Dragerwerk AG and Co. KgaA

Lübeck, Germany

Dragerwerk AG and Co. KgaA

Lübeck, Germany
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Petersen E.,University of Lübeck | Buchner H.,University of Cambridge | Eger M.,Dragerwerk AG and Co. KGaA | Rostalski P.,University of Lübeck
Biomedizinische Technik | Year: 2017

Electromyography (EMG) has long been used for the assessment of muscle function and activity and has recently been applied to the control of medical ventilation. For this application, the EMG signal is usually recorded invasively by means of electrodes on a nasogastric tube which is placed inside the esophagus in order to minimize noise and crosstalk from other muscles. Replacing these invasive measurements with an EMG signal obtained non-invasively on the body surface is difficult and requires techniques for signal separation in order to reconstruct the contributions of the individual respiratory muscles. In the case of muscles with small cross-sectional areas, or with muscles at large distances from the recording site, solutions to this problem have been proposed previously. The respiratory muscles, however, are large and distributed widely over the upper body volume. In this article, we describe an algorithm for convolutive blind source separation (BSS) that performs well even for large, distributed muscles such as the respiratory muscles, while using only a small number of electrodes. The algorithm is derived as a special case of the TRINICON general framework for BSS. To provide evidence that it shows potential for separating inspiratory, expiratory, and cardiac activities in practical applications, a joint numerical simulation of EMG and ECG activities was performed, and separation success was evaluated in a variety of noise settings. The results are promising. © 2017 Walter de Gruyter GmbH, Berlin/Boston 2017.

Kahl L.,Dragerwerk AG and Co. KGaA | Hofmann U.G.,Albert Ludwigs University of Freiburg
Medical Engineering and Physics | Year: 2016

This work compared the performance of six different fatigue detection algorithms quantifying muscle fatigue based on electromyographic signals. Surface electromyography (sEMG) was obtained by an experiment from upper arm contractions at three different load levels from twelve volunteers. Fatigue detection algorithms mean frequency (MNF), spectral moments ratio (SMR), the wavelet method WIRM1551, sample entropy (SampEn), fuzzy approximate entropy (fApEn) and recurrence quantification analysis (RQA%DET) were calculated. The resulting fatigue signals were compared considering the disturbances incorporated in fatiguing situations as well as according to the possibility to differentiate the load levels based on the fatigue signals. Furthermore we investigated the influence of the electrode locations on the fatigue detection quality and whether an optimized channel set is reasonable. The results of the MNF, SMR, WIRM1551 and fApEn algorithms fell close together. Due to the small amount of subjects in this study significant differences could not be found. In terms of disturbances the SMR algorithm showed a slight tendency to out-perform the others. © 2016 IPEM.

Gorges M.,University of Utah | Kuck K.,Dragerwerk AG and Co KGaA | Koch S.H.,University of Utah | Koch S.H.,University of Heidelberg | And 2 more authors.
Dimensions of Critical Care Nursing | Year: 2011

Although nurses perform the majority of the clinical tasks in an intensive care unit, current patient monitors were not designed to support a nurse's workflow. Nurses constantly triage patients, deciding which patient is currently in the most need of care. To make this decision, nurses must observe the patient's vital signs and therapeutic device information from multiple sources. To obtain this information, they often have to enter the patient's room. This study addresses 3 hypotheses. Information provided by far-view monitoring displays (1) reduces the amount of time to determine which patient needs care first, (2) increases the accuracy of assigning priority to the right patient, and (3) reduces nurses mental workload. We developed 2 far-view displays to be read from a distance of 3 to 5 m without entering the patient's room. Both display vital signs, trends, alarms, infusion pump status, and therapy support indicators. To evaluate the displays, nurses were asked to use the displays to decide which of 2 patients required their attention first. They made 60 decisions: 20 with each far-view display and 20 decisions with a standard patient monitor next to an infusion pump. Sixteen nurses (median age of 27.5 years with 2.75 years of experience) participated in the study. Using the 2 far-view displays, nurses more accurately and rapidly identified stable patients and syringe pumps that were nearly empty. Median decision times were 11.3 and 12.4 seconds for the 2 far-view displays and 17.2 seconds for the control display. The 2 far-view displays reduced median decision-making times by 4.8 to 5.9 seconds, increased accuracy in assignment of priority in 2 of 7 patient conditions, and reduced nurses' frustration with the triaging task. In aclinical setting, the proposed far-view display might reduce nurses' mental workload and thereby increase patient safety. Copyright © 2011 Lippincott Williams & Wilkins.

