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Biomedical subjects

W Künzel

Publications and source records attributed to W Künzel.

395 records · Page 22Linked to original sources
PubMedDate not supplied

[Hypotonic symptoms and pregnancy].

To our knowledge there is no study that answers the question, whether low blood pressure itself or the fall of blood pressure during standing have a negative effect on pregnant women. These patients suffer from signs of reduced central and/or peripheral blood flow like fatigue, headache, cold extremities, paresthesia, flickering, black outs and dizziness. In addition, it is of interest whether frequency, occurrence and intensity of these hypotensive symptoms alter during pregnancy. In a longitudinal study 12 hypotensive pregnant women were compared with 13 normotensive and later on in a randomized study 102 clinical healthy pregnant women were tested with a modified orthostatic test over defined time periods during pregnancy. Blood pressure and heart rate were registered in one minute intervals over 30 minute period with an automatic Dinamap measuring device. This period was subdivided in a 10 minutes lying period, 10 minutes standing period followed by a 10 minutes lying period. In addition, the pregnant women were asked about frequency, occurrence and intensity of typical hypotensive symptoms. The frequency of subjective symptoms were related to low blood pressure (p less than 0.001) but not to the fall in blood pressure during standing. The occurrence of different hypotensive symptoms (p less than 0.05) and their intensity (p less than 0.01) were most often in early pregnancy and decreased until term. We conclude that the subjective symptoms were twice as much during early pregnancy than during late pregnancy and were more often in patients with low blood pressure. Furthermore, fatigue, headache and cold extremities occur frequently during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Direct assessment of mesenteric vein compliance in the rat during pregnancy].

This study was designed for two purposes. The first was to establish an in-vitro technique for the comparative study of isolated capacitance veins during pregnancy. Secondly, to test the hypothesis that pregnancy is associated with an increase in venous compliance and the unstressed volume of the veins. Capacitance-size mesenteric veins were mounted in a pressurized myograph system equipped with a video dimension analyzing system and a servo pressure control unit, which was modified for venous studies. After equilibration, the transmural pressure was changed from 2 to 10 mmHg in 2 mmHg increments every 15 minutes. The calculated change in volume over this pressure range consisted of both a change in vessel diameter and in axial length. The veins from the nonpregnant rats exhibited a greater change in axial length than those from the pregnant rats (21% vs. 14%). Unexpectedly, the compliance (change in volume/change in pressure) of the veins from the pregnant rats was significantly less (42%) than those from the nonpregnant rats. However, the basic component of the change in vascular capacitance, the unstressed volume, was significantly greater in the veins from the pregnant rats (100%). We conclude that pregnancy causes alterations in the wall of the capacitance veins, which results in an apparent increase in volume at the expense of wall compliance. Secondly, the pressurized myograph system is a valuable tool for studying the physiology of the capacitance veins during pregnancy under rigorously controlled conditions.

Animals↗
PubMedDate not supplied

[Normalization of fetal heart rate and fetal blood pressure following reduction of uterine blood circulation].

UNLABELLED: To analyze the variability of fetal heart rate (FHR) after a temporary definite hypoxia, uterine blood flow (QUT) was totally reduced in 8 pregnant sheep. In 13 experiments the reduction lasted 60 sec and in 13 further experiments 180 sec. The normalization of FHR after reduction of QUT was compared with the change of fetal blood pressure (BP) and fetal oxygen saturation (SO2). RESULTS: During reduction of QUT the fall of FHR and the decrease of SO2 was significant (r = -0,43, 2 alpha less than 0,05). With the start of normalization there was a temporary correlation between the increase of FHR and the restauration of SO2 after 12-18 sec (r = 0,79, 2 alpha less than 0,001). Thus the initial rise of FHR might be caused by the chemoreceptors. Above all after longer reduction of QUT there were three typical reactions during the recovery period: increase of FHR and BP, short fall of FHR and BP and increase of FHR and continous fall of BP. The start of normalization of FHR after reduction of QUT depends on the restauration of SO2. Because of the variable FHR response it is not possible to describe the duration of the preceding hypoxia.

