Pulmonary Disease, Chronic Obstructive: A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.Lung Diseases, Obstructive: Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.Forced Expiratory Volume: Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.Sleep Apnea, Obstructive: A disorder characterized by recurrent apneas during sleep despite persistent respiratory efforts. It is due to upper airway obstruction. The respiratory pauses may induce HYPERCAPNIA or HYPOXIA. Cardiac arrhythmias and elevation of systemic and pulmonary arterial pressures may occur. Frequent partial arousals occur throughout sleep, resulting in relative SLEEP DEPRIVATION and daytime tiredness. Associated conditions include OBESITY; ACROMEGALY; MYXEDEMA; micrognathia; MYOTONIC DYSTROPHY; adenotonsilar dystrophy; and NEUROMUSCULAR DISEASES. (From Adams et al., Principles of Neurology, 6th ed, p395)Spirometry: Measurement of volume of air inhaled or exhaled by the lung.Respiratory Function Tests: Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.Bronchodilator Agents: Agents that cause an increase in the expansion of a bronchus or bronchial tubes.Vital Capacity: The volume of air that is exhaled by a maximal expiration following a maximal inspiration.Dyspnea: Difficult or labored breathing.Pulmonary Emphysema: Enlargement of air spaces distal to the TERMINAL BRONCHIOLES where gas-exchange normally takes place. This is usually due to destruction of the alveolar wall. Pulmonary emphysema can be classified by the location and distribution of the lesions.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Scopolamine Derivatives: Analogs or derivatives of scopolamine.Smoking: Inhaling and exhaling the smoke of burning TOBACCO.Oxygen Inhalation Therapy: Inhalation of oxygen aimed at restoring toward normal any pathophysiologic alterations of gas exchange in the cardiopulmonary system, as by the use of a respirator, nasal catheter, tent, chamber, or mask. (From Dorland, 27th ed & Stedman, 25th ed)Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Sputum: Material coughed up from the lungs and expectorated via the mouth. It contains MUCUS, cellular debris, and microorganisms. It may also contain blood or pus.Exercise Tolerance: The exercise capacity of an individual as measured by endurance (maximal exercise duration and/or maximal attained work load) during an EXERCISE TEST.Jaundice, Obstructive: Jaundice, the condition with yellowish staining of the skin and mucous membranes, that is due to impaired BILE flow in the BILIARY TRACT, such as INTRAHEPATIC CHOLESTASIS, or EXTRAHEPATIC CHOLESTASIS.Lung Diseases: Pathological processes involving any part of the LUNG.Emphysema: A pathological accumulation of air in tissues or organs.Cholinergic Antagonists: Drugs that bind to but do not activate CHOLINERGIC RECEPTORS, thereby blocking the actions of ACETYLCHOLINE or cholinergic agonists.Ipratropium: A muscarinic antagonist structurally related to ATROPINE but often considered safer and more effective for inhalation use. It is used for various bronchial disorders, in rhinitis, and as an antiarrhythmic.Albuterol: A short-acting beta-2 adrenergic agonist that is primarily used as a bronchodilator agent to treat ASTHMA. Albuterol is prepared as a racemic mixture of R(-) and S(+) stereoisomers. The stereospecific preparation of R(-) isomer of albuterol is referred to as levalbuterol.Respiratory Muscles: These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.Asthma: A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).Respiratory Insufficiency: Failure to adequately provide oxygen to cells of the body and to remove excess carbon dioxide from them. (Stedman, 25th ed)Bronchitis, Chronic: A subcategory of CHRONIC OBSTRUCTIVE PULMONARY DISEASE. The disease is characterized by hypersecretion of mucus accompanied by a chronic (more than 3 months in 2 consecutive years) productive cough. Infectious agents are a major cause of chronic bronchitis.Adrenal Cortex HormonesSmokeQuality of Life: A generic concept reflecting concern with the modification and enhancement of life attributes, e.g., physical, political, moral and social environment; the overall condition of a human life.Respiratory System Agents: Drugs used for their effects on the respiratory system.Bronchi: The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Adrenergic beta-2 Receptor Agonists: Compounds bind to and activate ADRENERGIC BETA-2 RECEPTORS.Bronchitis: Inflammation of the large airways in the lung including any part of the BRONCHI, from the PRIMARY BRONCHI to the TERTIARY BRONCHI.Polysomnography: Simultaneous and continuous monitoring of several parameters during sleep to study normal and abnormal sleep. The study includes monitoring of brain waves, to assess sleep stages, and other physiological variables such as breathing, eye movements, and blood oxygen levels which exhibit a disrupted pattern with sleep disturbances.Pulmonary Medicine: A subspecialty of internal medicine concerned with the study of the RESPIRATORY SYSTEM. It is especially concerned with diagnosis and treatment of diseases and defects of the lungs and bronchial tree.Inspiratory Capacity: The maximum volume of air that can be inspired after reaching the end of a normal, quiet expiration. It is the sum of the TIDAL VOLUME and the INSPIRATORY RESERVE VOLUME. Common abbreviation is IC.