Sleep apnea is a form of sleep disordered breathing which, if left untreated, can have a substantial negative impact on a person's general health and overall quality of life. Sleep apnea is a relatively complex condition and it can seem overwhelming to those with no familiarity of sleep disordered breathing. In order to understand the concept of sleep apnea in its entirety, it is necessary to present a clear definition of an apnea.
The word "apnea" is of Greek origin and literally means "without breath". According to the American Academy of Sleep Medicine, an apnea is characterized by at least an eighty percent decrease of airflow for a period of ten seconds or longer. Apneas themselves are actually relatively common: a single apnea does not necessarily indicate the presence of sleep apnea, and most people experience apneas at least occasionally. A person is determined to have the condition of "sleep apnea" when they experience apneas consistently over an extended period of time, to the point where they are no longer able to feel adequately rested after sleep.
The term sleep apnea is often used as a shorthand for obstructive sleep apnea (OSA). Obstructive sleep apnea is actually just one of several specific forms of sleep apnea. The other major form of sleep apnea is called central sleep apnea (CSA). While we will discuss CSA, more than 80% of patients with sleep apnea have OSA, and unless otherwise indicated, that is the condition we'll be referring to.
In anatomical terms, OSA occurs as a consequence of mechanical failure of the airway system. During sleep, people with OSA experience a stoppage of breath because the upper airway and soft tissue collapse, creating an obstruction. People with OSA still make an effort to breathe during an apnea, and eventually they break through the obstruction and are able to breathe. However, the breath taken following an apnea causes patients with OSA to be jerked out of the REM stage of sleep and into a different sleeping stage. One of the consequences of this abrupt movement across stages of sleep is an unhealthy reduction in oxygen levels.
In addition to lowered oxygen levels, people with OSA do not receive adequate rest during sleep because they are unnaturally brought out of REM. Certain chemical processes occur during REM which enable the human body to fully rest itself; sleep apnea short circuits these processes, which causes people to be drowsy and fatigued while they are awake. Sleep apnea also negatively affects other processes which involve growth and glucose absorption.
OSA patients do not wake up when they fall out of REM; they remain asleep and unaware that a stoppage of breathing has occurred. This explains how an untreated sleep apnea sufferer can sleep a full eight hours and still not feel rested: the apnea doesn't entirely rouse the person and consequently, people with sleep apnea will not remember any sleep disruptions. This remains true even for people with severe forms of sleep apnea: a person may experience several apneas per minute and not recall waking up at all during the night.
The term "sleep apnea" encompasses a few distinct types of sleep disordered breathing. As discussed in the General Introduction, the AASM definition of sleep apnea is a recurring decrease of airflow of at least eighty percent for ten seconds or longer. However, sleep apnea manifests in several different ways, and these ways have been divided into specific classifications. The three types of sleep apnea are as follows - Obstructive Sleep Apnea (OSA), Central Sleep Apnea (CSA) and Mixed Sleep Apnea.
Obstructive Sleep Apnea
The great bulk - approximately ninety percent - of patients who suffer from sleep disordered breathing possess obstructive sleep apnea (OSA). OSA patients have physiological-mechanical problems which cause their airway to collapse periodically and prevent them from breathing properly during sleep; the distinguishing feature of OSA is that patients exert considerable effort during sleep but are still unable to overcome the stoppage to their breathing. Sleep specialists use "effort belts" to conclusively demonstrate whether a person is exerting effort to breathe while they are asleep.
Central Sleep Apnea
A small minority of those suffering from sleep disordered breathing have central sleep apnea (CSA). Though a division of sleep apnea itself, CSA actually encompasses two forms of abnormal breathing - Cheyne-Stokes respiration and periodic breathing. Unlike obstructive sleep apnea, patients with CSA are either significantly less able or altogether unable to exert effort to breathe during the periodic stoppages which occur during sleep. In CSA, there are no chest movements and no struggling by patients. CSA is neurologically controlled and is linked to the brain's inability to properly manage the body's respiratory system; the hypothesized cause of this is abnormal carbon dioxide levels in the blood. As with OSA, an effort belt can be used to confirm the diagnosis of CSA. Patients with CSA tend to obtain assistance after having their sleeping behavior observed by a friend, spouse or relative.