Animals↗
PubMedDate not supplied

[Obstructive intestinal occlusion in the 3d trimester of pregnancy].

Abdominal pain refractory to analgetics in a II-para of third trimester pregnancy who had been operated on raised suspicion of intestinal obstruction. Diagnosis could only be established by surgical exploration after emptying the uterus by cesarean section, counteracting the even today high mortality of mother and fetus. The value of laboratory, roentgenologic and physical measures especially considering time factor as well as obstetrical management are being discussed.

Adult↗
PubMedDate not supplied

[Fetal shock syndrome].

Fetal hypoxia before and during delivery occurs if a critical limit of uterine and umbilical blood flow is achieved or subsided below that border. As a result of the increased catecholamine secretion a redistribution of blood flow to the different organs of the fetus takes place. The brain, lungs and adrenals are the preferentially perfused organs, whereas the tissues of the kidneys, the skin and other areas have a reduced blood supply. There is, however, no unlimited protective mechanism of the relatively well perfused organs during fetal shock. Brain injuries are dependent on glucose concentration and the arterial blood pressure. The irreversibility of fetal shock is introduced by the development of coagulation disorders and fibrin deposits in the fetal organs, the fall of blood pressure, fetal acidosis and an increased permeability of the blood vessels. Before this state is reached, cardiovascular alterations, changes in acid base status and the continuously measured PO2 take place. These signs should be used to prevent fetal injuries by application of the right measures at the right time.

Acid-Base Equilibrium↗
PubMedDate not supplied

[The uterine contraction stress test with oxytocin nasal spray in the diagnosis of hypoxemia].

Deceleration of the fetal heart rate are indications of fetal distress, which are commonly seen in connection with uterine contractions. The aim of the investigation was, whether nasal application of oxytocin (Syntocinon, Sandoz AG) is sufficient for the induction of contractions for an oxytocin-challenge-test. 232 oxytocin-challenge-tests in 85 risk patients between 29th-42nd week of gestation were analyzed in a retrospective and prospective way. The amounts of oxytocin nasal spray necessary for stimulating contractions were compared to the gestational age and maternal body weight (1 spray snuff = 4 IU Oxytocin). 20 pregnant women were given 8 IU oxytocin nasal spray after 10 minutes CTG-registration without any contractions. The incidence of induced contractions per ten minutes period were calculated. The amount of oxytocin nasal spray necessary for the stimulation of contractions decreased in relation to the increased gestational age and maternal body weight (oxytocin spray = 2.751-0.051 X (gestational age)-0.014 X (body weight), p less than 0.01). After a single application of 8 IU oxytocin nasal spray at least one contraction occurred in 13 out of 20 cases within the first 10 minutes. Between the 20th-30th minute the induced uterine contractions reached a maximum of 3 contractions per 10 minutes. No persisting contractions were observed. The application of 8 IU of oxytocin nasal spray is sufficient to induce in about 95% of the cases an oxytocin-challenge-test which gives information concerning the actual state of the fetus at risk.

Administration, Intranasal↗
PubMedDate not supplied

[Disorders of the fetal oxygen supply during labor--retrospect and prospect of diagnostic possibilities].

Uterine blood flow decreases during uterine contractions. Under physiological conditions there is however an uterine hemodynamic buffer mechanism to guarantee a sufficient oxygen supply to the fetus even during uterine contractions. Heart rate decelerations occur therefore not during the period of cervical dilation but in the second stage of labor. In disorders of pregnancy uterine blood flow is primarily reduced and the slightest uterine contraction exhibits signs of fetal hypoxia, i.e. deceleration of fetal heart rate. Heart rate decelerations signify the possibility of the deterioration of the fetal acid base status. But the degree of fetal acidosis can be estimated only by fetal scalp blood sampling. A valuable tool to predict fetal hazard is to measure the transcutaneous PO2. Numerous hypoxic episodes decrease not only the arterial PO2 but also the skin blood flow which demonstrates a reduced peripheral circulation. This, however, is an indication of severe fetal stress in utero.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Significance of partial pressure and pH value of umbilical venous blood and umbilical arterial blood in the diagnosis of the condition of the newborn infant following early or late cord clamping].

