Definitions of technical terms used in connection with breathing apparatus
In an atmosphere that may be oxygen-deficient, or toxic, an air supply can be carried on the back.
Abreathing apparatus orbreathing set is equipment which allows a person to breathe in a hostile environment where breathing would otherwise be impossible, difficult, harmful, or hazardous, or assists a person to breathe. Arespirator,medical ventilator, orresuscitator may also be considered to be breathing apparatus. Equipment that supplies or recycles breathing gas other than ambient air in a space used by several people is usually referred to as being part of alife-support system, and a life-support system for one person may include breathing apparatus, when the breathing gas is specifically supplied to the user rather than to the enclosure in which the user is the occupant.
All terms are defined in the context of breathing apparatus, and may have other meanings in other contexts not mentioned here. There are also many terms which are specific to underwater breathing apparatus (UBA) that may be found in theGlossary of underwater diving terminology.
Anair-filtering respirator is a breathing apparatus which removes particulates from the ambient air by passing it through afilter.
air-purifying respirator
Anair-purifying respirator is a respirator which uses a filter, cartridge, or canister to remove specific air contaminants by passing ambient air through the air-purifying component.[1] Contaminants may be filtered, adsorbed, or chemically altered by catalysis. No distinction is made based on the mechanism of passing the air through the purifying component – it may be the lungs of the user or a mechanical device.
Supplemental oxygen delivery system that automatically compensates for altitude using a barometric pressure sensor.[2]
ambulatory oxygen equipment
Supplementary oxygen delivery equipment weighing less than 10 pounds, intended for daily use, and designed to be carried by the patient The supply should last from four to six hours at a flow rate of 2 litres per minute. Compare withportable oxygen equipment.[3]
anaesthetic machine
anesthesia machine
Ananaesthetic machine is a medical device used to generate and precisely mix a flow of medical gases and inhalational anaesthetic agents of variable composition for the purpose of inducing and maintaining anaesthesia.[4]
anesthesia mask
anesthetic mask
anesthetic facemask
Ananesthesia mask is an orinasal facemask with an inflated cuff seal used to delivernon-invasive ventilation (NIV) of oxygen,entenox and anesthetic gases and vapours. They are usually transparent, with a single port, and may have a detachable hook ring to attach straps.[5][6]
aviation grade oxygen
gaseous aviator's breathing oxygen
High pressure oxygen of breathing grade with a lower allowable moisture content than medical oxygen.[7]
aviation supplemental oxygen
Aviation supplemental oxygen is oxygen provided to aircrew or passengers to reduce the risk of hypoxia at the reduced ambient pressures due to high cabin altitude.[2]
Abag valve mask is a hand-operated device used to provide positive pressure ventilation to patients who are not spontaneously breathing or not breathing sufficiently.
bilevel positive airway pressure
BiPAP
Breathing assist apparatus using a higher positive pressure on inspiration and lower positive pressure on expiration. Compare withcontinuous positive airway pressure
breathing apparatus
breathing set
Abreathing apparatus is a set of equipment that facilitates breathing in a hostile environment or for a person unable to adequately breathe unaided.
breathing gas
Abreathing gas is a mixture of gaseous chemical elements and compounds used forrespiration. Air is the most common and only natural breathing gas, but other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats Oxygen is the essential component for any breathing gas, at apartial pressure of between roughly 0.16 and 1.60bar at theambient pressure.[8][9][10]
breathing helmet
1. Abreathing helmet is a rigid respiratory user interface covering the head that also provides head protection against impact and penetration.[11] A diving helmet is possibly the most familiar example.
