Ventilators, Mechanical: Mechanical devices used to produce or assist pulmonary ventilation.Pneumonia: Infection of the lung often accompanied by inflammation.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.Pneumonia, Bacterial: Inflammation of the lung parenchyma that is caused by bacterial infections.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).Pneumonia, Viral: Inflammation of the lung parenchyma that is caused by a viral infection.Pneumonia, Pneumococcal: A febrile disease caused by STREPTOCOCCUS PNEUMONIAE.Pneumonia, Ventilator-Associated: Serious INFLAMMATION of the LUNG in patients who required the use of PULMONARY VENTILATOR. It is usually caused by cross bacterial infections in hospitals (NOSOCOMIAL INFECTIONS).Cryptogenic Organizing Pneumonia: An interstitial lung disease of unknown etiology, occurring between 21-80 years of age. It is characterized by a dramatic onset of a "pneumonia-like" illness with cough, fever, malaise, fatigue, and weight loss. Pathological features include prominent interstitial inflammation without collagen fibrosis, diffuse fibroblastic foci, and no microscopic honeycomb change. There is excessive proliferation of granulation tissue within small airways and alveolar ducts.Pneumonia, Pneumocystis: A pulmonary disease in humans occurring in immunodeficient or malnourished patients or infants, characterized by DYSPNEA, tachypnea, and HYPOXEMIA. Pneumocystis pneumonia is a frequently seen opportunistic infection in AIDS. It is caused by the fungus PNEUMOCYSTIS JIROVECII. The disease is also found in other MAMMALS where it is caused by related species of Pneumocystis.Pneumonia, Staphylococcal: Pneumonia caused by infections with bacteria of the genus STAPHYLOCOCCUS, usually with STAPHYLOCOCCUS AUREUS.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)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.Tidal Volume: The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.Pneumonia, Aspiration: A type of lung inflammation resulting from the aspiration of food, liquid, or gastric contents into the upper RESPIRATORY TRACT.Respiratory Insufficiency: Failure to adequately provide oxygen to cells of the body and to remove excess carbon dioxide from them. (Stedman, 25th ed)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)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 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.Community-Acquired Infections: Any infection acquired in the community, that is, contrasted with those acquired in a health care facility (CROSS INFECTION). An infection would be classified as community-acquired if the patient had not recently been in a health care facility or been in contact with someone who had been recently in a health care facility.Equipment Design: Methods of creating machines and devices.Pneumonia, Mycoplasma: Interstitial pneumonia caused by extensive infection of the lungs (LUNG) and BRONCHI, particularly the lower lobes of the lungs, by MYCOPLASMA PNEUMONIAE in humans. In SHEEP, it is caused by MYCOPLASMA OVIPNEUMONIAE. In CATTLE, it may be caused by MYCOPLASMA DISPAR.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.Intensive Care Units: Hospital units providing continuous surveillance and care to acutely ill patients.Pneumonia, Lipid: Pneumonia due to aspiration or inhalation of various oily or fatty substances.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.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.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 Care Units: The hospital unit in which patients with respiratory conditions requiring special attention receive intensive medical care and surveillance.Mass Casualty Incidents: Events that overwhelm the resources of local HOSPITALS and health care providers. They are likely to impose a sustained demand for HEALTH SERVICES rather than the short, intense peak customary with smaller scale disasters.Respiratory Rate: The number of times an organism breathes with the lungs (RESPIRATION) per unit time, usually per minute.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.Lung Diseases, Interstitial: A diverse group of lung diseases that affect the lung parenchyma. They are characterized by an initial inflammation of PULMONARY ALVEOLI that extends to the interstitium and beyond leading to diffuse PULMONARY FIBROSIS. Interstitial lung diseases are classified by their etiology (known or unknown causes), and radiological-pathological features.Pulmonary Ventilation: The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.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.Equipment Failure: Failure of equipment to perform to standard. The failure may be due to defects or improper use.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.