The two primary reasons for the development of central sleep apnea are heart problems and pain relieving medication (opioids). People also occasionally develop CSA as a consequence of high altitude; brain tumors are another, though considerably rarer, cause of central sleep apnea. Unlike patients who have OSA, patients with CSA essentially require artificial breathing during sleep - they require a machine which can breathe for them.
Mixed Sleep Apnea
An even smaller minority of patients have a mixture of central sleep apnea factors and obstructive sleep apnea factors - that is, they display characteristics which occur in both of these distinct forms of disordered breathing. Dealing with mixed sleep apnea is a difficult task and typically patients require a complicated treatment regimen.
While many people are unfamiliar with sleep apnea, the condition is not a modern health issue. Though significant progress in diagnosing and treating sleep apnea has occurred only within the past 50 years, the symptoms of sleep apnea -- including heavy snoring and daytime drowsiness -- have been noted for at least the last two millennia.
In the 19th century, sleep apnea was sometimes referred to as "Pickwickian Syndrome" due to the fact that a character from the Charles Dickens novel The Pickwick Papers appears to suffer from the disease. The character - Joe - was nearly always tired and sleepy and he had a habit of falling asleep frequently during the day. Pickwickian Syndrome is now considered to be essentially synonymous with Obesity Hypoventilation Syndrome (OHS) rather than sleep apnea, however, and modern medical science places less emphasis on obesity as a contributing factor to sleep apnea than the science of previous eras.
In 1965, the first polysomnograph successfully recorded apneas during sleep. Between 1970 and 1980, a substantial amount of research was conducted and many of the most foundational concepts in sleep apnea were uncovered. Perhaps the most significant breakthrough in the history of sleep apnea occurred in 1981 when Colin Sullivan, an Australian academic, physician and sleep disorder researcher, set forth his idea of non-invasive continuous positive airway pressure (CPAP) therapy in a paper published in the Australian journal The Lancet. Dr. Sullivan propounded that the mechanical problems associated with sleep apnea could be corrected with air pressure transferred through a face mask.
Dr. Sullivan had tested the first CPAP machine in 1980. A construction worker saddled with severe OSA came to Dr. Sullivan' practice, searching for any solution to the sleep problems that had plagued him for years. Initially prescribed a tracheotomy, the patient balked. Dr. Sullivan next recommended the use of positive airway pressure: he had devised a tube that attached to an airflow generator and - at the other end - to the patient' face. After experimenting with several pressure settings, the patient was eventually able to fall asleep; when he woke up, he told the doctor that it was the best he had slept in years.
From there, Dr. Sullivan tested his invention on several other patients. While his machine looked nothing like the CPAP devices available for use today, the basic mechanical function is largely the same. Today, the use of continue positive airway pressure (CPAP) is widely accepted as the best form of treatment for obstructive sleep apnea.
Since the publication of Dr. Sullivan's seminal paper, sleep physicians have continued to make improvements in our general understanding and treatment of sleep apnea. Considerable progress has been made in determining the risk factors, causes, associations and long-term consequences of the disorder. Patient comfort has also improved over time: thanks to medical research and patient feedback, treatment for sleep apnea is as unobtrusive and effective as ever. Patients can now receive excellent therapy outcomes without having to live with the uncomfortable and debilitating symptoms associated with untreated sleep apnea.
The only way to conclusively determine whether a given individual has sleep apnea is to obtain a sleep study in either a home or laboratory setting. Before obtaining such a study, it is advisable that people be on the lookout for a variety of symptoms which are known to result from sleep apnea. Sleep apnea is particularly likely to be present if several of these symptoms are displayed simultaneously. Below is a list of the classic symptoms of sleep apnea.
Observed breathing decrease
Sleep apnea is defined as an 80 percent or greater decrease in breathing for 10 seconds or longer. Many patients with sleep apnea have had someone observe such a decrease in breathing. Having an observer is an important form of visual confirmation of sleep apnea.
