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Biomedical subjects

H P Hoffarth

Publications and source records attributed to H P Hoffarth.

At least 19 recordsLinked to original sources
PubMed1997

Nonspecific inhalative challenge tests--methods and importance.

Nonspecific bronchial hyperresponsiveness is a common symptom, the prevalence depends especially on the inhalative exposure and on the status of atopy. Testing of nonspecific bronchial hyperresponsiveness is easy to perform and can be done with different methods. They all are reliable and safe for the patient. To assess the result of provocation challenge, it is necessary to look at all lung function parameters as well as on the clinical signs. A lot of persons with nonspecific bronchial hyperresponsiveness develop a constant airway disease within the next years. So, early detection of nonspecific bronchial hyperresponsiveness is very important to control these patients or for starting therapy.

Anti-Asthmatic Agents↗
PubMed1994

[Bronchial hyperreactivity and obstructive respiratory tract diseases. A 2.8 year follow-up study].

BACKGROUND: Nonspecific bronchial hyperreactivity (BHR) is under discussion as a possible risk factor for the development of chronic obstructive pulmonary disease. METHOD: Within the framework of a prospective study, we investigated the course of the disease in 50 inpatients with BHR, and the clinical symptoms of airways disease (coughing, dyspnea and expectoration) with no manifest airways obstruction at rest (Rt < 3.5 cm H2O/l/s) on admission to the hospital. The unspecific inhalative provocation challenge was carried out with metacholine. The presence of BHR was assumed when the resting respiratory resistance (Rt) of < 3.5 cm H2O/l/s increased to more than 6 cm H2O/l/s. On admission to hospital, all the patients were treated with inhalative bronchodilators and glucocorticosteroids. RESULTS: After an average period of 2.8 years, BHR was no longer measurable in only 7 of the patients (14%), while 28 patients (56%) continued to have a BHR with clinical symptomatology presenting. In 15 patients (30%), manifest airways obstruction at rest, with an average Rt of 6.4 cm H2O/l/s developed. In patients with an uncharacteristic cough, dyspnea and unremarkable lung function parameters at rest, a provocation test should be done to identify BHR. A prognosis can, however, not be established on the basis of a single demonstration of BHR, but only after observation over a longer period.

Adult↗
PubMed1994

[Nonspecific inhalative provocation in the sheep as an asthma model--correlation of respiratory and cardiovascular effects].

Respiratory responses after inhalative challenge tests using methacholine (MCH) are intensively investigated and described in the literature. There is however a considerable lack of knowledge about the correlation of bronchoconstrictory responses to cardiovascular changes like pulmonary arterial pressure or blood gas tensions after unspecific challenges with methacholine or with specific allergens. Ten yearling sheep inhaled MCH-aerosols in increasing concentrations of 0.5, 1.0, 2.0, 5.0 and 10% for one minute respectively in 15 minutes intervals. Airway resistance (RI), dynamic elastance (Edyn) were measured along with systemic and pulmonary artery pressure. Transcutaneously measured oxygen partial pressure (PtcO2) was recorded and correlated to arterial blood gas samples. Mean threshold concentrations of MCH for changes in RI and Edyn were found at 0.9% and for PC100 of 2.2% MCH. Bronchoconstriction was detected with a latency of 30-40 s. Maximum responses occurred after 2-5 min (p < 0.0005) after onset of the challenge. Within 15 minutes, baseline values were almost reached. While mean inspiratory air-flow remained almost unaltered, increased airway resistance and work of breathing was compensated by an increased transpulmonary pressure. A decrease in tidal volume and a rise in respiratory frequency left ventilation almost unaltered. MCH-challenge results in insignificant changes in systemic arterial pressure, while pulmonary arterial pressure increased by more than 50% of the basic value. Arterial PO2 decreased by more than 20 mmHg and was closely correlated to transcutaneously measured O2-pressure (e = 0.93). However, PaCO2 did not increase significantly. (ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1993

[Whole body plethysmography for determining intrathoracic gas volume].

For early diagnosis of lung diseases the plethysmographic measurement of IGV is important. The influences of gases in the abdomen as the influences of pressure swings between mouth and alveolar space were several times investigated and did not show clinical relevance. The position of the mouthpiece in relation to the measured person should be taken carefully into consideration. We compared for the measurement of the occlusion-angel, which allows the calculation of the IGV, the panting- with the breathing going-on method. On 42 persons there were no significant differences between the results (o different laboratories: painting--breathing going-on = 2.8 resp. -0.6%). We prepare the breathing going-on method because it seems better that the person does not change his breathing level what could happen during the otherwise necessary instruction of the person.

Adult↗
PubMed1992

DNA damage in human white blood cells after inhalative exposure to methylenediphenyl diisocyanate (MDI)--case report.