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.Tracheostomy: Surgical formation of an opening into the trachea through the neck, or the opening so created.Noninvasive Ventilation: Techniques for administering artificial respiration without the need for INTRATRACHEAL INTUBATION.Cross Infection: Any infection which a patient contracts in a health-care institution.Pulmonary Gas Exchange: The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.Masks: Devices that cover the nose and mouth to maintain aseptic conditions or to administer inhaled anesthetics or other gases. (UMDNS, 1999)Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.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).Inhalation: The act of BREATHING in.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.Idiopathic Interstitial Pneumonias: A group of interstitial lung diseases with no known etiology. There are several entities with varying patterns of inflammation and fibrosis. They are classified by their distinct clinical-radiological-pathological features and prognosis. They include IDIOPATHIC PULMONARY FIBROSIS; CRYPTOGENIC ORGANIZING PNEUMONIA; and others.Data Display: The visual display of data in a man-machine system. An example is when data is called from the computer and transmitted to a CATHODE RAY TUBE DISPLAY or LIQUID CRYSTAL display.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.Suction: The removal of secretions, gas or fluid from hollow or tubular organs or cavities by means of a tube and a device that acts on negative pressure.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.Infant, Newborn: An infant during the first month after birth.Bronchoalveolar Lavage: Washing out of the lungs with saline or mucolytic agents for diagnostic or therapeutic purposes. It is very useful in the diagnosis of diffuse pulmonary infiltrates in immunosuppressed patients.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.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.Man-Machine Systems: A system in which the functions of the man and the machine are interrelated and necessary for the operation of the system.Streptococcus pneumoniae: A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.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.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.Critical Care: Health care provided to a critically ill patient during a medical emergency or crisis.Equipment Contamination: The presence of an infectious agent on instruments, prostheses, or other inanimate articles.Pressure: A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Tracheotomy: Surgical incision of the trachea.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.Murine pneumonia virus: A species of the genus PNEUMOVIRUS causing pneumonia in mice.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.Pneumocystis jirovecii: A species of PNEUMOCYSTIS infecting humans and causing PNEUMOCYSTIS PNEUMONIA. It also occasionally causes extrapulmonary disease in immunocompromised patients. Its former name was Pneumocystis carinii f. sp. hominis.Dimensional Measurement Accuracy: The closeness of a determined value of a physical dimension to the actual value.Nursing, Team: Coordination of nursing services by various nursing care personnel under the leadership of a professional nurse. The team may consist of a professional nurse, nurses' aides, and the practical nurse.Transportation of Patients: Conveying ill or injured individuals from one place to another.Critical Illness: A disease or state in which death is possible or imminent.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.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).Pneumocystis: A genus of ascomycetous FUNGI, family Pneumocystidaceae, order Pneumocystidales. It includes various host-specific species causing PNEUMOCYSTIS PNEUMONIA in humans and other MAMMALS.Exhalation: The act of BREATHING out.Humidity: A measure of the amount of WATER VAPOR in the air.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.Equipment Safety: Freedom of equipment from actual or potential hazards.Respiratory Paralysis: Complete or severe weakness of the muscles of respiration. This condition may be associated with MOTOR NEURON DISEASES; PERIPHERAL NERVE DISEASES; NEUROMUSCULAR JUNCTION DISEASES; SPINAL CORD DISEASES; injury to the PHRENIC NERVE; and other disorders.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)Capnography: Continuous recording of the carbon dioxide content of expired air.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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Legionnaires' Disease: An acute, sometimes fatal, pneumonia-like bacterial infection characterized by high fever, malaise, muscle aches, respiratory disorders and headache. It is named for an outbreak at the 1976 Philadelphia convention of the American Legion.Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.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.Therapy, Computer-Assisted: Computer systems utilized as adjuncts in the treatment of disease.