PubMed1989

Pharmacokinetic studies on fenoterol in maternal and cord blood.

Fenoterol plasma concentrations were measured by radioimmunoassay in 38 pregnant women at different stages of preterm labor and in cord blood. Eight women were treated intravenously until delivery with 1.0 to 4 micrograms/min of fenoterol for periods ranging from 27 hours to 27 days; blood samples were taken at the same time as cord blood. In these women the fenoterol concentrations in cord blood ranged from 18 to 53% of the maternal concentrations. In eight women treated intravenously with 1.2 to 4.0 micrograms/min for 2 to 15 days, the infusion was stopped 1.3 to 38 hours before delivery. In these instances the concentrations in cord blood reached as much as 90% of the maternal, meaning that the rate of elimination from fetal plasma is lower than that from maternal plasma. Five women were treated daily with 20 to 30 mg per os for 3 to 17 days (three of these women had also had intravenous treatment before). The ratio of cord to maternal blood concentrations was higher than in women receiving the drug intravenously, the relative times of sampling being the same. The findings suggest that: (1) the placental transfer of fenoterol is higher than that found in previous studies in humans and animals with tritium-labeled substances; (2) the rate of fenoterol elimination from fetal plasma after intravenous and oral long-term therapy is lower than that from maternal plasma; (3) after oral administration, the ratios of fetal to maternal fenoterol concentrations are higher than after intravenous infusion.

Administration, Oral↗
PubMed1989

[Pelvimetry with magnetic resonance tomography].

Magnetic resonance imaging (MRI) in the mediosagittal and transverse planes was used to measure the antero-posterior and transverse diameters of the minor pelvic cavity. The measurements for the diameters were larger than those usually found in the literature. The antero-posterior pelvic inlet diameter, the most important measurement for obstetrics, was on average 11.9 cm in contrast to the generally accepted length of 11.0 cm.

Adolescent↗