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Respiratory Therapy: Care of patients with deficiencies and abnormalities associated with the cardiopulmonary system. It includes the therapeutic use of medical gases and their administrative apparatus, environmental control systems, humidification, aerosols, ventilatory support, bronchopulmonary drainage and exercise, respiratory rehabilitation, assistance with cardiopulmonary resuscitation, and maintenance of natural, artificial, and mechanical airways.Expectorants: Agents that increase mucous excretion. Mucolytic agents, that is drugs that liquefy mucous secretions, are also included here.Airway Obstruction: Any hindrance to the passage of air into and out of the lungs.Positive-Pressure Respiration: A method of mechanical ventilation in which pressure is maintained to increase the volume of gas remaining in the lungs at the end of expiration, thus reducing the shunting of blood through the lungs and improving gas exchange.Nebulizers and Vaporizers: Devices that cause a liquid or solid to be converted into an aerosol (spray) or a vapor. It is used in drug administration by inhalation, humidification of ambient air, and in certain analytical instruments.Respiratory Mucosa: The mucous membrane lining the RESPIRATORY TRACT, including the NASAL CAVITY; the LARYNX; the TRACHEA; and the BRONCHI tree. The respiratory mucosa consists of various types of epithelial cells ranging from ciliated columnar to simple squamous, mucous GOBLET CELLS, and glands containing both mucous and serous cells.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.alpha 1-Antitrypsin Deficiency: Deficiency of the protease inhibitor ALPHA 1-ANTITRYPSIN that manifests primarily as PULMONARY EMPHYSEMA and LIVER CIRRHOSIS.Hypercapnia: A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Pneumonia: Infection of the lung often accompanied by inflammation.Inhalation: The act of BREATHING in.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.Respiratory Mechanics: The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Exercise Test: Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Breathing Exercises: Therapeutic exercises aimed to deepen inspiration or expiration or even to alter the rate and rhythm of respiration.Work of Breathing: RESPIRATORY MUSCLE contraction during INHALATION. The work is accomplished in three phases: LUNG COMPLIANCE work, that required to expand the LUNGS against its elastic forces; tissue resistance work, that required to overcome the viscosity of the lung and chest wall structures; and AIRWAY RESISTANCE work, that required to overcome airway resistance during the movement of air into the lungs. Work of breathing does not refer to expiration, which is entirely a passive process caused by elastic recoil of the lung and chest cage. (Guyton, Textbook of Medical Physiology, 8th ed, p406)Hospitalization: The confinement of a patient in a hospital.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Bronchoalveolar Lavage Fluid: Washing liquid obtained from irrigation of the lung, including the BRONCHI and the PULMONARY ALVEOLI. It is generally used to assess biochemical, inflammatory, or infection status of the lung.Airway Resistance: Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.Respiration, Artificial: Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Sleep Apnea Syndromes: Disorders characterized by multiple cessations of respirations during sleep that induce partial arousals and interfere with the maintenance of sleep. Sleep apnea syndromes are divided into central (see SLEEP APNEA, CENTRAL), obstructive (see SLEEP APNEA, OBSTRUCTIVE), and mixed central-obstructive types.Comorbidity: The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.Disease Progression: The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.Lung Volume Measurements: Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.Noninvasive Ventilation: Techniques for administering artificial respiration without the need for INTRATRACHEAL INTUBATION.Exhalation: The act of BREATHING out.Helium: Helium. A noble gas with the atomic symbol He, atomic number 2, and atomic weight 4.003. It is a colorless, odorless, tasteless gas that is not combustible and does not