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DYSPNEA
American Thoracic Society- Consensus Statement on Dyspnea
American Journal of Respiratory and Critical Care Medicine/MedscapeWire
Breathing discomfort or significant breathlessness is a serious problem for many persons in the U.S. Approximately 14 million Americans suffer from chronic obstructive pulmonary disease (COPD). Another 10 million citizens (approximately five percent of the population) have asthma. When interstitial lung disease, neuromuscular disorders, lung cancer, and cardiac disease are added to the mix, it is clear that many people suffer from the difficult, labored, uncomfortable breathing known as dyspnea.
The January issue of the American Journal of Respiratory and Critical Care Medicine includes a consensus statement on dyspnea by 18 experts from the American Thoracic Society which was endorsed by the ATS Board of Directors. A unifying theory about dyspnea or significant breathlessness is that itresults from a mismatch between central respiratory motor activity and the incoming information from receptors in the airways, lungs, and chest wall structures. This disassociation between the motor command and
the mechanical response of the respiratory system frequently produces a sensation of respiratory discomfort that afflicts millions of people.
As pointed out in this consensus statement, respiratory diseases such as COPD and asthma, which narrow airways and increase airway resistance, as well as diseases of the functional part of the lung such as pulmonary fibrosis, commonly cause dyspnea. However, dyspnea, like hunger or thirst, is largely a sensation which arises from multiple sources rather that from stimulation of a single neural receptor. Also, the severity of dyspnea, as well as the sensation of breathlessness, varies widely among patients.
In many cases, the primary problem behind dyspnea involves heart, lung, or neuromuscular abnormalities, which physicians identify by taking a history and doing a physical exam. Then doctors focus on the symptoms of breathlessness, including trying to determine quality, intensity, duration, frequency, and the amount of distress or discomfort. In the statement, physicians are urged to distinguish between two broad categories:
conditions associated with cardiovascular dyspnea involving inadequate oxygen delivery to the tissues; and
pulmonary dyspnea or conditions associated with a heightened respiratory drive, altered pulmonary mechanisms, or gas exchange abnormalities.
Sometimes the problem involves a combination of symptoms associated with two major illnesses such as COPD and congestive heart failure. According to the consensus statement, even after dealing with the underlying problem such as heart disease, the patient often continues to experience significant breathlessness. Many of the therapeutic interventions suggested by this consensus statement relieve dyspnea by addressing different pathophysiologic mechanisms in the body, such as improving respiratory muscle function and altering central perceptions of the problem.
These include:
1. Exercise Training
Controlled studies have shown that dyspnea upon exertion decreases and exercise tolerance improves in response to exercise training, even in patients with advanced disease. It is now well established that for patients with COPD who remain breathless despite optimal drug therapy, exercise training can confer significant symptomatic benefits.
2. Pharmacologic Therapy
Two types of medications have proven useful in alleviating dyspnea: opiates and drugs that reduce anxiety. A number of studies have shown that opiates acutely relieve dyspnea and improve exercise performance in patients with COPD. The drugs to reduce anxiety have the potential to relieve ventilatory response related to the available amounts of oxygen in the blood, as well as by lowering the emotional response to dyspnea.
3. Fans
The movement of cool air with a fan has been observed to reduce dyspnea in pulmonary patients. A decrease in the temperature of the facial skin alters feedback to the brain and modifies the perception of dyspnea. Cool air has been shown in normal volunteers to reduce dyspnea in response to excess carbon dioxide in the blood.
4. Altered Breathing Patterns
Breathing retraining including diaphragmatic breathing and pursed lip breathing has been advocated to relieve dyspnea in COPD patients. During a breathing retraining period, many patients adopt slower, deeper breathing techniques; however, they often resort to spontaneous, fast, shallow breathing patterns when the training ends.
5. Continuous Positive Airway Pressure (CPAP)
In various studies, CPAP has been shown to relieve dyspnea during asthma attacks, when patients are being weaned from ventilators, and during exercise sessions for patients with advanced COPD.
6. Nutrition
Several investigators have shown improvement in respiratory muscle function in response to short-term use of nutritional repletion by an intravenous route.
7. Positioning
Patients with COPD often change body position to improve dyspnea. They tend to lean forward to improve overall respiratory muscle strength and to reduce their symptoms.
8. Steroids
Steroid use can be beneficial to pulmonary patients by reducing airway inflammation and by increasing vital capacity in chronic lung inflammation. However, steroids have adverse effects, including muscle wasting and weakness. These potential problems need to be balanced against possible gains in lung function associated with this drug. Cognitive-behavioral Approaches In patients with different pain syndromes, distraction, relaxation, and education about symptoms have modified the intensity of pain, increased tolerance, and decreased distress. Improvements in dyspnea and anxiety have been shown to follow distractions such as music during exercise, although long-term effects have been minimal. However, exercise in a monitored, supportive environment has been shown to be a powerful method of overcoming apprehension, anxiety, and/or fear associated with exertional dyspnea.
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How patients feel about dyspnea
Few research studies have examined dyspnea from the patient's perspective. But in one retrospective study, hospitalized patients pointed to five recurring themes: fear, helplessness, loss of vitality, concern about legitimacy, and preoccupation.
