Medical Terminology

Some common Pulmonology and Sleep Diagnostic terms.

Medical Terminology

  • Airway Resistance.
    Airway Resistance is a concept in respiratory physiology that describes the resistance of the respiratory tract to airflow during inspiration and expiration. Airway resistance can be measured using impulse oscillometry.
  • Allergy.
    An allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid. Allergy is one of four forms of hypersensitivity and is formally called type I (or immediate) hypersensitivity. Allergic reactions are distinctive because of excessive activation of certain white blood cells called mast cells and basophils by a type of antibody called Immunoglobulin E (IgE). This reaction results in an inflammatory response which can range from uncomfortable to dangerous.
  • Asthma.
    Asthma (from the Greek ásthma, "panting") is a common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Common symptoms include wheezing, coughing, chest tightness, and shortness of breath.

    Asthma is thought to be caused by a combination of genetic and environmental factors. Its diagnosis is usually made based on the pattern of symptoms, response to therapy over time, and spirometry. It is clinically classified according to the frequency of symptoms, forced expiratory volume in one second (FEV1), and peak expiratory flow rate. Asthma may also be classified as atopic(extrinsic) or non-atopic (intrinsic).

    Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist (such as salbutamol). Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by the use of inhaled corticosteroids. Leukotriene antagonistsare less effective than corticosteroids and thus less preferred. The prevalence of asthma has increased significantly since the 1970s. As of 2010, 300 million people were affected worldwide. In 2009 asthma caused 250,000 deaths globally.
  • Bronchiectasis.
    Bronchiectasis (brong-ke-EK-tah-sis) is a condition in which damage to the airways causes them to widen and become flabby and scarred. The airways are tubes that carry air in and out of your lungs.

    Bronchiectasis often is caused by an infection or other condition that injures the walls of the airways or prevents the airways from clearing mucus. Mucus is a slimy substance. It helps remove inhaled dust, bacteria, and other small particles from the airways. In bronchiectasis, your airways slowly lose their ability to clear out mucus. The mucus builds up, and bacteria begin to grow. This leads to repeated, serious lung infections.

    Each infection causes more damage to the airways. Over time, the airways can't properly move air in and out of the lungs. As a result, the body's vital organs might not get enough oxygen. Bronchiectasis can lead to serious health problems, such as respiratory failre, atelectasis (at-eh-LEK-tah-sis), and heart failure.
  • Capnography.
    Capnography is the measurement of carbon dioxide (CO2) into the airway of a patient during the respiratory cycle, ie the measurement of CO2 partial pressure in the exhaled air. Stands out as a monitoring technique noninvasive gas exchange that offers information on production levels of CO2 on pulmonary perfusion and also on alveolar ventilation. It also plays an important role in the early detection of respiratory diseases and in the control cycle removal of CO2 during medical procedures that require the use of anesthesia.

    The capnograph charged instrument will measure the concentration of carbon dioxide numerical and practically all of these instruments rely on the principle of the absorption of CO2 by an infrared beam. The normal value of exhaled CO2 partial pressure is 38 mmHg to a barometric pressure of 760 mmHg, and normal blood pressure of said gas between 36 and 44mmHg. The measurement of the partial pressure of CO2 (PCO2) can be represented against time or against exhaled volume. This plot is what is known as capnography, and there are two types depending on whether PCO2 levels are plotted against time - Capnography conventional - or against expired volume - volumetric capnography.
  • Chronic Obstructive Pulmonary Disease (COPD).
    COPD, or chronic obstructive pulmonary (PULL-mun-ary) disease, is a progressive disease that makes it hard to breathe. "Progressive" means the disease gets worse over time. COPD can cause coughing that produces large amounts of mucus (a slimy substance), wheezing, shortness of breath, chest tightness, and other symptoms.

    Cigarette smoking is the leading cause of COPD. Most people who have COPD smoke or used to smoke. Long-term exposure to other lung irritants—such as air pollution, chemical fumes, or dust—also may contribute to COPD.
  • Diffusing Capacity (DLCO).
    Diffusing capacity (DLCO) is the part of a comprehensive series of tests (the pulmonary function tests) that is done to determine the overall ability of the lung to transport gas into and out of the blood. DLCO is reduced in certain diseases of the lung and heart. This test has been standardized according to a position paper by a task force of the European Respiratory and American Thoracic Societies.

