Airway hyperresponsiveness (AHR) of small airways assessed by impulse oscillation (IOS) in adult asthma
| Autor: | Tetsuya Oguri, Osamu Takakuwa, Takamitsu Asano, Hisatoshi Hijikata, Hiroya Ichikawa, Yutaka Ito, Atsushi Nakamura, Ken Maeno, Takehiro Uemura, Akio Niiimi, Masaya Takemura, Kensuke Fukumitsu, Hirotsugu Ohkubo, Norihisa Takeda |
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| Rok vydání: | 2015 |
| Předmět: |
Spirometry
medicine.medical_specialty medicine.diagnostic_test Small airways business.industry medicine.medical_treatment Airway hyperresponsiveness respiratory system medicine.disease respiratory tract diseases Internal medicine Anesthesia Exhaled nitric oxide medicine Methacholine Respiratory system business Saline medicine.drug Asthma |
| Zdroj: | 5.3 Allergy and Immunology. |
| Popis: | Background: Small airways are likely involved in asthma, but whether small airways disease play relevant roles in specific asthma phenotypes is unknown. Only a few studies addressed AHR of small airways by using IOS in adult asthma. Purpose: To investigate AHR of small airways with a use of IOS and its relation to clinical and functional features. Method: Among stable asthmatics referred to our clinic from Aug 2013 to Jan 2015, 19 patients (mean age 44 yrs; 13 males; 7 taking inhaled steroid) who showed AHR to methacholine (Mch) at a prescreening and gave informed consent to the study were enrolled. They underwent IOS followed by spirometry at baseline and after inhalations of saline and doubling Mch concentrations (0.039 to 20 mg/ml) until FEV1 fell by 20%. Result: IOS indices R5 (respiratory resistance at 5 Hz) and R20 (that at 20 Hz) significantly increased after the final Mch dose of each patient. R5, an index of total airways resistance, increased by 88±41% (ΔR5), while R20, that of large airways resistance, changed by 25±21% (ΔR20). We classified patients by the ΔR20/ΔR5 ratio; in patients with the ratio of 0.7 (central AHR dominant group; n=9). Asthma duration and severity, history of childhood asthma, and exhaled nitric oxide levels did not differ. Conclusion: Asthma phenotype with small airways-dominant AHR likely exist, but larger studies are needed for further exploration. |
| Databáze: | OpenAIRE |
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