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Biomedical subjects

A Obermayer

Publications and source records attributed to A Obermayer.

9 recordsLinked to original sources
PubMed2002

[Critical infusion incident caused by incorrect use of a patient-controlled analgesia pump].

We report on the case of a 17-year-old male patient who received a PCA pump after nephrectomy for postoperative analgesia. The syringe of the PCA pump was filled with 50 mg morphine and positioned about 25 cm above the heart. Since the piston of the syringe was not bolted while the pump was switched off, an unnoticed accidental evacuation of the whole content of the syringe into the intravenous line of the patient occurred because of gravity. This problem exists not only with PCA pumps, but can happen with syringe pumps in general. The incident, which can only be explained by strongly reduced venous pressure, was detected by chance. No harm resulted for the patient, but under different conditions it could have been lethal. This critical incident was caused by various factors: incorrect application in combination with insufficient experience or training, stress, inadequate handing-over of the patient and a lack of arrangements and instructions for procedures in routine situations. Suggestions for preventing such dangerous critical incidents are made and discussed. In particular, an algorithm for the correct procedure when inserting or changing the syringe of a syringe pump is presented.

Adolescent↗
PubMed1995

[Simulation as a method for solving medical technical problems].

The present paper first presents a comprehensive overview of the methodological aspects of simulation. It lists the various approaches to the modelling of real-world systems and emphasizes the respective constraints on the interpretation of model data. For this purpose, a classification of typical applications of simulation models is given, and is followed by a discussion of three structurally different ways of constructing a model. The correct matching of these modelling concepts to the particular application problem in hand is discussed, with special consideration being given to the drawing of conclusions from, and the interpretation of, the simulation results. To round of the classification, the simulation models are differentiated in accordance with the nature of their implementation. By defining application type, modelling concept and model implementation, an understanding of the validity and appropriate application of any industrial model is derived.

Computer Simulation↗
PubMed1991

[Measurement of O2 concentration in the fresh gas supply of the Kuhn system].

To accomplish the requirement of inspiratory O2-concentration measurement on the Ayre-T-piece modified by Kuhn we developed a special device. It is mounted in the fresh gas hose and then connected to the sensor of the O2-concentration measuring and warning instrument of the circle system.

Anesthesia, Inhalation↗
PubMed1986

[Comparative studies of CPAP systems using a respiration simulator. I. Evaluation criteria].

Assessment of the performance of modern ventilators that combine spontaneous breathing and mechanical ventilation is orientated not only towards the assessment of the inspiratory and expiratory resistance within the system, but also towards the functional criteria for the inspiratory and expiratory valves. This conclusion is particularly valid for CPAP procedures, as in this case patients must perform the entire work of breathing by themselves. As it has proved to be extremely problematic to carry out comparative testing of ventilators on patients in the intensive care unit, a breathing simulator has been developed, the use of which has enabled us to have a "patient" at our disposal who can tolerate the procedures for measuring the performance of ventilators with IMV and with CPAP without injury. The pressure-flow characteristics and the work of breathing can thus be measured under constant conditions and with various ventilation systems. Exact analysis of the pressure curve pattern under standardized conditions proved to be of value for assessing the suitability of CPAP in the case of both demand-valve systems and continuous flow systems. Appropriate assessment criteria have been worked out; the course of the test and the results for two ventilators are discussed as an example, using these criteria.

Evaluation Studies as Topic↗
PubMedDate not supplied

[Development of a mathematical model for simulation of artificial ventilation].

This article describes a mathematical model for the simulation of artificial ventilation employing only the figures for air pressure and air flow between respirator and lungs. A discussion of methodological aspects of the problem shows that the model of the respiratory system can be reduced to an equivalent circuit diagram comprising only resistances and capacitances. The structure of the mathematical model is oriented to the elements of the real respiratory system, and its modularity permits ready adaptation to a variety of real-life situations. Particular emphasis was placed on the correct parametrization of the model with the aid of data originally collected from physical experiments. Finally, some selected model runs that demonstrate the range of validity and the accuracy of the model are presented.

Airway Resistance↗