Misplaced Pages

#663336

91-585: In 1913, Parker B. Francis founded the predecessor to Puritan-Bennett, originally incorporated as Oxygen Gas Company, which was a manufacturer and distributor of oxygen and hydrogen. In 1920 the company changed its name to the Kansas City Oxygen Company and then again in 1931 to Puritan Compressed Gas Corporation as it continued to expand. In 1940, V. Ray Bennett and Associates, Inc was founded by Ray Bennett in Santa Monica, CA. In 1945 Bennett applies for

182-671: A 3D-printed open-source prototype device called VentilAid. The makers describe it as a last resort device when professional equipment is missing. The design is publicly available. The first Ventilaid prototype requires compressed air to run. On March 21, 2020, the New England Complex Systems Institute (NECSI) began maintaining a strategic list of open source designs being worked on. The NECSI project considers manufacturing capability, medical safety and need for treating patients in various conditions, speed dealing with legal and political issues, logistics and supply. NECSI

273-435: A boundary marked in most places by a temperature inversion (i.e. a layer of relatively warm air above a colder one), and in others by a zone that is isothermal with height. Although variations do occur, the temperature usually declines with increasing altitude in the troposphere because the troposphere is mostly heated through energy transfer from the surface. Thus, the lowest part of the troposphere (i.e. Earth's surface)

364-407: A component of an anesthesia machine ). Ventilators are sometimes called "respirators", a term commonly used for them in the 1950s (particularly the "Bird respirator" ). However, contemporary medical terminology uses the word " respirator " to refer to a face-mask that protects wearers against hazardous airborne substances. In its simplest form, a modern positive pressure ventilator , consists of

455-452: A compressible air reservoir or turbine, air and oxygen supplies, a set of valves and tubes, and a disposable or reusable "patient circuit". The air reservoir is pneumatically compressed several times a minute to deliver room-air, or in most cases, an air/oxygen mixture to the patient. If a turbine is used, the turbine pushes air through the ventilator, with a flow valve adjusting pressure to meet patient-specific parameters. When over pressure

546-505: A factor of 1/ e (0.368) every 7.64 km (25,100 ft), (this is called the scale height ) -- for altitudes out to around 70 km (43 mi; 230,000 ft). However, the atmosphere is more accurately modeled with a customized equation for each layer that takes gradients of temperature, molecular composition, solar radiation and gravity into account. At heights over 100 km, an atmosphere may no longer be well mixed. Then each chemical species has its own scale height. In summary,

637-630: A familiar piece of medical equipment. The unit was sold as the Bird Mark 7 Respirator and informally called the "Bird". It was a pneumatic device and therefore required no electrical power source to operate. In 1965, the Army Emergency Respirator was developed in collaboration with the Harry Diamond Laboratories (now part of the U.S. Army Research Laboratory ) and Walter Reed Army Institute of Research . Its design incorporated

728-528: A great favourite with European anaesthetists for four decades, prior to the introduction of models controlled by electronics. It was independent of electrical power and caused no explosion hazard. The original Mark I unit was developed to become the Manley Mark II in collaboration with the Blease company, which manufactured many thousands of these units. Its principle of operation was very simple, an incoming gas flow

819-738: A large quantity of ventilators to the National Emergency Strategic Stockpile. From west to east, the companies include Canadian Emergency Ventilators Inc, Bayliss Medical Inc, Thornhill Medical, Vexos Inc, and CAE Inc. Air The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth 's planetary surface (both lands and oceans ), known collectively as air , with variable quantities of suspended aerosols and particulates (which create weather features such as clouds and hazes ), all retained by Earth's gravity . The atmosphere serves as

910-511: A layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of ultraviolet radiation (UV) from the Sun by the ozone layer, which restricts turbulence and mixing. Although the temperature may be −60 °C (−76 °F; 210 K) at the tropopause, the top of the stratosphere is much warmer, and may be near 0 °C. The stratospheric temperature profile creates very stable atmospheric conditions, so