support combustion. It was first detected in the sun and is now obtained from natural gas. Medically it is used as a diluent for other gases, being especially useful with oxygen in the treatment of certain cases of respiratory obstruction, and as a vehicle for general anesthetics. (Dorland, 27th ed)Home Care Services, Hospital-Based: Hospital-sponsored provision of health services, such as nursing, therapy, and health-related homemaker or social services, in the patient's home. (Hospital Administration Terminology, 2d ed)Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Respiratory System: The tubular and cavernous organs and structures, by means of which pulmonary ventilation and gas exchange between ambient air and the blood are brought about.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Pulmonary Ventilation: The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Bronchiectasis: Persistent abnormal dilatation of the bronchi.Respiration: The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).Metered Dose Inhalers: A small aerosol canister used to release a calibrated amount of medication for inhalation.Pulmonary Gas Exchange: The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.Bronchoscopy: Endoscopic examination, therapy or surgery of the bronchi.Anoxia: Relatively complete absence of oxygen in one or more tissues.Phosphodiesterase 4 Inhibitors: Compounds that specifically inhibit PHOSPHODIESTERASE 4.Continuous Positive Airway Pressure: A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. (On-Line Medical Dictionary [Internet]. Newcastle upon Tyne(UK): The University Dept. of Medical Oncology: The CancerWEB Project; c1997-2003 [cited 2003 Apr 17]. Available from: http://cancerweb.ncl.ac.uk/omd/)Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Total Lung Capacity: The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: VITAL CAPACITY plus RESIDUAL VOLUME; INSPIRATORY CAPACITY plus FUNCTIONAL RESIDUAL CAPACITY; TIDAL VOLUME plus INSPIRATORY RESERVE VOLUME plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus EXPIRATORY RESERVE VOLUME plus residual volume.Exercise Therapy: A regimen or plan of physical activities designed and prescribed for specific therapeutic goals. Its purpose is to restore normal musculoskeletal function or to reduce pain caused by diseases or injuries.Acute Disease: Disease having a short and relatively severe course.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Ethanolamines: AMINO ALCOHOLS containing the ETHANOLAMINE; (-NH2CH2CHOH) group and its derivatives.Statistics, Nonparametric: A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)Respiratory Tract DiseasesDiaphragm: The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Cough: A sudden, audible expulsion of air from the lungs through a partially closed glottis, preceded by inhalation. It is a protective response that serves to clear the trachea, bronchi, and/or lungs of irritants and secretions, or to prevent aspiration of foreign materials into the lungs.Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.Mucus: The viscous secretion of mucous membranes. It contains mucin, white blood cells, water, inorganic salts, and exfoliated cells.Glycopyrrolate: A muscarinic antagonist used as an antispasmodic, in some disorders of the gastrointestinal tract, and to reduce salivation with some anesthetics.Glucocorticoids: A group of CORTICOSTEROIDS that affect carbohydrate metabolism (GLUCONEOGENESIS, liver glycogen deposition, elevation of BLOOD SUGAR), inhibit ADRENOCORTICOTROPIC HORMONE secretion, and possess pronounced anti-inflammatory activity. They also play a role in fat and protein metabolism, maintenance of arterial blood pressure, alteration of the connective tissue response to injury, reduction in the number of circulating lymphocytes, and functioning of the central nervous system.Anti-Inflammatory Agents: Substances that reduce or suppress INFLAMMATION.Forced Expiratory Flow Rates: The rate of airflow measured during a FORCED VITAL CAPACITY determination.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Indans: Aryl CYCLOPENTANES that are a reduced (protonated) form of INDENES.Positive-Pressure Respiration, Intrinsic: Non-therapeutic positive end-expiratory pressure occurring frequently in patients with severe airway obstruction. It can appear with or without the administration of external positive end-expiratory pressure (POSITIVE-PRESSURE RESPIRATION). It presents an important load on the inspiratory muscles which are operating at a mechanical disadvantage due to hyperinflation. Auto-PEEP may cause profound hypotension that should be treated by intravascular volume expansion, increasing the time for expiration, and/or changing from assist mode to intermittent mandatory ventilation mode. (From Harrison's Principles of Internal Medicine, 12th ed, p1127)Breath Tests: Any tests done on exhaled air.