    In respiratory physiology, the diffusing capacity has a long history of great utility, but the words themselves are now misleading because they are archaic: neither is diffusion measured nor is the value obtained from this test a capacity nor even a capacitance, but in fact a conductance. While the term diffusing capacity is retained in the United States for reasons of historical continuity, terminology using transfer factor is now preferred in Europe and elsewhere. Nevertheless, there are 7 - 8 times more citations for the original terminology in PubMed, so any change in usage will be slow to happen.

    Worse still, the term diffusing capacity is positively misleading, since gas transport is not diffusion limited in all but the most extreme cases, such as for oxygen uptake at very low ambient oxygen or at very high pulmonary blood flow. Critics of the term "diffusion capacity" argue that it may be misleading for other reasons as well, and point out two problems with the term. The first is that the test measures not just diffusion across the alveolar-capillary membrane, but also takes into account factors affecting the chemical combination of a given gas with hemoglobin. The second criticism is that the test is typically measured under submaximal conditions and doesn't truly reflect a functional capacity. For these reasons the term "transfer factor" has been proposed to better reflect the physiological process being measured.

    Finally, the diffusing capacity does not directly measure the primary cause of hypoxemia, or low blood oxygen, namely mismatch of ventilation to perfusion:

    1. Not all pulmonary arterial blood goes to areas of the lung where gas exchange can occur (the anatomic orphysiologic shunts), and this poorly oxygenated blood rejoins the well oxygenated blood from healthy lung in the pulmonary vein. Together, the mixture has less oxygen than that blood from the healthy lung alone, and so is hypoxemic.
    2. Similarly, not all inspired air goes to areas of the lung where gas exchange can occur (the anatomic and the physiological dead spaces), and so is wasted.
  • Electroencefolograma (EEG).
    An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain. Special sensors (electrodes ) are attached to your head and hooked by wires to a computer. The computer records your brain's electrical activity on the screen or on paper as wavy lines. Certain conditions, such as seizures, can be seen by the changes in the normal pattern of the brain's electrical activity.
  • Emphysema.
    Emphysema is a lung condition in which tiny air sacs in the lungs - alveoli - fill up with air. As the air continues to build up in these sacs, they expand, and may break or become damaged and form scar tissue. The patient becomes progressively short of breath. Emphysema is a type of COPD (chronic obstructive pulmonary disease). The main cause of emphysema is long-term regular smoking.
  • Lung Cancer.
    Lung cancer is the uncontrolled growth of abnormal cells that start off in one or both lungs; usually in the cells that line the air passages. The abnormal cells do not develop into healthy lung tissue, they divide rapidly and form tumors. As tumors become larger and more numerous, they undermine the lung’s ability to provide the bloodstream with oxygen. Tumors that remain in one place and do not appear to spread are known as “benign tumors”.

    Malignant tumors, the more dangerous ones, spread to other parts of the body either through the bloodstream or the lymphatic system. Metastasis refers to cancer spreading beyond its site of origin to other parts of the body. When cancer spreads it is much harder to treat successfully.
  • Maintenance Of Wakefulness Test (MWT).
    The Maintenance of Wakefulness Test (MWT) is used to measure how alert you are during the day. It shows whether or not you are able to stay awake for a defined period of time. This is an indicator of how well you are able to function and remain alert in quiet times of inactivity.

    The test is based on the idea that your ability to stay awake may be more important to know in some cases than how fast you fall asleep. This is the case when the MWT is used to see how well a sleep disorders patient is able to stay awake after starting treatment. It is also used to help judge whether a patient is too tired to drive or perform other daily tasks.
  • Obstructive Sleep Apnea (OSA).
    Obstructive sleep apnea is a condition in which the flow of air pauses or decreases during breathing while you are asleep because the airway has become narrowed, blocked, or floppy. A pause in breathing is called an apnea episode. A decrease in airflow during breathing is called a hypopnea episode. Almost everyone has brief apnea episodes while they sleep. All of the muscles in your body become more relaxed during sleep. This includes the muscles that help keep the airway open and allow air to flow into the lungs.