1001-418: A life-threatening emergency for people using ventilators in a home care setting. Battery power may be sufficient for a brief loss of electricity, but longer power outages may require going to a hospital. The history of mechanical ventilation begins with various versions of what was eventually called the iron lung , a form of noninvasive negative-pressure ventilator widely used during the polio epidemics of

SECTION 10

#1733115854664

1092-574: A mass of about 5.15 × 10  kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner with increasing altitude, with no definite boundary between the atmosphere and outer space . The Kármán line , at 100 km (62 mi) or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in

1183-621: A medical products company with product lines in respiratory care, diagnostic imaging and analgesic pharmaceuticals . In 1998, Puritan-Bennett Aero Systems (PBASCO) was sold to BE Aerospace Inc. In 2000, Tyco International acquired Mallinckrodt to become a Tyco Healthcare company. In 2007, Covidien spun off from Tyco International and inherited Puritan Bennett along with other Tyco Healthcare Brands. In 2015, Medtronic acquired Covidien and inherited all brands, including Puritan Bennett. On February 20 2024, Medtronic announced that it will discontinue Puritan Bennett ventilators and exit

1274-485: A million miles away, were found to be reflected light from ice crystals in the atmosphere. When light passes through Earth's atmosphere, photons interact with it through scattering . If the light does not interact with the atmosphere, it is called direct radiation and is what you see if you were to look directly at the Sun. Indirect radiation is light that has been scattered in the atmosphere. For example, on an overcast day when you cannot see your shadow, there

1365-459: A patent for the BR-X2 ventilator developed during WWII for delivery of intermittent positive pressure ventilation to pilots after he witnessed several crashes caused by pilots passing out in unpressurized aircraft at high altitude. He would later invent a mechanical ventilator as an alternative to the iron lung machine. V. Ray Bennett and Associates, Inc was acquired by Puritan in 1956 and the next year

1456-733: A protective buffer between the Earth's surface and outer space , shields the surface from most meteoroids and ultraviolet solar radiation , keeps it warm and reduces diurnal temperature variation (temperature extremes between day and night ) through heat retention ( greenhouse effect ), redistributes heat and moisture among different regions via air currents , and provides the chemical and climate conditions allowing life to exist and evolve on Earth. By mole fraction (i.e., by quantity of molecules ), dry air contains 78.08% nitrogen , 20.95% oxygen , 0.93% argon , 0.04% carbon dioxide , and small amounts of other trace gases . Air also contains

1547-615: A rapid supply of 30,000 ventilators capable of treating COVID-19 patients. A major worldwide design effort began during the 2019-2020 coronavirus pandemic after a Hackaday project was started, in order to respond to expected ventilator shortages causing higher mortality rate among severe patients. On March 20, 2020, the Irish Health Service began reviewing designs. A prototype is being designed and tested in Colombia . The Polish company Urbicum reports successful testing of

1638-469: A small weighted arm visible to the lower right of the front panel. This was a robust unit and its availability encouraged the introduction of positive pressure ventilation techniques into mainstream European anesthetic practice. The 1955 release of Forrest Bird 's "Bird Universal Medical Respirator" in the United States changed the way mechanical ventilation was performed, with the small green box becoming

1729-445: A variable amount of water vapor , on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature and atmospheric pressure vary with altitude . Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and respiration of terrestrial animals is found only within 12 kilometres (7.5 mi) from the ground. Earth's early atmosphere consisted of accreted gases from

1820-530: A ventilator only while sleeping and resting, mainly employ a nasal mask. Invasive methods require intubation , which for long-term ventilator dependence will normally be a tracheotomy cannula, as this is much more comfortable and practical for long-term care than is larynx or nasal intubation. As failure may result in death, mechanical ventilation systems are classified as safety-critical systems , and precautions must be taken to ensure that they are highly reliable, including their power supply . Ventilatory failure

1911-544: Is 14 °C (57 °F; 287 K) or 15 °C (59 °F; 288 K), depending on the reference. The average atmospheric pressure at sea level is defined by the International Standard Atmosphere as 101325 pascals (760.00  Torr ; 14.6959  psi ; 760.00  mmHg ). This is sometimes referred to as a unit of standard atmospheres (atm) . Total atmospheric mass is 5.1480×10 kg (1.135×10 lb), about 2.5% less than would be inferred from

