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Biomedical subjects

A Huch

Publications and source records attributed to A Huch.

At least 181 records · Page 10Linked to original sources
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↗
PubMed1981

In vivo oxygen dissociation curve for whole fetal blood: fitting the Adair equation and blood gas nomogram.

Oxygen tension, oxygen saturation of haemoglobin, plasma pH and carbon dioxide tension were analysed from 436 blood samples of the umbilical arteries and umbilical vein and 33 blood samples obtained by puncture of the arteria radialis of newborn younger than one day. A computer was used to fit the data to the Adair equation, and to calculate the pH-and Pco2-shift of the oxygen dissociation curve. The results were translated into a Po2-So2-pH-Pco2-nomogram.

Blood Gas Analysis↗
PubMed1981

Comparison of continuous transcutaneous Po2 measurement with intermittent arterial Po2 determinations in fetal lambs.

This study determined the validity of transcutaneous Po2 (tcPo2) versus Pao2 determinations in the sheep fetus. In 7 fetal lambs catheters were placed in the carotid artery and the trachea, and ECG leads and a tcPo2 electrode were attached. Intermittently determined Pao2 values were compared to continuously recorded tcPo2 values. Fetal tcPo2 values ranging from 12 to 29 mmHg were achieved by changing the gas mixture the ewe breathed or by inflation of a balloon catheter in the maternal aorta. Transcutaneous Po2 correlated strongly with Pao2 (r = .91). These studies indicate that the tcPo2 electrode precisely and accurately reflects Pao2 in the fetal lamb. Limitations of tcPo2 measurements regarding prolonged attachment of the electrode to the fetal skin as well as fetal skin tolerance to the heat of the electrode have been identified. With this electrode the changes in oxygen tension can be compared with changes in fetal cardiovascular variables, eg, heart rate, blood pressure, and ECG, for a better understanding of the effects of hypoxemia on the fetus.

Animals↗