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Biomedical subjects

R Huch

Publications and source records attributed to R Huch.

At least 181 records · Page 10Linked to original sources
PubMed1985

Neonatal oxygen-cardiorespirograms.

To those used to intermittent blood sampling, intermittent viewing of ECG, or intermittent counting of heart and respiratory rates, the rapid changes in these variables, as revealed when monitored continuously, must come as a surprise. These rapid changes are found even in quiet, healthy infants. Because of this variability and the diagnostic significance of each single variable, the potential of these variables can be utilized only if they are continuously recorded. It is like studying movement from a videorecording instead of from a couple of photographs taken at different intervals. Knowing normal levels and the trend of changes in all the variables, it becomes easier and more accurate to predict significant clinical changes than before. Or, in M. E. Avery's words, "Those of us who have used continuous monitors would not like to return to the era of sporadic sampling of information."

Electrocardiography↗
PubMed1984

[Incidence of HBsAG in symptom-free pregnant women. Results of screening at the University of Zurich Gynecology Clinic].

Passive and active immunization prevent materno-fetal and postnatal hepatitis B-virus infection. Precondition for interruption of perinatal transmission is knowledge of the mothers' hepatitis B markers before delivery. In switzerland the prevalence of chronic asymptomatic pregnant HBsAG carriers is not known. From February to December 1983 all pregnant women at the Obstetric Clinic, University Hospital of Zurich were screened for HBsAG. 30 out of 2550 women were HBsAG positive (1.2%); the prevalence among Swiss women is 0.5%, and among immigrants 1.9%. It is suggested that screening for HBsAG be confined to pregnant women who belong to a risk group and to immigrants, and that all children born of HBsAG positive mothers be immunized actively and passively regardless of the presence of HBeAG and/or anti-HBe.

Female↗
PubMed1984

Homeostasis of fetal lactate metabolism in late pregnancy and the changes during labor and delivery.

Electrochemical enzymatic measurements of whole blood lactate concentrations were performed in 110 deliveries. In the majority of uncomplicated vaginal deliveries and of elective cesarean sections cord blood levels were higher than maternal concentrations and, as indicated by a positive arterio-venous difference for the cord vessels, lactate is originating in the fetus. In cases with clinical signs of fetal distress production of lactate due to anaerobic glycolysis is markedly increased. Differently from some other studies with uncomplicated vaginal deliveries, maternal lactate concentrations remained below fetal levels in almost 80%, which is explained by a conservative management of the second stage of labor with active pushing being restricted to the final phase of expulsion. The question whether also in late pregnancy the undisturbed human fetus in utero produces lactate or makes use of placental lactate as a substrate for its oxidative metabolism - as has been shown for some animal species - cannot be answered from the presently available evidence.

Energy Metabolism↗
PubMed1984

[Late primiparity: what has changed in the last 25 years?].

The case reports of late primiparae greater than 35 years of age were analysed in respect of the change of anamnestic risks, of the course of pregnancy, birth and puerperium, as well as of infant data. The incidence of late primiparae rose in our clinic from A 1.8% (n = 292, infants n = 294), via B 2.6% (n = 210, infants n = 213) to C 3.7% (n = 222, infants n = 225.) Previous history of internistic diseases was rare during all periods. In period C, the anamnestic risk "Status after sterility treatment" attains increasing importance (17%). The incidence of pre-eclamptic toxaemia (toxaemia associated with oedema, proteinuria and hypertension) with blood pressure levels greater than 140/90 mgHg and proteinuria greater than 1 0/00 is 5-7% for all periods. Preeclampsia and eclampsia are rare. During the C period, almost every tenth late primigravida received tocolytics. In 1979, 31% of the late primiparae were subjected to genetic amniocentesis, whereas in 1982 the percentage was 51% of the late primiparae. Spontaneous deliveries decreased from 81% (A) to 50% (C). The rates of Caesarean sections increased from 11% (A) via 21% (B) to 35% (C); hence, they were twice as high during all periods than among the entirety of hospital patients included in this study. The increase in the quota of Caesarean sections is due to the indications "foetal distress ante partum", "breech presentation" and the liberal use of Caesarean section in underweight infants. For example, the category of newborn with a bodyweight below 2500 g, the rate of Caesarean sections increased from 7% (A) to 56% (C).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1984

The oscillating 'vena cava syndrome' during quiet standing--an unexpected observation in late pregnancy.

While studying the lung function of pregnant women at term in four different postures, we were surprised to note marked cyclic accelerations in the heart rate in two-thirds of the women when in a standing position. The mean cycle length was 105 s (range: 1-4 min) and the amplitude had a mean of 27 beats/min (range: 9-51). Blood flow velocity measurements with ultrasound Doppler over the femoral vein showed that there was an intermittent reduction of flow during quiet standing. When the venous return ceased, maternal heart rate increased, cardiac output decreased and blood pressure fell. After the venous blood flow was restored, maternal heart rate, cardiac output and blood pressure returned to normal until the cycle started again. Concomitant with these maternal heart rate changes, different patterns of fetal heart rate were observed. About 70% of the fetuses showed reduction in the long-term variability, increase in fetal heart rate or periodic accelerations. Although no woman fainted during quiet standing, the maternal circulatory changes were consistent with those seen in the classical vena cava syndrome.

Blood Flow Velocity↗
PubMed1984

Transcutaneous oxygen tension and capillary morphologic characteristics and density in patients with chronic venous incompetence.

