Wyniki wyszukiwania - BazTech

1

A novel methodology for signal recovery in linear time invariant system for medicine applications

Melo M. D. B., Araujo H. X., Da Rocha F.

Przegląd Elektrotechniczny

|

2016

|

R. 92, nr 10

199--203

EN

This paper presents a deconvolution based method that allows the improvement of the time response of a Swan-Ganz catheter. The goal of the deconvolution method is to obtain the input signal of an LTI system from the knowledge of its output and its impulse response. The noise causes degradation of the recovered signal, and this phenomenon is also discussed. The deconvolved signal is enriched in function of the cutoff frequency of the filter. It is shown that as the cutoff frequency increases, the deconvolved signal becomes more nosier. A Butterworth digital filter of third order, multiplied by the reverse impulse response was used in the frequency domain, and the response in frequency for the 1/H(s) function, limited for the various cutoff frequency of the filter are shown. It can be clearly observed that for higher cutoff frequency magnitude, the signal becomes completely distorted. Experiments with animals were used to measure the impulse response and the obtained results were satisfactory, with average error of 8.9%. The results suggest that the method can be useful in applications of linear systems.

PL

Opisano metodę poprawy odpowiedzi czasowej cewnika typu Swan_ganz bazująca na rozplocie. Umożlia to ocenę sygnału wejściowego na podstawie odpowiedzi układu I znajomosci odpowiedzi impulsowej. . W pracy analizowano wpływ filtru cyfrowego na parametry sygnału. Metode z dobrym rezultatem przetestowano na zwierzętach.

2

Analysis of actual accuracy in cardiac output measurements by means of thermodilution

Gawlikowski M., Pustelny T.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2012

|

Vol. 60, nr 3

581-587

EN

The essential examination in hemodynamic monitoring of the patient is the cardiac output (CO) measurement. Nowadays, in clinical practice the most popular method is indicator dilution, particularly thermodilution. It is realized by applying the Swan-Ganz catheter and observing changes of the indicator concentration. This method is sensitive to many factors and the obtained results should be treated cautiously. The paper presents theoretical and experimental studies of metrological phenomena in CO measurements by means of thermodilution, paying special attention to medical aspects of the measurements. It has been pointed out that the actual unreliability of the mentioned method reaches values from 20% to 45%, which is in opposition to the technical data of patient's monitors (typical accuracy about 5%).

3

The pulmonary arteries as a source of unreliability in thermodilution cardiac output measurement

Gawlikowski M., Pustelny T., Przywara-Chowaniec B., Struk P.

Molecular and Quantum Acoustics

|

2008

|

Vol. 29

83-91

EN

One of the most fundamental examination in intensive care medicine is cardiac output (CO) measurement, realized by pulmonary artery catherization. The thermodilution CO estimation method is not resistant to various kinds of disturbances, which significantly decreases its sensitivity and specificity. The paper depicts investigations related to analysis of presumable new source of unreliability – asymmetric blood flow through pulmonary vessels. The investigations consisted of two phases: clinical examination (to obtain anatomical data) and computer modeling (to simulate the flow symmetry).