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Biomedical subjects

Wiebke Gogarten

Publications and source records attributed to Wiebke Gogarten.

16 recordsLinked to original sources
PubMed2006

The influence of new antithrombotic drugs on regional anesthesia.

PURPOSE OF REVIEW: Antithrombotic drugs are known to increase the risk of spinal epidural hematoma after neuraxial blockade. During the last few years, several new anticoagulants have been introduced, some of them more potent than the drugs currently available. More potency, however, may also indicate a higher risk of bleeding. RECENT FINDINGS: Case series from the last few years indicate that spinal epidural hematoma is more common then previously estimated, with a prevalence from 1: 100,000 in obstetric patients to as high as 1: 3,600 in female orthopedic patients. In order to diminish this risk, most national societies have issued guidelines in which time intervals were established between administration of antithrombotic drugs and performance of neuraxial blockade. SUMMARY: Guidelines are perceived to be capable of reducing the incidence of spinal epidural hematoma with the inherent risk of permanent paraplegia. These guidelines, however, will only be a valuable aid for clinicians if they are constantly updated and newer antithrombotic drugs are included. Although the resurge of peripheral nerve blocks may diminish patient hazards, deep nerve blocks such as lumbar sympathetic blockade are not devoid of serious complications and should probably be handled in the same way as neuraxial blockade.

Adenosine Diphosphate↗
PubMed2006

Percutaneous fetoscopic patch coverage of spina bifida aperta in the human--early clinical experience and potential.

OBJECTIVE: The current operative approach for fetal repair of spina bifida aperta requires maternal laparotomy and hysterotomy. Following technical feasibility studies in sheep, we performed percutaneous fetoscopic patch coverage of this lesion in 3 human fetuses between 23 + 4 and 25 + 3 weeks of gestation. METHODS AND RESULTS: Whereas the patch detached in the first case 3 weeks after the procedure, it covered the exposed neural tissue in the 2 other fetuses beyond their delivery. Two of the three children survived, but 1 unexpectedly died from a ventilation problem in its 3rd week of life. In 1 of the 2 survivors, ventriculoperitoneal shunt insertion was delayed. CONCLUSIONS: Percutaneous fetoscopic patch coverage of spina bifida aperta is feasible in human fetuses and offers a substantial reduction of maternal trauma compared to open fetal repair. Further clinical experience is now required before the efficacy of the new approach to protect the exposed neural tissue from mechanical and chemical damage and to improve hindbrain herniation can be evaluated.

Aborted Fetus↗
PubMed2005

Maternal cardiac disease.

PURPOSE OF REVIEW: An estimated 0.5-4% of pregnant patients have cardiac disease, such as rheumatic disease, which is decreasing in Western countries, uncorrected congenital heart disease, cardiomyopathy and ischaemic heart disease. There has been an increase in maternal mortality due to cardiac causes. Congenital heart disease is becoming the most common source of cardiac problems in the pregnant patient, because patients are increasingly likely to survive to childbearing age with the improvement of surgery. RECENT FINDINGS: The increasing age of patients conceiving their first child is also an important factor. A comprehensive understanding of the physiology of pregnancy and the pathophysiology of maternal cardiac disease is of great importance for anaesthesiologists, gynaecologists and cardiologists involved in peripartum care. SUMMARY: We try to give a brief and comprehensive review on this topic.

Journal Article↗
PubMed2004

Amniotic air insufflation during minimally invasive fetoscopic fetal cardiac interventions is safe for the fetal brain in sheep.

BACKGROUND: Amniotic air insufflation during experimental fetoscopic fetal cardiac interventions greatly improves the visualization of intra-amniotic contents. The purpose of this study was to assess any histologically discernible effects from this approach on the fetal brain after short-term studies and long-term survival in sheep. METHODS: Thirty pregnant ewes between 80 and 110 days of gestation underwent amniotic air insufflation during various fetoscopic fetal cardiac interventions. After 18 short-term and 12 long-term studies, the brains of the operated fetuses and-if available-their unoperated siblings were examined for hemorrhage, embolism, infarctions, inflammatory changes, and abnormal cortical maturation. RESULTS: Amniotic air insufflation during minimally invasive fetoscopic fetal cardiac interventions did not result in any histologically discernible damage to the brain in short-term and long-term studies in any but 2 sibling sheep. In the 2 affected siblings, a small area of chronic cortical frontal lobe infarction was observed after long-term survival. CONCLUSIONS: Amniotic air insufflation during minimally invasive percutaneous fetoscopic fetal cardiac interventions is safe for the fetal brain and does not compromise maternal hemodynamics in sheep. These findings encourage further investigation of the role this technique might play during fetoscopic fetal cardiac interventions in humans.

Amnion↗
PubMed2004

Fetal surgery, anaesthesiological considerations.

