Search PubMed⌕ Search

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↗
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

Pulse oximetry used for documenting oxygen saturation and right-to-left shunting immediately after birth.

The objective of this study was to investigate the clinical applicability of pulse oximetry to measure haemoglobin oxygen saturation and heart rate in the first 20 min of life and to analyse the effect of pre- or post-ductal (hand, respectively, foot) fixation of sensors on oxygen saturation. Measurements were carried out on 53 newborn infants selected at random after delivery by caesarean section. Signal detection occurred significantly faster from the hand (50% after 1.3 min, 90% after 4 min) than from the foot (50% after 3.1 min, 90% after 9 min). Both fixation sites showed equally great sensitivity to motion. The heart rates from pulse oximetry recordings were up to 30% lower than those from ECG recordings. Saturation values from the hand were nearly always higher than those from the foot (median difference in the 5th min was 10%; between the 5th and 10th min it was 7%; no significant difference occurred after the 17th min). We conclude that pulse oximetry can be used for documenting oxygenation and right-to-left shunting in newborn infants during the first minutes of life in spite of limitations due to incomplete pulse wave detection and artifacts.

Foot↗
PubMed1990

Biochemical changes in the mother and the fetus during labor and its significance for the management of the second stage.

In 69 patients with uneventful pregnancies, term labor was studied prospectively with respect to length of second stage, number of bearing down efforts, maternal and fetal levels of lactate, epinephrine and norepinephrine. Maternal venous blood concentrations were measured in early labor and at the time of delivery while samples from umbilical artery and vein provided fetal blood. There was a significant rise of lactate and catecholamines in maternal blood during labor and at delivery fetal lactate concentration was lower than the maternal level while for epinephrine and norepinephrine fetal levels were higher. For all three compounds umbilical artery concentrations were higher than umbilical venous levels. While there was no correlation between the biochemical parameters in maternal blood and length of second stage maternal lactate and norepinephrine concentration at the time of delivery significantly correlated with the number of bearing down efforts. Umbilical artery lactate correlated with both, length of second stage and number of bearing down efforts.

Epinephrine↗
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↗