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.Intermittent Positive-Pressure Breathing: Application of positive pressure to the inspiratory phase of spontaneous respiration.Equipment Failure Analysis: The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.Radiography, Thoracic: X-ray visualization of the chest and organs of the thoracic cavity. It is not restricted to visualization of the lungs.Lung Diseases: Pathological processes involving any part of the LUNG.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.Length of Stay: The period of confinement of a patient to a hospital or other health facility.Mycoplasma pneumoniae: Short filamentous organism of the genus Mycoplasma, which binds firmly to the cells of the respiratory epithelium. It is one of the etiologic agents of non-viral primary atypical pneumonia in man.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)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.Bronchoscopy: Endoscopic examination, therapy or surgery of the bronchi.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.Models, Anatomic: Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.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.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.Interactive Ventilatory Support: Mechanical ventilation delivered to match the patient's efforts in breathing as detected by the interactive ventilation device.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.Barotrauma: Injury following pressure changes; includes injury to the eustachian tube, ear drum, lung and stomach.Pulmonary Eosinophilia: A condition characterized by infiltration of the lung with EOSINOPHILS due to inflammation or other disease processes. Major eosinophilic lung diseases are the eosinophilic pneumonias caused by infections, allergens, or toxic agents.Pasteurization: Treatment of food with physical methods such as heat, high pressure, radiation, or electric current to destroy organisms that cause disease or food spoilage.Trimethoprim-Sulfamethoxazole Combination: This drug combination has proved to be an effective therapeutic agent with broad-spectrum antibacterial activity against both gram-positive and gram-negative organisms. It is effective in the treatment of many infections, including PNEUMOCYSTIS PNEUMONIA in AIDS.Respiratory Muscles: These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.Bronchopneumonia: Inflammation of the lung parenchyma that is associated with BRONCHITIS, usually involving lobular areas from TERMINAL BRONCHIOLES to the PULMONARY ALVEOLI. The affected areas become filled with exudate that forms consolidated patches.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.Electric Power Supplies: Devices that control the supply of electric current for running electrical equipment.Hospitalization: The confinement of a patient in a hospital.Hypercapnia: A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Airway Obstruction: Any hindrance to the passage of air into and out of the lungs.Pneumonia, Progressive Interstitial, of Sheep: Chronic respiratory disease caused by the VISNA-MAEDI VIRUS. It was formerly believed to be identical with jaagsiekte (PULMONARY ADENOMATOSIS, OVINE) but is now recognized as a separate entity.Apnea: A transient absence of spontaneous respiration.Pleural Cavity: Paired but separate cavity within the THORACIC CAVITY. It consists of the space between the parietal and visceral PLEURA and normally contains a capillary layer of serous fluid that lubricates the pleural surfaces.Quadriplegia: Severe or complete loss of motor function in all four limbs which may result from BRAIN DISEASES; SPINAL CORD DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; or rarely MUSCULAR DISEASES. The locked-in syndrome is characterized by quadriplegia in combination with cranial muscle paralysis. Consciousness is spared and the only retained voluntary motor activity may be limited eye movements. This condition is usually caused by a lesion in the upper BRAIN STEM which injures the descending cortico-spinal and cortico-bulbar tracts.Infant, Premature: A human infant born before 37 weeks of GESTATION.Chest Wall Oscillation: A respiratory support system used to remove mucus and clear airway by oscillating pressure on the chest.TracheitisExtracorporeal Membrane Oxygenation: Application of a life support system that circulates the blood through an oxygenating system, which may consist of a pump, a membrane oxygenator, and a heat exchanger. Examples of its use are to assist victims of smoke inhalation injury, respiratory failure, and cardiac failure.Infant, Premature, DiseasesIntensive Care Units, Neonatal: Hospital units providing continuing surveillance and care to acutely ill newborn infants.Influenza, Human: An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the NASAL MUCOSA; the PHARYNX; and conjunctiva, and by headache and severe, often generalized, myalgia.Pneumothorax: An accumulation of air or gas in the PLEURAL CAVITY, which may occur spontaneously or as a result of trauma or a pathological process. The gas may also be introduced deliberately during