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Biomedical subjects

W Gogarten

Publications and source records attributed to W Gogarten.

27 records · Page 2Linked to original sources
PubMed1997

[Obstetrical pain therapy].

Until today, the use of epidural analgesia in obstetrics still remains controversial. In the opinion of many obstetricians the use of an epidural for a healthy laboring parturient is not necessary and can lead to potentially harmful side effects. However, painful labor leads to a maternal stress reaction with the release of epinephrine and norepinephrine. The resulting vasoconstriction of uterine arteries can induce fetal asphyxia in an otherwise healthy fetus or can aggravate asphyxia in already compromised fetuses. Several studies show that epidural analgesia can attenuate the maternal stress reaction and thereby improve maternal and fetal well-being, as long as precautions are taken. The avoidance of maternal hypotension with sufficient volume preload with lactated Ringer's solution or colloids, and decreasing the concentration of local anaesthetics by adding opioids will prevent an increase in instrumental deliveries. With the use of patient-controlled epidural analgesia (PCEA) the amount of local anaesthetics can even further be reduced.

Analgesia, Epidural↗
PubMed1997

[Risks and complications following peridural anesthesia].

Postoperative neurological sequelae in patients that have received epidural anaesthesia are not necessarily caused by the epidural anaesthetic technique. As a whole, adverse neurological outcomes following epidural anaesthesia may be subdivided into 3 different ethiological categories. A first category involves events that are not at all caused by the epidural, but merely due to the interference of anaesthesia and/or surgery with a preexisting medical condition. A second category includes mishaps such as backache, arachnoiditis, and post-dural puncture headache that are solely due to the epidural anaesthesia. Finally, epidural anaesthesia may be a contributory factor in the development of post-anaesthetic complications attributable to a pre-existing medical condition that are triggered by anaesthesia, surgery or childbirth. These complications include some of the most dramatic sequelae of major neuraxial blockade, such as spinal epidural abscess, spinal infarction, and spinal hematoma. Although extremely rare, the latter complications often result in permanent major neurological deficits. The present manuscript is a review of the most recent, literature addressing post-anaesthetic sequelae, and will discuss their incidence, pathophysiology, clinical course, diagnosis, prevention, and treatment.

Anesthesia, Epidural↗
PubMed1994

Effect of acute Yersinia enterocolitica infection on intestinal barrier function in the mouse.

BACKGROUND: Yersinia enterocolitica is an important cause of diarrhea, but little is known about the underlying mechanisms. We therefore studied the impact of acute Y. enterocolitica infection on intestinal barrier function in a mouse model. METHODS: For this purpose CD-1 mice were infected with Y. enterocolitica (serotype 08; 6 x 10(7) viable bacteria), and alternating current impedance analysis was performed on days 1, 2, 3, 5, and 8 after infection. RESULTS: The infection resulted in a decrease in epithelial resistance from 18.0 +/- 0.9 omega.cm2 (controls) to 12.1 +/- 0.5 omega.cm2 (day 1, p < 0.001), from which the animals recovered by day 5. To locate this loss in barrier function, the horizontal distribution of local conductances was measured by voltage scanning, yielding two results. First, conductance was homogeneously distributed across the chamber area, excluding erosions or ulcers among the gross surface area and favoring tight junction opening as the source of barrier dysfunction. Second, the conductance of villus tips was compared with that of the intervillus region (consisting of lateral villus walls plus crypts). On day 1 the former was increased by 74% and the latter by 18%. Then, two other mechanisms of diarrhea were tested, namely malabsorption and secretion. First, the increase in ISC after the addition of 3-O-methylglucose, representing Na(+)-glucose cotransport, was shown not to be impaired. Second, bumetanide-inhibitable ISC, representing electrogenic Cl- secretion, also did not differ between controls and infected animals. CONCLUSIONS: Our data show that epithelial barrier dysfunction plays a role in Y. enterocolitica infection, while Na(+)-glucose cotransport and electrogenic Cl- secretion are unaltered.

Acute Disease↗
PubMed1993

Epithelial ion transport in the ileal J-pouch after proctocolectomy in the rat.

