Sylvia Lehmann
RWTH Aachen University
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Featured researches published by Sylvia Lehmann.
Acta Dermato-venereologica | 2009
Hagen Ott; Sven Stanzel; Christine Ocklenburg; H.F. Merk; Jens M. Baron; Sylvia Lehmann
Atopic dermatitis (AD) has been sub-classified into extrinsic and intrinsic types according to the presence or not of allergen-specific IgE antibodies. Although total serum IgE levels are frequently elevated in AD, their potential to predict allergen-specific IgE (asIgE) has rare ly been studied. We investigated 103 children with AD and suspected allergen-specific sensitization. A thorough clinical examination, a structured medical history and total serum IgE and asIgE measurements were performed. Fifty-three male and 50 female patients, median age 35 months (range 3 months to 17 years), were recruited. Sixty-three percent of patients were asIgE positive, while 37% did not reveal such IgE antibodies; median total serum IgE levels were 224.0 kU/l (14-12,013 kU/l) and 25.2 kU/l (0-4352 kU/l), respectively. Associations of asIgE status with atopic co-morbidity and total serum IgE levels were statistically significant. At a cut-off total serum IgE level of 106 kU/l (sensitivity 68.7%; specificity 92.3%), positive and negative predicted values (93.6% and 64.3%, respectively) were determined. Clinical decision points predictive of positive asIgE results were identified in 90%, 95% and 99% of patients, respectively. Total serum IgE values were significantly associated with the asIgE status of investigated patients. However, these preliminary data warrant further large-scale investigations before total serum IgE levels can be regarded as a clinically useful parameter between patients with extrinsic atopic dermatitis and intrinsic atopic dermatitis.
Therapeutic Advances in Respiratory Disease | 2014
Sylvia Lehmann; Claus Pfannenstiel; Frank Friedrichs; Kristina Kröger; Norbert Wagner; Klaus Tenbrock
Background: Allergic bronchopulmonary aspergillosis (ABPA) is a severe complication in patients with cystic fibrosis (CF), resulting in deterioration of lung function and impairment of overall prognosis. Standard therapy consists of high dosage, long-term corticosteroid treatment. This carries the risk of serious side effects such as immune suppression, diabetes and osteoporosis. Antifungal drugs such as itraconazole may cause interactions with other drugs and drug levels need to be monitored. Omalizumab treatment has been tried in several case studies. Methods: This was a retrospective study of six patients (four female, two male, age 4–33 years old) with CF and ABPA treated with omalizumab within an observation period of 7.5 years. Results: All patients showed clinical and laboratory stability or even an improvement within the treatment and post-treatment observation period, although omalizumab therapy was less effective in patients with progressed lung disease and long-term ABPA. Side effects of systemic steroids were reduced. Conclusion: Omalizumab has the potential to be an additional and solitary treatment option in patients with CF and ABPA. Early onset treatment may be beneficial and patients with early stage of lung disease seem to benefit more.
Pediatric Pulmonology | 2016
Sylvia Lehmann; Steffen Leonhardt; Chuong Ngo; Lukas Bergmann; Ines Ayed; Simone Schrading; Klaus Tenbrock
Electrical impedance tomography (EIT) delivers information about global and regional ventilation. Linearity of EIT during tidal breathing is known. We investigated the feasibility of EIT during lung function tests in pediatric patients with cystic fibrosis (CF) and healthy controls.
Clinical Respiratory Journal | 2018
Sylvia Lehmann; Steffen Leonhardt; Chuong Ngo; Lukas Bergmann; Simone Schrading; Konrad Heimann; Norbert Wagner; Klaus Tenbrock
Electrical Impedance Tomography (EIT) is a tomographic, radiation‐free technique based on the injection of a harmless alternating current.
Physiological Measurement | 2017
Chuong Ngo; Steffen Leonhardt; Tony Zhang; Markus J. Lüken; Berno J. E. Misgeld; Thomas Vollmer; Klaus Tenbrock; Sylvia Lehmann
Electrical impedance tomography (EIT) provides global and regional information about ventilation by means of relative changes in electrical impedance measured with electrodes placed around the thorax. In combination with lung function tests, e.g. spirometry and body plethysmography, regional information about lung ventilation can be achieved. Impedance changes strictly correlate with lung volume during tidal breathing and mechanical ventilation. Initial studies presumed a correlation also during forced expiration maneuvers. To quantify the validity of this correlation in extreme lung volume changes during forced breathing, a measurement system was set up and applied on seven lung-healthy volunteers. Simultaneous measurements of changes in lung volume using EIT imaging and pneumotachography were obtained with different breathing patterns. Data was divided into a synchronizing phase (spontaneous breathing) and a test phase (maximum effort breathing and forced maneuvers). The EIT impedance changes correlate strictly with spirometric data during slow breathing with increasing and maximum effort ([Formula: see text]) and during forced expiration maneuvers ([Formula: see text]). Strong correlations in spirometric volume parameters [Formula: see text] ([Formula: see text]), [Formula: see text]/FVC ([Formula: see text]), and flow parameters PEF, [Formula: see text], [Formula: see text], [Formula: see text] ([Formula: see text]) were observed. According to the linearity during forced expiration maneuvers, EIT can be used during pulmonary function testing in combination with spirometry for visualisation of regional lung ventilation.