PNEUMOTHORAX, ARTIFICIAL.Acute Disease: Disease having a short and relatively severe course.Administration, Inhalation: The administration of drugs by the respiratory route. It includes insufflation into the respiratory tract.Air Filters: Barriers used to separate and remove PARTICULATE MATTER from air.Thoracic Wall: The outer margins of the thorax containing SKIN, deep FASCIA; THORACIC VERTEBRAE; RIBS; STERNUM; and MUSCLES.ManikinsRespiratory Tract Infections: Invasion of the host RESPIRATORY SYSTEM by microorganisms, usually leading to pathological processes or diseases.Burns, Inhalation: Burns of the respiratory tract caused by heat or inhaled chemicals.Sepsis: Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by HYPOTENSION despite adequate fluid infusion, it is called SEPTIC SHOCK.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.Fatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.Smoke Inhalation Injury: Pulmonary injury following the breathing in of toxic smoke from burning materials such as plastics, synthetics, building materials, etc. This injury is the most frequent cause of death in burn patients.Pneumonia of Swine, Mycoplasmal: A chronic, clinically mild, infectious pneumonia of PIGS caused by MYCOPLASMA HYOPNEUMONIAE. Ninety percent of swine herds worldwide are infected with this economically costly disease that primarily affects animals aged two to six months old. The disease can be associated with porcine respiratory disease complex. PASTEURELLA MULTOCIDA is often found as a secondary infection.Hyaline Membrane Disease: A respiratory distress syndrome in newborn infants, usually premature infants with insufficient PULMONARY SURFACTANTS. The disease is characterized by the formation of a HYALINE-like membrane lining the terminal respiratory airspaces (PULMONARY ALVEOLI) and subsequent collapse of the lung (PULMONARY ATELECTASIS).Pseudomonas Infections: Infections with bacteria of the genus PSEUDOMONAS.Pneumococcal Vaccines: Vaccines or candidate vaccines used to prevent infections with STREPTOCOCCUS PNEUMONIAE.Hospital Mortality: A vital statistic measuring or recording the rate of death from any cause in hospitalized populations.Trachea: The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Lung Volume Measurements: Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.Anti-Infective Agents: Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection.Pneumocystis carinii: The prototype species of PNEUMOCYSTIS infecting the laboratory rat, Rattus norvegicus (RATS). It was formerly called Pneumocystis carinii f. sp. carinii. Other species of Pneumocystis can also infect rats.Empyema: Presence of pus in a hollow organ or body cavity.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.Pulmonary Atelectasis: Absence of air in the entire or part of a lung, such as an incompletely inflated neonate lung or a collapsed adult lung. Pulmonary atelectasis can be caused by airway obstruction, lung compression, fibrotic contraction, or other factors.Pulmonary Disease, Chronic Obstructive: A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.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)Legionella pneumophila: A species of gram-negative, aerobic bacteria that is the causative agent of LEGIONNAIRES' DISEASE. It has been isolated from numerous environmental sites as well as from human lung tissue, respiratory secretions, and blood.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)Gas Scavengers: Apparatus for removing exhaled or leaked anesthetic gases or other volatile agents, thus reducing the exposure of operating room personnel to such agents, as well as preventing the buildup of potentially explosive mixtures in operating rooms or laboratories.Anesthesiology: A specialty concerned with the study of anesthetics and anesthesia.Infection Control: Programs of disease surveillance, generally within health care facilities, designed to investigate, prevent, and control the spread of infections and their causative microorganisms.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)Prone Position: The posture of an individual lying face down.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/)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)Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.