SECTION 20

#1733115854664

2002-405: Is a disaster-situation ventilator made using a freely-licensed design, and ideally, freely-available components and parts. Designs, components, and parts may be anywhere from completely reverse-engineered to completely new creations, components may be adaptations of various inexpensive existing products, and special hard-to-find and/or expensive parts may be 3D printed instead of sourced. During

2093-561: Is a type of breathing apparatus , a class of medical technology that provides mechanical ventilation by moving breathable air into and out of the lungs , to deliver breaths to a patient who is physically unable to breathe, or breathing insufficiently. Ventilators may be computerized microprocessor-controlled machines, but patients can also be ventilated with a simple, hand-operated bag valve mask . Ventilators are chiefly used in intensive-care medicine , home care , and emergency medicine (as standalone units) and in anesthesiology (as

2184-408: Is about 1.2 kg/m (1.2 g/L, 0.0012 g/cm ). Density is not measured directly but is calculated from measurements of temperature, pressure and humidity using the equation of state for air (a form of the ideal gas law ). Atmospheric density decreases as the altitude increases. This variation can be approximately modeled using the barometric formula . More sophisticated models are used to predict

2275-414: Is about 28.946 or 28.96  g/mol. This is decreased when the air is humid. The relative concentration of gases remains constant until about 10,000 m (33,000 ft). In general, air pressure and density decrease with altitude in the atmosphere. However, temperature has a more complicated profile with altitude and may remain relatively constant or even increase with altitude in some regions (see

2366-442: Is because clouds (H 2 O) are strong absorbers and emitters of infrared radiation. This is also why it becomes colder at night at higher elevations. The greenhouse effect is directly related to this absorption and emission effect. Some gases in the atmosphere absorb and emit infrared radiation, but do not interact with sunlight in the visible spectrum. Common examples of these are CO 2 and H 2 O. The refractive index of air

2457-1429: Is called paleoclimatology . The three major constituents of Earth's atmosphere are nitrogen , oxygen , and argon . Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by mole fraction in the coldest portions of the atmosphere to as much as 5% by mole fraction in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor). The remaining gases are often referred to as trace gases, among which are other greenhouse gases , principally carbon dioxide, methane, nitrous oxide, and ozone. Besides argon, other noble gases , neon , helium , krypton , and xenon are also present. Filtered air includes trace amounts of many other chemical compounds . Many substances of natural origin may be present in locally and seasonally variable small amounts as aerosols in an unfiltered air sample, including dust of mineral and organic composition, pollen and spores , sea spray , and volcanic ash . Various industrial pollutants also may be present as gases or aerosols, such as chlorine (elemental or in compounds), fluorine compounds and elemental mercury vapor. Sulfur compounds such as hydrogen sulfide and sulfur dioxide (SO 2 ) may be derived from natural sources or from industrial air pollution. Mole fraction

2548-447: Is close to, but just greater than, 1. Systematic variations in the refractive index can lead to the bending of light rays over long optical paths. One example is that, under some circumstances, observers on board ships can see other vessels just over the horizon because light is refracted in the same direction as the curvature of Earth's surface. The refractive index of air depends on temperature, giving rise to refraction effects when

2639-477: Is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide closer to the exobase. The atoms and molecules are so far apart that they can travel hundreds of kilometres without colliding with one another. Thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space . These free-moving particles follow ballistic trajectories and may migrate in and out of

2730-445: Is no direct radiation reaching you, it has all been scattered. As another example, due to a phenomenon called Rayleigh scattering , shorter (blue) wavelengths scatter more easily than longer (red) wavelengths. This is why the sky looks blue; you are seeing scattered blue light. This is also why sunsets are red. Because the Sun is close to the horizon, the Sun's rays pass through more atmosphere than normal before reaching your eye. Much of

2821-555: Is normally the case. A first series is manufactured by Boston Scientific . The plans are to be freely available online to the general public without royalties. The COVID-19 pandemic has led to shortages of essential goods and services - from hand sanitizers to masks to beds to ventilators. Countries around the world have experienced shortages of ventilators. Furthermore, fifty-four governments, including many in Europe and Asia, imposed restrictions on medical supply exports in response to