Baether W.,Dragerwerk AG and Co. KGaA | Zimmermann S.,Leibniz University of Hanover | Gunzer F.,German University in Cairo
Analyst | Year: 2012

Ion mobility spectrometry (IMS) is well known for its very high sensitivity, and thus IMS spectra are commonly used in the identification of trace gases. Extracting quantitative information from IMS spectra is, in contrast, difficult, especially regarding the reproducibility due to the nature of the processes involved in the measurement of the spectra. Here we present data extracted from signal decay curves obtained with a pulsed IMS, which can support the determination of substance concentrations in the lower ppb range with good stability. © 2012 The Royal Society of Chemistry.

Ibach B.,RWTH Aachen | Benzko J.,RWTH Aachen | Schlichting S.,Dragerwerk AG and Co. KGaA | Zimolong A.,Synagon GmbH | Radermacher K.,RWTH Aachen
Biomedizinische Technik | Year: 2012

With the increasing documentation requirements and communication capabilities of medical devices in the operating room, the integration and modular networking of these devices have become more and more important. Commercial integrated operating room systems are mainly proprietary developments using usually proprietary communication standards and interfaces, which reduce the possibility of integrating devices from different vendors. To overcome these limitations, there is a need for an open standardized architecture that is based on standard protocols and interfaces enabling the integration of devices from different vendors based on heterogeneous software and hardware components. Starting with an analysis of the requirements for device integration in the operating room and the techniques used for integrating devices in other industrial domains, a new concept for an integration architecture for the operating room based on the paradigm of a service-oriented architecture is developed. Standardized communication protocols and interface descriptions are used. As risk management is an important factor in the field of medical engineering, a risk analysis of the developed concept has been carried out and the first prototypes have been implemented. © 2012 by Walter de Gruyter.

Baether W.,Dragerwerk AG and Co. KGaA | Zimmermann S.,Leibniz University of Hanover | Gunzer F.,German University in Cairo
International Journal for Ion Mobility Spectrometry | Year: 2010

Ion mobility spectrometry (IMS) is a well-known method for detecting hazardous compounds in air. Most ion mobility spectrometers use a radioactive source to provide electrons with high energy (5-50 keV) to ionize analytes in a series of chemical reactions. Instead of a radioactive source, we use a non-radioactive electron gun which can be operated in pulsed mode. Thus a delay time between ionization and ion extraction can be introduced which offers the possibility to use the signal decay characteristic of substances as a further discrimination parameter. The influence of voltages supplied to the reaction region and to the electron gun on signal intensities and decay times will be investigated in order to obtain further insight into the dependence of this signal decay on different experimental parameters and correspondingly into the underlying mechanisms. © 2010 Springer-Verlag.

Gunzer F.,German University in Cairo | Baether W.,Dragerwerk AG and Co. KGaA | Zimmermann S.,Leibniz University of Hanover
International Journal for Ion Mobility Spectrometry | Year: 2011

Ion mobility spectrometry (IMS) has been an important tool for decades in the field of trace gas analysis of substances such as explosives, drugs of abuse or chemical warfare agents. In recent years, its application has been extended to more complex set ups. In this paper we present the application of a standard IMS device equipped with a novel pulsed electron gun for ionization in the investigation of the chemical warfare agent simulant dimethyl methylphosphonate (DMMP). The signal decay times of the reactant ion peak (RIP), the DMMP monomer and dimer have been investigated. Thus, further information could be obtained of the innovative application of different signal decay times in order to filter out signals of contaminants with focus on the decay dependence on the concentration. Additionally, further details regarding the still not fully understood underlying decay mechanisms have been found. © 2011 Springer-Verlag.