Snoring, particularly very loud snoring, is a familiar symptom of sleep apnea and is a normal consequence of airway failure.
Sleep apnea patients report excessive daytime sleepiness which results from inadequate rest. The level of tiredness and fatigue reported by patients exceeds that which would be justified based on their mental and physical responsibilities during the day.
Falling asleep in the middle of activities
Patients often report falling asleep without forethought in the middle of commonplace activities during the day (i.e. conversation, work, driving, etc.).
This is more subtle symptom which may not be present in every individual instance. Headaches may be caused by excessive carbon dioxide levels.
This is a subtle (and somewhat vague) symptom which is reported by patients and presumably results from inadequate rest.
Having only one of these symptoms may not necessarily indicate sleep apnea. As mentioned previously, The likelihood of sleep apnea increases significantly when several of these symptoms are present at the same time. Persons who possess one or more of these symptoms are encouraged to obtain a screening test.
Long Term Consequences
If left untreated, sleep apnea can cause a variety of serious health problems; this is true regardless of whether someone has a mild, middling or severe case of sleep apnea. The following is a list of some of the substantial health issues which can arise as a consequence of sleep apnea.
Sleep disordered breathing has been linked to the development of hypertension (or high blood pressure). Hypertension is a serious health issue and can have a severe negative impact on one's quality of life.
Sleep apnea has been linked to a number of different heart issues. The lungs of people with sleep apnea are restricted as a result of low oxygen levels, and this means the heart has to work harder to push blood through the system and keep the body functioning. Patients with sleep apnea have increased likelihood of heart attack, increased risk of abnormal heart rate and other heart problems as well.
Puffy or swollen ankles have been known to develop in some patients, particularly those suffering from more severe forms of sleep disordered breathing.
Patients who have sleep apnea possess a higher rate of diabetes when compared with the general population. However, as with obesity, it is not totally clear whether the association is a matter of correlation or causation.
There are several ways to clinically detect sleep apnea. The two main methods through which sleep apnea is detected are home sleep tests and laboratory based sleep tests. Though these tests are both effective in identifying the presence of sleep disordered breathing, they differ in ways which are potentially diagnostically relevant. However, before obtaining either a home or laboratory based sleep test, patients typically show clear symptoms of sleep apnea which are observed by others; as a result, they generally obtain a screening test, which is used as a filtering mechanism to sort out those who have a high probability of sleep apnea from those who do not.
While screening tests are aimed at the general public, home and laboratory based sleep tests are geared toward those who believe they have some form of sleep disordered breathing. Below are summaries of these two distinct tests; these summaries should be useful for patients who are unsure about which option they should select. As always, we also recommend that you make this decision with the help and consultation of your primary care physician.
Home Sleep Tests
Home based sleep examinations are an increasingly popular means to obtain a diagnosis for sleep disordered breathing. Home sleep tests are comparatively inexpensive and have the advantage of being able to provide a diagnosis in the comfort and privacy of a patient's home. Home tests typically involve high quality equipment and can produce reliable diagnoses on a consistent basis.
Home based examinations do have a few weaknesses, however: home tests often have difficulty in determining the precise pressure levels which should be used by patients; home tests also lack the ability to detect in which stage of sleep the patient is experiencing trouble. In general, home tests cannot account for many of the small details which distinguish one patient from another. Most troublingly, home tests are ineffective in the event of equipment failure. If a vital piece of equipment happens to fall off during the course of your therapy, you won't have an experienced technician to diagnose the problem and re-attach any disconnected machinery.
Laboratory Based Sleep Tests
Compared with home tests, laboratory based sleep tests offer a more comprehensive, detail-oriented means to arrive at a diagnosis for sleep apnea. Laboratory tests can either be conducted in a hospital setting or in an independent laboratory; patients who opt for a hospital laboratory test can expect to pay roughly twice what they would pay for an independent laboratory test. Both types of laboratory based sleep tests will have stand-by physicians capable of providing assistance and detailed individualized feedback. As mentioned earlier, laboratory sleep tests are more thorough than home tests and are able to determine with considerable accuracy the treatment solution for patients (i.e. pressure levels, equipment, etc.).