The transparent oxygen electrode, recently developed by Huch and his co-workers, permits monitoring of transcutaneous oxygen tension (tcPO2) at defined sites on the capillaroscopic image obtained by videomicroscopy. This combined system has been applied to study the nutritional skin capillaries of patients with chronic venous incompetence (CVI). The results of 44 studies in 17 patients with CVI demonstrated a direct correlation between tcPO2 and density and morphologic characteristics of the superficial capillaries. The mean tcPO2 was 47.7 +/- 14.4 mm Hg at the site of incompetent perforating veins of the ankle without major trophic changes. There was no statistically significant difference between the mean values obtained in patients and control subjects (56.8 +/- 9.9 mm Hg). Videomicroscopic examination revealed dilated and tortuous capillaries surrounded by halo formations. In areas of hyperpigmentation, induration, and hyperkeratosis, significantly decreased mean tcPO2 (22.5 +/- 7.0 mm Hg; p less than .001) corresponded to reduced capillary density (less than 10 capillaries/mm2). In avascular skin areas (scar tissue, white atrophy) tcPO2 was measured at 0 mm Hg. No capillaries, or a greatly reduced number, were visible at such sites, resulting in a distance between capillary and cathode tip of the oxygen sensor of greater than 100 micron. The combined system of tcPO2 measurement and simultaneous videomicroscopy gives new pathophysiologic information on the development of skin ulcers and may be useful for the objective comparison of different therapeutic modalities at the microcirculatory level.

Adult↗
PubMed1984

The neonatal oxycardiorespirogram.

The neonatal oxycardiorespirogram is the simultaneous recording of respiration rate, respiration waveform, instantaneous heart rate, transcutaneous oxygen tension, and relative skin perfusion or "blood flow" from newborn infants. It is important in monitoring the high risk infant to assess the cardiovascular and respiratory function of the patient. The techniques for obtaining the various signals of the oxycardiorespirogram are reviewed and the usual method for making this recording is presented. Several examples of typical oxycardiorespirograms are given.

Biomedical Engineering↗
PubMed1983

Some effects of maternal pethidine administration on the newborn.

The effects of maternal pethidine administration (100 mg intramuscularly) were investigated in 150 infants at 1-2 h after birth, 95 infants whose mothers had not received pethidine served as a control group. Pethidine administration showed no effect on pH or PCO2 of cord blood and neonatal arterial blood at 1-2 h after birth if the time interval between pethidine administration and delivery was less than or equal to 1 h. However, when the interval was greater than 1 h: umbilical vein blood PCO2 was higher; neonatal arterial blood PCO2 was higher; neonatal baseline heart rate was higher, although long-term variability was similar; the percentage time spent crying was considerably reduced compared with the corresponding values in the control group. The long-term effects of pethidine are unknown but the adverse neonatal factors particularly if the time interval between administration of the drug and delivery is greater than 1 h should be kept in mind.

Carbon Dioxide↗
PubMed1983

A device for easier collection of fetal scalp blood.

Since its introduction in 1961 the analysis of fetal scalp blood has become an indispensable tool in modern intrapartum obstetric management. However, the procedure to obtain a fetal blood sample remains rather cumbersome. A new device - with a light source inside - was developed which allows collection of fetal scalp blood directly into a capillary tube. The instrument can be used single-handed and since no change of instrumentation during this procedure is necessary, blood collection can be performed rapidly. Moreover, the depth of the incision into the fetal scalp is predefined to give maximal safety to the procedure.

Blood Specimen Collection↗
PubMed1983

A transparent transcutaneous oxygen electrode for simultaneous studies of skin capillary morphology, flow dynamics and oxygenation.

Transcutaneous PO2 (tcPO2) measurements have become a standard method for a monitoring arterial PO2 of patients with cardio-respiratory problems. Direct heating of a silver/silverchloride anode induces a local hyperemia of the skin, which permits measurements of PO2 on the skin surface polarographically. This technique has been applied recently to quantify skin variability in peripheral arterial occlusive disease, to predict the optimal amputation level or skin transplant survival. However, so far local capillary morphology could not be correlated to tcPO2 data. The purpose of the newly developed electrode was to abolish this disadvantage and to be able to correlate capillary morphology and distribution to local tcPO2 by means of videomicroscopy or dynamic fluorescence videomicroscopy. The middle part of the new electrode consists of a glass cylinder (diameter 4.5 mm) and only one 15 micron Platinum cathode, which provides a negligible O2-consumption of the electrode itself (approx. 5.5 x 10(-3) mmHg/min). The careful optical grinding of the glass cylinder gives a good transparency for observing the capillaries through the incident light microscope of the videomicroscopy system. The electrode is covered by a 25 micron Teflon membrane, which also constitutes no essential optical barrier. By focusing at the tip of the Platinum cathode and the adjacent capillaries the distance between both objects or the intercapillary distance can be measured. The new combined system of transcutaneous PO2 measurements and simultaneous videomicroscopy has great potential as a practical method to provide new insights into local skin oxygen supply and the local microcirculatory flow distribution and capillary morphology.

Capillaries↗
PubMed1981

Distribution of observed patterns in fetal transcutaneous oxygen tension.

The interaction between intrauterine pressure, fetal heart rate, and fetal transcutaneous oxygen tension (tcPO2) may be classified into 10 pattern types. Eight of them indicate the reduction in fetal tcPO2 caused by uterine contractions and by fetal heart rate decelerations. Two pattern types show the effect of stasis and of pressure resulting in decreased fetal tcPO2. In 32 recordings from Uppsala, Sweden, and 11 from Zurich, Switzerland, 1,161 contractions were analyzed. A similar distribution of the patterns was found in the two hospitals in uncomplicated deliveries in the first stage of labor. In 15% of the contractions in the first stage of labor, fetal tcPO2 was affected by stasis or pressure, whereas this occurred in 48% of the 265 contractions in the second stage of labor. Thus, in most instances, fetal tcPO2 should be expected to give reliable information in the first stage, whereas the stasis and the pressure pattern must be recognized for the evaluation of fetal tcPO2 in the second stage of labor.

Female↗