Noninvasive Ventilation: Techniques for administering artificial respiration without the need for INTRATRACHEAL INTUBATION.Respiratory Insufficiency: Failure to adequately provide oxygen to cells of the body and to remove excess carbon dioxide from them. (Stedman, 25th ed)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.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).Masks: Devices that cover the nose and mouth to maintain aseptic conditions or to administer inhaled anesthetics or other gases. (UMDNS, 1999)Obesity Hypoventilation Syndrome: HYPOVENTILATION syndrome in very obese persons with excessive ADIPOSE TISSUE around the ABDOMEN and DIAPHRAGM. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic HYPOXIA; HYPERCAPNIA; POLYCYTHEMIA; and long periods of sleep during day and night (HYPERSOMNOLENCE). It is a condition often related to OBSTRUCTIVE SLEEP APNEA but can occur separately.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.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.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.Neuromuscular Diseases: A general term encompassing lower MOTOR NEURON DISEASE; PERIPHERAL NERVOUS SYSTEM DISEASES; and certain MUSCULAR DISEASES. Manifestations include MUSCLE WEAKNESS; FASCICULATION; muscle ATROPHY; SPASM; MYOKYMIA; MUSCLE HYPERTONIA, myalgias, and MUSCLE HYPOTONIA.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)Ventilators, Mechanical: Mechanical devices used to produce or assist pulmonary ventilation.Respiratory Rate: The number of times an organism breathes with the lungs (RESPIRATION) per unit time, usually per minute.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.Respiratory Care Units: The hospital unit in which patients with respiratory conditions requiring special attention receive intensive medical care and surveillance.Hypercapnia: A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Pulmonary Disease, Chronic Obstructive: A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.Ventilation: Supplying a building or house, their rooms and corridors, with fresh air. The controlling of the environment thus may be in public or domestic sites and in medical or non-medical locales. (From Dorland, 28th ed)Hypoventilation: A reduction in the amount of air entering the pulmonary alveoli.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)Pulmonary Gas Exchange: The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.Pulmonary Ventilation: The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Tracheostomy: Surgical formation of an opening into the trachea through the neck, or the opening so created.Tidal Volume: The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.Equipment Design: Methods of creating machines and devices.Tracheotomy: Surgical incision of the trachea.Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Aerophagy: Spasmodic swallowing of air.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.Pulmonary Edema: Excessive accumulation of extravascular fluid in the lung, an indication of a serious underlying disease or disorder. Pulmonary edema prevents efficient PULMONARY GAS EXCHANGE in the PULMONARY ALVEOLI, and can be life-threatening.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/)Intensive Care Units: Hospital units providing continuous surveillance and care to acutely ill patients.Respiratory Distress Syndrome, Adult: A syndrome characterized by progressive life-threatening RESPIRATORY INSUFFICIENCY in the absence of known LUNG DISEASES, usually following a systemic insult such as surgery or major TRAUMA.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.High-Frequency Ventilation: Ventilatory support system using frequencies from 60-900 cycles/min or more. Three types of systems have been distinguished on the basis of rates, volumes, and the system used. They are high frequency positive-pressure ventilation (HFPPV); HIGH-FREQUENCY JET VENTILATION; (HFJV); and high-frequency oscillation (HFO).Acute Disease: Disease having a short and relatively severe course.Respiratory Muscles: These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.ManikinsBlood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.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.Evidence-Based Emergency Medicine: A way of providing emergency medical care that is guided by a thoughtful integration of the best available scientific knowledge with clinical expertise in EMERGENCY MEDICINE. This approach allows the practitioner to critically assess research data, clinical guidelines, and other information resources in order to correctly identify the clinical problem, apply the most high-quality intervention, and re-evaluate the outcome for future improvement.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.Anoxia: Relatively complete absence of oxygen in one or more tissues.Humidity: A measure of the amount of WATER VAPOR in the air.Intensive Care Units, Pediatric: Hospital units providing continuous surveillance and care to acutely ill infants and children. Neonates are excluded since INTENSIVE CARE UNITS, NEONATAL is available.