Biomedical subjects

R Huch

Publications and source records attributed to R Huch.

257 records · Page 15Linked to original sources

PubMedDate not supplied

A triple electrode for simultaneous investigations of transcutaneous oxygen tension, laser-Doppler flowmetry and dynamic fluorescence video microscopy.

A newly designed triple probe is introduced for measurements of transcutaneous oxygen tension, laser Doppler flowmetry (LDF) and microangiodynamics of skin capillaries by dynamic video microscopy with and without fluorochromes. The performance of the triple probe was checked in 9 healthy volunteers (6 women, 3 men; mean age: 34 years) and 9 patients (5 women, 4 men; mean age: 67 years) with peripheral arterial occlusive disease (PAOD). The mean Doppler ankle/arm pressure ratio was 0.54 +/- 0.30. Six patients suffered from severe claudication, 2 from rest pain and 1 patient had toe and forefoot necrosis. The foot dorsum was selected as measuring site. After recording baseline values of skin surface PO2 (ssPO2) at 37 degrees C, LDF and capillary images, a suprasystolic compression at the ankle level was performed for 4 min. Thirty seconds before cuff opening 0.2 ml/1 l blood volume of 20% sodium fluorescein was injected in an antecubital vein. Sodium fluorescein arrival times, filling times and maximum fluorescent light intensity times were measured, and ssPO2 and LDF were recorded continuously during postocclusive reactive hyperemia (PORH). The results indicate an adequate function of the triple probe. The mean resting ssPO2 was 2.0 +/- 1.9 mm Hg in PAOD patients and 4.0 +/- 3.9 mm Hg in controls (p = 0.185). Maximum ssPO2 during PORH was significantly reduced (p = 0.008) in patients (3.1 +/- 2.1 mm Hg) compared to healthy subjects (11.8 +/- 7.7 mm Hg). Resting LDF values were 6.5 +/- 6.4 perfusion units (PU) in PAOD patients versus 10.3 +/- 8.2 AU in controls (p = 0.295). Peak LDF during PORH was significantly reduced (p = 0.005) in patients (19.5 +/- 6.4 PU) versus healthy subjects (33.8 +/- 11.5 PU.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Doppler sonographic determination of specific hemodynamic changes in fetal circulation during the last four weeks before birth].

The observation of characteristic flow changes measured by Doppler ultrasound in the fetal descending aorta a short time before delivery led us to systematically analyse our measurement data. For the retrospective analysis, records with a total of 115 measurements taken in the last four weeks prior to spontaneous onset of labour from 90 women with normal pregnancies were used. For each of the four weekly periods there were between 15 and 50 measurements. Both qualitative and quantitative flow parameters were evaluated. The findings showed: 1. No significant changes in the blood flow characteristics of the uteroplacental and fetoplacental vessels; 2. A clear widening of the diameter of the aorta; 3. A decrease in the mean flow velocity in the descending aorta; 4. A steep decrease in maximum velocity during late systole, sometimes so pronounced that a notch in the flow envelope was observed. The time when the changes occurred was found to be 2 weeks prior to spontaneous onset of labour. These changes in the fetal circulation, which can be called "term effect", occur along with other developments taking place towards the time of birth. They are probably related to the beginning of spontaneous contractions and indicate an adaptation to the changing supply conditions occurring a few days before the onset of labour.

Aorta, Thoracic↗

PubMedDate not supplied

[Doppler ultrasound studies before and following short-term maternal stress in late pregnancy].

Ten gravidae with normal course of pregnancy in the third trimester underwent a bicycle stress test (semi-supine, 75 W, 3 min). By means of pulsed Doppler sonography, a lowering of the resistance index (RI) in the maternal femoral artery from 93% to 69% was ascertained, though also a rise in maximum systolic velocity (VMAX (syst)) from 73 cm/sec to 194 cm/sec, in maximum diastolic velocity (VMAX diast)) from 5 cm/sec to 61 cm/sec, and in the time-averaged maximum velocity (TAVMAX) from 20 cm/sec to 101 cm/sec. These changes are statistically significant. In the maternal common carotid artery these parameters remained stable or changed little, for example VMAX (diast), which dropped from 24 cm/sec before to 19 cm/sec after exercise, and the RI, which rose from 77% to 84%. Neither in the uteroplacental vessels nor in the umbilical artery were any changes in the RI found (40% to 42% and 58% to 57%, respectively). The fetal cardiotachograms were normal in all cases, while not all cases manifested a rise in fetal heart rate following maternal stress. These results indicate that uteroplacental perfusion and the umbilical circulation remain constant. Doppler sonography thus demonstrates directly and noninvasively that provided placental function is normal the uteroplacental and fetoplacental circulation are not influenced by moderate physical exertion.

Blood Flow Velocity↗

PubMedDate not supplied

[Is orthostatic circulatory regulation more difficult in multiple pregnancy? Results of a prospective longitudinal study].

In 7 multiple pregnancies the changes in maternal and fetal cardiac-circulation parameters resulting from a passive change in presentation from left lateral to steady upright were measured for the duration of pregnancy and the puerperium and compared with corresponding data from a single-fetus collective. The hypothesis that in multiple pregnancies the greater uterine contents lead to more severe problems of return flow from the lower extremities, and that these problems tend to lead a more pronounced form of uterovascular syndrome, was confirmed on the basis of the physiological data. The fact that the uterine contractions usually correlate with the maternal cyclic heart rate accelerations and peak toward the end of the third trimester of pregnancy supports the view that these contractions play a role in regulating circulation.

Blood Pressure↗

PubMedDate not supplied

[Kinetocardiotocography--KCTG--during pregnancy in an ambulatory care patient sample and in hospitalized patients with special reference to tocolysis].

With kinetocardiotocography (KCTG), fetal movements can be registered parallel to the fetal heart rate. Hewlett Packard equipment of the series 1350 A allows the movements to be registered an quantified on the CTG paper. In this study, hospitalized pregnant women > 26 gestational weeks (GW) on i.v. tocolysis, and out-patients > 34 GW at the out patient department were examined with KCTG and the results compared. A wide distribution of fetal activity was seen in both groups. With advancing pregnancy, the number of fetal movements as well as the duration of activity per time unit decreased, whereas the length of time of individual movements slightly increased, in both groups. No statistically significant difference was seen between different gestational ages nor between the two groups. KCTG is being increasingly used to monitor the fetal condition, especially for risk pregnancies. It can provide additional information in the form of a biophysical variable.

Adult↗