Puritan Bennett - Misplaced Pages Continue

2912-503: Is nowadays often replaced by a computer-controlled turbopump . Modern ventilators are electronically controlled by a small embedded system to allow exact adaptation of pressure and flow characteristics to an individual patient's needs. Fine-tuned ventilator settings also serve to make ventilation more tolerable and comfortable for the patient. In Canada and the United States, respiratory therapists are responsible for tuning these settings, while biomedical technologists are responsible for

3003-487: Is released, the patient will exhale passively due to the lungs ' elasticity, the exhaled air being released usually through a one-way valve within the patient circuit called the patient manifold. Ventilators may also be equipped with monitoring and alarm systems for patient-related parameters (e.g., pressure, volume, and flow) and ventilator function (e.g., air leakage, power failure, mechanical failure), backup batteries, oxygen tanks, and remote control. The pneumatic system

3094-513: Is so tenuous that some scientists consider it to be part of interplanetary space rather than part of the atmosphere). It extends from the thermopause (also known as the "exobase") at the top of the thermosphere to a poorly defined boundary with the solar wind and interplanetary medium . The altitude of the exobase varies from about 500 kilometres (310 mi; 1,600,000 ft) to about 1,000 kilometres (620 mi) in times of higher incoming solar radiation. The upper limit varies depending on

3185-481: Is sometimes referred to as volume fraction ; these are identical for an ideal gas only. ppm: parts per million by molecular count The concentration of CO 2 has been increasing in recent decades , as has that of CH 4 . Water vapor is about 0.25% by mass over full atmosphere Water vapor varies significantly locally The average molecular weight of dry air, which can be used to calculate densities or to convert between mole fraction and mass fraction,

3276-429: Is staffed with scientists from Harvard and MIT and others who have an understanding of pandemics, medicine, systems, risk, and data collection. The University of Minnesota Bakken Medical Device Center initiated a collaboration with various companies to bring a ventilator alternative to the market that works as a one-armed robot and replaces the need for manual ventilation in emergency situations. The Coventor device

3367-520: Is the inability to sustain a sufficient rate of CO 2 elimination to maintain a stable pH without mechanical assistance, muscle fatigue, or intolerable dyspnea. Mechanical ventilators are therefore carefully designed so that no single point of failure can endanger the patient. They may have manual backup mechanisms to enable hand-driven respiration in the absence of power (such as the mechanical ventilator integrated into an anaesthetic machine ). They may also have safety valves, which open to atmosphere in

3458-456: Is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about 12 km (7.5 mi; 39,000 ft), although this altitude varies from about 9 km (5.6 mi; 30,000 ft) at the geographic poles to 17 km (11 mi; 56,000 ft) at the Equator , with some variation due to weather. The troposphere is bounded above by the tropopause ,

3549-412: Is too low to conduct a significant amount of energy to or from the skin. This layer is completely cloudless and free of water vapor. However, non-hydrometeorological phenomena such as the aurora borealis and aurora australis are occasionally seen in the thermosphere. The International Space Station orbits in this layer, between 350 and 420 km (220 and 260 mi). It is this layer where many of

3640-475: Is typically the warmest section of the troposphere. This promotes vertical mixing (hence, the origin of its name in the Greek word τρόπος, tropos , meaning "turn"). The troposphere contains roughly 80% of the mass of Earth's atmosphere. The troposphere is denser than all its overlying layers because a larger atmospheric weight sits on top of the troposphere and causes it to be most severely compressed. Fifty percent of

3731-577: The F-layer of the ionosphere where they encounter enough atmospheric drag to require reboosts every few months, otherwise, orbital decay will occur resulting in a return to Earth. Depending on solar activity, satellites can experience noticeable atmospheric drag at altitudes as high as 700–800 km. The division of the atmosphere into layers mostly by reference to temperature is discussed above. Temperature decreases with altitude starting at sea level, but variations in this trend begin above 11 km, where