In ulcerative colitis and polyposis coli, creation of an ileal pouch with ileoanal anastomosis after proctocolectomy has become a common surgical method. The aim of our study was to characterize the adaptation of the epithelial ion transport function in the pouch by using electrophysiologic techniques. Proctocolectomy and ileoanal anastomosis was performed in rats either with (pouch) or without (control) creation of an ileal J-pouch. To characterize the epithelial barrier function, impedance analysis was performed 6 months after surgery. Epithelial resistance was 29 +/- 2 omega.cm2 in controls and was unchanged in the pouch (28 +/- 4 omega.cm2; NS). In contrast, subepithelial resistance increased from 33 +/- 3 omega.cm2 to 54 +/- 5 omega.cm2 (P < 0.01) owing to work hypertrophy of the muscle layers in the pouch. To detect changes in net ion transport, ion tracer fluxes were measured in the Ussing chamber. In control ileum, absorptive net Na and Cl fluxes of similar magnitude were present, indicating that electroneutral NaCl absorption was the predominant ion transport system. Neither Isc nor net Na and Cl fluxes were significantly altered in the pouch. Glucose-coupled Na absorption was measured as the 3-o-methyl-glucose-induced increase in Isc. Km remained unaltered, while Vmax decreased from 7.5 +/- 2.1 mu eq.h-1 cm-2 in controls to 1.7 +/- 0.8 mu eq.h-1 cm-2 (P < 0.05) in the pouch. Then, maximal transport capacity for electrogenic Cl secretion was measured as the Cl-induced increase in Isc blockable by serosal bumetanide (in the presence of theophylline and prostaglandin E1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMedDate not supplied

Simultaneous in utero assessment of AV nodal and ventricular electrophysiologic parameters in the fetal sheep heart.

BACKGROUND: Fetal tachyarrhythmias are usually of supraventricular origin. To investigate whether specific electrophysiologic properties of the fetal heart contribute to this preponderance by either favoring supraventricular tachycardias or by rendering ventricular tachycardias unlikely, we measured fetal electrophysiologic parameters in utero using transuterine fetal transesophageal electrocardiograms in fetal sheep. Since overdrive pacing may help to establish the mechanism of an arrhythmia and may be used to treat fetal tachycardias, different modes of transesophageal pacing in utero were also assessed. METHODS AND RESULTS: Decapolar electrophysiology catheters were fetoscopically inserted into the esophagus of 9 fetal sheep (pregnancy duration 94- 105 days, term = 145 days). Electrocardiograms were recorded simultaneously from all adjacent bipoles and from two pacing wires sutured onto the fetal shoulders. Pacing was attempted either via two adjacent electrodes of the intraesophageal catheter or via the most distal and most proximal electrode. Fetal cycle length, PQ, and QT intervals were close to (approx. 75 %), but fetal QRS duration was < 20 % of maternal values, thus shifting the relation between activation and repolarization towards longer excitation wave lengths. Fetal QT dispersion was small (< or = 10 ms). Atrial pacing was achieved in all fetuses using distant electrodes, and with lower thresholds when compared to closely spaced bipolar electrodes (p < 0.05). CONCLUSIONS: (I) An altered relation between ventricular activation and repolarization and a low dispersion of ventricular repolarization may protect the fetal heart against ventricular reentrant tachycardias. (II) Relatively normal fetal AV nodal conduction delay already provides one of the prerequisites for supraventricular reentrant tachycardias involving the AV node at this stage of fetal development. (III) High-rate esophageal pacing of the fetal atria is best achieved using widely spaced bipolar pacing electrodes.

Animals↗
PubMedDate not supplied

Effects of cafedrine/theodrenaline, etilefrine and ephedrine on uterine blood flow during epidural-induced hypotension in pregnant sheep.

INTRODUCTION: Maternal hypotension is a major concern in obstetric anesthesia, and concerns have been raised about standard vasopressor therapy with ephedrine. Therefore, we evaluated the maternal and fetal hemodynamic effects of two potential alternatives to ephedrine. METHODS: Hypotension was induced by epidural administration of lidocaine in 6 chronically instrumented pregnant ewes (at 118-122 days of gestation, term 145 days). Three treatments were studied: 25 mg ephedrine, 5 mg etilefrine and 100 mg cafedrine/5 mg theodrenaline (C/T) intravenously. Mean fetal and maternal blood pressure and heart rate, uterine blood flow, as well as fetal and maternal arterial blood gases were recorded for 60 min. RESULTS: All three vasopressors increased maternal blood pressure, accompanied by a significant increase in uterine blood flow. C/T caused marked maternal tachycardia, whereas ephedrine decreased maternal heart rate. Maternal and fetal blood gases did not change during any of the three treatment regimens. CONCLUSION: All three vasopressors restored maternal blood pressure and uterine blood flow after epidurally induced maternal hypotension. However, restoration of uterine perfusion was delayed and less pronounced with C/T.

Acid-Base Equilibrium↗