2. In medical terminology, a breathing helmet is synonymous with abreathing hood, and need not have any rigid protective structure.[12]
breathing hood
Abreathing hood is a type of respiratory interface that completely covers the head and neck, and optionally the shoulders or upper torso,[11] with a loose-fitting bag, which may have a neck seal or be relatively close fitting at the neck or shoulders. They are used in escape breathing apparatus of several kinds (escape hoods),[13] and as a route for supplementary oxygen (oxygen hoods). Breathing hoods with full length visors are commonly used with free-flow supplied air respirators for industrial work like in spray painting, boatbuilding, and woodworking workshops.[14]Atmosphere-supply hoods are often free-flow type, with a high enough flow rate to ensure that there is constant outflow at the lower edge to prevent contamination.
breathing mask
Abreathing mask is afacepiece that covers the mouth and nose, and optionally other parts of the face or head, to constrain and direct the flow of breathing gas as part of a breathing apparatus.
bubble CPAP
Bubble CPAP is a non-invasive ventilation apparatus for newborns withinfant respiratory distress syndrome (IRDS). It is one of the methods by whichcontinuous positive airway pressure (CPAP) is delivered to a spontaneously breathing newborn to maintain lung volumes during expiration. With this method, blended and humidified air with supplementaloxygen is delivered via short binasal prongs or a nasal mask and pressure in the circuit is maintained by immersing the distal end of the expiratory tubing in water. The depth to which the tubing is immersed underwater limits the pressure generated in the airways of the infant by hydrostatic back-pressure.[15]
Lightweight and compact system for generating emergency oxygen supply by chemical reaction.[2]
closed circuit breathing apparatus
Closed circuit breathing apparatus is equipment to facilitate breathing which recycles exhaledsupplied breathing gas by removing carbon dioxide and adding oxygen to compensate for metabolic usage before returning the gas to the user for repeated inhalation. Also known asrebreather equipment.
continuous positive airway pressure mask
continuous positive airway pressure
Continuous positive airway pressure (CPAP) is a form of ventilation in which a level of pressure greater than ambientatmospheric pressure is continuously applied to theupper respiratory tract of a person. The application of positive pressure may be intended to prevent upper airway collapse, or to reduce the work of breathing.[18]
counterlung
Acounterlung on arebreather is an airtight bag of strong flexible material that holds the volume of the exhaled gas until it is inhaled again. There may be a single counterlung, or one on each side of the scrubber, which allows a more even flow rate of gas through the scrubber, which can reducework of breathing and improve scrubber efficiency by a more consistentdwell time.
Physiologicaldead space is the volume of ventilated gas that does not reach parts of the lung in which gas exchange occurs.[19] Breathing apparatus usually add somemechanical dead space to increase the total dead space of the system of breathing apparatus and user.
demand valve
Ademand valveis a flow control mechanism that detects a pressure drop on the downstream side and opens the valve to compensate for the pressure drop. In supplied gas breathing apparatus this provides the user with a breath of gas at approximately the pressure set and maintained within the facepiece. When the user stops inhaling, the downstream pressure increases until the demand valve closes to stop the flow. A type of downstream pressure controlledpressure regulator that is relatively insensitive to upstream pressure.
diameter index safety system
DISS
Diameter index safety system is a type of outlet valve that uses one of a set of connections specific to the gas used to prevent delivery of the wrong gas.
diluter-demand
Supplementary oxygen supply system which provides oxygen via ademand valve and dilutes it with ambient air to a suitable concentration.[2]
dust mask
Adust mask is a flexible paper filter held over the nose and mouth by elastic or rubber straps for personal comfort against non-toxic nuisancedusts. They are not intended to provide protection from toxic airborne hazards.[20][21]
Anelastomeric respirator is a reusable respirator made of rubber. They usually come with replaceable filters, and can be fitted with either chemical cartridges orparticulate filters.[22]
An electronic delivery system (EDS) is an electronically controlled system of supplemental oxygen delivery, which supplies a pulse dose (bolus) of oxygen at the start of inhalation to economise on oxygen use.,[23] See alsoelectrical pulse demand oxygen system.