PURPOSE OF REVIEW: Refined techniques and skills have enabled sophisticated prenatal diagnosis in utero and resulted in the newly evolving specialty of fetal surgery in a few centres worldwide. Most of the procedures performed today have been preceded by extensive experimental research in animals, whereas fetal anaesthesia is mainly based on clinical experience and a few studies performed in pregnant sheep. RECENT FINDINGS: Major limitations of fetal surgery include the high frequency of preterm labour and delivery which may offset any fetal benefit of the surgical procedure. The development of more potent tocolytic drugs than the drugs currently available may thus be compared to the meaning of potent immunosuppressive agents in organ transplantation. Fetal mortality and maternal morbidity consequently lead to a more cautious way of treatment, as with the development of endoscopic fetal surgery. SUMMARY: The invasive fetal surgery is still considered as being in a research stage in most cases. Therefore most procedures are performed as minimally invasive, avoiding substantial risks by accessing the uterus through minimal openings. Some new devices are under investigation for monitoring the myometrial electrical activity and mechanical contractility and the fetal electroencephalogram, the continuous monitoring of the fetal arterial oxygen saturation, PO2 and PCO2, and for monitoring fetal cerebral oxygenation, blood volume and blood flow by near infrared spectroscopy.

Journal Article↗
PubMed2004

The effects of S+-ketamine and racemic ketamine on uterine blood flow in chronically instrumented pregnant sheep.

UNLABELLED: Ketamine could be a useful maternal analgesic in obstetric surgery, as it might avoid the need for opioid administration and associated side effects in the newborn. Racemic ketamine passes the placental barrier and has oxytocin-like properties but does not seem to affect uterine blood flow (UBF). S(+)-ketamine was recently approved for clinical use, but its effects on UBF have not been evaluated. Therefore, we studied the effects of S(+)-ketamine on maternal and fetal hemodynamic variables. Equianalgesic doses of S(+)-ketamine (10 mg.kg(-1).h(-1)) or racemic ketamine (20 mg.kg(-1).h(-1)) were infused in 12 chronically instrumented pregnant sheep. Maternal and fetal vital signs, blood gases, and UBF were recorded over 120 min. Neither compound affected uterine perfusion or maternal and fetal hemodynamics. Whereas racemic ketamine increased maternal (+19%) and fetal (+11%) PCO(2) significantly, S(+)-ketamine was without effect. However, both compounds significantly decreased maternal (racemic, -0.05; S(+), -0.03) and fetal (racemic, -0.06; S(+), -0.02) pH. The effects of racemic ketamine and S(+)-ketamine on uterine perfusion are similar, and because of its limited effect on hemodynamics and respiration, S(+)-ketamine might therefore be of interest as an analgesic in the obstetric setting. IMPLICATIONS: The effects of S(+)-ketamine on uterine perfusion and maternal/fetal hemodynamics are similar to those of the racemic mixture in chronically instrumented pregnant sheep. A decreased effect of S(+)-ketamine, as compared with the racemic mixture, on maternal and fetal PCO(2) levels was noted.

Acid-Base Equilibrium↗
PubMed2003

Spinal anaesthesia for obstetrics.

For a long time, epidural anaesthesia has been considered the method of choice for Caesarean delivery. The increased incidence of hypotension by the rapid onset of sympathetic blockade under spinal anaesthesia has been associated with a decline in uteroplacental blood flow and significant fetal acidosis, which may compromise neonatal well-being. Nevertheless, a decrease in fetal pH has not been shown to reduce neonatal Apgar or neurobehavioural assessment scores. Maternal blood pressure can be preserved with little side effects with low doses of vasopressors. On the other hand, spinal anaesthesia conveys significant advantages over epidural anaesthesia such as the simplicity of its use and the speed of onset, which allows neuraxial anaesthesia in urgent Caesarean sections and thus reduces the necessity for general anaesthesia. The small doses of local anaesthetics required to perform spinal anaesthesia reduce the risks of systemic toxicity to zero. Spinal anaesthesia is now considered the method of choice for urgent Caesarean section. The use of intrathecal opioids has profoundly changed the quality of spinal anaesthesia, with improved analgesia, a reduction in local anaesthetic requirements and shorter duration of motor blockade. Preliminary studies indicate that spinal anaesthesia may be safely performed in patients with severe pre-eclampsia, in whom spinal anaesthesia was previously considered contraindicated.

Anesthesia, Obstetrical↗
PubMed2003

Tumor necrosis factor alpha stimulates adenylyl cyclase activity in human myometrial cells.

Cytokines such as tumor necrosis factor alpha (TNFalpha) have been implicated in amniotic fluid infections and preterm and term labor. The underlying mechanisms are incompletely understood. In some smooth muscle cells, TNFalpha affects function of the beta-adrenergic/adenylyl cyclase pathway. The present study was performed to examine the effects of chronic TNFalpha exposure on adenylyl cyclase activity in cell cultures of human myometrium. Chronic TNFalpha exposure led to a dose- and time-dependent increase in basal-, GTP-, NaF-, and forskolin-stimulated adenylyl cyclase (AC) activity. The increase in AC activity was not mediated by changes in the expression of the heterotrimeric G proteins G(s)alpha or G(i)alpha as determined by immunoblotting. In addition, increases in AC activity occurred in the presence of indomethacin, indicating that these changes were not provoked by TNFalpha-induced changes in prostaglandin production. The present results suggest that TNFalpha-induced increases in AC activity in human myometrial cells obtained from the lower uterine segment occur at the level of G-protein/AC interaction or at the level of the AC enzyme itself.

