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Biomedical subjects

E Pleger

Publications and source records attributed to E Pleger.

18 recordsLinked to original sources
PubMed1990

[Definition and clinical significance of oscillation parameters (fixed frequency technic)].

Starting from the polyvalent sense of a limitation of the maximum available respiratory flow there is to be pointed to the necessity of the decentralized measurement of resistance. The instrument IfM E1 permits the use of the simple forced oscillation technique for estimations of ROS and the derived values delta ROS and STAV all over the country. The advanced forced oscillation method, based on the fixed frequency technique, contained the option for estimation of the residual volume and especially the phase-angle. The knowledge of psi, Re and phi can make the oscillatory testing of airways resistance more surely. Taking into consideration the dependence of the phase signal on lung volume can state noninvasive different facts about the compliance of the lung-thoracic-diaphragm system.

Airway Resistance↗
PubMed1989

[Optimizing monofrequent oscillometry].

Against the background of the working hypothesis of the 1-parametric Siregnost FD 5 forced oscillation technique-phase angle psi may be invariant in a clinical reference population-the hypothetical straight Ros-P line is in good agreement with the crowd of extremely nonlinear Rre-P-lines only within narrow limits. Neglecting phase angle measurements it might be useful to insert a known linear resistor into the airway to determine the pertaining Rre-P relation. In spite of selective tuning to the oscillation frequency of 10 Hz there is full sensitivity to stationary flow; alinear stationary flow characteristics of resistors can be readily determined by forced oscillation. There is a marked improvement in the P-psi/Rre-phi-evaluating system with respect both to the symmetry of phase angle and unequivocality of pressure when the reference phase angle alpha is shifted from 81 degrees to 0 degrees. Using digital data acquisition and processing, a flexible evaluation technique with monitor-oriented test management, automatical calculation of secondary values and multidimensional presentation of results on a graphical display is provided, which has proved its worth in experimental and clinical-physiological studies.

Airway Resistance↗
PubMed1989

[Theoretical and experimental studies of the diagnostic relevance and comparability of mechanical oscillation parameters].

The practical application of the forced oscillation technique for the analysis of the mechanics of respiration is hampered by the fact that the measured frequency-dependent impedance values R(f) and X(f) cannot be related directly to the parameters airway resistance Raw and pulmonary compliance CL. Furthermore, various derived oscillatory parameters are employed which are not directly comparable even with one another. In order to be able to estimate the diagnostic relevance and comparability of the impedance curves R(f) and X(f), their form-specific characteristics R = R(5)-R(20) and X(5), as also the equipment-specific parameters Ros (Siregnost FD5) and Rfo (custo vit), the relationships of these oscillatory parameters to Raw and CL were simulated in a structural model of the respiratory system, and tested in the real system. It was shown that already from frequencies of f greater than 10Hz upwards, R(f) no longer reacts to an increase in resistance in the peripheral region of the lung, and at 20 Hz indicates only the upper airway component of a global obstruction demonstrated body-plethysmographically with Raw. The diagnostic information on peripheral airway obstruction is contained in both components R(f) and X(f) of the respiratory impedance; with increasing obstruction and increasing frequency, it progressively reverts to the X(f) curve. Therefore, by including X(f) in the resistance evaluation for the parameters Ros and Rfo, the underevaluation of R(f) as compared with Raw can in part be compensated for, although an overe stimation at low Raw values with Ros and a large scatter of the Rfo values in the case of large Raw figures has to be accepted.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1989

[Practical experiences with 2 oscillatory measuring procedures, Siregnost FD 5 and custo vit, in the assessment of chronic airway obstruction].

In patients with chronic obstructive airway disease, comparative examinations using body plethysmography were performed with a view to evaluating the effectiveness of two forced oscillation techniques, fixed-frequency and poly-frequency techniques in estimating disorders of respiration mechanics. At slight and moderate elevations in bronchial flow resistance, a better agreement was found between the custo vit resistance figure and body plethysmography. A differentiation of healthy subjects from patients with low-grade obstruction by means of the FD 5, requires the establishment of the phase angle (phi), too, while in the case of the custo vit unit, this is possible by demonstrating the frequency dependence of the impedance. Patients with more severe disease with secondary emphysematous changes, reveal a clear difference between the phase signal (psi) primarily measured on the FD 5, and the phase angle. Forced oscillation usefully supplements spirometery in the respiratory basic diagnostic work-up employed through-out treatment. Fixed-frequency techniques require the determination of the phase angle for assessment of peripheral obstructions; the advantage of the poly-frequency technique can be seen in the largely specific demonstration of the frequency dependency of the resistance.

Airway Resistance↗
PubMed1989

[Oscillometric differentiation of lung fibrosis and lung emphysema].