emergency escape breathing device
emergency evacuation breathing device
(EEBD) Emergency breathing apparatus intended to allow the user to escape from and enclosed space which is immediately dangerous to life or health. The endurance is generally no more than adequate for the purpose. Typically self-contained compressed air apparatus with 600 litres free air capacity. Required by amended SOLAS ch.II-2 and the IMO MSC/Circ.849 for all ships on international routes.[24][25]
Escape hoods are emergency breathing apparatus that entirely cover the head and provide a few minutes of autonomy to escape from a dangerous area.The main configurations are the smoke hood, which has a carbon monoxide and particulate filter, and the more general purpose escape hood which has an air purification cartridge that also removes other toxic gases from the ambient air. They are air purifying respiratory protective devices and can only be used if the ambient air contains enough oxygen.[13]
escape breathing apparatus
escape respirator
escape set
Anescape set is a type of self contained breathing apparatus for use in emergencies, intended to allow the user to pass through areas without a breathable atmosphere to a place of relative safety where the ambient air is safe to breathe. These are self contained ambient pressure systems, and include:
1. An item ofpersonal protective equipment that primarily guards the airways from a contaminated local environment, by either delivering safe breathing gas or as a filter or supporting structure for filters to purify ambient air. It may also protect the eyes and facial skin.
3. An item covering the mouth and nose intended to protect the local environment from contamination by the breath of the user.
facepiece
Afacepiece is the interface between the user and the breathing apparatus. It is the part of a breathing apparatus that fits against the user's face and through which the breathing gas passes during inhalation and exhalation. It may be sealed around the perimeter to prevent leakage to or from the environment, or may include a port to combine gas supply from the environment with gas supplied from the breathing apparatus. Also referred to as amask,breathing mask, orfacemask. Compare withmouthpiece,helmet andhood.
face tent
A mask that covers the nose and mouth but does not seal around the edges, used to provide a controlled concentration of oxygen over the lower face and increase moisture for patients who have facial burns or a broken nose, or who are claustrophobic. Difficult to control the concentration of oxygen delivered.[27]
Agas extender is an apparatus for extending the endurance of a breathing gas supply, for example, by re-using some of the gas in a rebreather circuit.The term is relatively frequently applied to semi-closed rebreather systems, but is not used very often.[29][30][31] Compare withoxygen conserving device anddemand pulse device
Heated humidified high-flow therapy, also known as high flow nasal cannula (HFNC) or high flow therapy (HFT), is a type of respiratory support that delivers a flow of medical breathing gas to a patient of up to 60 L/min and 100% oxygen through a large bore nasal cannula. originally used for neonates, it is also effective in some adults to treat hypoxemia and work of breathing issues. The key components are a gas blender, heated humidifier, heated circuit, and cannula.[33]
helium reclaim system
Ahelium reclaim system is the equipment used to recover exhaled helium based breathing gas from surface-supplied divers so that it can be recycled, as a cost saving mechanism.[34][35][36]
high flow nasal oxygen therapy
High flow nasal oxygen therapy is a system which uses a heated and humidified blend of air and oxygen delivered via a high flow nasal cannula (HFNC). It is a standard of care in some clinical situations for infants, children, and preterm neonates and is finding increasing use for adults.[37]
high flow oxygen device
Ahigh flow oxygen device is a supplementary oxygen delivery system with relatively high flow rates of a consistent mixture. An example is theventuri mask.[37]
Anasal cannula is tubing used to deliver supplemental oxygen at levels from 1 to 6 L/min. It has two short prongs that fit into the nostrils for delivery, that are connected to a common tube, which is usually hooked over the ears.[43] See alsoreservoir cannula
nasal mask
Anasal mask is a user respiratory interface which covers the nose and seals against the upper lip, the sides of the nose, and the bridge of the nose.[44]
nasal pillow mask
Anasal pillow mask is a respiratory user interface which seals on the rim of the nostrils. It is used in stable patients with sleep-disordered breathing.[44]
negative pressure breathing
1. (medical) Ventilation in which the surface of the thorax is exposed to pressure below the ambient pressure during inspiration. Used as a method of artificial respiration (iron lung).[45]
2. (diving) Breathing where the pressure of the breathing gas at the mouth is lower than the ambient pressure at the thorax. This can happen due to hydrostatic effects with back mounted counterlungs or badly adjusted cracking pressure on a demand regulator.