Adenylyl Cyclases↗
PubMed2003

Fetal plasma concentrations after intraamniotic sufentanil in chronically instrumented pregnant sheep.

BACKGROUND: Rapid progress is being made in fetal surgery. Because the fetus is capable of pain perception after the 26th week of gestation, adequate postoperative fetal pain management is essential. The preferred approach would provide fetal analgesia without affecting the mother. Intraamniotically administered sufentanil may be an interesting option if it achieves therapeutic plasma concentrations (PCs) in the fetus but not the mother. METHODS: After approval of the study, 25 or 50 microg sufentanil was administered intraamniotically in 10 chronically instrumented pregnant ewes. Maternal and fetal vital signs, arterial blood gases, and uterine blood flow were recorded over 120 min. Sufentanil PCs were determined before and 1, 3, 5, 10, 15, 30, 45, 60, 90, and 120 min after injection. Statistical analysis was performed using one- or two-way analysis of variance followed by Dunnett or Tukey test, as appropriate (P < 0.05; data presented as median [95% confidence interval]). RESULTS: After 25 microg sufentanil, fetal PC stabilized at 134 +/- 89 pg/ml (after 10 min), and maternal PCs stabilized at 44 +/- 11 pg/ml (after 15 min). After 50 microg sufentanil, fetal PCs stabilized at 134 +/- 35 pg/ml (after 15 min), and maternal PCs reached 80 +/- 25 pg/ml (at 30 min). Injection of 25 microg sufentanil intraamniotically did not affect maternal or fetal hemodynamics, uterine blood flow, or arterial blood gases. Fetal heart rate increased after administration of 50 microg sufentanil (maximum change at 10 min: +16 +/- 12%). CONCLUSION: The sheep fetus absorbs sufentanil after intraamniotic instillation. Significantly greater PCs were obtained in the fetal lamb as compared with the ewe. This suggests that investigation of intraamniotic opioids for fetal analgesia might be worthwhile.

Amnion↗
PubMed2002

Intra-amniotic multimodal fetal echocardiography in sheep: a novel imaging approach during fetoscopic interventions and for assessment of high-risk pregnancies in which conventional imaging methods fail.

During fetoscopic interventions, intraesophageal placement of intravascular ultrasound (US) catheters for fetal hemodynamic monitoring may result in esophageal injury in very small fetuses. Moreover, conventional fetal imaging by the transvaginal or transabdominal routes may be impossible in some high-risk pregnancies. The purpose of our study in sheep was to assess the potential of a phased-array intravascular US catheter for intra-amniotic fetal echocardiography. The catheter was percutaneously inserted into the amniotic cavity in seven pregnant ewes at between 78 to 98 days of gestation and permitted high-quality 2-D imaging of the fetal heart and multimodal Doppler assessment of fetal cardiovascular flows. Fetoscopic examination of intra-amniotic contents after intra-amniotic imaging was finished did not display any injury to intra-amniotic contents. The intra-amniotic imaging approach may provide an effective alternative in humans for monitoring during fetoscopic interventions, and to assess fetal anatomy and hemodynamics in high-risk pregnancies when sufficient images cannot be obtained by conventional routes.

Amniotic Fluid↗
PubMedDate not supplied

Pediatric assist with the Medos and Excor systems in small children.

Pediatric long-term ventricular support with paracorporeal assist devices is performed in only a few institutions. We report on our experience with two pediatric paracorporeal devices, which have been implanted in neonates, infants, and small children. Seven children with ages ranging from 2 weeks to 6 years and a body weight of 3 to 19 kg were provided with either a Medos or a BerlinHeart System. The underlying heart diseases included dilative cardiomyopathy (n = 3), endocardial fibroelastosis (n = 2), Ebstein anomaly, and status post redo aortic valve replacement (n = 1). All children were in New York Heart Association class IV and were inotrope dependent. Three children were provided with a Medos system and 4 children with a BerlinHeart Excor device. In 6 cases, left ventricular support, and in 1 case, right ventricular support was performed. All patients were stabilized with univentricular mechanical support. The perioperative course was uneventful, and end-organ function was well recovered. Reexploration for bleeding and evacuation of mediastinal blood clots was necessary in all three neonates but not in any of the older infants. Severe thromboembolic events were only noticed in the neonates. Successful bridge to transplantation was performed in 6 of the 7 patients (87.5%). Our late results have been quite encouraging, as they readily prove that pediatric long-term mechanical support is possible with a high quality of life and an acceptable low complication rate.

Cardiac Output, Low↗