Asthma and Sleep Apnea



The following is a copy of the ASAA article on the subject, written by Robert C. Basner, MD, and the link to the article:
**Asthma and Sleep Apnea -- ASAA article**

Asthma and OSA

By Robert C. Basner, MD

Obstructive sleep apnea (OSA) and nocturnal asthma are two distinct entities that come under the broad classification of "sleep-disordered breathing." Each of these disorders maybe mistaken for the other, since both may involve repetitive arousals associated with changes in oronasal airflow, respiratory effort and/or decreases in SaO2 during sleep. Thus, patients with asthma may not only have similar presentations to those with OSA, including daytime sleepiness secondary to sleep disruption, but nocturnal asthma may closely mimic OSA even on standard polysomnography.

COMMON FACTORS
Asthma and OSA may overlap in a significant number of patients. This may be due to the prevalence of each disorder in the population, but there are common pathophysiologic factors. Congestion of the nasopharynx and sinuses may predispose to worsening bronchoconstriction as well as OSA, as might the resultant mouth breathing, which itself could be a factor in both bronchoconstriction and OSA. Similarly, the presence of one of these entities may cause or worsen the other.

Irritation of the upper airways may predispose to decreased lung function at night. Sleep disruption secondary to asthma could cause periodic breathing and decreased upper airway muscle activity, two factors that may lead to upper airway obstruction during sleep. Finally, hypoxemia itself may predispose to increased bronchial reactivity.

TREATMENT
It has been shown that nasal CPAP is effective therapy for patients with concomitant OSA and asthma. In a small group of patients, CPAP improved both nocturnal and diurnal peak expiratory airflow up to two weeks after beginning therapy. When CPAP was applied in patients with nocturnal asthma only, nocturnal expiratory airflow was not improved, and sleep quality worsened.

The use of supplemental oxygen alone has been found to be beneficial in a limited number of patients with nocturnal hypoxemia due to asthma, but more studies need to be done to assess its safety and efficacy in this setting. These data illustrate the importance of accurate diagnostic assessment both clinically and in the sleep laboratory. Polysomnography in the patient with known or suspected asthma and OSA with and without CPAP titration is ideally done by a sleep technologist with credentials in respiratory care, and with meaningful supervision from a pulmonary or sleep physician.

During a nasal CPAP titration in a patient with known asthma, technicians need to be careful not to increase CPAP for respiratory events that are not upper airway obstruction. Assessing the patients for wheezing or obvious expiratory airflow limitation is particularly helpful in this regard. It is perferable to study such patients when asthma is relatively stable, since a fair assessment of the need for OSA treatment during a night of symptomatic asthma is difficult to achieve, and effective long-term CPAP levels are difficult to adjust under such circumstances. Providing bronchodilator therapy under the supervision of an RCP and physician can be very helpful in increasing patient comfort and ability to sleep, as well as in delineating asthma vs. upper airway obstruction.

PATIENT EDUCATION AND FOLLOW-UP
Education and follow-up are important for patients with concomitant asthma and OSA who have begun receiving CPAP. RCPs are in an excellent position to be of benefit in this setting. Peak expiratory airflow, symptoms of shortness of breath, wheezing, snoring, worsening sleep quality and/or daytime sleepiness should be routinely monitored. Chest pain or dyspnea during CPAP use should be immediately reported to the supervising physician. The need for warm air humidification in conjunction with the CPAP circuit should always be considered in the asthmatic patient.

The patient with asthma is at risk for sleep disruption secondary to medications commonly used for this condition. In particular, theophylline, beta adrenergic agents and systemic steroids have been associated with fragmented and generally non-restorative sleep. On the other hand, effective use of agents has been shown to improve sleep quality in nocturnal asthma. Patients should not withdraw themselves from asthma medications because they are feeling better on CPAP; such withdrawal can only be made in consultation with the supervising physician.

When asthma and OSA co-exist, successful treatment of one is dependent upon the accurate identification and effective treatment of the other. All RCPs have a role to play in the successful diagnosis and ongoing management of such patients.

Dr. Basner is associate professor of medicine in the respiratory and critical care section of the University of Illinois at Chicago College of medicine, and director of the Center for Sleep and Ventilatory Disorders at University of Illinois Hospital. He is also a member of the ASAA medical and research advisory committee.

Sleep Notes is produced in conjunction with the American Sleep Apnea Association. For information about the ASAA, contact them at 1424 K Street NW Ste. 302, Washington, DC 20005; 202-293-3650.

Sleep Tracks, Advance for Managers of Respiratory Care, April, 1996.


