Millions of people suffer from various types of respiratory disorders that cause abnormal breathing patterns. Examples of such respiratory disorders include sleep apnea, asthma and emphysema, each of which is briefly discussed below.
Sleep Apnea
Sleep apnea is a disease in which breathing ceases during sleep. It is associated with increased mortality and morbidity, including sudden death, heart failure, hypertension, stroke, and neuropsychiatric and behavioral disturbances.
Obstructive sleep apnea (OSA) is a very common type of sleep apnea, which often affects obese persons. This disorder occurs when a person's upper airway becomes partially or completely blocked, causing breathing to be interrupted intermittently during sleep. The blocked or obstructed breathing prevents deep stages of sleep, often resulting in daytime drowsiness.
There are a number of different reasons that the upper airway can become obstructed. For example, obstruction can result from upper airway abnormalities, such as enlarged tonsils or enlarged adenoids. Other upper airway abnormalities may result from obesity, an abnormally wide neck, or from an anatomically narrowed upper airway. Such abnormalities often result in excess tissue within the throat, which cause the upper airway to become blocked when throat muscles relax during sleep.
The most commonly prescribed treatment for obstructive sleep apnea is continuous positive airway pressure (CPAP). In CPAP treatment, the patient sleeps wearing a facial or nasal mask that delivers air pressure that stents the airway open. For many patients, CPAP therapy works well. However, many other patients find the masks very uncomfortable, preventing them from sleeping, and often causing them to remove the masks and thus avoid their treatment. Further, CPAP therapy has had no effect in some patients and has even resulted in increased episodes of apnea in some patients.
Other conventional treatments for obstructive sleep apnea include use of anti-depressant drugs, such as protriptyline (often marketed as Vivactil™ or Triptil™). In addition to not always being effective, protriptyline has a number of side effects, such as dizziness, drowsiness, dryness of mouth, headaches, increased appetite, nausea, tiredness or weakness, unpleasant taste and weight gain. Less frequent side effect include diarrhea, heartburn, increased sweating, trouble in sleeping, and vomiting. There are also rare but more severe side effects, such as blurred vision, confusion or delirium, constipation (especially in the elderly), decreased sexual ability (more common with amoxapine and clomipramine), difficulty in speaking or swallowing, eye pain, fainting, fast or irregular heartbeat (pounding, racing, skipping) and hallucinations.
OSA can also be treated surgically. However the costs are high, the risks are high, and the success rates vary greatly depending on the procedure and the experience and skills of the surgeon. Additionally, the surgery can affect speech and the ability to swallow.
Another type of sleep apnea is central sleep apnea (CSA), which is a different than OSA. CSA is a neurological disorder that results from problems with breathing control mechanisms, as opposed to airway blockage (as with OSA). CSA can occur, for example, due to the portion of the brain that controls breathing failing to signal the body to breathe. Persons suffering from CSA are often awoken during sleep, leading to sleep deprivation, and thus, daytime drowsiness.
While CPAP therapy is sometime used with patients suffering from CSA, other types of mechanical ventilation are often the only treatment available to ensure continued breathing. Unfortunately, complications may result from prolonged mechanical ventilation.
A further type of respiratory disorder that occurs during sleep is hypopnea, which is generally defined as decrease in airflow by at least 50% for ten seconds or more. In this document, hypopnea will be considered a type of sleep apnea, even though shallow breathing continues during hypopnea.
Diagnosis of sleep apnea is not simple because there can be many different reasons for disturbed sleep. While there are various tests for evaluating a person for sleep apnea, most are very expensive and sometime inconclusive. Typically a patient is required to sleep overnight at a sleep treatment center, so that the patient can be monitored and diagnosed. Such overnight stays are typically very expensive and are sometimes inconclusive because the patient either did not exhibit their normal sleep patterns or because the patient does not experience sleep apnea every night. Additionally, since treatments for OSA and CSA are often different, it is important that the type of sleep apnea be accurately diagnosed.
As is evident from the above description, there is the need for improved systems and methods for diagnosing sleep apnea and treating sleep apnea. This will allow appropriate treatments to be prescribed. Further, even after a treatment is being provided, it is important to chronically monitor a person's breathing in order to determine if specific treatments are working, to determine if treatments can be fine tuned and/or to determine if alternative treatments should be used.
Asthma
Asthma is a disease of the respiratory system, which includes a person's nose, mouth, trachea, lungs, and air tubes or airways that connect the nose and mouth with the lungs (these tubes are called bronchi and bronchioles). When a person breathes, the muscles that are wrapped around the airways are very loose and relaxed. Since the lining inside the airways is very thin, the relaxed state of the muscles allows the airways to open widely so that air easily passes in and out of the small air sacs (called alveoli) that make up the lungs. Breathing includes the moving of air in and out of the lungs.
During an asthma attack, the muscles around the airways tighten, or “spasm” and the lining inside the airways swell or thicken, and become blocked with thick mucous. This makes the airways much thinner than usual so it is harder to move air in and out of the air sacs, making it difficult to breathe. During an asthma attack, it is actually harder to breathe out than it is to breathe in. This means that during an asthma attack, it takes much longer to breathe out (expire) than it does to breathe in (inspire). Since it is so hard to breathe out during an asthma attack, more and more air gets trapped inside the lungs making a person feel like they can't breathe in or out.
There are different types of asthma, including allergy-induced asthma and activity-induced asthma. Additionally, there are different severities of asthma, including mild, intermittent, moderate and severe asthma. Different types of asthma and different severities of asthma may be treated in different manners. Accordingly, it is desirable to be able to obtain information that is useful in diagnosing the type and/or severity of a person's asthmatic condition. Further, even after a person's asthma has been diagnosed, the proper treatment needs to be provided. Treatments include medication, altering diet and/or altering activities. However, even if two different people have the same symptoms, they may not react in the same way to the same treatment. That is, not all types of treatments work well with all people. Accordingly, even after a treatment regimen has been prescribed, it is important to chronically monitor a person's breathing in order to determine if specific treatments are working, to determine if treatments can be fine tuned and/or to determine if alternative treatments should be used.
Emphysema
Emphysema is an abnormal condition of the lungs, which belongs to a group of conditions called Chronic Obstructive Pulmonary Disease (COPD). Emphysema, which generally develops gradually over a number of years, typically results in an increased shortness of breath, not relieved by sitting upright, and a chronic cough. The shortness of breath is generally worse on exertions such as walking up a flight of stairs or eating a big meal. Eventually, breathing becomes harder and harder causing fatigue, weakness, and weight loss. Emphysema can result for various reasons, such as chronic bronchitis, or chronic irritation to the lungs by dust, pollution, and cigarette smoking. Such chronic irritations cause the tiny air sacs in the lungs to loose their elasticity and become distended, causing inhaled air to become trapped in the air sacs. As with most respiratory disorders, there is no cure for emphysema but there are numerous treatments that can help relieve the shortness of breath.
There are different causes and severities for emphysema, each of which can be treated in multiple different manners. Accordingly, it is desirable to be able to obtain information that is useful in diagnosing the type and/or severity of the emphysema. Further, even after a treatment is being provided, it is important to chronically monitor a person's breathing in order to determine if specific treatments are working, to determine if treatments can be fine tuned and/or to determine if alternative treatments should be used.
As can be appreciated from the above description, it would be useful to provide a means for temporarily and/or chronically monitoring various breathing disorders in order to properly diagnose the disorders, treat the disorders, and monitor the treatment of the disorders.