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.Monitoring, Physiologic: The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.High-Frequency Jet Ventilation: Respiratory support system used primarily with rates of about 100 to 200/min with volumes of from about one to three times predicted anatomic dead space. Used to treat respiratory failure and maintain ventilation under severe circumstances.Intensive Care: Advanced and highly specialized care provided to medical or surgical patients whose conditions are life-threatening and require comprehensive care and constant monitoring. It is usually administered in specially equipped units of a health care facility.Technetium Tc 99m Pentetate: A technetium imaging agent used in renal scintigraphy, computed tomography, lung ventilation imaging, gastrointestinal scintigraphy, and many other procedures which employ radionuclide imaging agents.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).Bronchoscopy: Endoscopic examination, therapy or surgery of the bronchi.Lung Diseases, Obstructive: Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Aerosols: Colloids with a gaseous dispersing phase and either liquid (fog) or solid (smoke) dispersed phase; used in fumigation or in inhalation therapy; may contain propellant agents.Dyspnea: Difficult or labored breathing.Ventilation-Perfusion Ratio: The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)Length of Stay: The period of confinement of a patient to a hospital or other health facility.Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.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.Hospital Mortality: A vital statistic measuring or recording the rate of death from any cause in hospitalized populations.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.Amyotrophic Lateral Sclerosis: A degenerative disorder affecting upper MOTOR NEURONS in the brain and lower motor neurons in the brain stem and SPINAL CORD. Disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. Clinical manifestations include progressive weakness, atrophy, FASCICULATION, hyperreflexia, DYSARTHRIA, dysphagia, and eventual paralysis of respiratory function. Pathologic features include the replacement of motor neurons with fibrous ASTROCYTES and atrophy of anterior SPINAL NERVE ROOTS and corticospinal tracts. (From Adams et al., Principles of Neurology, 6th ed, pp1089-94)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.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)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)Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Ventilator-Induced Lung Injury: Lung damage that is caused by the adverse effects of PULMONARY VENTILATOR usage. The high frequency and tidal volumes produced by a mechanical ventilator can cause alveolar disruption and PULMONARY EDEMA.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)Treatment Failure: A measure of the quality of health care by assessment of unsuccessful results of management and procedures used in combating disease, in individual cases or series.Lung Compliance: The capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562)Air Pressure: The force per unit area that the air exerts on any surface in contact with it. Primarily used for articles pertaining to air pressure within a closed environment.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)One-Lung Ventilation: Techniques for supplying artificial respiration to a single lung.Laryngeal Masks: A type of oropharyngeal airway that provides an alternative to endotracheal intubation and standard mask anesthesia in certain patients. It is introduced into the hypopharynx to form a seal around the larynx thus permitting spontaneous or positive pressure ventilation without penetration of the larynx or esophagus. It is used in place of a facemask in routine anesthesia. The advantages over standard mask anesthesia are better airway control, minimal anesthetic gas leakage, a secure airway during patient transport to the recovery area, and minimal postoperative problems.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.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").Respiratory Distress Syndrome, Newborn: A condition of the newborn marked by DYSPNEA with CYANOSIS, heralded by such prodromal signs as dilatation of the alae nasi, expiratory grunt, and retraction of the suprasternal notch or costal margins, mostly frequently occurring in premature infants, children of diabetic mothers, and infants delivered by cesarean section, and sometimes with no apparent predisposing cause.Lung Volume Measurements: Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.Maximal Voluntary Ventilation: Measure of the maximum amount of air that can be breathed in and blown out over a sustained interval such as 15 or 20 seconds. Common abbreviations are MVV and MBC.Respiratory Dead Space: That part of the RESPIRATORY TRACT or the air within the respiratory tract that does not exchange OXYGEN and CARBON DIOXIDE with pulmonary capillary blood.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.Diaphragm: 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.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Intermittent Positive-Pressure Breathing: Application of positive pressure to the inspiratory phase of spontaneous respiration.Apnea: A transient absence of spontaneous respiration.Lung Injury: Damage to any compartment of the lung caused by physical, chemical, or biological agents which characteristically elicit inflammatory reaction. These inflammatory reactions can either be acute and dominated by NEUTROPHILS, or chronic and dominated by LYMPHOCYTES and MACROPHAGES.Respiratory Physiological Phenomena: Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.Prone Position: The posture of an individual lying face down.Inhalation: The act of BREATHING in.Airway Obstruction: Any hindrance to the passage of air into and out of the lungs.