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Biomedical subjects

E Merz

Publications and source records attributed to E Merz.

At least 19 recordsLinked to original sources
PubMed2005

2D and 3D Ultrasound in the evaluation of normal and abnormal fetal anatomy in the second and third trimesters in a level III center.

Between July 2000 and December 2003, a total number of 3,472 fetuses was evaluated by two-dimensional (2D) and three-dimensional (3D) ultrasonography. All examinations were carried out as part of a detailed level III ultrasound examination for fetal anomalies. The gestational age was between 11 and 35 weeks. A 3D endovaginal probe (5 - 7 MHz) was used for examinations between 11 and 13 weeks, and an abdominal 3D probe (5 MHz) after 13 weeks. Four different 3D image display modes were employed in visualizing fetal malformations: triplanar orthogonal display; surface display; transparent display; and the combined transparent and color display (= glass body-rendering). In 906 of the 3,472 high-risk pregnancies, fetuses with one to five fetal defects were found (mean 1.17). The total number of detected defects was 1,012, exclusive of 48 fetal heart defects. Fetal heart defects were excluded from this study since a reliable demonstration of these defects was not possible by 3D ultrasound. Comparing the 2D and 3D techniques, 3D sonography proved advantageous in 60.8 % of the defects, with the benefit derived from the exact tomographic survey using the multiplanar view in 69.9 % of these cases, from a more precise demonstration of the defect in the surface view in 25.2 %, from a distinct demonstration in the transparent view in 3.9 %, and from a precise demonstration in the combined transparent and color view in 1.0 %. In 42 of the 1,012 malformations (4.2 %), a defect was accurately identified or verified with 3D ultrasound only. 3D ultrasound proves not only a useful tool in appreciating the severity of a fetal defect, but also provides more convincing evidence of a normal fetus than conventional two-dimensional sonograms in cases with increased risk of a recurrent surface malformation.

Congenital Abnormalities↗
PubMed2005

[Transducer hygiene -- an underrated topic?].

Transducers are medical products that are categorized as uncritical, semicritical and critical, depending on their applications and perceived risks. Uncritical medical products are transducers that solely come in contact with the intact skin, such as transducers used for sonography of the abdomen or breast. Semicritical medical products are transducers that come in contact with mucosal membranes or diseased skin, comprising transducers used for transesophageal, transvesical, transvaginal, transrectal and perineal sonography. Critical medical products are transducers that come in contact with blood, internal tissues or organs, such as transducers used for intraoperative sonography. Under the most unfavorable circumstances, sonographic transducers can become contaminated with pathogenic agents (e. g., MRSA, HBV, HCV, HIV, Herpes viruses) and turn into a not to be underrated source of infection. For this reason, correct handling as well as cleaning and disinfection of the transducers are indispensable. Depending on the application, the recommended handling of the transducers differs. Transducers counted to the uncritical medical products are adequately cleaned by removal of the applied ultrasound gel with subsequent wipe disinfection (e. g., foam spray). Transducers counted to the semicritical medical products, such as transvaginal or perineal transducers , should be exclusively used after a suitable cover has been applied. A Latex(R) allergy must be excluded before the examination. The cover is to be disposed after completion of the examination and the transducer itself cleaned and disinfected. The disinfecting agent must be antiviral but also compatible with the material (caution: damage to the transducer membrane when using an unsuited alcoholic disinfecting agent). In case of rupture of the protecting cover during the examination, the transducer is considered contaminated with secretion or even blood and must be thoroughly cleaned with subsequent disinfection, whereby ample contact time must be allowed for the disinfecting agent. Coarse contamination of the transducer should be removed with disposable tissue. Above all, dried blood spots should be avoided. Intraoperatively used transducers (= critical medical products), which, for instance, come in contact with abdominal organs, are subject to applicable rules and regulation for cleaning and disinfection. Before each use, an adequately long sterile cover must be placed over the transducer and connecting cable. When the examination is completed, the cover is removed and discarded, and the transducer cleaned and disinfected. The applicability of a reusable medical product implies that each manufacturer is obligated to provide care instruction, including formulated instructions for cleaning and disinfection. This entails that each manufacturer of sonographic equipment must make available a detailed summary of the appropriate disinfectants suitable for the respective transducers. Customarily, recommendations for care and cleaning of the transducers can be found in the manual that comes with the sonographic unit. In the absence of such a manual, a written request should be sent to the manufacturer of the sonographic equipment. Sonographic equipment manufacturers and disinfectant producers prefer disinfecting agents for instruments that are based on glutaraldehyde, aldehydes and quaternary agents, mostly for reason of material compatibility rather than their anti-infective effectiveness. Most recommended disinfectants are not tested for antiviral properties, but this is obligatory when applied to transducers that enter a body cavity potentially harboring a virus load - regardless whether the work is done with protective cover . Further information about the topic "medical products" can be found in the guidelines for hospital hygiene and infection prevention published by the Robert Koch Institute (Section: Required Hygienic Standards for Medical Products ), the website of the Robert Koch Institute for hospital hygiene control and the Rules and Regulation for Medical Products Distributors .