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Airway Remodeling: The structural changes in the number, mass, size and/or composition of the airway tissues.Adrenergic beta-Agonists: Drugs that selectively bind to and activate beta-adrenergic receptors.Budesonide: A glucocorticoid used in the management of ASTHMA, the treatment of various skin disorders, and allergic RHINITIS.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Walking: An activity in which the body advances at a slow to moderate pace by moving the feet in a coordinated fashion. This includes recreational walking, walking for fitness, and competitive race-walking.Functional Residual Capacity: The volume of air remaining in the LUNGS at the end of a normal, quiet expiration. It is the sum of the RESIDUAL VOLUME and the EXPIRATORY RESERVE VOLUME. Common abbreviation is FRC.Muscarinic Antagonists: Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.Pulmonary Heart Disease: Hypertrophy and dilation of the RIGHT VENTRICLE of the heart that is caused by PULMONARY HYPERTENSION. This condition is often associated with pulmonary parenchymal or vascular diseases, such as CHRONIC OBSTRUCTIVE PULMONARY DISEASE and PULMONARY EMBOLISM.Bronchioles: The small airways branching off the TERTIARY BRONCHI. Terminal bronchioles lead into several orders of respiratory bronchioles which in turn lead into alveolar ducts and then into PULMONARY ALVEOLI.Smoking Cessation: Discontinuation of the habit of smoking, the inhaling and exhaling of tobacco smoke.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.Residual Volume: The volume of air remaining in the LUNGS at the end of a maximal expiration. Common abbreviation is RV.Predictive Value of Tests: In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.Dry Powder Inhalers: A device that delivers medication to the lungs in the form of a dry powder.Activities of Daily Living: The performance of the basic activities of self care, such as dressing, ambulation, or eating.Oximetry: The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.Interleukin-8: A member of the CXC chemokine family that plays a role in the regulation of the acute inflammatory response. It is secreted by variety of cell types and induces CHEMOTAXIS of NEUTROPHILS and other inflammatory cells.Partial Pressure: The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Androstadienes: Derivatives of the steroid androstane having two double bonds at any site in any of the rings.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Moraxellaceae Infections: Infections with bacteria of the family MORAXELLACEAE.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Moraxella (Branhamella) catarrhalis: Gram-negative aerobic cocci of low virulence that colonize the nasopharynx and occasionally cause MENINGITIS; BACTEREMIA; EMPYEMA; PERICARDITIS; and PNEUMONIA.Macrophages, Alveolar: Round, granular, mononuclear phagocytes found in the alveoli of the lungs. They ingest small inhaled particles resulting in degradation and presentation of the antigen to immunocompetent cells.alpha 1-Antitrypsin: Plasma glycoprotein member of the serpin superfamily which inhibits TRYPSIN; NEUTROPHIL ELASTASE; and other PROTEOLYTIC ENZYMES.Spain: Parliamentary democracy located between France on the northeast and Portugual on the west and bordered by the Atlantic Ocean and the Mediterranean Sea.Peak Expiratory Flow Rate: Measurement of the maximum rate of airflow attained during a FORCED VITAL CAPACITY determination. Common abbreviations are PEFR and PFR.Health Status: The level of health of the individual, group, or population as subjectively assessed by the individual or by more objective measures.Exercise: Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.Ventilators, Negative-Pressure: Body ventilators that assist ventilation by applying intermittent subatmospheric pressure around the thorax, abdomen, or airway and periodically expand the chest wall and inflate the lungs. They are relatively simple to operate and do not require tracheostomy. These devices include the tank ventilators ("iron lung"), Portalung, Pneumowrap, and chest cuirass ("tortoise shell").Isodesmosine: 2-(4-Amino-4-carboxybutyl)-1-(5-amino-5-carboxypentyl)-3,5-bis(3-amino-3-carboxypropyl)pyridinium. A rare amino acid found in elastin, formed by condensation of four molecules of lysine into a pyridinium ring.Desmosine: A rare amino acid found in elastin, formed by condensation of four molecules of lysine into a pyridinium ring.United StatesSelf Care: Performance of activities or tasks traditionally performed by professional health care providers. The concept includes care of oneself or one's family and friends.Muscle Weakness: A vague