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FiO2
Fraction of inspired oxygen (''FI''O2), correctly denoted with a capital ''I'', is the molar or volumetric fraction of oxygen in the inhaled gas. Medical patients experiencing difficulty breathing are provided with oxygen-enriched air, which means a higher-than-atmospheric ''FI''O2. Natural air includes 21% oxygen, which is equivalent to ''FI''O2 of 0.21. Oxygen-enriched air has a higher ''FI''O2 than 0.21; up to 1.00 which means 100% oxygen. ''FI''O2 is typically maintained below 0.5 even with mechanical ventilation, to avoid oxygen toxicity, but there are applications when up to 100% is routinely used. Often used in medicine, the ''FI''O2 is used to represent the percentage of oxygen participating in gas-exchange. If the barometric pressure changes, the ''FI''O2 may remain constant while the partial pressure of oxygen changes with the change in barometric pressure. Equations ;Abbreviated alveolar air equation :P_A \ce = \frac , , and are the partial pressures of oxygen in alv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horowitz Index
The Horowitz index or Horovitz index (also known as the Horowitz quotient or the P/F ratio) is a ratio used to assess lung function in patients, particularly those on ventilators. Overall, it is useful for evaluating the extent of damage to the lungs. The simple abbreviation as oxygenation can lead to confusion with other conceptualizations of oxygenation index. The Horowitz index is defined as the ratio of partial pressure of oxygen in blood ( PaO2), in millimeters of mercury, and the fraction of oxygen in the inhaled air (FiO2) — the ''PaO2''/''FiO2 ratio''. This is calculated by dividing the PaO2 by the FiO2. ''Example:'' patient who is receiving an FiO2 of .5 (i.e., 50%) with a measured PaO2 of 60 mmHg has a ''PaO2''/''FiO2 ratio'' of 120. In healthy lungs, the Horowitz index depends on age and usually falls between 350 and 450. A value below 300 is the threshold for mild lung injury, and 200 is indicative of a moderately severe lung injury. A value below 100 is a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acute Respiratory Distress Syndrome
Acute respiratory distress syndrome (ARDS) is a type of respiratory failure characterized by rapid onset of widespread inflammation in the lungs. Symptoms include shortness of breath (dyspnea), rapid breathing (tachypnea), and bluish skin coloration (cyanosis). For those who survive, a decreased quality of life is common. Causes may include sepsis, pancreatitis, trauma, pneumonia, and aspiration. The underlying mechanism involves diffuse injury to cells which form the barrier of the microscopic air sacs of the lungs, surfactant dysfunction, activation of the immune system, and dysfunction of the body's regulation of blood clotting. In effect, ARDS impairs the lungs' ability to exchange oxygen and carbon dioxide. Adult diagnosis is based on a PaO2/FiO2 ratio (ratio of partial pressure arterial oxygen and fraction of inspired oxygen) of less than 300 mm Hg despite a positive end-expiratory pressure (PEEP) of more than 5 cm H2O. Cardiogenic pulmonary edema, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
APACHE II
APACHE II ("Acute Physiology and Chronic Health Evaluation II") is a severity-of-disease classification system, one of several ICU scoring systems. It is applied within 24 hours of admission of a patient to an intensive care unit (ICU): an integer score from 0 to 71 is computed based on several measurements; higher scores correspond to more severe disease and a higher risk of death. The first APACHE model was presented by Knaus et al. in 1981. Application APACHE II was designed to measure the severity of disease for adult patients admitted to intensive care units. It has not been validated for use in children or young people aged under 16. This scoring system is used in many ways which include: # Some procedures or some medicine is only given to patients with a certain APACHE II score # APACHE II score can be used to describe the morbidity of a patient when comparing the outcome with other patients. # Predicted mortalities are averaged for groups of patients in order to spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung Injury
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the primary muscle that drives breathing is the Thoracic diaphragm, diaphragm. The lungs also provide airflow that makes Animal communication#Auditory, vocalisation including speech possible. Humans have two lungs, a ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alveolar Air Equation