Communicable Disease Control↗
PubMed2004

[Introital and perineal sonography in diagnosing stress urinary incontinence - possible clinical applications].

Urogynecological ultrasound as a part of the diagnostic work-up of stress urinary incontinence enables the morphologic and dynamic assessment of the lower urinary tract and has replaced radiography in the primary diagnostic work-up of stress urinary incontinence. It is possible to classify the sonographically identified changes of the endopelvic fascia, whereby any dynamic changes must be interpreted in context with the clinical findings. Stress urinary incontinence, besides voiding dysfunction, recurrent urinary tract infections and dyspareunia, may be associated with urethral diverticula, which can be detected by ultrasound. Postoperative voiding problems, de novo urgency or recurrent urinary tract infections can be assessed by demonstrating possible causes, such as haematomas, overcorrection with postvoid residual, misplacement of the tape at the level of the bladder neck or intravesical displacement of suture or tape material. Introital and perineal ultrasound might also be used for monitoring the proper placement of sutures to reduce postoperative complications.

Female↗
PubMed2001

Familial fatal fetal cardiomyopathy with isolated myocardial calcifications: a new syndrome?

We describe three male sib fetuses with isolated myocardial calcifications resulting in intrauterine fetal death (IUFD) as early as the second trimester. No evidence for an underlying mitochondrial cytopathy, dystrophinopathy or myopathy was found. There were no signs of inflammation or a metabolic disorder, and the mother had no prenatal exposure of teratogenic drugs. Furthermore, no mutation in the Barth syndrome gene (G4.5) could be detected. Because isolated calcification of the heart and IUFD are not typical of any previously described inherited cardiomyopathy, it may represent a new familial fetal cardiomyopathy.

Calcinosis↗
PubMed2001

Reference values of fetal aortic flow velocity waveforms and associated intra-observer reliability in normal pregnancies.

OBJECTIVES: It was the aim of the present study to calculate new Doppler reference ranges for blood flow velocities (Vmax, Vmean, Vmin) and resistance indices (PI, RI) for the fetal descending aorta by automatic waveform analysis. DESIGN: Cross-sectional prospective study. SUBJECTS: Nine hundred and twenty-six low-risk pregnancies at 18-41 weeks' gestation. METHODS: Aortic blood flow velocities were derived with pulsed-wave color Doppler. Measurements were carried out at the level of the diaphragm. Reference ranges for the individual measuring parameters were constructed based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle. Further investigated were intra-observer reliability and the influence exerted by different measuring sites (aortic arch, diaphragm, below the renal vessels) on the aortic Doppler flow spectrum. RESULTS: Although a significant increase in aortic blood flow velocity was observed at 18-41 weeks' gestation (Vmax = 48.2 cm/s to 110.3 cm/s (P < 0.001), Vmean = 20 cm/s to 47.5 cm/s (P < 0.001) and Vmin = 7.6 cm/s to 18.6 cm/s (P < 0.001)), there were no significant changes in the pulsatility or resistance indices. The resistance indices PI and RI as well as absolute blood flow velocities (Vmax, Vmin) were significantly lower with increasing distance from the heart. Initial decreases were measured between the aortic arch and the diaphragm: PI, 2.34 to 1.87 (P < 0.0001); RI, 0.87 to 0.79 (P < 0.0001); Vmin: 8.5 cm/s to 15.0 cm/s (P < 0.0001). Furthermore, systolic blood flow velocities (Vmax) were decreased below the renal vessels from 97 cm/s to 64 cm/s (P < 0.0007). No significant changes were recorded in intensity-weighted mean flow velocities (Vmean). The intra-observer reliability was low, but of no clinical relevance. CONCLUSIONS: At constant measuring conditions, the reference ranges for blood flow velocities and resistance indices in the fetal aorta calculated by the authors serve as the basis for Doppler ultrasound antenatal examinations in a normal patient population and enable the early diagnosis of fetal risk.

Aorta, Thoracic↗