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Use of continuous positive airway pressure reduces airway reactivity in adults with asthma.

ABSTRACT: Asthma is characterised by airway hyperreactivity, which is primarily treated with ?-adrenergic bronchodilators and anti-inflammatory agents. However, mechanical strain during breathing is an important modulator of airway responsiveness and we have previously demonstrated in animal models that continuous positive airway pressure (CPAP) resulted in lower in vivo airway reactivity. We now evaluated whether using nocturnal CPAP decreased airway reactivity in clinically-stable adults with asthma. Adults with stable asthma and normal spirometry used nocturnal CPAP (8-10 cmH(2)O) or sham treatment (0-2 cmH(2)O) for 7 days. Spirometry and bronchial challenges were obtained before and after treatment. The primary outcome was the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC(20)). The CPAP group (n=16) had a significant decrease in airway reactivity (change in (?)logPC(20) 0.406, p<0.0017) while the sham group (n=9) had no significant change in airway reactivity (?logPC(20) 0.003, p=0.9850). There was a significant difference in the change in airway reactivity for the CPAP versus the sham group (?logPC(20) 0.41, p<0.043). Our findings indicate that chronic mechanical strain of the lungs produced using nocturnal CPAP for 7 days reduced airway reactivity in clinically stable asthmatics. Future studies of longer duration are required to determine whether CPAP can also decrease asthma symptoms and/or medication usage.

SUBMITTER: Busk M

PROVIDER: S-EPMC4727535 | biostudies-literature | 2013 Feb

REPOSITORIES: biostudies-literature

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Use of continuous positive airway pressure reduces airway reactivity in adults with asthma.

Busk Michael M Busk Nancy N Puntenney Paula P Hutchins Janet J Yu Zhangsheng Z Gunst Susan J SJ Tepper Robert S RS

The European respiratory journal 20120726 2

Asthma is characterised by airway hyperreactivity, which is primarily treated with β-adrenergic bronchodilators and anti-inflammatory agents. However, mechanical strain during breathing is an important modulator of airway responsiveness and we have previously demonstrated in animal models that continuous positive airway pressure (CPAP) resulted in lower in vivo airway reactivity. We now evaluated whether using nocturnal CPAP decreased airway reactivity in clinically-stable adults with asthma. Ad ...[more]

PMID: 22835615

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Project description:INTRODUCTION:Although radiation therapy (RT) is an effective treatment for malignant atelectasis, its accurate delivery is challenging because of difficulty differentiating between tumor and atelectatic lung. Furthermore, reexpansion of lung during treatment repositions tumor and normal structures necessitating replanning to ensure treatment accuracy. Facilitating lung reexpansion before initiation of RT may improve RT treatment accuracy, spare normal tissue, and reduce obstructive symptoms. We report a case of reexpansion of right upper lobe (RUL) atelectasis caused by use of continuous positive airway pressure (CPAP) before RT. CASE REPORT:A 52-year-old woman presented with dyspnea and cough. Imaging studies showed an RUL mass with atelectasis. Bronchoscopy showed extrinsic compression of the RUL and middle lobe bronchi. Biopsy showed small cell lung cancer. Staging with positron emission tomography-computed tomography (CT) and contrast enhanced CT of brain showed no other disease. Following 4 cycles of platinum-based chemotherapy, CT imaging showed a decrease in tumor volume, but persistent RUL atelectasis. She agreed to participate in an institutional study to evaluate the use of CPAP to reduce respiratory motion and immobilize tumors during RT. During CPAP training, she complained of vertigo, headache, and weakness and refused simulation. The next day she reported less dyspnea and completed training and CT simulation without difficulty. CT simulation with CPAP showed reexpansion of the RUL. Lung volume increased from 2170 to 3767 mL (74 %). Gross tumor volume, clinical volume, and planning volume decreased 46%, 45%, and 38%, respectively. Mean lung dose and mean heart dose decreased 20% and 51%, respectively. CPAP was used daily for 1 hour before and during treatment. Cone beam CT scans showed that the RUL remained inflated throughout treatment. CONCLUSION:This is the first reported use of CPAP for reexpansion of atelectasis before RT planning and treatment. Reexpansion of atelectasis improved RT planning, decreased dose to uninvolved lung, and removed the need for replanning. Further study of CPAP as an initial intervention to improve RT delivery in patients with malignant atelectasis is warranted.

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Use of continuous positive airway pressure reduces airway reactivity in adults with asthma.

Publications

Use of continuous positive airway pressure reduces airway reactivity in adults with asthma.

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