Non-invasive ventilation (NIV) is the use of medical breathing support administered through a face mask, nasal mask, or a helmet. It is termed "non-invasive" because it is delivered without a need fortracheal intubation.[49]
non-rebreather mask
Anon-rebreather mask (NRB) is a device used to deliversupplemental oxygen to a spontaneously breathing person. An NRB allows the delivery of relatively high concentrations of oxygen while using a constant flow rate, with relatively low waste, by accumulating the oxygen flow during exhalation in a soft bag, to be inhaled at the start of the next breath, so a bolus of oxygen is taken into the deeper parts of the lungs where much of it reaches the alveoli where gas exchange takes place.
Aircraft system which passes engine compressor bleed air through anoxygen concentrator, heat exchanger and pressure regulator to provide oxygen enriched pressurised air for the aircrew.[2]
open circuit breathing apparatus
Open circuit breathing apparatus is breathing apparatus that does not recycle any of the breathing gas, and discharges it all to the surroundings.[52] Open circuit breathing apparatus may be further classified as continuous flow (or free-flow) or demand supplied.[53] Both constant flow and demand supply can also provide gas from two sources, one of them being the ambient atmosphere, in what is generally referred to as supplemental oxygen provision.[54]
oral mask
Anoral mask is a respiratory user interface which fits inside the mouth between the teeth and lips, with a guide to prevent the tongue from obstructing the airway. They are not often used.[44]
Anoxygen conserving device is a mechanism that makes more efficient use of the available oxygen by a breathing apparatus. Several approaches to this problem have been used, with variable efficiency, complexity, reliability and weight tradeoffs. Often safety and reliability are more important than efficiency, and the overall risk must be considered.
oxygen hood
Anoxygen hood is a plastic hood used for high flow oxygen therapy in infants. It surrounds the head and has an opening for the neck. A high flow rate is necessary to prevent carbon dioxide accumulation. Supplied gas must be warmed and humidified.[37]
oxygen mask
Anoxygen mask is an interface between an oxygen delivery system and the human user. It provides a method to transferoxygen breathing gas from a storage tank or other source to thelungs. Oxygen masks may cover only the nose and mouth (oral-nasal mask) or the entire face (full-face mask).
oxygen tent
Anoxygen tent is a delivery method for supplemental oxygen. It consists of a canopy placed over the whole body or part of the body including the nose and mouth, into which an oxygen enriched gas supply is introduced, at a rate which will avoid excessive buildup of carbon dioxide.
Apartial rebreather mask is anorinasal mask used for oxygen therapy for people who are spontaneously breathing. It allows full flow from the reservoir bag during inhalation, but only allows exhaled gas from the anatomical dead space where no gas exchange has occurred to reenter the reservoir bag during exhalation, The rest of the exhaled gas is dumped to the ambient atmosphere. The gas admitted to the reservoir bag is rebreathed on the next inhalation along with fresh gas. It typically delivers 50 to 80% oxygen.[37]
Pin index safety system is a medical gas high pressure connection standard using connectors with indexing pins specific to the gas to prevent supply of the wrong gas. Compare with low pressurediameter index safety system DISS.
pocket mask
pocket CPR mask
Apocket mask, pocket face mask or CPR mask, is a compact device used to safely deliverrescue breaths during acardiac arrest orrespiratory arrest by providing a sealed connection to the respiratory tract that is isolated from direct contact with the recipient's exhalations by a filter or non-return valve.
portable gaseous oxygen system
Aircraft emergency oxygen system using a high pressure oxygen cylinder with regulator as supply.[2]
portable oxygen equipment
Supplementary oxygen provision equipment that is easily moved but not designed to be carried, and weighs more than about 10 pounds (4.5 kg).[3] Compare withambulatory oxygen equipment
positive airway pressure
Positive airway pressure (PAP) is a mode of respiratory ventilation used in the treatment of sleep apnea, respiratory failure, in newborn infants (neonates), and for the prevention and treatment of atelectasis in patients with difficulty taking deep breaths.
positive pressure breathing
1. (diving) Breathing when pressure of the breathing gas at the mouth exceeds the ambient pressure at the thorax. Can be caused by use of a positive pressure mask, upright position, chest mounted rebreather counterlung, or supine position with a twin-hose regulator.
