Biomedical subjects

C Hillenbach

Publications and source records attributed to C Hillenbach.

3 recordsLinked to original sources

PubMed1996

Lung function testing: the dilemma of predicted values in relation to the individual variability.

Quantitated lung function parameters are usually interpreted in relation to so-called "normal ranges' obtained from healthy study groups. The aim of this paper is the critical review of formulas and the evaluation of intraindividual variation in modern lung function testing. To which extent is the total variation of lung function parameters in cross-sectional studies (usually serving as basis for the normal range) attributed to the intraindividual variation between repeated measurements? This question raises a further question: are lung function values in the normal range really normal? To assess spirometric and body plethysmographic parameters 26 healthy subjects from three medical centers underwent 30-72 measurements over a period of 2 months for the determination of variations due to (1) intraindividual variation over time and (2) interindividual variation. For each subject, predicted values of different lung function parameters published by Quanjer et al. [Eur Respir J 1993; 6:5-40.1], of intrathoracic gas volume by Ulmer et al. [Die Lungenfunktion; Stuttgart, Thieme, 1991] and of total airway resistance by Ruehle and Matthys [Pneumologie 1976;153:223] were applied. When converted into percent predicted and adjusted for differences in medical centers, the intraindividual standard deviation was estimated to be about half of the interindividual standard deviation. We conclude that the normal range of lung function parameters derived from the standard deviation within populations is too wide for the assessment of individual values. Interpretation of individual lung function measurements should primarily be based on the "individual normal range' derived from former lung function measurements of the individual and only secondly on the "predicted value'.

Adult↗

PubMed1995

[Pilot project for evaluation of lung function reference values].

Lung function tests were performed in this study on 139 adults (mean age 36 years), as well as on 91 female persons between 16 and 18 years of age (the latter just starting on their professional careers), the lungs being healthy in each case in both groups. The findings were compared with the currently accepted reference value formulae after Quanjer et al., and Zapletal as well as further developed reference value formulae after Brändli et al., Most of the measurement data obtained by spirometry for the BGFA group of probands are between the two recommended reference values for adults with better coincidence with Brändli's predictions (exceptions being MMEF25-75 MEF 50 and MEF 25). In our studies we obtained higher values than the reference median values after Quanjer and Zapletal for IVC, FVC, FEV1 and PEF by 6-8% and 5-15%, respectively, whereas the values for adults differ from the predictions made by Brändli et al. by -4% to +5%. The flow data MMEF 75-25, MEF 50 and especially MEF 25 are set at too low levels (by 5-23%) by Zapletal's and Brändli's values. Comparatively, the values predicted by Quanjer et al. for the above mentioned flow-volume parameters (with the exception of MEF 75) are too high by 4% to 12%. There are also considerable differences in respect of the reference values for IGV to the tune of +15% in the BGFA group compared to Quanjer et al.; in the BAFAM group the values differ from those of Zapletal et al. by +17%. RV yields results in the BGFA group which are higher by 11% than according to Quanjer's formulae, whereas in the BAFAM group they are higher by 15% compared to Zapletal's predictions. In respect of Rt there are differences to the predictions by Rühle and Matthys by +16% (BGFA group) and +13% (BAFAM group), respectively. The BAFAM group differs from Zapletal's predictions by +11%. Looking at the reference limit values the overall impression is confirmed that the predictions after Quanjer et al. and mostly also those by Zapletal are too low in respect of the abovementioned lung function parameters (in the majority of cases not 5% of the examined probands, as expected, are below those levels, but only about 2%). Females, who had been underrepresented in the previous healthy proband groups, show larger deviations than males in respect of most of the parameters.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1995

[Measuring single breath diffusing capacity in a patient sample with healthy lungs--comparison with the European Coal and Steel Community standard values].

The measurement values of the diffusion parameters TLCO (diffusion capacity) and KCO (transfer coefficient) of 107 healthy subjects not suffering from pulmonary diseases were compared with the EC/European Community for Coal and Steel (ECCS) standard value formulas (2-5). The diffusion parameter KCO is markedly better described by the 1993 standard value formula than by the 1983 ECCS version. Men yield higher measured values than predicted by the 1993 EC formulas. The diffusion parameters of smokers are significantly lower than those of non-smokers.

Adolescent↗