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Biomedical subjects

R Huch

Publications and source records attributed to R 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 critical hemoglobin/hematocrit value in obstetrics].

During pregnancy, there are characteristics changes in the hemoglobin and hematocrit values. Compared with the norm for nonpregnant women, there is an increase in the total number of erythrocytes and in the plasma volume. An overproportional increase of the latter results in hydremia. The normal physiologic range for hemoglobin during pregnancy is 11.5-13.0 (13.5) g/dl; anemia is, by definition, present when the values are under 11 g/dl and is quite common in pregnancy. Since it is caused almost exclusively (95%) by iron deficiency, iron therapy or routine iron supplementation can influence its incidence. Values outside the norm range are associated with complications during pregnancy and with growth retardation of the fetus.

Female↗
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↗
PubMed1979

Integrated interpretation of fetal heart rate, intrauterine pressure and fetal transcutaneous PO2.

By a study of the patterns of changes and the temporal relationship in fetal heart rate, intrauterine pressure, fetal tcPO2 and 'flow', a series of ten typical examples of combined patterns are described. Fetal tcPO2 is affected by the level of the fetal oxygenation and by the blood flow beneath the electrode. Should the latter be below a certain critical level fetal tcPO2 will be lower than fetal scalp blood PO2. By the integrated analysis of the four simultaneously recorded variables the different factors dominating fetal tcPO2 may be identified.

Female↗
PubMed1979

Correlation between fetal scalp tcPO2 and microblood samples.

In summary we would like to state that the correlation between tcPO2 recorded from human fetal scalp and microblood PO2 is quite good. High tcPO2 values are very reassuring for the clinician and indicate a good oxygenation of the fetus. In the presence of a low tcPO2 reading, other signs of fetal hypoxia like abnormal heart rate patterns or a low microblood PO2 are required to confirm the diagnosis. If a low tcPO2 is the only sign suggestive of fetal hypoxia and all other parameters are normal, we recommend removal of the electrode and reapplication in a different spot.

Blood Gas Analysis↗