The Bronchial Response, but not the Pulmonary Response to Inhaled Methacholine Is Dependent on the Aerosol Deposition Pattern
| Autor: | Hans Hedenström, Mary Kämpe, Birgitta Schmekel, Lars Lagerstrand, Gunnemar Stålenheim, Göran Hedenstierna, Per Wollmer |
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| Rok vydání: | 1994 |
| Předmět: |
Adult
Male Pulmonary and Respiratory Medicine medicine.medical_specialty medicine.drug_class Specific Airway Conductance Critical Care and Intensive Care Medicine Bronchial Provocation Tests Internal medicine Bronchodilator Ventilation-Perfusion Ratio medicine Humans Radionuclide Imaging Lung Methacholine Chloride Aerosols Multiple inert gas elimination technique Pulmonary Gas Exchange business.industry Airway Resistance respiratory system medicine.disease Asthma respiratory tract diseases Aerosol Deposition (aerosol physics) Bronchial hyperresponsiveness Anesthesia Cardiology Technetium Tc 99m Pentetate Arterial blood Female Methacholine Blood Gas Analysis Bronchial Hyperreactivity Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | Chest. 106:1781-1787 |
| ISSN: | 0012-3692 |
| DOI: | 10.1378/chest.106.6.1781 |
| Popis: | The clinical effect of inhaled radio-labeled (Technetium-99m diethylenetriamine-pentaacetic acid) methacholine was studied in two separate experiments performed in eight symptom-free asthmatics with bronchial hyperresponsiveness. Aerosols were formed by two different nebulizers, producing either mainly small aerosol particles (2-microns mass median aerodynamic diameter [MMAD]) for peripheral, or mainly large aerosol particles (9-microns MMAD) for large airway deposition. The intended site of deposition was confirmed by gamma camera recordings. Changes in specific airway conductance (sGaw) were set as an index of central airway constriction, and functional alterations in the gas exchanging parts of the lung were estimated by multiple inert gas elimination technique (MIGET) and arterial blood gas analyses. The main finding was that the responses, as measured by the changes in arterial blood gases and by MIGET, were similar in the two experiments, while the fall in sGaw was significantly larger after deposition in the main bronchi than in the peripheral airways (p0.05). The time courses of the abnormalities in the gas exchanging elements were much longer than those of the responses of the central airways, and the abnormalities were recorded still at the end of the experiment 2 h after challenge in most patients. A discrepancy in dose dependency and time courses suggests differences in mechanism and/or dynamics of the responses exerted by the various target organs. Interaction in the process of clearance from the lung of inhaled methacholine by the bronchial circulation may have contributed to the observed discrepancies. |
| Databáze: | OpenAIRE |
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