2. (medical) Providing ventilation to a patient using positive pressure delivered by a ventilator or bag valve mask[57]
3. (altitude) Providing oxygen pressurised above cabin pressure to a person in apartial-pressure suit at very high altitude.
positive pressure breathing apparatus
(occupational health and safety, diving) Breathing apparatus in which pressure of the supplied gas in the facepiece exceeds the ambient pressure at all times. Any leakage at the facepiece seal is outward and contamination from the environment is less likely.[1]
Apowered air-purifying respirator (PAPR) is a type ofrespirator that consists of a headgear-and-fan assembly that passes ambientair through purifying units that remove contaminants and deliver clean air to the inside of the headgear covering the user's face or mouth and nose. Also known as positive-pressure masks, blower units, or just blowers.
pressure controlled ventilation
Mechanical ventilation in which breaths are provided at a set pressure and a set rate. Volume delivery may vary from breath to breath depending on lung compliance.[58]
pressure-demand system
Oxygen supply system that provides pure oxygen on demand at a pressure slightly above ambient, as is necessary for cabin altitudes above 34,000 feet. A type ofpositive pressure breathing system used with apressure suit.[2]
pressure regulated volume control
Mechanical ventilation which is a combination of pressure and volume controlled ventilation. A preset tidal volume is delivered at a set rate at the lowest possible pressure.[58]
pressure support ventilation
Pressure controlled mechanical ventilation triggered by patient effort.[58]
Oxygen delivery device that senses the start of inhalation and provides a metered bolus, which if correctly matched to requirements, will be sufficient and effectively inhaled into the alveoli. Such systems can be pneumatically or electrically controlled.[60]
pulse oximeter
Apulse oximeter is a non-invasive device that monitors pulse rate and blood oxygen saturation level.[2]
Arebreather is a closed circuit or semi-closed circuit breathing apparatus that absorbs thecarbon dioxide of a user'sexhaled breath to permit the recycling of the substantially unusedoxygen 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, conserve expensive gases, and for underwater use, reducing or eliminating the bubbles produced by an open circuit system. 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 alife-support system.
regulator
Apressure regulator (colloquially regulator), is avalve that controls the pressure of a fluid to a desired value, using negative feedback from the controlled pressure. Regulators are used for gases and liquids, and can be an integral device with a pressure setting, a restrictor and a sensor all in the one body, or consist of a separate pressure sensor, controller and flow valve. Two baasic types may be distinguished: The pressure reduction regulator which mainatains a set pressure on the outlet side, and the back-pressure regulator which maintains a set pressure on the inlet side.[61][62].
reservoir cannula
Areservoir cannula is an oxygen conserving supplemental oxygen administration device which accumulates constant flow oxygen in a small reservoir below the nose during exhalation and delivers in a bolus it at the beginning of the next inhalation, which ensures that most of it reaches the parts of the lung in which gas exchange occurs, and little is wasted in dead space.[63]
respirator
1. Arespirator may refer to a breathing apparatus that purifies ambient atmosphere, making it fit to breathe.[64]
2. Seeventilator. Medical breathing apparatus that provides breaths to a person impaired in their ability to breathe.[64]
respiratory gas humidification
Respiratory gas humidification is the process of artificially conditioning respiratory gas for the patient during therapy, and involves humidification, warming, and occasionally filtration of the gas being delivered.
