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- Pulmonary Introduction
- Sleep Disorders
- Sleep Apnea
What is your Snore Score?- Quit Smoking
Prepare to quit
Using Medications
Staying Smoke Free- Asthma
Kinds of Medicines
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Sleep Disorders
The Bloomington Hospital Sleep Lab is directed by Drs. Wesley Ratliff and Russell Dukes. For information regarding sleep disturbances people should consult their primary care physician. Other sources of information include the Bloomington Hospital Sleep Lab (353-5740), or various Internet sites including Sleepnet ("everything you wanted to know about sleep but are too tired to ask") at http://www.sleepnet.com.
Sleeping problems are one of the most common medical concerns of the United States population. Insomnia is often taken for granted by the typical American as part of the living in a fast paced world.
Studies have suggested that at any time 20-40% of the US population suffers from insomnia at any given time, and as many as 9% suffer from insomnia on a chronic basis. Because our society tends to devalue sleep and people are fearful of being labeled as depressed, many (if not most) insomniacs do not seek medical attention. They subsequently suffer the consequences that occur with sleep deprivation. Although insomnia is the most common of the sleep disorders, it is not the most disabling.
Sleep disordered breathing is far more serious and just as equally undermanaged from a medical standpoint. Sleep disordered breathing is defined as any alteration in the respiratory pattern that occurs during sleep. It can be divided into two categories: sleep apnea (the cessation of breathing), or sleep hypopnea (a decrease in airflow during sleep).
The most common cause of sleep-disordered breathing is obstructive sleep apnea (OSA). OSA occurs when the sleeping patient stops breathing due to a temporary obstruction to airflow. This obstruction to airflow typically occurs in the posterior pharynx. Recent epidemiological studies have demonstrated that a surprisingly high prevalence of this problem. Approximately 4% of middle-aged men and 2% of middle-aged women were found to have OSA; unfortunately 95% of the 5-10 million Americans with OSA are unaware of their problem. This had led Dr. William C. Dement, director of the Stanford Sleep Disorder Clinic and Research Center, to claim that sleep deprivation and undiagnosed sleep disorders are America's number one health problem.
Whether it is caused by insomnia or sleep disordered breathing, sleep deprivation can lead to serious consequences. Excessive sleepiness is blamed for 200,000 to 400,000 motor vehicle accidents per year, accounting for nearly half of all accident related fatalities. Sleep deprivation also leads to poor job performance, increased chances of job related injury, and overall loss of productivity with significant economic impact. Insomnia is often undertreated due to patients reluctance to seek attention, but sleep disordered breathing can be undiagnosed due to its subtle onset and underappreciation of the typical signs and symptoms of the disease both by patients and physicians.
OSA is more common in men than women and has long been associated with obesity. The "typical" patient with severe OSA is a middle-aged male who is significantly overweight, snores loudly, and suffers from marked daytime sleepiness. Obesity has been shown to cause a decrease of the airway caliber in the posterior pharynx making it prone to collapse during sleep and subsequent obstructive sleep apnea. However, OSA can be found in the non-obese, and recent studies have suggested that neck size is a better predictor of OSA than obesity alone. Men with neck sizes larger than 16" to 17" and women with sizes greater than 15" to 16" should be considered at high risk of OSA.
Other anatomic abnormalities that decrease the airway size, can be: enlarged tonsils, tongue or jaw abnormalities, or some congenital deformities. All lead to an increased risk of OSA.
Sleep disordered breathing is usually confirmed with a sleep study (polysomnography). Sleep studies are typically performed in a sleep laboratory where the patient is kept overnight and multiple parameters are measured. These include respiratory effort and airflow, arterial oxygen saturation, sleep stages, limb muscle activity, and cardiac rhythm. The equipment needed to monitor these variables is not cumbersome and usually does not significantly interfere with sleep quality.
In order for patients to feel refreshed they need not only reasonable quantity of sleep, but also good quality sleep. Sleep that is fragmented and contains a decrease in REM (rapid eye movement) sleep will lead to excessive daytime somnolence. Thus quantifying different stages of sleep is an important variable to measure and reductions in REM sleep are classic findings in OSA.
From a breathing standpoint the major variable measured is the respiratory disturbance index (RDI). This is the number of apneic or hypopneic events that occur during an hour of sleep. RDI values of 5 or less are considered normal, typically patients DON'T have severe symptoms with an RDI of less than 20. Not uncommonly patients with severe OSA will have an RDI of 60 or greater (one event per minute of sleep)!
If polysomnography confirms the presence of significant OSA various treatment modalities are available. Often times the cases of mild OSA are largely positional in nature (occurring while patients are sleeping on their backs), these can be treated with devices to keep patients off their backs. Most other patients with more significant apnea will require therapy aimed at maintaining the potency of the airway in the posterior pharynx. These include weight loss, CPAP masks (a device that keeps the airway open by applying positive air pressure), oral appliances, and surgical techniques. Although most sleep authorities feel that nasally administered CPAP is the primary treatment modality at the present time, the optimal treatment for any single patient will depend on a number of factors.
It is also clear that at the present time none of the available treatment modalities is ideal and there is much research being undertaken in search of more permanent, successful, and better tolerated therapies.
Although excessive sleepiness is often the primary complaint of patients, OSA leads to many more serious medical problems. Patients with sleep apnea are at increased risk of hypertension, myocardial infarction (heart attack), congestive heart failure, and strokes. Patients with diagnosed but untreated OSA have clearly been shown to have a decrease in expected survival, largely due to excessive mortality from cardiovascular complications.
The importance of this information is magnified when one considers the possibility that only 5% of the patients in the US with OSA have been recognized and treated. This has lead Dr. Dement, considered by many to the be the father of American sleep medicine, to describe the US as "a vast reservoir of ignorance about sleep disorders." Fortunately the importance of sleep and sleep abnormalities is becoming more widely understood by the medical community. Diagnostic sleep laboratories have markedly increased in size and number in response to this problem. The Bloomington Hospital Sleep Lab performs over 300 sleep studies a year.
Pulmonary Introduction | Sleep Disorders
Sleep Apnea (What is your Snore Score?)
Quit Smoking (Prepare to quit, Using Medications, Staying Smoke Free)
Asthma (Kinds of Medicines, Special Hints)