Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. Respiratory failure is classified as either Type 1 or Type 2, based on whether there is a high carbon dioxide level, and can be acute or chronic. In clinical trials, the definition of respiratory failure usually includes increased respiratory rate, abnormal blood gases, and evidence of increased work of breathing. Respiratory failure causes an altered mental status due to ischemia in the brain.
Dead space is the volume of air that is inhaled that does not take part in the gas exchange, because it either remains in the conducting airways or reaches alveoli that are not perfused or poorly perfused. It means that not all the air in each breath is available for the exchange of oxygen and carbon dioxide. Mammals breathe in and out of their lungs, wasting that part of the inhalation which remains in the conducting airways where no gas exchange can occur.
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath. Oxygen is added to replenish the amount metabolised by the user. This differs from open-circuit breathing apparatus, where the exhaled gas is discharged directly into the environment. The purpose is to extend the breathing endurance of a limited gas supply, and, for covert military use by frogmen or observation of underwater life, eliminating the bubbles produced by an open circuit system and in turn not scaring wildlife being filmed. A rebreather is generally understood to be a portable unit carried by the user. The same technology on a vehicle or non-mobile installation is more likely to be referred to as a life-support system.
An arterial blood gas (ABG) test, or arterial blood gas analysis (ABGA) measures the amounts of arterial gases, such as oxygen and carbon dioxide. An ABG test requires that a small volume of blood be drawn from the radial artery with a syringe and a thin needle, but sometimes the femoral artery in the groin or another site is used. The blood can also be drawn from an arterial catheter.
Nasogastric intubation is a medical process involving the insertion of a plastic tube through the nose, down the esophagus, and down into the stomach. Orogastric intubation is a similar process involving the insertion of a plastic tube through the mouth. Abraham Louis Levin invented the NG tube. Nasogastric tube is also known as Ryle's tube in Commonwealth countries, after John Alfred Ryle.
Exhalation is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing. This happens due to elastic properties of the lungs, as well as the internal intercostal muscles which lower the rib cage and decrease thoracic volume. As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air. During forced exhalation, as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles generate abdominal and thoracic pressure, which forces air out of the lungs.
Hypercapnia (from the Greek hyper = "above" or "too much" and kapnos = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous product of the body's metabolism and is normally expelled through the lungs. Carbon dioxide may accumulate in any condition that causes hypoventilation, a reduction of alveolar ventilation (the clearance of air from the small sacs of the lung where gas exchange takes place) as well as resulting from inhalation of CO2. Inability of the lungs to clear carbon dioxide, or inhalation of elevated levels of CO2, leads to respiratory acidosis. Eventually the body compensates for the raised acidity by retaining alkali in the kidneys, a process known as "metabolic compensation".
Soda lime, a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO), is used in granular form within enclosed breathing environments like general anesthesia and its breathing circuit, submarines, rebreathers, and recompression chambers. Its purpose is to eliminate carbon dioxide from breathing gases, preventing carbon dioxide retention and, eventually, carbon dioxide poisoning. The creation of soda lime involves treating slaked lime with a concentrated sodium hydroxide solution.
Oxygen therapy, also referred to as supplemental oxygen, is the use of oxygen as medical treatment. Supplemental oxygen can also refer to the use of oxygen enriched air at altitude. Acute indications for therapy include hypoxemia, carbon monoxide toxicity and cluster headache. It may also be prophylactically given to maintain blood oxygen levels during the induction of anesthesia. Oxygen therapy is often useful in chronic hypoxemia caused by conditions such as severe COPD or cystic fibrosis. Oxygen can be delivered via nasal cannula, face mask, or endotracheal intubation at normal atmospheric pressure, or in a hyperbaric chamber. It can also be given through bypassing the airway, such as in ECMO therapy.
Capnography is the monitoring of the concentration or partial pressure of carbon dioxide (CO
2) in the respiratory gases. Its main development has been as a monitoring tool for use during anesthesia and intensive care. It is usually presented as a graph of CO
2 (measured in kilopascals, "kPa" or millimeters of mercury, "mmHg") plotted against time, or, less commonly, but more usefully, expired volume (known as volumetric capnography). The plot may also show the inspired CO
2, which is of interest when rebreathing systems are being used. When the measurement is taken at the end of a breath (exhaling), it is called "end tidal" CO
2 (PETCO2).
Total organic carbon (TOC) is an analytical parameter representing the concentration of organic carbon in a sample. TOC determinations are made in a variety of application areas. For example, TOC may be used as a non-specific indicator of water quality, or TOC of source rock may be used as one factor in evaluating a petroleum play. For marine surface sediments average TOC content is 0.5% in the deep ocean, and 2% along the eastern margins.
A carbon dioxide sensor or CO2 sensor is an instrument for the measurement of carbon dioxide gas. The most common principles for CO2 sensors are infrared gas sensors (NDIR) and chemical gas sensors. Measuring carbon dioxide is important in monitoring indoor air quality, the function of the lungs in the form of a capnograph device, and many industrial processes.
A gas detector is a device that detects the presence of gases in an area, often as part of a safety system. A gas detector can sound an alarm to operators in the area where the leak is occurring, giving them the opportunity to leave. This type of device is important because there are many gases that can be harmful to organic life, such as humans or animals.
Gastric tonometry describes the measurement of the carbon dioxide level inside the stomach in order to assess the degree of blood flow to the stomach and bowel.
A breathing circuit is those parts of a breathing apparatus, which direct the flow of supplied breathing gas to, and sometimes from, the user. The breathing circuit may be open, closed, or semi-closed, depending on whether breathing gas is recycled. A closed or semi-closed circuit will include components which remove carbon dioxide from the exhaled gas and add oxygen before it is delivered for inhalation, so that the mixture remains stable and suitable for supporting life. Terminology may vary slightly between fields of application. In diving and industrial rebreathers, the closed or semi-closed breathing circuit may also be called the loop, or breathing loop. In medical equipment the closed or semi-closed circuit may be called the circle system.
Exalenz Bioscience Ltd. is a biotechnology company that develops and manufactures non-invasive diagnostic medical devices for gastrointestinal and liver conditions. The company's technology uses a continuous flow of a patient's breath to diagnose illness. Exalenz is headquartered in Modi’in, Israel and is publicly traded on the Tel Aviv Stock Exchange as EXEN. U.S. headquarters are in Jersey City, New Jersey.
Advanced airway management is the subset of airway management that involves advanced training, skill, and invasiveness. It encompasses various techniques performed to create an open or patent airway – a clear path between a patient's lungs and the outside world.
Metacresol purple or m-cresol purple, also called m-cresolsulfonphthalein, is a triarylmethane dye and a pH indicator. It is used as a capnographic indicator for detecting detect end-tidal carbon dioxide to ensure successful tracheal intubation in an emergency. It can be used to measure the pH in subzero temperatures of saline or hypersaline media.
Carbon dioxide angiography is a diagnostic radiographic technique in which a carbon dioxide (CO2) based contrast medium is used - unlike traditional angiography where the contrast medium normally used is iodine based – to see and study the body vessels. Since CO2 is a non-radio-opaque contrast medium, angiographic procedures need to be performed in subtraction angiography (DSA).
Workplace exposure monitoring is the monitoring of substances in a workplace that are chemical or biological hazards. It is performed in the context of workplace exposure assessment and risk assessment. Exposure monitoring analyzes hazardous substances in the air or on surfaces of a workplace, and is complementary to biomonitoring, which instead analyzes toxicants or their effects within workers.