respiratory protection
respiratory protective equipment
Respiratory protective equipment (RPE) is a type ofpersonal protective equipment designed to protect the wearer from a variety of airborne hazards in the form of gas, fume, mist, dust or vapour over the long or short term. Respirators filter the ambient air to remove harmful materials and atmosphere supplying breathing apparatus provides clean breathing gas to the user.[65]
resuscitator
Aresuscitator is apparatus using positive pressure to inflate the lungs of anunconscious person who isnot breathing, in order to keep themoxygenated and alive.[citation needed] There are three basic types: amanual version (also known as abag valve mask) consisting of a mask and a large hand-squeezed plastic bulb using ambient air, or with supplemental oxygen from a high-pressure tank. The second type is theexpired air or breath powered resuscitator. The third type is anoxygen powered resuscitator. These are driven by pressurized gas delivered by a regulator, and can either be automatic or manually controlled.[66]
Acarbon dioxide scrubber is equipment that absorbs carbon dioxide from gas passed through it. In breathing apparatus it is a container packed with carbon dioxide absorbent material, mostlystrong bases, through which the exhaled gas passes. The absorbent may be granular or in the form of a moulded cartridge.[67] Gas flow through the scrubber may be in one direction in a loop rebreather, or both ways in a pendulum rebreather.
self-contained breathing apparatus
Aself-contained breathing apparatus (SCBA) is a type of atmosphere-supplying respirator in which the breathing gas source is carried by the user.[1]
self-contained self-rescue device
self-contained self-rescuer
Aself-contained self-rescue device, SCSR, self-contained self-rescuer, or air pack is a small, lightweight belt or harness-worn portable apparatus for providing breathable gas when the surrounding atmosphere lacks oxygen or is contaminated with toxic gas. There are two forms of SCSR: respirators and rebreather oxygen sources. Compare withescape set andescape respirator
Asemi-closed circuit rebreather, also sometimes called a gas extender, is a class of self contained breathing apparatus in which a single breathing gas mixture such asnitrox ortrimix is injected into the loop at a constant rate to replenish oxygen consumed from the loop by the diver. Excess gas must be constantly vented from the loop in small volumes to make space for fresh, oxygen-rich gas. As oxygen and inert gas are continuously vented, semi-closed circuit is wasteful of both oxygen and inert components, but much less so than open circuit.[68]
simple face mask
Asimple face mask (SFM) is a basic disposable mask, made of clear plastic, to provideoxygen therapy for spontaneously breathing patients who need a concentration of supplemental oxygen in the range of 40 to 60%. Simple face masks are low flow delivery systems.[27]
smoke hood
Asmoke hood is an airtight bag with a transparent visor worn over the head and sealed at the neck. It has anair filter connected to the outside atmosphere with a mouthpiece to breathe through. Smoke hoods are emergency respirators intended to protect people escaping from fire from the effects ofsmoke inhalation.[69][70][71]
supplied-air respirator
Asupplied-air respirator (SAR) or air-line respirator is a breathing apparatus used in places where the ambient air may not be safe to breathe. It uses an air hose to supply air from outside the danger zone to a facepiece.[72]
synchronised intermittent mandatory ventilation
Ventilator mode to provide assisted ventilation for patients with some spontaneous breathing effort.[58]
Auser respiratory interface is the delivery system by which the breathing apparatus controls breathing gas flow to and from the user. Compare withfacepiece.
A preset tidal volume is delivered at a set rate by mechanical ventilator. Peak pressure can vary from breath to breath depending on lung compliance, and may be limited by an alarm setting.[58]
volume support ventilation
Ventilator support of patient initiated breathing based on a set volume delivery.[58]
the energy expended to inhale and exhale abreathing gas. It is usually expressed as work per unit volume, for example, joules per litre, or as a work rate (power), such as joules per min or equivalent units, as it is not particularly useful without a reference to volume or time. It can be calculated in terms of the pulmonary pressure multiplied by the change in pulmonary volume, or in terms of the oxygen consumption attributable to breathing.[75]
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