Gorges M.,University of Utah | Westenskow D.R.,University of Utah | Kuck K.,Dragerwerk AG and Co. KGaA | Orr J.A.,University of Utah
Journal of Clinical Monitoring and Computing | Year: 2010

Background. Vasoactive drug infusion rates are titrated to achieve a desired effect, e.g., mean arterial blood pressure (MAP), rather than using infusion rates based on body weight. The purpose of this study is to evaluate a method to automatically identify a patient's sensitivity to sodiumnitroprusside, dobutamine or dopamine and to evaluate, whether an advisory system that predicts MAP 5 min in the future enhances a clinician's ability to titrate sodiumnitroprusside infusions. Methods. We used published models implemented in MATLAB to simulate the response of 100 individual patients to infusions of sodium-nitroprusside, dopamine and dobutamine. The simulated patient's sensitivity to the three drugs was identified using an adaptive filter approach, where MAP was altered in a binary stepwise fashion. Next, 9 nurses were asked to control the MAP of 6 of the simulated patients. For half of the patients, we used the identified sensitivity to predict and display MAP 5 min into the future. Results. Identifying each individual patient's sensitivity improved the accuracy of the MAP prediction by 75% for sodium-nitroprusside, 82% for dopamine and 52% for dobutamine over the MAP prediction based on an "average" patient's sensitivity. The advisory system shortened the median time to reach the desired MAP from 10.2 to 4.1 min, decreased the median number of infusion rate changes from 6 to 4, and resulted in a significant reduction of mental workload and effort. Discussion. Patient-specific drug sensitivity identification significantly improved the prediction of future MAP. By predicting and displaying the expected MAP 5 min in the future, the advisory system helped nurses titrate faster, reduced their perceived workload and might improve patient safety. © Springer 2010.

Tan C.,Fraunhofer Institute for Biomedical Engineering | Gajovic-Eichelmann N.,Fraunhofer Institute for Biomedical Engineering | Polzius R.,Dragerwerk AG and Co. KGaA | Hildebrandt N.,Fraunhofer Institute for Applied Polymer Research | Bier F.F.,Fraunhofer Institute for Biomedical Engineering
Analytical and Bioanalytical Chemistry | Year: 2010

The detection of the major active component of cannabis, Δ9-tetrahydrocannabinol (THC), becomes increasingly relevant due to its widespread abuse. For control purposes, some easy-to-use, sensitive and inexpensive test methods are needed. We have developed a fluorescence immunoassay utilising THC-fluorescein conjugate as tracer. Fluorescence spectroscopy of the conjugate revealed an unusual property: The relatively weak fluorescence of a dilute tracer solution was increased by a factor of up to 5 after binding of a THC-specific antibody. Fluorescence lifetime measurements in aqueous solutions suggested two different tracer conformations both associated with quenching of fluorescein fluorescence by the intramolecular THC moiety. After antibody binding, the tracer enters a third conformation in which fluorescence quenching of fluorescein is completely suppressed. Utilising this property, we established a homogeneous competitive immunoassay (homogeneous increasing fluorescence immunoassay) with low detection limits. The test requires only two reagents, the new tracer molecule and an anti-THC antibody. A single test takes only 8 min. The dynamic detection range for THC is 0.5 to 20 ng/mL in buffer, with a limit of detection (LOD) of 0.5 ng/mL. The test also works in diluted saliva samples (1:10 dilution with buffer) with an LOD of 2 ng/mL and a dynamic range of 2-50 ng/mL. © 2010 Springer-Verlag.

Nauber A.,Dragerwerk AG and Co KGaA | Tschuncky P.,Drager Safety AG and Co. KGaA
ECS Transactions | Year: 2013

Reliable detection of low level toxic gas impurities in breathing air is one of the challenging tasks in Dräger products. Among our detector portfolio electrochemical sensors belong to our key technology, which we try to improve continuously in terms of sensitivity, selectivity and stability. Ionic Liquids offer the advantages of displaying a huge electrochemical open window with negligible background currents. They can be designed task specific for the application they are used in and besides outstanding chemical inertness they offer the intrinsic advantage of being nonvolatile, which makes it possible to construct sensors that even can be used under zero humidity conditions which e.g. can be found for H2S monitoring in deserts e.g. in oil fields. © 2014 The Electrochemical Society.

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