Biomedical subjects
Publications and source records attributed to W Mährlein.
An epidemiological evaluation of chronic obstructive bronchitis in miners showed that smoking ranges in first place in the aetiopathogenesis. In addition, after prolonged underground exposure, the irritating nuisance of the respiratory tract must be considered as causal cofactor.
The value of measuring the median pressure of the pulmonary artery for the prognosis of silicosis remains undebatable since the development of pulmonary heart disease has multifactorial causes and extreme interindividual variations. On the other side, during the course of silicosis disease, the increase of pressure is relatively small or even absent during years. Thus, measuring of mean pulmonary artery pressure is only required at larger intervals.
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For the early diagnostics of chronic nonspecific pulmonary disease reversible functional disorders in persons without any symptoms and those with manifest obstruction should be identified. Provocation tests with acetylcholine-ultrasonic-aerosol have proved themselves. In 25 persons without any respiratory symptoms and in 27 patients with manifest obstruction the reactions of increased airway resistance to the hemodynamic of the pulmonary circuit were studied. It is possible to separate clearly groups with different pulmonary artery stream resistance measured by means of microheart-catheterization after inhalation of 0.01% acetylcholine-ultrasonic-aerosol.
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A simple method for the estimation of the closing volume is demonstrated and the values got from 120 healthy males are cited as reference values. The exactness of measuring in sufficient for the practical demands. The results correspond to those in literature.
The closing volume method is suitably to be used in exposed groups of the population, the preliminary diagnostics of them is inconspicuous, in order to establish in time beginning and thus therapeutically influencible alterations of the small respiratory tract. In such a group of test persons only relatively slight connections with the other conventional lung standard methods are the result, by means of which its independence is emphasized. On the other hand less promising seems to be the application of the method in the verification of a "small airways obstruction" in smokers, whose vital capacity, forced expiratory volume and residual volume are within the normal.
Investigations in 77 healthy persons and 94 patients with a manifest obstructive lung disease have led to the result that not only the central but also the peripheral part of the bronchial system are influenced by the bronchial reactivity. Accordingly the examination of the bronchial reactivity (0.01% acetylcholine solution as ultrasonic aerosol) enable in healthy persons a certain differentiation between smokers and non-smokers if the single breath test by means of the slope index are used. Therefore the method of investigation may be recommended for the early detection of functional disorders of persons with inhalatory exposure to noxious substances.
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The possibility of early detection of pulmonary hypertension is rather late according to the large capacity of the lung vessels in the condition of rest. Consequently the parameters of the pulmonary circulation were measured in 89 healthy subjects and 261 men suffering from silicosis in rest and bicycle exercise by means of the microcatheter technique and statistically compared with other parameters of lung function. In conclusion it can be said there is a statistical correlation between pressure at rest and during exercise conditions, but this is not available in an individual case. Furthermore the pressure values of persons suffering from silicosis are higher than those of the healthy group at rest and the pressure rise is higher in the ill group during exercise. Statistically there is a slight correlation between the pressure behavior and the FEV1, Rtot, PO2, DCO and of minor importance to VC, RC and FRC.
The influence of hypobaric hypoxia at the pulmonary gaseous exchange and the hemodynamics of the pulmonary circulation was tested by 12 healthy subjects at the age from 33 to 47 years. They were submitted to a basis investigation with determination of VC, VE, VO2, VCO2, Hb, PO2A/a, pH, HR, ECG, PVd, PAp, HZV, RL. These investigations were followed by stress examination by means of the bicycle ergometry in four rectangular steps during conditions of normoxia and of hypobaric hypoxia in a low-pressure chambre at 66.5 kPa (500 Torr) each of 6 min duration. During the influence of hypoxia a PO2a-decrease in a sense of partial insufficiency could be already observed at rest during conditions of a decreased alveolar oxygen-partial-pressure. At the same time was found a significant increase of the systolic peripheral and the diastolic pulmonary arterial pressure. At the increasing step by step ergometric exercise during conditions of the hypoxia stress were growing significance evidence of different reactions of the pulmonary and cardiocirculatory parameters occurred.
Bronchial hyperreactivity (tested with 0.01% acetylcholine ultrasonic aerosol) and ventilatory inhomogeneity (tested with V2/V1-parameter of the flow-volume diagram) using the pneumotest apparatus were studied. Patients with high bronchial reactivity are frequently showing not only ventilatory disorders of distribution but sometimes also an additional increase due to the bronchial provocation. Bronchial reactivity testing combined with the flow-volume diagram allows to estimate the predominant site of the bronchospastic response either centrally or also in the more peripheral parts of the bronchial system. By testing bronchial reactivity persons without any symptoms and with no evident spirometric alterations can be separated in dependence on the relative increase of total airway flow resistance as well on smoking habits. That does not succeed with the appliance of the inhomogeneity parameters V2/V1. The results obtained in this study are of value for preventive measures, for early detection of risk factors in premorbid stages, for assessment of prognosis in chronic nonspecific lung disease, for an adequate therapy and also for the rehabilitation of patients in jobs with inhalation of noxious dusts.
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As a task in the research project Chronic Lung Diseases the method of testing bronchial reactivity by provocation with acetylcholine as an ultrasonic aerosol was developed. Indications for an uniform standardized application and policy are given.
Examinations performed with the help of the body-plethysmographic inhomogeneity parameter REmax/RE0 prove the close connection between the development of chronic unspecific pulmonary diseases and the appearance of disturbances of the ventilatory distribution. The functional disturbance metioned is further increased by the bronchial provocation and may partly be demonstrated in a characteristic way also in inconspicuous initial findings. The body-plethysmographic inhomogeneity parameter REmax/RE0 is, however, not suited for the early diagnosis of chronic unspecific pulmonary diseases, since with its help the verification of disturbances of the ventilatory distribution is successful only then, when the total resistance is already increased. For the final judgment of the aptitude of the bronchial reactivity test for the increase of the valency of methods of the distribution analysis in the early diagnosis further examinations are necessary.
On 62 welders and in a control group consisting of 90 test persons dynamic functional parameters of the lungs were established. In these cases welders older than 40 years after an activity lasting at least 2 decades gave references to a chronic obstructive disease of the respiratory tract, which after exclusion of other etiological factors may be regarded as a sequel of irritatively and toxically effecting welding fumes and gases.
In the last years the number of derivated electrocardiograms with several approaches to the problem has permanently increased. Therefore, the computer analysis seems to be obvious. The reliability of the analogo-digital-computer Express Analyzer Cardiograph EAC-2, Medexport Moscow, was for the employment for occupational medical examinations investigated on 252 experimental persons and compared with the independent manual analysis, which was carried out by two physicians. 80 per cent of the available ECGs were automatically correctly arranged into groups and all the inconspicuous electrocardiograms were sorted out, since it occurs on no account that an electrocardiogram which was recognized as pathological by means of manual analyses, was analysed as falsely normal by the computer EAC-2. Consequently, EAC-2 at low technical interference susceptibility may be very useful for the ECG-diagnosis by means of the computer during the screening investigations.