Puritan Bennett - Misplaced Pages Continue

3822-738: The United States Department of Health and Human Services . In preparation for a possible epidemic of respiratory disease, the newly created office awarded a $ 6 million contract to Newport Medical Instruments , a small company in California, to make 40,000 ventilators for under $ 3,000 apiece. In 2011, Newport sent three prototypes to the Centers for Disease Control . In 2012, Covidien , a $ 12 billion/year medical device manufacturer, which manufactured more expensive competing ventilators, bought Newport for $ 100 million. Covidien delayed and in 2014 cancelled

3913-639: The United States Food and Drug Administration for the new ventilator. On May 29, NASA reported that eight manufacturers were selected to manufacture the new ventilator. On April 7, 2020, Prime Minister Justin Trudeau announced that the Canadian Federal Government would be sourcing thousands of 'Made in Canada' ventilators. A number of organisations responded from across the country. They delivered

4004-588: The infrared to around 1100 nm. There are also infrared and radio windows that transmit some infrared and radio waves at longer wavelengths. For example, the radio window runs from about one centimetre to about eleven-metre waves. Emission is the opposite of absorption, it is when an object emits radiation. Objects tend to emit amounts and wavelengths of radiation depending on their " black body " emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. Colder objects emit less radiation, with longer wavelengths. For example,

4095-433: The magnetosphere or the solar wind. Every second, the Earth loses about 3 kg of hydrogen, 50 g of helium, and much smaller amounts of other constituents. The exosphere is too far above Earth for meteorological phenomena to be possible. However, Earth's auroras —the aurora borealis (northern lights) and aurora australis (southern lights)—sometimes occur in the lower part of the exosphere, where they overlap into

4186-402: The mesopause that marks the top of this middle layer of the atmosphere. It is the coldest place on Earth and has an average temperature around −85  °C (−120  °F ; 190  K ). Just below the mesopause, the air is so cold that even the very scarce water vapor at this altitude can condense into polar-mesospheric noctilucent clouds of ice particles. These are the highest clouds in

4277-451: The solar nebula , but the atmosphere changed significantly over time, affected by many factors such as volcanism , impact events , weathering and the evolution of life (particularly the photoautotrophs ). Recently, human activity has also contributed to atmospheric changes , such as climate change (mainly through deforestation and fossil fuel -related global warming ), ozone depletion and acid deposition . The atmosphere has

4368-428: The temperature section). Because the general pattern of the temperature/altitude profile, or lapse rate , is constant and measurable by means of instrumented balloon soundings , the temperature behavior provides a useful metric to distinguish atmospheric layers. This atmospheric stratification divides the Earth's atmosphere into five main layers: The exosphere is the outermost layer of Earth's atmosphere (though it

4459-511: The tropopause . This layer extends from the top of the troposphere at roughly 12 km (7.5 mi; 39,000 ft) above Earth's surface to the stratopause at an altitude of about 50 to 55 km (31 to 34 mi; 164,000 to 180,000 ft). The atmospheric pressure at the top of the stratosphere is roughly 1/1000 the pressure at sea level . It contains the ozone layer , which is the part of Earth's atmosphere that contains relatively high concentrations of that gas. The stratosphere defines

4550-543: The 2019–2020 COVID-19 pandemic , various kinds of ventilators have been considered. Deaths caused by COVID-19 have occurred when the most severely infected experience acute respiratory distress syndrome , a widespread inflammation in the lungs that impairs the lungs' ability to absorb oxygen and expel carbon dioxide. These patients require a capable ventilator to continue breathing. Among ventilators that might be brought into use for treating people with COVID-19, there have been many concerns. These include current availability,

4641-558: The Kármán line, significant atmospheric effects such as auroras still occur. Meteors begin to glow in this region, though the larger ones may not burn up until they penetrate more deeply. The various layers of Earth's ionosphere , important to HF radio propagation, begin below 100 km and extend beyond 500 km. By comparison, the International Space Station and Space Shuttle typically orbit at 350–400 km, within