A workplace-related inhalative exposure test in a challenge chamber was performed on an industrial worker in a methylenediphenyl diisocyanate (MDI) atmosphere from 5 to 20 ppb and the isolated white blood cell DNA was analysed by electrophoresis, anion-exchange chromatography and melting behaviour. The results of electrophoresis indicate that inhaled MDI induces double-strand breaks of DNA. Some of the DNA fragments were estimated to be in the region of 100-500 bp. Anion-exchange chromatography confirmed this finding. Following denaturation and rapid renaturation the results demonstrated that some DNA fragments are cross-linked by MDI. Comparing the melting curves before and after inhalative exposure in the challenge test chamber, genomic DNA revealed differences in the shape of the melting curve (hyperchromic effect). The results suggest that occupational MDI exposure could be associated with white blood cell DNA damage.

Administration, Inhalation↗
PubMed1991

[Assessment of cyclic and phasic oxygen saturation using pulse oximetry in the diagnosis of nocturnal respiratory disorders].

Nocturnal pulse oximetry is frequently used in screening studies when diagnosing nocturnal respiratory disorders. Short-term cyclic desaturations of oxygen can serve to indicate recurring apnoeas, whereas long-lasting phasic reductions of oxygen saturation are predominantly seen in hypoventilation. However, there are no uniform assessment criteria. We developed a computer programme for the differentiated assessment of cyclic and phasic oxygen desaturations. With this programme it is possible to characterise the individual phases in respect of gradient and duration of the decrease in oxygen saturation, of the starting, minimal and final values and the total duration of the desaturation phase. This enables determination of the rate of incidence of various forms of desaturation during nocturnal recording. The results of this differentiated analysis of nocturnal pulse oximetry in patients with sleep apnoea syndrome (n = 6) and with chronic obstructive airways disease with respiratory insufficiency (n = 6) and without respiratory insufficiency (n = 6) are demonstrated as model examples.

Apnea↗
PubMed1991

[Nocturnal oxygen saturation in patients with coronary heart disease--dependent on degree of left ventricular functional impairment].

It is assumed, that patients with coronary heart disease (CHD) more often suffer from sleep related disorders of breathing than healthy subjects. A relation to an impaired left ventricular performance is discussed. In 40 CHD-patients and 30 cardio-respiratory healthy controls we therefore measured arterial oxygenation during sleep by means of pulse-oximetry. Our results show a marked increase in the frequency of nocturnal oxygen-desaturations along with the degree of impaired left ventricular function independent of a special sleep apnea risk. In case of cardiac insufficiency at rest cyclical oxygen-desaturations were observed ten times as often as in the healthy controls. A central disturbance of the respiratory control, which leads to periodic breathing (type Cheyne-Stokes) has to be discussed. Because of the general high risk of CHD-patients concerning the development of nocturnal complications of their disease, sleep-related disturbances of ventilation have to be detected early by means of routinely applied screening-methods.

Adult↗
PubMed1991

[The inhalation 1 concentration test for the assessment of bronchial reactivity].

An unspecific bronchial provocation challenge with a 1-concentration test is a reliable method to distinguish between normal and hyperreactive persons. The patient inhales a bronchoconstricting substance such as methacholine. A significant change of lung function, for example an increase of airway resistance, characterizes a hyperreactive bronchial system. The continuous registration of transcutaneous oxygen pressure is helpful concerning a strong reaction or a peripheral airway obstruction. An exaggerated increase of airway resistance after provocation test can be treated rapidly by inhalation of sympathicomimetics. No complications were registered. Comparative studies showed a good reproducibility of this method. Summarizing, the 1-concentration test is simple, easy to perform and suitable especially for investigations in occupational medicine or epidemiology.

Airway Resistance↗
PubMed1990

[Inhalation therapy with selective beta 2-sympathomimetic drugs. Effect of pirbuterol administered via the Autohaler and salbutamol administered via the Diskhaler in obstructive respiratory tract disease].

The therapeutic success of salbutamol inhalation with the powder inhalator (Diskhaler) and of pirbuterol with an inhalation-triggered metered aerosol (Autohaler) was determined by comparing the degrees of bronchodilation in 13 patients suffering from chronic obstructive airways disease. Rt and IGV were determined by whole-body plethysmography and FEV1, peak flow and MEF50 by spirometry, and pulse rates were also measured. On average, Rt values decreased by 40 per cent; the other lung function parameters responded correspondingly. Duration of action extended to 4 hours after dosage. Pulse rates and lung functions measured after administration of the products did not differ, either. In such studies as this, whole-body plethysmographic results are superior to those obtained by spirometry.

Adult↗