complaint of debility, fatigue, or exhaustion attributable to weakness of various muscles. The weakness can be characterized as subacute or chronic, often progressive, and is a manifestation of many muscle and neuromuscular diseases. (From Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251)Ventilator Weaning: Techniques for effecting the transition of the respiratory-failure patient from mechanical ventilation to spontaneous ventilation, while meeting the criteria that tidal volume be above a given threshold (greater than 5 ml/kg), respiratory frequency be below a given count (less than 30 breaths/min), and oxygen partial pressure be above a given threshold (PaO2 greater than 50mm Hg). Weaning studies focus on finding methods to monitor and predict the outcome of mechanical ventilator weaning as well as finding ventilatory support techniques which will facilitate successful weaning. Present methods include intermittent mandatory ventilation, intermittent positive pressure ventilation, and mandatory minute volume ventilation.Respiratory Tract Infections: Invasion of the host RESPIRATORY SYSTEM by microorganisms, usually leading to pathological processes or diseases.Quadriceps Muscle: The quadriceps femoris. A collective name of the four-headed skeletal muscle of the thigh, comprised of the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.Theophylline: A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3',5'-CYCLIC NUCLEOTIDE PHOSPHODIESTERASE that degrades CYCLIC AMP thus potentiates the actions of agents that act through ADENYLYL CYCLASES and cyclic AMP.Muscle Strength: The amount of force generated by MUSCLE CONTRACTION. Muscle strength can be measured during isometric, isotonic, or isokinetic contraction, either manually or using a device such as a MUSCLE STRENGTH DYNAMOMETER.Tasmania: An island south of Australia and the smallest state of the Commonwealth. Its capital is Hobart. It was discovered and named Van Diemen's Island in 1642 by Abel Tasman, a Dutch navigator, in honor of the Dutch governor-general of the Dutch East Indian colonies. It was renamed for the discoverer in 1853. In 1803 it was taken over by Great Britain and was used as a penal colony. It was granted government in 1856 and federated as a state in 1901. (From Webster's New Geographical Dictionary, 1988, p1190 & Room, Brewer's Dictionary of Names, p535)Almitrine: A respiratory stimulant that enhances respiration by acting as an agonist of peripheral chemoreceptors located on the carotid bodies. The drug increases arterial oxygen tension while decreasing arterial carbon dioxide tension in patients with chronic obstructive pulmonary disease. It may also prove useful in the treatment of nocturnal oxygen desaturation without impairing the quality of sleep.Practice Guidelines as Topic: Directions or principles presenting current or future rules of policy for assisting health care practitioners in patient care decisions regarding diagnosis, therapy, or related clinical circumstances. The guidelines may be developed by government agencies at any level, institutions, professional societies, governing boards, or by the convening of expert panels. The guidelines form a basis for the evaluation of all aspects of health care and delivery.Inflammation Mediators: The endogenous compounds that mediate inflammation (AUTACOIDS) and related exogenous compounds including the synthetic prostaglandins (PROSTAGLANDINS, SYNTHETIC).Chi-Square Distribution: A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Snoring: Rough, noisy breathing during sleep, due to vibration of the uvula and soft palate.Netherlands: Country located in EUROPE. It is bordered by the NORTH SEA, BELGIUM, and GERMANY. Constituent areas are Aruba, Curacao, Sint Maarten, formerly included in the NETHERLANDS ANTILLES.Ventilation-Perfusion Ratio: The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)Oxidative Stress: A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.Length of Stay: The period of confinement of a patient to a hospital or other health facility.Pulmonary Diffusing Capacity: The amount of a gas taken up, by the pulmonary capillary blood from the alveolar gas, per minute per unit of average pressure of the gradient of the gas across the BLOOD-AIR BARRIER.Intermittent Positive-Pressure Ventilation: Application of positive pressure to the inspiratory phase when the patient has an artificial airway in place and is connected to a ventilator.Hypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.Acidosis, Respiratory: Respiratory retention of carbon dioxide. It may be chronic or acute.Lung Neoplasms: Tumors or cancer of the LUNG.Drug Therapy, Combination: Therapy with two or more separate preparations given for a combined effect.Cholestasis: Impairment of bile flow due to obstruction in