Article and link from the University of Michigan Health System, May 2005
University of Michigan Health System article - May 2005


Breathing disorders during sleep are common among asthmatics, may help predict severe asthma
UMHS research presented at American Thoracic Society meeting suggests doctors analyze sleep-related problems for clues to patients’ asthma

ANN ARBOR, MI When asthmatics are awake, they can turn to their inhalers to open their airways. But when they sleep, many of them continue to struggle with breathing – and an understanding of their sleep-related problems may help doctors better diagnose and treat their patients' asthma, according to new University of Michigan Health System research.

Symptoms of sleep apnea and other breathing problems during sleep are common among people with asthma, according to the research, which is being presented today at the American Thoracic Society's 2005 International Conference in San Diego.

Given this preliminary finding from an ongoing study, researchers say doctors should examine their asthma patients' sleep patterns more often, especially when the patients continue to have trouble even with regular use of inhalers and other common asthma treatments.

“The more you look for sleep apnea in patients with asthma, the more you find it,” says William F. Bria II, M.D., medical co-director of the UMHS Asthma Airways Program and associate professor of internal medicine in the U-M Medical School.

“This tells us that a lot more people with asthma need to have sleep studies,” Bria says. “When patients are having problems with asthma, their doctors need to look at more than whether they are taking enough puffs from their inhalers.”

Researchers examined the connection between sleep-related breathing disorders by giving questionnaires to patients with asthma. Of the 115 subjects included in the study so far, most were in one of the most severe stages of asthma.

Most participants were being treated for asthma with inhalers and other medications, but they were still symptomatic, says Mihaela Teodorescu, M.D., a pulmonary medicine specialist, research fellow in sleep medicine and a lecturer at UMHS, who is presenting the findings at the ATS meeting and who is leading the study.

Large percentages of the people included in the study – 33 percent of men and 49 percent of women – were found to be at risk for obstructive sleep apnea, a condition in which people stop breathing for periods of time during sleep.

Those numbers are based on the symptoms of sleep apnea reported by the subjects, including 86 percent who said they snored with any frequency, 38 percent who snored regularly and 31 percent who said a family member had witnessed their pauses in breathing during sleep. The symptoms of sleep apnea were related to the severity of asthma, independent of other conditions that could influence asthma. In addition, 55 percent of these people said they experienced excessive daytime sleepiness.

Although the study is still ongoing, Teodorescu says the early findings should encourage doctors to consider sleep apnea as a possible aggravating condition in their asthma patients.

“We hope that eventually, by addressing this earlier, we'll be able to help sooner with patients' asthma control,” Teodorescu says.

These early findings offer one more reason people should be tested for sleep disorders, a vast majority of which are under-diagnosed, says Ronald Chervin, M.D ., M.S., director of the Sleep Disorders Center and Michael S. Aldrich Sleep Disorders Laboratory at UMHS. Some 80 percent of men and 90 percent of women who have sleep apnea don't know it, he says.

“We might be able to control some of these patients' asthma better if we could identify and treat their apnea,” says Chervin, associate professor of neurology at the U-M Medical School.

He also notes that many asthmatics complain of daytime sleepiness, which is often assumed to be a result of the asthma itself. Instead, the study is finding that apnea symptoms rather than asthma severity best predict daytime sleepiness. The investigators hope that attention to the overlap of sleep apnea and asthma might one day lead to better nighttime sleep and daytime alertness for asthmatics.

In addition to Teodorescu, Bria and Chervin, the authors are Flavia Consens, M.D., clinical assistant professor of neurology; Michael Coffey, M.D., associate professor of internal medicine; Ann Durance, R.N., a clinical nurse at UMHS; Kevin Weatherwax, a project associate in the Department of Neurology; John Palmisano, clinical coordinator in the Department of Neurology; Peter Mancuso, Ph.D., assistant professor at the School of Public Health; and Jesica Pedroza, all from the University of Michigan; and Srinivas Bhadriraju, M.D., of Emory University and formerly of the University of Michigan.

The research is funded by the National Institutes of Health, through the support of the U-M General Clinical Research Center and a UMHS neurology training grant.

For more information about the UMHS Asthma Airways Program, visit www.med.umich.edu/intmed/allergy/asthma.htm. For more information about the UMHS Sleep Disorders Center and Michael S. Aldrich Sleep Disorders Laboratory, visit www.med.umich.edu/neuro/sleeplab/.

Reference: American Thoracic Society annual meeting, poster abstract D97/501.
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Links to other articles on Asthma and Sleep Apnea:

The Impact of Sleep-Disordered Breathing on Other Airway Diseases, Pulmonary Reviews.com, January 2006