SECTION 50

#1733115854664

4732-459: The Sun is approximately 6,000  K (5,730  °C ; 10,340  °F ), its radiation peaks near 500 nm, and is visible to the human eye. Earth is approximately 290 K (17 °C; 62 °F), so its radiation peaks near 10,000 nm, and is much too long to be visible to humans. Because of its temperature, the atmosphere emits infrared radiation. For example, on clear nights Earth's surface cools down faster than on cloudy nights. This

4823-411: The absence of power to act as an anti-suffocation valve for spontaneous breathing of the patient. Some systems are also equipped with compressed-gas tanks, air compressors or backup batteries to provide ventilation in case of power failure or defective gas supplies, and methods to operate or call for help if their mechanisms or software fail. Power failures , such as during a natural disaster, can create

4914-420: The aptly-named thermosphere above 90 km. Because in an ideal gas of constant composition the speed of sound depends only on temperature and not on pressure or density, the speed of sound in the atmosphere with altitude takes on the form of the complicated temperature profile (see illustration to the right), and does not mirror altitudinal changes in density or pressure. The density of air at sea level

5005-421: The atmosphere also cools by emitting radiation, as discussed below. The combined absorption spectra of the gases in the atmosphere leave "windows" of low opacity , allowing the transmission of only certain bands of light. The optical window runs from around 300 nm ( ultraviolet -C) up into the range humans can see, the visible spectrum (commonly called light), at roughly 400–700 nm and continues to

5096-399: The atmosphere and may be visible to the naked eye if sunlight reflects off them about an hour or two after sunset or similarly before sunrise. They are most readily visible when the Sun is around 4 to 16 degrees below the horizon. Lightning-induced discharges known as transient luminous events (TLEs) occasionally form in the mesosphere above tropospheric thunderclouds . The mesosphere is also

5187-489: The atmosphere based on characteristics such as temperature and composition, namely the troposphere , stratosphere , mesosphere , thermosphere (formally the ionosphere ) and exosphere . The study of Earth's atmosphere and its processes is called atmospheric science (aerology), and includes multiple subfields, such as climatology and atmospheric physics . Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann . The study of historic atmosphere

5278-637: The average sea level pressure and Earth's area of 51007.2 megahectares, this portion being displaced by Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the pressure is measured. Thus air pressure varies with location and weather . If the entire mass of the atmosphere had a uniform density equal to sea level density (about 1.2 kg per m ) from sea level upwards, it would terminate abruptly at an altitude of 8.50 km (27,900 ft). Air pressure actually decreases exponentially with altitude, dropping by half every 5.6 km (18,000 ft) or by

5369-414: The blue light has been scattered out, leaving the red light in a sunset. Different molecules absorb different wavelengths of radiation. For example, O 2 and O 3 absorb almost all radiation with wavelengths shorter than 300 nanometres . Water (H 2 O) absorbs at many wavelengths above 700 nm. When a molecule absorbs a photon, it increases the energy of the molecule. This heats the atmosphere, but

5460-557: The challenge of making more and lower cost ventilators, effectiveness, functional design , safety, portability, suitability for infants, assignment to treat other illnesses, and operator training. Deploying the best possible mix of ventilators can save the most lives. Although not formally open-sourced, the Ventec V+ Pro ventilator was developed in April 2020 as a shared effort between Ventec Life Systems and General Motors , to provide

5551-470: The company to grow even more as they targeted international markets. In 1968 the parent company reorganized itself as the Puritan-Bennett Corporation and consolidated its medical marketing department into a single unit. In 1995, Nellcor acquired Puritan-Bennett and the newly expanded company was renamed Nellcor Puritan Bennett. In 1997, Nellcor Puritan Bennett became a part of Mallinckrodt ,

SECTION 60

#1733115854664

5642-469: The company was renamed Bennett Respiration Products, Inc. By the 60's the company had added products such as the bubble jet and a heated humidifier to its oxygen therapy line. In 1967 Puritan released the MA-1 Volume Ventilator, an invention of Bennet's. This virtually replaced the cumbersome iron lung and made Bennet and Puritan recognizable names in the larger medical equipment field. This allowed