The alveolar gas equation is the method for calculating partial pressure of alveolar oxygen (). The equation is used in assessing if the lungs are properly transferring oxygen into the blood. The alveolar air equation is not widely used in clinical medicine, probably because of the complicated appearance of its classic forms. The partial pressure of oxygen () in the pulmonary alveoli is required to calculate both the alveolar-arterial gradient of oxygen and the amount of right-to-left cardiac shunt, which are both clinically useful quantities. However, it is not practical to take a sample of gas from the alveoli in order to directly measure the partial pressure of oxygen. The alveolar gas equation allows the calculation of the alveolar partial pressure of oxygen from data that is practically measurable. It was first characterized in 1946. Assumptions The equation relies on the following assumptions: * Inspired gas contains no carbon dioxide () * Nitrogen (and any other gases e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Community Acquired Pneumonia
Community-acquired pneumonia (CAP) refers to pneumonia contracted by a person outside of the healthcare system. In contrast, hospital-acquired pneumonia (HAP) is seen in patients who are in a hospital or who have recently been hospitalized in the last 48 hours. Those who live in long-term care facilities or who had pneumonia after 48 hours of hospitalization for another cause are also classified as having CAP (they were previously designated as having HCAP (healthcare associated pneumonia)). CAP is common, affecting people of all ages, and its symptoms occur as a result of oxygen-absorbing areas of the lung ( alveoli) becoming colonized by a pathogenic microorganism (such as bacteria, viruses or fungi). The resulting inflammation and tissue damage causes fluid to fill the alveoli, inhibiting lung function and causing the symptoms of the disease. Common symptoms of CAP include dyspnea, fever, chest pains and cough. 10% of those with CAP are hospitalized. The 30 day mortality for tho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Gas Tension
Blood gas tension refers to the partial pressure of gases in blood. There are several significant purposes for measuring gas tension. The most common gas tensions measured are oxygen tension (PxO2), carbon dioxide tension (PxCO2) and carbon monoxide tension (PxCO). The subscript ''x'' in each symbol represents the source of the gas being measured: "''a''" meaning arterial, "''A''" being alveolar, "''v''" being venous, and "''c''" being capillary. Blood gas tests (such as arterial blood gas tests) measure these partial pressures. Oxygen tension ;Arterial blood oxygen tension (normal) PaO2 – Partial pressure of oxygen at sea level ( in the atmosphere, 21% of the standard atmospheric pressure of ) in arterial blood is between . ;Venous blood oxygen tension (normal) PvO2 – Oxygen tension in venous blood at sea level is between . Carbon dioxide tension Carbon dioxide is a by-product of food metabolism and in high amounts has toxic effects including: dyspnea, acidosis and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PaO2
Blood gas tension refers to the partial pressure of gases in blood. There are several significant purposes for measuring gas tension. The most common gas tensions measured are oxygen tension (PxO2), carbon dioxide tension (PxCO2) and carbon monoxide tension (PxCO). The subscript ''x'' in each symbol represents the source of the gas being measured: "''a''" meaning arterial, "''A''" being alveolar, "''v''" being venous, and "''c''" being capillary. Blood gas tests (such as arterial blood gas tests) measure these partial pressures. Oxygen tension ;Arterial blood oxygen tension (normal) PaO2 – Partial pressure of oxygen at sea level ( in the atmosphere, 21% of the standard atmospheric pressure of ) in arterial blood is between . ;Venous blood oxygen tension (normal) PvO2 – Oxygen tension in venous blood at sea level is between . Carbon dioxide tension Carbon dioxide is a by-product of food metabolism and in high amounts has toxic effects including: dyspnea, acidosis and altered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxemia
Hypoxemia (also spelled hypoxaemia) is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia is usually caused by pulmonary disease. Sometimes the concentration of oxygen in the air is decreased leading to hypoxemia. Definition ''Hypoxemia'' refers to the low level of oxygen in arterial blood. Tissue hypoxia refers to low levels of oxygen in the tissues of the body and the term ''hypoxia'' is a general term for low levels of oxygen. Hypoxemia is usually caused by pulmonary disease whereas tissue oxygenation requires additionally adequate circulation of blood and perfusion of tissue to meet metabolic demands. Hypoxemia is usually defined in terms of reduced partial pressure of oxygen (mm Hg) in arterial blood, but also in terms of reduced content of oxygen (ml oxygen per dl blood) or percentage saturation of hemoglobin (the oxygen-binding protein within red blood cells) with oxygen, which is either found singly o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
