Positive Airway Pressure for the Treatment of Asthma
研究概览
地位
详细说明
Asthma is a chronic respiratory disease characterized by airway inflammation and airway hyperresponsiveness, which causes airflow obstruction. It is extremely prevalent, affecting an estimated 22 million Americans, and costly with loss of productivity and direct healthcare costs in the billions of dollars. The incidence and prevalence of asthma are increasing, both in the US and around the world. This increase comes despite greater understanding of the inflammatory and allergic basis for asthma, and despite better antiinflammatory medications. One explanation for the increasing prevalence of asthma is the concomitant increase in obesity, with the majority of Americans now overweight or obese. Numerous studies have convincingly linked asthma and obesity, and demonstrated increased obstruction with weight gain and decreased obstruction with weight loss. However, the mechanisms that underlie this linkage are not known.
We believe that low lung volumes contribute to the pathogenesis and severity of asthma. End-expiratory lung volume is decreased in obesity, and likely falls further during sleep, particularly in overweight and obese patients. Both upper and lower airway resistance increase with decreasing lung volumes, as airways become smaller. However, prior work has shown that lower airway resistance increases out of proportion to the decrease in lung volume that occurs during sleep in asthma patients. This difference between controls and people with asthma has not been further explored, yet may provide insight into asthma pathogenesis and provide potential targets for therapy.
Therefore, we propose a series of experiments to define the impact of lung volumes during sleep on airway resistance. One of these experiments will be to to test the hypothesis that lung stretch can be used therapeutically by tonically and dynamically increasing lung volumes during sleep using bi-level positive airway pressure. This research can help delineate asthma pathogenesis and may help improve therapeutic options in this exceedingly common disease.
研究类型
注册 (实际的)
阶段
- 不适用
联系人和位置
学习地点
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Massachusetts
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Boston、Massachusetts、美国、02115
- Brigham and Women's Hospital
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参与标准
资格标准
适合学习的年龄
接受健康志愿者
有资格学习的性别
描述
Inclusion Criteria:
- mild to moderate asthma, diagnosed by a physician, OR
- mild to moderate asthma and CPAP treated OSA. Must be compliant with CPAP therapy (greater than 4 hours per night, at least 4 nights/week)
Exclusion Criteria:
- lung disease other than asthma or OSA
- medications known to affect respiratory function (apart from asthma and rhinitis therapy)
- abnormal nasal anatomy
- current smokers and ex-smokers (quit within the last 3 months, or >10 pack-years)
- pregnant women - women of child bearing age will undergo a urine pregnancy test before enrollment and during the course of the study, as some of the study procedures cannot be performed during pregnancy and because pregnancy often changes asthma symptoms and severity.
- severe asthma - defined as a recent exacerbation (doctor or ER visit for asthma, or oral steroid use, within the previous 4 weeks) or frequent exacerbations (>4 exacerbations in the last year.
- severe obstructive sleep apnea requiring supplemental oxygen in addition to CPAP therapy.
- the regular use of prescription (e.g. zolpidem) or over-the-counter sleep aids (e.g. Benadryl).
- Central sleep apnea
学习计划
研究是如何设计的？
设计细节
- 主要用途：治疗
- 分配：随机化
- 介入模型：交叉作业
- 屏蔽：无（打开标签）
武器和干预
参与者组/臂 |
干预/治疗 |
|---|---|
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实验性的：Usual Care first, then Bilevel PAP
Subjects will begin the study by continuing their usual care for 4 weeks.
They will complete questionnaires and breathing tests at the start and end of this 4 week period.
After a "Washout Period" of an additional 4 weeks of usual care, they will then start Bilevel PAP therapy for 4 weeks.
Just before and after the Bilevel PAP they will complete questionnaires and breathing tests.
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Subjects will use bilevel PAP each night for 4 weeks.
The pressure levels will be adjusted by the investigators to increase lung volumes during the night.
其他名称：
Subjects will continue with their usual asthma care.
Investigators will make no changes to their medications or other habits.
Subjects will continue with their usual asthma care in between the Usual Care and Bilevel PAP periods.
Investigators will make no changes to their medications or other habits.
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实验性的：Bilevel PAP first, then Usual Care
Subjects will begin the study by starting on Bilevel PAP for 4 weeks.
Just before and after the Bilevel PAP they will complete questionnaires and breathing tests.
After a 4 week "Washout Period" of usual care, they will start a Usual Care period for 4 weeks.
They will complete questionnaires and breathing tests at the start and end of this 4 week period.
|
Subjects will use bilevel PAP each night for 4 weeks.
The pressure levels will be adjusted by the investigators to increase lung volumes during the night.
其他名称：
Subjects will continue with their usual asthma care.
Investigators will make no changes to their medications or other habits.
Subjects will continue with their usual asthma care in between the Usual Care and Bilevel PAP periods.
Investigators will make no changes to their medications or other habits.
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研究衡量的是什么？
主要结果指标
结果测量 |
措施说明 |
大体时间 |
|---|---|---|
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Asthma Control Test
大体时间：Every 4 weeks during the 12 week study (at the start and end of the Usual Care period, and at the start and end of the Bilevel PAP intervention period)
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Well validated questionnaire of asthma symptoms which includes 5 written questions.
Each question is answered on a scale of 1-5, which are summed to report a range of asthma control from 5 to 25 (higher score indicates better asthma control).
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Every 4 weeks during the 12 week study (at the start and end of the Usual Care period, and at the start and end of the Bilevel PAP intervention period)
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Airway Reactivity as Measured by Methacholine Challenge (PC20)
大体时间：Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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This is a physiological measurement derived from repeated breathing maneuvers which measures airway reactivity.
Subjects are exposed to higher and higher concentrations of an airway irritant (in this case methacholine), and between each dose perform spirometry.
The test is stopped after the forced expiratory volume in 1 second (FEV1) falls 20% below the baseline.
The concentration of methacholine at which this occurs is called the PC20.
Methacholine challenges are routinely used in the diagnosis of asthma, and in many asthma research studies to measure changes in airway reactivity.
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Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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次要结果测量
结果测量 |
措施说明 |
大体时间 |
|---|---|---|
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Epworth Sleepiness Scale (ESS)
大体时间：Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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8 item questionnaire to measure daytime sleepiness, with total score reported 0 (less sleepy) to 24 (most sleepy).
Scores greater than or equal to 10 are considered excessive daytime sleepiness.
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Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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Pittsburgh Sleep Quality Index (PSQI)
大体时间：Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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Well validated questionnaire used frequently to measure sleep quality over the prior 1 month.
It consists of 19 individual items that combine to form 7 components summed to create one global score.
The overall score is between 0 (better sleep) and 21 (worse sleep).
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Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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Short Form (SF-36) Health Survey
大体时间：Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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Well validated quality of life questionnaire that measures eight sub-sections, which are summed to yield a score from 0 (maximal disability) to 100 (no disability).
The eight subsections are: vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning, mental health.
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Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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FEV1 %Predicted
大体时间：Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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Performed as part of spirometry
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Every 4 weeks during the 12 week study (at the start and end of the usual care period, and at the start and end of the Bilevel PAP intervention period)
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合作者和调查者
调查人员
- 首席研究员：Robert L Owens, MD、Brigham and Women's Hospital
研究记录日期
研究主要日期
学习开始
初级完成 (实际的)
研究完成 (实际的)
研究注册日期
首次提交
首先提交符合 QC 标准的
首次发布 (估计)
研究记录更新
最后更新发布 (实际的)
上次提交的符合 QC 标准的更新
最后验证
更多信息
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