In short, home tests offer a relatively inexpensive diagnosis for sleep apnea, but may not be able to deliver a sufficiently detailed treatment plan. Laboratory based sleep tests are able to employ more sophisticated examination techniques and therefore offer a more complete diagnosis.
Developed in 1981 by Australian sleep physician Dr. Colin Sullivan, Continuous Positive Airway Pressure (CPAP) therapy is a medical technique which addresses the physiological issues possessed by those who have sleep disordered breathing. Patients who have sleep apnea experience mechanical failure of the airway during sleep and as a consequence are unable to receive adequate rest. CPAP therapy uses a constant stream of air to forcibly "push" the airway open and prevent it from collapsing so patients can have a healthy breathing cycle.
In CPAP therapy, patients use a variety of parts and supplies; the two primary tools used in therapy are the CPAP machine and mask. The CPAP machine is a sophisticated device which provides a constant stream of air at varying levels of pressure. The stream of air from the machine travels through a tube and a special facial mask and artificially corrects the periodic stoppages experienced by patients. The facial mask is supposed to form a personalized seal which prevents air from escaping and compromising the quality of your therapy.
There are a variety of machines used in CPAP therapy. The three main types of machines are standard CPAP machines, Bi-Level machines and Auto machines. Traditional CPAP machines deliver a fixed pressure level which is manually set and manually adjusted by the patient; Bi-Level machines typically have a wider range of pressure (usually between 5cm to 30cm) and are equipped with pressure relief technologies; Auto machines automatically make pressure adjustments during therapy to ensure that patients consistently receive proper pressure levels.
CPAP therapy also involves a variety of facial masks. The three main types of masks are nasal masks, nasal pillow masks and full face masks. Nasal masks are the most common type and have a soft cushion which usually covers the entire mouth; nasal pillow masks are somewhat less obtrusive and have a set of pillow cushions which sit just below the nares; full face masks have a cushion which typically covers a larger portion of the face and will prevent mouth breathing. Masks tend to generate a substantial level of difficulty for patients because adjusting to a mask involves discomfort and can be a nuisance. This is particularly true during the early stages of therapy.
Patients who use CPAP therapy to treat sleep disordered breathing reap numerous significant, life-altering benefits. People with untreated sleep apnea tend to suffer a range of negative consequences, such as depression, irritability, excessive daytime sleepiness, headaches, memory loss, sexual dysfunction as well as various performance deficiencies. What's more, patients also experience general heart problems, hypertension and swollen ankles. CPAP therapy can alleviate these symptoms and make a major contribution toward improving the patient's overall quality of life.
To help patients adapt to the new therapy, there are a number of techniques to help ease you into therapy. First, you can try wearing the mask for just a few hours per night initially. As you get used to the mask, you can eventually start wearing it for longer periods until you feel comfortable having it on all night long. Second, you can use the comfort features on your CPAP machine to help keep your pressure levels as comfortable as possible.
Patients who suffer from sleep disordered breathing are at a greater risk for a wide variety of health issues. Among these maladies are hypertension, general heart problems (including greater likelihood of heart attack), diabetes, depression, sexual dysfunction, excessive daytime sleepiness, memory loss, concentration problems and other issues as well. Hence, sleep disordered breathing affects both general health and quality of life. Fortunately, CPAP therapy has the potential to make a major positive contribution and significantly improve the lives of those who have sleep apnea.
In the short term, patients who comply and follow through with CPAP therapy will experience a substantial boost to their psychological and physical health. After using their CPAP equipment, patients can expect to wake up feeling more refreshed and rejuvenated; patients will feel rested, alert and ready to start a new day. Unlike most treatments, you won't have to wait long to see the results, either: as soon as patients begin using their equipment, they can expect to feel significantly better when they wake up in the morning.