5733-589: The contract. BARDA started over again with a new company, Philips , and in July 2019, the FDA approved the Philips ventilator, and the government ordered 10,000 ventilators for delivery in mid-2020. On April 23, 2020, NASA reported building, in 37 days, a successful COVID-19 ventilator, named VITAL ("Ventilator Intervention Technology Accessible Locally"). On April 30, NASA reported receiving fast-track approval for emergency use by

5824-417: The cooperation of the anaesthesia department at Harvard University . Mechanical ventilators began to be used increasingly in anaesthesia and intensive care during the 1950s. Their development was stimulated both by the need to treat polio patients and the increasing use of muscle relaxants during anaesthesia. Relaxant drugs paralyse the patient and improve operating conditions for the surgeon but also paralyse

5915-409: The coronavirus pandemic. The capacities to produce and distribute invasive and non-invasive ventilators vary by country. In the initial phase of the pandemic, China ramped up its production of ventilators, secured large amounts of donations from private firms, and dramatically increased imports of medical devices worldwide. As a result, the country accumulated a reservoir of ventilators throughout

6006-415: The definition. Various authorities consider it to end at about 10,000 kilometres (6,200 mi) or about 190,000 kilometres (120,000 mi)—about halfway to the moon, where the influence of Earth's gravity is about the same as radiation pressure from sunlight. The geocorona visible in the far ultraviolet (caused by neutral hydrogen) extends to at least 100,000 kilometres (62,000 mi). This layer

6097-434: The gas molecules are so far apart that its temperature in the usual sense is not very meaningful. The air is so rarefied that an individual molecule (of oxygen , for example) travels an average of 1 kilometre (0.62 mi; 3300 ft) between collisions with other molecules. Although the thermosphere has a high proportion of molecules with high energy, it would not feel hot to a human in direct contact, because its density

6188-403: The layer where most meteors burn up upon atmospheric entrance. It is too high above Earth to be accessible to jet-powered aircraft and balloons, and too low to permit orbital spacecraft. The mesosphere is mainly accessed by sounding rockets and rocket-powered aircraft . The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by

6279-473: The lungs. Electric motors were, however, a problem in the operating theatres of that time, as their use caused an explosion hazard in the presence of flammable anaesthetics such as ether and cyclopropane . In 1952, Roger Manley of the Westminster Hospital , London, developed a ventilator which was entirely gas-driven and became the most popular model used in Europe. It was an elegant design, and became

6370-745: The machine could deliver the set volume in volume control ventilation. Microprocessor control led to the third generation of intensive care unit (ICU) ventilators, starting with the Dräger EV-A in 1982 in Germany which allowed monitoring the patient's breathing curve on an LCD monitor . One year later followed Puritan Bennett 7200 and Bear 1000, SERVO 300 and Hamilton Veolar over the next decade. Microprocessors enable customized gas delivery and monitoring, and mechanisms for gas delivery that are much more responsive to patient needs than previous generations of mechanical ventilators. An open-source ventilator

6461-645: The maintenance. In the United Kingdom and Europe the management of the patient's interaction with the ventilator is done by critical care nurses. The patient circuit usually consists of a set of three durable, yet lightweight plastic tubes, separated by function (e.g. inhaled air, patient pressure, exhaled air). Determined by the type of ventilation needed, the patient-end of the circuit may be either noninvasive or invasive. Noninvasive methods, such as continuous positive airway pressure (CPAP) and non-invasive ventilation , which are adequate for patients who require

6552-482: The mass of Earth's atmosphere is distributed approximately as follows: By comparison, the summit of Mount Everest is at 8,848 m (29,029 ft); commercial airliners typically cruise between 10 and 13 km (33,000 and 43,000 ft) where the lower density and temperature of the air improve fuel economy; weather balloons reach 30.4 km (100,000 ft) and above; and the highest X-15 flight in 1963 reached 108.0 km (354,300 ft). Even above

6643-553: The number of ventilators needed and used during the pandemic. When data is often not available for ventilators specifically, estimates are sometimes made based on the number of intensive care unit beds available, which often contain ventilators. In 2006, president George W. Bush signed the Pandemic and All-Hazards Preparedness Act , which created the Biomedical Advanced Research and Development Authority (BARDA) within