small bile ducts (INTRAHEPATIC CHOLESTASIS) or obstruction in large bile ducts (EXTRAHEPATIC CHOLESTASIS).Fenoterol: An adrenergic beta-2 agonist that is used as a bronchodilator and tocolytic.Matrix Metalloproteinase 12: A secreted matrix metalloproteinase which is highly expressed by MACROPHAGES where it may play a role in INFLAMMATION and WOUND HEALING.Patient Readmission: Subsequent admissions of a patient to a hospital or other health care institution for treatment.Body Mass Index: An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)Pilot Projects: Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.Masks: Devices that cover the nose and mouth to maintain aseptic conditions or to administer inhaled anesthetics or other gases. (UMDNS, 1999)Bronchoconstriction: Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention.Maximal Expiratory Flow Rate: The airflow rate measured during the first liter expired after the first 200 ml have been exhausted during a FORCED VITAL CAPACITY determination. Common abbreviations are MEFR, FEF 200-1200, and FEF 0.2-1.2.Mucin 5AC: A gel-forming mucin that is primarily found on the surface of gastric epithelium and in the RESPIRATORY TRACT. Mucin 5AC was originally identified as two distinct proteins, however a single gene encodes the protein which gives rise to the mucin 5A and mucin 5C variants.Pneumonectomy: The excision of lung tissue including partial or total lung lobectomy.CyclopropanesSex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Respiration Disorders: Diseases of the respiratory system in general or unspecified or for a specific respiratory disease not available.Rhinovirus: A genus of PICORNAVIRIDAE inhabiting primarily the respiratory tract of mammalian hosts. It includes over 100 human serotypes associated with the COMMON COLD.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Primary Health Care: Care which provides integrated, accessible health care services by clinicians who are accountable for addressing a large majority of personal health care needs, developing a sustained partnership with patients, and practicing in the context of family and community. (JAMA 1995;273(3):192)Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.Home Care Services: Community health and NURSING SERVICES providing coordinated multiple services to the patient at the patient's homes. These home-care services are provided by a visiting nurse, home health agencies, HOSPITALS, or organized community groups using professional staff for care delivery. It differs from HOME NURSING which is provided by non-professionals.Physical Endurance: The time span between the beginning of physical activity by an individual and the termination because of exhaustion.Randomized Controlled Trials as Topic: Works about clinical trials that involve at least one test treatment and one control treatment, concurrent enrollment and follow-up of the test- and control-treated groups, and in which the treatments to be administered are selected by a random process, such as the use of a random-numbers table.Haemophilus influenzae: A species of HAEMOPHILUS found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through VIII.Intubation, Intratracheal: A procedure involving placement of a tube into the trachea through the mouth or nose in order to provide a patient with oxygen and anesthesia.Terbutaline: A selective beta-2 adrenergic agonist used as a bronchodilator and tocolytic.Quinolones: A group of derivatives of naphthyridine carboxylic acid, quinoline carboxylic acid, or NALIDIXIC ACID.Doxapram: A central respiratory stimulant with a brief duration of action. (From Martindale, The Extra Pharmocopoeia, 30th ed, p1225)Nutritional Support: The administration of nutrients for assimilation and utilization by a patient by means other than normal eating. It does not include FLUID THERAPY which normalizes body fluids to restore WATER-ELECTROLYTE BALANCE.Pulmonary Alveoli: Small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.Cystic Fibrosis: An autosomal recessive genetic disease of the EXOCRINE GLANDS. It is caused by mutations in the gene encoding the CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR expressed in several organs including the LUNG, the PANCREAS, the BILIARY SYSTEM, and the SWEAT GLANDS. Cystic fibrosis is characterized by epithelial secretory dysfunction associated with ductal obstruction resulting in AIRWAY OBSTRUCTION; chronic RESPIRATORY INFECTIONS; PANCREATIC INSUFFICIENCY; maldigestion; salt depletion; and HEAT PROSTRATION.Air Pollution: The presence of contaminants or pollutant substances in the air (AIR POLLUTANTS) that interfere with human health or welfare, or produce other harmful environmental effects. The substances may include GASES; PARTICULATE MATTER; or volatile ORGANIC CHEMICALS.