In three groups of healthy subjects and patients with pulmonary fibrosis or pulmonary emphysema, the secondary periodical oscillatory phenomena observed under conditions of normal breathing and a slow VC manoeuvre on the Siregnost FD 5 were broken down into a volume- and a flow-synchronous component, as also a third component with no correlation with either volume or flow, and which can be observed in the primary parameters Ros and psi, as also the secondary parameters Rre and phi. While both fibrotic patients and healthy subjects revealed a volume-inverse phase behaviour, patients with pulmonary emphysema revealed a volume-proportional phase behaviour. This difference in volume dependence is explained by the difference in elastic recoil in patients with fibrosis as compared with those suffering from emphysema, and the associated different influence on the filling of the lungs with air and blood.

Adult↗
PubMed1989

[Report of a trial of polyfrequent oscillo-resistometry with the custo vit equipment].

With the aim of determining the significance of the principle of the multi-frequency forced oscillation technique employed by the custo vit to determine the airway resistance, measurements were performed on a number of test subjects, employing a unit available with three different software modifications. A comparison with the resistance values obtained with other equipment (whole-body plethysmograph, Siregnost FD5), revealed the diagnostic usefulness of the technique of frequency-dependent resistance. It was also confirmed that the phase angles, also obtainable with the custo vit, play a considerable role in the significant differentiation of the degree of obstruction. The differences in comparison with other methods are critically examined, and proposals made for a further improvement of the forced oscillation technique employed by the custo vit.

Airway Resistance↗
PubMed1987

[The oscillation method for the diagnosis of respiratory function of adults--arrangement and possibilities for optimization. 4. The oscillatory residual volume determination (RVOS)].

The residual volume can oscillatorily be estimated in an easy way with the help of diving-gas. The oscillatory unit, furnished with a sensor of density, serves as a quick helium-analyser. An overestimation of the residual volume can appear as a result of the high volatility of the used gas, an underestimation can result because of the non-registration of lung parts with entrapped air. Therefore a differentiated interpretation of the curve of wash-in is suggested. Thus a good conformity can be found with the body plethysmographic results also in patients with obstructive airways diseases including persons with disturbances of ventilatory distribution.

Helium↗
PubMed1987

[Oscillation method in the diagnosis of respiratory function in adults--classification and possibilities for optimization. 1. Basic problems and introduction to the method].

There is pointed to the necessity, to clear up pathophysiologically a limitation of the maximum available respiratory volume or flow. The required investigations of breathing mechanics for registering the impedance under quiet breathing and measuring the residual volume are possible with the oscillation method at the base. There are listed the insecurities of the taken parameter with a short description of the basic theory of the oscillation method (fixed frequency technique).

Adult↗
PubMed1987

[Oscillation method in the diagnosis of respiratory function in adults--classification and possibilities for optimization. 2. Oscillatory resistance (ROS)].

The oscillatory resistance (Ros) can be measured routinely by simple set frequency technique under physiological conditions relatively independent of age and cooperation of the examinee. It is as a complex number of the breathing mechanics only relatively comparable with the body plethysmographic resistance. Taking into consideration the dependence on actual lung volume and seriousness of obstruction one can give statements adequately reliable for practice with the help of ROS within a limit from 1 to 10 hPa/l/s. By varying of measuring frequency and reference resistor the estimation of low and middle endobronchial obstructions can be optimized (also without additional measuring of the phase-angle).

Airway Resistance↗
PubMed1987

[Oscillation method in respiratory function diagnosis of adults--integration and optimizing possibilities. 3. The phase angle].

The importance of the phase angle in oscillatory measurements of resistance depends on the presence or absence of an endobronchial obstruction. In case there is an obstruction, a negative phase angle is first of all an expression of the low compliance of the larger airways and points to an underestimation of the real flow resistance. If there is no obstruction one can state facts about the peripheral compliance, in particular taking into consideration the dependence of the phase signal on actual lung volume. It is recommended to supply the basic ventilation tests with an additional determination of a second angle (beta) from the inspiratory part of the psi/V-curve. That allows to separate normal persons and patients with lung fibrosis and emphysema.

Airway Obstruction↗
PubMed1985

[Can oscillatory estimation of airway resistance in chronic obstructive patients be improved by the use of double reference resistance?].

Tests were carried out on the usefulness of doubling the reference resistor during airways resistance measurement by forced oscillation method (set frequency technique). Measurements on 110 random subjects using the standard reference tube (Zo = 10 hPa/1/s) for comparison showed almost identical Ros values using the experimental tube, while the latter gave higher Ros values as obstruction increased. Comparisons with the bodyplethysmographic Rt on 65 patients with a chronic obstructive airways disease yielded a closer approximation to the identity curve from 7.0 hPa/1/s using this modified technique. The practical conclusion is to recommend the use of the double reference resistor for the basic clinical diagnosis of obstructive airways disease, both in quantifying advanced grade obstructions and in assessing the damaged respiratory mechanism in chronically ill patients with pronounced ventilatory resistance.

Adult↗