The condition of the newborn at birth is documented by the Apgar score and by the blood gas analysis of the umbilical arterial blood. The question arises whether the estimations are still valid if the cord is clamped late. The investigations have been performed on 20 newborn at term: 10 babies were clamped late and 10 immediately after birth. The blood was analysed from both vessels near the placenta and the child. The pH, base excess, PCO2 and PO2 showed in both groups the expected gradients along the umbilical circulation. There was also no difference of these parameters between the two groups of early (EC) and late (LC) cord clamping: pH LC 7,26 (SD 0.05), EC 7.32 (SD 0,04)), base excess (LC - 7.7 meq/1 (SD 2.3); EC -5.2 meq/1 (SD 5.0)), PCO2 (LC 52 mmHg (SD 7); EC 44 mmHg (SD 6)) and P02 (LC 18 mmHg (SD 3); EC 17 mmHg (SD 3)). From these observations it may be concluded that the start of ventilation does not influence the blood gases in the umbilical vessels of the late clamped newborn. It may be caused by the sudden ceasing of the umbilical circulation at birth.

Acid-Base Imbalance↗
PubMedDate not supplied

[Cord clamping at birth - considerations for choosing the right time (author's transl)].

UNLABELLED: From the historical point of view, cord clamping has been performed in natural child birth some time after the fetus has been delivered and after the expulsion of the placenta. In 1877 already Hayem could show that in late cord clamping (LC) the concentration of erythrocytes in the newborn blood is elevated if compared to early clamping (EC) of the unbilical cord. It was concluded that is was a result of placental transfusion. The underlying mechanism of the placental transfusion is the hydrostatic pressure between the placenta and the fetus, supported by uterine contraction and the time of cord clamping after birth. Placental transfusion is diminished if cord clamping is performed in less than 180 sec and if the newborn baby is positioned 20 cm and more above the placental insertion. The newborn responds to placental transfusion with an increase of hemoglobin and hematocrit, an elevated blood pressure, although significant differences in cardiac output could not be established. Renal function is increased and effective renal blood flow associated with the blood volume of the newborn. In cases of caesarean section a higher incidence of respiratory distress occurs if placental transfusion does not take place. In utero placental transfusion occurs if the fetus is hypoxic obviously to increase the oxygen supply to the fetal tissue. IN CONCLUSION: "In order to give the newborn the blood, that it need physiologically cord clamping should be performed not immediately after birth, but one should wait as long until the umbilical vein has been empty and is collapsed." (Bumm 1902).

Acidosis↗
PubMedDate not supplied

[Behavior of blood pressure and heart rate at rest and during standing in pregnancy].

This study was designed to answer three questions: 1. Is there a change in systolic blood pressure, diastolic blood pressure and heart rate during pregnancy? 2. Are there alterations of these parameters during standing? 3. Is there a relationship between mean arterial blood pressure and heart rate at rest and during standing? In a randomized study 161 clinically healthy pregnant women between 8th and 41st week of pregnancy were tested with a modified orthostatic test over defined time periods during pregnancy. Systolic and diastolic blood pressure and heart rate were registered in one minute intervals over a 30 minute period with an automatic Dinamap measuring device. This period was subdivided in a 10 minutes lying period, 10 minutes standing period followed by a 10 minutes lying period. There was a marked increase in systolic and diastolic blood pressure at rest with the beginning of the 34th week of gestation (p < 0.05 and p < 0.01). Despite this, maternal heart rate continued to rise over the whole course of pregnancy (p < 0.01). Furthermore, women with a fall in heart rate on standing were only seen in late pregnancy. Finally, pregnant women with a low mean arterial blood pressure (< or = 85 mmHg) did not experience a fall in blood pressure on standing more frequently than normal controls (> 85 mmHg). We conclude that a fall in blood pressure on standing is not dependent on blood pressure at rest during pregnancy.

Adolescent↗