    Normally, the upper throat still remains open enough during sleep to let air pass by. However, some people have a narrower throat area. When the muscles in their upper throat relax during sleep, their breathing can stop for a period of time (often more than 10 seconds). This is called apnea. Snoring in people with obstructive sleep apnea is caused by the air trying to squeeze through the narrowed or blocked airway. However, everyone who snores does not have sleep apnea.
  • Oral Appliance.
    An oral appliance is a device that a patient will wear for a certain period of time to treat various orofacial disorders. Such appliances are commonly used to treat sleep apnea and TMJ disorders. A sleep apnea oral appliance is typically molded to fit a particular patient's teeth by someone specializing in treating sleep disorders. Appliances usually function by moving the lower jaw forward in order to open up the airway during sleep, thus promoting better breathing and less apneas. Some oral appliances restrict tongue movement in order to prevent the tongue from blocking the airway. Oral appliances have a mixed success rate in treating sleep apnea. They are generally more successful at treating mild and moderate sleep apnea and less effective at treating severe sleep apnea. They may bring the level of apnea a patient experiences down significantly but fail to completely eliminate it. Their popularity stems largely from the fact that most patients find them more comfortable than CPAP machines (the most common sleep apnea treatment). Because they are perceived as comfortable, patients are more likely to wear them consistently and comply with treatment.
  • Overnight CPAP Titration (CPAP).
    This overnight sleep study is used to find the correct pressure to treat your Sleep Apnea. Prior to starting the test, a technician helps you select the mask that best fits your face. During the test, the machine pressures will be gradually adjusted to determine the pressure that corrects your sleep apnea.
  • Overnight Polysomnography (PSG).
    Polysomnography (PSG) is a physiological test used in the study of sleep disorders, such as sleep apnea, narcolepsy, and insomnia. The study is normally done at night in a sleep lab and requires wire attachments from machines to the patients. These wire attachments help to measure brain function, eye movement, muscle activity, heart rhythm, and respiration during the polysomnography.
  • Pneumonia.
    Pneumonia (nu-MO-ne-ah) is an infection in one or both of the lungs. Many germs—such as bacteria, viruses, and fungi—can cause pneumonia.

    The infection inflames your lungs' air sacs, which are called alveoli (al-VEE-uhl-eye). The air sacs may fill up with fluid or pus, causing symptoms such as a cough with phlegm (a slimy substance), fever, chills, and trouble breathing.
  • Pulmonary Embolism (PE).
    Pulmonary embolism (PULL-mun-ary EM-bo-lizm), or PE, is a sudden blockage in a lung artery. The blockage usually is caused by a blood clot that travels to the lung from a vein in the leg.

    A clot that forms in one part of the body and travels in the bloodstream to another part of the body is called an embolus (EM-bo-lus).
  • Pulmonary Function Test (PFT).
    Pulmonary function tests are a group of tests that measure how well the lungs take in and release air and how well they move gases such as oxygen from the atmosphere into the body's circulation.
  • Sarcoidosis.
    Sarcoidosis (sar-koy-DO-sis) is a disease of unknown cause that leads to inflammation. This disease affects your body’s organs. Normally, your immune system defends your body against foreign or harmful substances. For example, it sends special cells to protect organs that are in danger.

    These cells release chemicals that recruit other cells to isolate and destroy the harmful substance. Inflammation occurs during this process. Once the harmful substance is gone, the cells and the inflammation go away.

    In people who have sarcoidosis, the inflammation doesn't go away. Instead, some of the immune system cells cluster to form lumps called granulomas (gran-yu-LO-mas) in various organs in your body.
  • Sinusitis.
    Sinusitis is the medical term for inflammation (irritation and swelling) of the sinuses. It's usually caused by infection. The sinuses are the moist air spaces within the bones of the face around the nose.