According to the patients, dyspnea triggered fear, which made the problem worse by making breathing more difficult. The patients also said that they felt helpless because they couldn't control their breathing.
The patients reported feeling a loss of vitality--with vitality being defined as the will to live. Patients were also concerned whether caregivers viewed their complaints as legitimate. Because dyspnea is a subjective complaint,
it can't be "proven." The last theme was preoccupation with the problem. The patients believed that if they didn't concentrate on their breathing, they might stop breathing, which contributed to the anxiety-dyspnea cycle.
Researchers also asked the patients what helped them during an acute episode of dyspnea. Their answer? "To be cared for by a knowledgeable and compassionate nurse." The patients needed to know that the nurse understood how frightened they were. Nurses who acknowledged the patients' fear, remained calm, and demonstrated breathing techniques helped moderate their fear.
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Lung or Respiratory Disease:
What do the lungs do?
The main function of the lungs is (rapid) gas exchange. This is accomplished by a well-coordinated interaction of the lungs with the central nervous system, the diaphragm and chest wall musculature, and the circulatory system.
Gas exchange occurs in the alveolus where the thin laminar blood flow and inspired air are separated only by a thin tissue layer. Gas exchange takes 0.25 seconds or 1/3 of the total transit time of a red cell. The entire blood volume of the body passes through the lungs each minute in the resting state, that is 5 liters per minute. The total surface area of the lung is about 80 meters square, equivalent to the size of a tennis court.
Only about 10% of the lung is occupied by solid tissue, whereas the remainder is filled with air and blood. Supporting structures of the lung must be delicate to allow gas exchange, yet strong enough to maintain architectural integrity, that is sustain alveolar structure. The functional structure of the lung can be divided into (1) the conducting airways (dead air space), and (2) the gas exchange portions. The two plumbing systems are: airways for ventilation, and the circulatory system for perfusion. Both are under low pressure.
Lung conditions and terms:
Respiratory infection - Can be caused by anything from the rhinovirus, parainfluenza virus, respiratory syncytial virus, influenza virus, and multiple other viruses. Mild cases are known as the common cold, severe cases become Pneumonia, and can be life threatening.
Obstructive pulmonary disease:
Chronic obstructive pulmonary disease (COPD), also called chronic obstructive lung disease, is a term that is used for two closely related diseases of the respiratory system: chronic bronchitis and emphysema. In many patients these diseases occur together, although there may be more symptoms of one than the other. Most patients with these diseases have a long history of heavy cigarette smoking.
Influenza:
Commonly called "the flu," is caused by the influenza virus, which infects the respiratory tract. The virus generally spreads from person-to-person when an infected person coughs or sneezes. Compared with other respiratory infections like the common cold, the flu can cause severe illness and lead to serious, and life-threatening complications in all age groups.
Typical flu symptoms include fever, dry cough, sore throat, runny or stuffy nose, headache, muscle aches, and extreme fatigue. Children may experience gastrointestinal problems like nausea, vomiting, and diarrhea but such symptoms are not common in adults. Although the term "stomach flu" is sometimes used to describe gastrointestinal illnesses, this is caused
by other organisms and is not related to “true” flu.
Sarcoidosis:
Also known as Sarcoid or Boeck's disease, is a multi-system auto-immune disease. It is a systemic granulomatous disease especially involving the lungs with resulting fibrosis but can also effect skin, liver, spleen, eyes, bones, brain, parotid glands and other soft tissue organs. Sarcoidosis is not contagious, it's onset may appear without any symptoms and it can cause lifelong ailments. At this time there is no cause or cure for sarcoidosis.
Pulmonary fibrosis:
Shortness of breath is the main symptom possibly first appearing during exercise. The condition then may progress to the point where any exertion is impossible. If the disease progresses, the person may be short of breath even at rest. This happens because scarring occurs in the tissue between the air sacs, with the lung becoming stiff.
Pulmonary hypertension:
A rare and incurable disease. It most often strikes young women in the prime of their lives, causing high blood pressure in the lungs, which produces progressive breathlessness and ultimately death.
Pulmonary embolism:
An obstruction of a blood vessel in the lungs, usually due to a blood clot, which blocks a coronary artery. Symptoms include chest pain, chest wall tenderness, back pain, shoulder pain, upper abdominal pain, syncope, hemoptysis, shortness of breath, painful respiration or new onset of wheezing.
Dyspnea:
Shortness of breath, or dyspnea, is a feeling of difficult or labored breathing that is out of proportion to the level of physical activity. It is a symptom of a variety of different diseases or disorders and may be either acute or chronic. It results from a combination of impulses relayed to the brain from nerve endings in the lungs, rib cage, chest muscles, or diaphragm, combined with the patient's perception and interpretation of
the sensation. Patients can feel an unpleasant shortness of breath, increased tiredness in the chest muscles, a panicky feeling of being smothered, or tightness and cramping in the chest wall.
Sources:
Cornell University Medical College
Sarcoidosis Online Sites
American Lung Association
Pulmonary Hypertension Association eMedicine
Blue Cross and Blue Shield of Massachusetts
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