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.United StatesLung Diseases, Obstructive: Any disorder marked by obstruction of conducting airways of the lung. AIRWAY OBSTRUCTION may be acute, chronic, intermittent, or persistent.Legionella: Gram-negative aerobic rods, isolated from surface water or thermally polluted lakes or streams. Member are pathogenic for man. Legionella pneumophila is the causative agent for LEGIONNAIRES' DISEASE.Pneumococcal Infections: Infections with bacteria of the species STREPTOCOCCUS PNEUMONIAE.Clinical Protocols: Precise and detailed plans for the study of a medical or biomedical problem and/or plans for a regimen of therapy.Child, Hospitalized: Child hospitalized for short term care.Immunocompromised Host: A human or animal whose immunologic mechanism is deficient because of an immunodeficiency disorder or other disease or as the result of the administration of immunosuppressive drugs or radiation.Organ Dysfunction Scores: Ratings that express, in numerical values, the degree of impairment or abnormality in the function of specific organs.Patient Transfer: Interfacility or intrahospital transfer of patients. Intrahospital transfer is usually to obtain a specific kind of care and interfacility transfer is usually for economic reasons as well as for the type of care provided.Pentamidine: Antiprotozoal agent effective in trypanosomiasis, leishmaniasis, and some fungal infections; used in treatment of PNEUMOCYSTIS pneumonia in HIV-infected patients. It may cause diabetes mellitus, central nervous system damage, and other toxic effects.Chlamydial Pneumonia: Pneumonia caused by infections with the genus CHLAMYDIA; and CHLAMYDOPHILA, usually with CHLAMYDOPHILA PNEUMONIAE.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)Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Bacteremia: The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.AIDS-Related Opportunistic Infections: Opportunistic infections found in patients who test positive for human immunodeficiency virus (HIV). The most common include PNEUMOCYSTIS PNEUMONIA, Kaposi's sarcoma, cryptosporidiosis, herpes simplex, toxoplasmosis, cryptococcosis, and infections with Mycobacterium avium complex, Microsporidium, and Cytomegalovirus.Colony Count, Microbial: Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.Pasteurellosis, Pneumonic: Bovine respiratory disease found in animals that have been shipped or exposed to CATTLE recently transported. The major agent responsible for the disease is MANNHEIMIA HAEMOLYTICA and less commonly, PASTEURELLA MULTOCIDA or HAEMOPHILUS SOMNUS. All three agents are normal inhabitants of the bovine nasal pharyngeal mucosa but not the LUNG. They are considered opportunistic pathogens following STRESS, PHYSIOLOGICAL and/or a viral infection. The resulting bacterial fibrinous BRONCHOPNEUMONIA is often fatal.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Pandemics: Epidemics of infectious disease that have spread to many countries, often more than one continent, and usually affecting a large number of people.Anesthesia, Closed-Circuit: Inhalation anesthesia where the gases exhaled by the patient are rebreathed as some carbon dioxide is simultaneously removed and anesthetic gas and oxygen are added so that no anesthetic escapes into the room. Closed-circuit anesthesia is used especially with explosive anesthetics to prevent fires where electrical sparking from instruments is possible.Thoracic Diseases: Disorders affecting the organs of the thorax.Pulmonary Fibrosis: A process in which normal lung tissues are progressively replaced by FIBROBLASTS and COLLAGEN causing an irreversible loss of the ability to transfer oxygen into the bloodstream via PULMONARY ALVEOLI. Patients show progressive DYSPNEA finally resulting in death.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.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.Brain Death: A state of prolonged irreversible cessation of all brain activity, including lower brain stem function with the complete absence of voluntary movements, responses to stimuli, brain stem reflexes, and spontaneous respirations. Reversible conditions which mimic this clinical state (e.g., sedative overdose, hypothermia, etc.) are excluded prior to making the determination of brain death. (From Adams et al., Principles of Neurology, 6th ed, pp348-9)Evaluation Studies as Topic: Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.Hospitals, University: Hospitals maintained by a university for the teaching of medical students, postgraduate training programs, and clinical research.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.Klebsiella Infections: Infections with bacteria of the genus KLEBSIELLA.Doxapram: A central respiratory stimulant with a brief duration of action. (From Martindale, The Extra Pharmocopoeia, 30th ed, p1225)Hypoalbuminemia: A condition in which albumin level in blood (SERUM ALBUMIN) is below the normal range. Hypoalbuminemia may be due to decreased hepatic albumin synthesis, increased albumin catabolism, altered albumin distribution, or albumin loss through the urine (ALBUMINURIA).Bronchodilator Agents: Agents that cause an increase in the expansion of a bronchus or bronchial tubes.Right to Die: The right of the patient or the patient's representative to make decisions with regard to the patient's dying.Klebsiella pneumoniae: Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans.Guideline Adherence: Conformity in fulfilling or following official, recognized, or institutional requirements, guidelines, recommendations, protocols, pathways, or other standards.Pseudomonas aeruginosa: A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.