Biomedizinische Technik | 2017
Chuong Ngo; Sarah Spagnesi; Carlos Munoz; Sylvia Lehmann; Thomas Vollmer; Berno J. E. Misgeld; Steffen Leonhardt
Abstract There is a lack of noninvasive pulmonary function tests which can assess regional information of the lungs. Electrical impedance tomography (EIT) is a radiation-free, non-invasive real-time imaging that provides regional information of ventilation volume regarding the measurement of electrical impedance distribution. Forced oscillation technique (FOT) is a pulmonary function test which is based on the measurement of respiratory mechanical impedance over a frequency range. In this article, we introduce a new measurement approach by combining FOT and EIT, named the oscillatory electrical impedance tomography (oEIT). Our oEIT measurement system consists of a valve-based FOT device, an EIT device, pressure and flow sensors, and a computer fusing the data streams. Measurements were performed on five healthy volunteers at the frequencies 3, 4, 5, 6, 7, 8, 10, 15, and 20 Hz. The measurements suggest that the combination of FOT and EIT is a promising approach. High frequency responses are visible in the derivative of the global impedance index ΔZeit(t,fos).
Biomedizinische Technik | 2014
Sylvia Lehmann; Klaus Tenbrock; Simone Schrading; Robert Pikkemaat; Christoph Hoog Antink; Susana Aguiar Santos; Jan Spillner; Norbert Wagner; Steffen Leonhardt
\Delta {Z_{{\text{eit}}}}(t,{f_{{\text{os}}}}).
Hautarzt | 2007
Hagen Ott; Sylvia Lehmann; G. Wurpts; H.F. Merk; A. Viardot-Helmer; E. Rietschel; Jens M. Baron
The oEIT signals consist of three main components: forced oscillation, spontaneous breathing, and heart activity. The amplitude of the oscillation component decreases with increasing frequency. The band-pass filtered oEIT signal might be a new tool in regional lung function diagnostics, since local responses to high frequency perturbation could be distinguished between different lung regions.
Hautarzt | 2007
Hagen Ott; Sylvia Lehmann; G. Wurpts; H.F. Merk; A. Viardot-Helmer; E. Rietschel; Jens M. Baron
Abstract Electrical impedance tomography (EIT) is a radiation-free technique generating cross-sectional images of the lung. EIT visualizes global and regional ventilation by illustrating the distribution of electrical bioimpedance. With an electrode belt around the patient’s thorax, rotating injection-couples of a harmless alternating current allow voltage measurement of the remaining electrodes. This enables the reconstruction of a tomogram with highly dynamic changes within ventilation. We report on a female six-year-old patient with cystic fibrosis and complete destruction of the upper and middle lobe of the right lung. Lobectomy, a rare therapeutic option in patients with cystic fibrosis that needs to be considered in cases of severe localized destruction, was performed. We show a pre- and postoperative documentation of static (radiology) and dynamic investigation tools (spirometry) in correlation with EIT as a new non-invasive and radiation-free diagnostic tool for this patient group.
biomedical engineering | 2017
Chuong Ngo; Stefan Winter; Steffen Leonhardt; Thomas Vollmer; Bernhard Penzlin; Berno J. E. Misgeld; Karl Krüger; Sylvia Lehmann
Anaphylaxis represents a severe, systemic and potentially fatal hypersensitivity reaction that severely impairs the life of affected children and their caregivers. With an estimated life time prevalence of 0.05% to 2%, it is not a rare disease. Therefore every physician caring for children at risk for anaphylaxis should be familiar with this disease pattern. Foods are the most frequent triggers in children; less frequent causes include drugs and insect venom. Particularly in case of idiopathic anaphylaxis, systemic mastocytosis should be ruled out as a potential differential diagnosis in this age group as well. First line emergency treatment consists of parenteral epinephrine in a weight-adjusted dosage, and after cardiovascular stabilization systemic antihistamines and corticosteroids as well as inhaled beta-mimetics can be administered. Affected patients, their relatives and other caregivers should receive extensive training in order to guarantee an adequate emergency management of anaphylactic children.