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1

Spirometry: quantification of the shape of the maximal expiratory flow-volume curve

Gólczewski T., Lubiński W.

Biocybernetics and Biomedical Engineering

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2008

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Vol. 28, no. 3

17-25

EN

The relationship between Forced Expiratory Volume in one second (FEV1) and the Forced Vital Capacity (FVC) is intensively used in diagnosing because of its quantitative description with the index FEV1/FVC. There is not such index for the relationship between airflows (Peak Expiratory Flow (PEF) and Maximal Expiratory Flow at xx% of FVC (MEFxx, where xx = 75, 50, 25%)). Our aim was to describe that relationship quantitatively with the angle alfa between the 4-dimensional vector F = [PEF, MEF75, MEF50, MEF25] and the plane determined by two reference vectors: the mean of such vectors for the young and elderly. The reference vectors were found with data for 1,120 males and 1,625 females - Polish (white) population, healthy, never-smoking, aged 18 - 85 yrs, who performed a technically adequate spirometry maneuver. Upper Limit of Normal (ULN) was determined with the linear regression of the 5th percentiles of alfa on age (0.074*age + 2.76). Such an ULN seems to well indicate both improper examination and non-healthy persons.

2

Identification of mechanical parameters of respiratory system during ventilatory support of lungs

Pałko K. J., Kozarski M., Darowski M.

Biocybernetics and Biomedical Engineering

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2005

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Vol. 25, no. 1

73-81

EN

Identification of mechanical parameters of lungs by using a pressure method with an added compliance is presented in this paper. This method is based on periodically connecting an additional external mechanical compliance to the respirator-lungs circuit, to determine the values of the mechanical parameters of the respiratory system from measurements of the pressure in specific phases of the respiratory cycle. The expiratory flow was measured to estimate the time constant and the respiratory resistance. The identification of the parameters of lungs is connected with the dynamic signal analysis of the pressure courses registered in a very short time (< 200 ms) at the beginning of the expiratory phase, when the respiratory muscles are non-active. The measurement system is driven by the computer, which is also used to analyse the signals received from the lung model. The results confirm that the measurement time of 200 ms is sufficient to determine the lung compliance.

3

System do pomiaru limitowania przepływu wydechowego metodą NEP

Buchała G., Gajda J., Sroka R., Żegleń T.

Pomiary Automatyka Kontrola

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2001

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R. 47, nr 7/8

18-21

PL

W pracy przedstawiono komputerowy system pomiarowy skonstruowany w Zakładzie Metrologii AGH i przeznaczony do badania zjawiska limitowania przepływu wydechowego u dzieci z przewlekłymi chorobami układu oddechowego. Zastosowana metoda badania polega na pobudzaniu układu oddechowego ujemnymi impulsami ciśnienia (negative expiratory pressure pulses - NEP), generowanymi u wylotu dróg oddechowych pacjenta. Skonstruowany system umożliwia cyfrową rejestrację wymuszonych zmian ciśnienia oraz odpowiadających im zmian przepływu powietrza. Wyniki pomiaru są przetwarzane w celu wyznaczenia wartości parametrów kryterialnych jak również są prezentowane w postaci graficznej w celu ułatwienia procesu diagnostycznego.

EN

The digital measurement system designed for investigation of the expiratory How limitation phenomenon is presented in the paper. The presented system was assembled and programmed in Department of Instrumentation and Measurement University of Mining and Metallurgy. The applied measuring method depends on excitation of the tested respiratory system by negative expiratory pressure pulses - NEP, generated at outlet of patient airducts. The system allows acquisition of the measured data of forced pressure pulse and corresponding time course of the volumetric airflow. The diagnostic parameters are estimated as the results of on-line data processing. The graphical presentation of the measuring results on the monitor screen increases effectiveness of the diagnostic process.