Oftentimes, patients with untreated sleep apnea also experience morning headaches which can be highly irritating and painful. Headaches of this sort are the result of excessive carbon dioxide absorbed by the body. Patients will no longer experience headaches of this kind after they begin CPAP therapy. Patients who comply will also lessen the likelihood of developing the negative health issues described above.
More importantly in the long run, patients actively treating their sleep apnea can expect their risk of serious health concerns to dissipate. The risk of cardiovascular problems are caused by a lack of REM sleep: patients with sleep apnea have trouble breathing during REM and consequently, can't stay in REM long enough to recharge their bodies. This lack of REM disrupts many internal processes, and detrimentally affects the long term health of the patient.
CPAP changes all of that. Continuous positive airway pressure works to keep the patient's upper airway open, which allows them to get the airflow they need to breathe properly. Effective sleep requires a proper respiratory cycle, and once the airway has been propped open, there's no reason patients can't get the rest they require.
The ultimate consequence is that, not only do patients feel better on a day-to-day basis, but they can also rest easy knowing that the CPAP machine is making a dramatic difference in their long term health. With proper breathing, the patient will be able to get the refreshing REM sleep they need to function, and the body receives the kind of nourishing rest that keeps the heart happy and healthy.
Sleep apnea is an increasingly widespread health problem which afflicts approximately four percent of men and two percent of women, although these estimates are probably lower than the actual total of affected people. CPAP therapy is a reliable means to combat this health problem and improve general health and quality of life. You may also find that you're less argumentative and in a much better mood through the day.
CPAP Therapy is a reliable, safe and effective means to treat sleep disordered breathing and help patients improve both their general health and overall quality of life. However, even the most adeptly implemented therapy routine will occasionally have unwanted side effects. The side effects of CPAP therapy vary in type and magnitude; in general there are effects associated with airflow and pressure as well as problems stemming from the mask. No matter how unpleasant they may be, all of the side effects of CPAP therapy can either be eliminated or at least mitigated with a bit of effort.
Mask Side Effects
Adjusting to wearing a mask is one of the hardest parts of CPAP therapy. Adjusting to a CPAP mask requires a considerable amount of patience, effort and perseverance because CPAP masks often present a range of comfort and fitting issues. There are two main side effects associated with masks and, fortunately for patients, you can address both swiftly.
Facial marks and blemishes are among the most common side effects associated with masks. Occasionally, when the mask is removed following use, patients display marks and blemishes which are unsightly and unpleasant. The usual explanation for these marks and blemishes is an improper mask fit; however, these effects can also be caused by the type of cushion being used. The solution for facial marks and blemishes is straightforward: correct the fit or procure a different type of cushion material.
Another typical side effect of masks is general discomfort. As with facial marks and blemishes, discomfort is usually caused by an incorrect fit or an uncomfortable cushion material. Fixing a poor fit is typically quite simple: patients can make manual adjustments with their mask frame or headgear, or they can obtain a new mask size which better suits them. If patients cannot adjust to their cushion over time they have the option of obtaining a new cushion made of different material.
Airflow and Pressure Side Effects
Alongside masks, adjusting to the airflow and pressure levels of CPAP therapy is another common source of difficulty for patients. Having air artificially channeled down one' airway (at various pressure levels) is an unusual phenomenon and unsurprisingly it tends to bring about complications. Patients most often complain that airflow causes nasal irritation, nasal congestion, nasal dryness and throat soreness. One dependable means for treating these unpleasant effects is heated humidification: a heated humidifier will warm and moisturize the air before it is channeled through your airway and alleviate all of these various undesirable side effects.
There are several methods for helping patients adjust to the pressure levels of therapy. Certain machines include a special "ramp feature" which delays the onset of pressure for a specified period of time; with the ramp feature patients can fall asleep before they even notice the pressure levels of therapy. If patients have a non-auto machine they can manually adjust pressure levels to better suit them; auto machines will automatically adjust pressure levels to provide an individualized experience. Patients may need to obtain a new machine with a different pressure range if they find that their machine cannot provide the pressure levels they require.