6734-504: The orbital decay of satellites. The average mass of the atmosphere is about 5 quadrillion (5 × 10 ) tonnes or 1/1,200,000 the mass of Earth. According to the American National Center for Atmospheric Research , "The total mean mass of the atmosphere is 5.1480 × 10  kg with an annual range due to water vapor of 1.2 or 1.5 × 10  kg, depending on whether surface pressure or water vapor data are used; somewhat smaller than

6825-614: The pandemic in Wuhan. Western Europe and the United States, which outrank China in their production capacities, suffered a shortage of supplies due to the sudden and scattered outbreaks throughout the North American and European continents. Finally, Central Asia , Africa , and Latin America , which depend almost entirely on importing ventilators, suffered severe shortages of supplies. Healthcare policy-makers have met serious challenges to estimate

6916-523: The previous estimate. The mean mass of water vapor is estimated as 1.27 × 10  kg and the dry air mass as 5.1352 ±0.0003 × 10  kg." Solar radiation (or sunlight) is the energy Earth receives from the Sun . Earth also emits radiation back into space, but at longer wavelengths that humans cannot see. Part of the incoming and emitted radiation is absorbed or reflected by the atmosphere. In May 2017, glints of light, seen as twinkling from an orbiting satellite

7007-408: The principle of fluid amplification in order to govern pneumatic functions. Fluid amplification allowed the respirator to be manufactured entirely without moving parts, yet capable of complex resuscitative functions. Elimination of moving parts increased performance reliability and minimized maintenance. The mask is composed of a poly(methyl methacrylate) (commercially known as Lucite ) block, about

7098-413: The respirator to synchronize with the breathing of the patient. Intensive care environments around the world revolutionized in 1971 by the introduction of the first SERVO 900 ventilator (Elema-Schönander), constructed by Björn Jonson . It was a small, silent and effective electronic ventilator, with the famous SERVO feedback system controlling what had been set and regulating delivery. For the first time,

7189-480: The respiratory muscles. In 1953 Bjørn Aage Ibsen set up what became the world's first Medical/Surgical ICU utilizing muscle relaxants and controlled ventilation. In the United Kingdom, the East Radcliffe and Beaver models were early examples. The former used a Sturmey-Archer bicycle hub gear to provide a range of speeds, and the latter an automotive windscreen wiper motor to drive the bellows used to inflate

7280-422: The satellites orbiting the Earth are present. The mesosphere is the third highest layer of Earth's atmosphere, occupying the region above the stratosphere and below the thermosphere. It extends from the stratopause at an altitude of about 50 km (31 mi; 160,000 ft) to the mesopause at 80–85 km (50–53 mi; 260,000–280,000 ft) above sea level. Temperatures drop with increasing altitude to

7371-496: The size of a pack of cards, with machined channels and a cemented or screwed-in cover plate. The reduction of moving parts cut manufacturing costs and increased durability. The bistable fluid amplifier design allowed the respirator to function as both a respiratory assistor and controller. It could functionally transition between assistor and controller automatically, based on the patient's needs. The dynamic pressure and turbulent jet flow of gas from inhalation to exhalation allowed

7462-447: The stratosphere lacks the weather-producing air turbulence that is so prevalent in the troposphere. Consequently, the stratosphere is almost completely free of clouds and other forms of weather. However, polar stratospheric or nacreous clouds are occasionally seen in the lower part of this layer of the atmosphere where the air is coldest. The stratosphere is the highest layer that can be accessed by jet-powered aircraft . The troposphere

7553-444: The temperature stabilizes over a large vertical distance through the rest of the troposphere. In the stratosphere , starting above about 20 km, the temperature increases with height, due to heating within the ozone layer caused by the capture of significant ultraviolet radiation from the Sun by the dioxygen and ozone gas in this region. Still another region of increasing temperature with altitude occurs at very high altitudes, in

7644-442: The thermopause varies considerably due to changes in solar activity. Because the thermopause lies at the lower boundary of the exosphere, it is also referred to as the exobase . The lower part of the thermosphere, from 80 to 550 kilometres (50 to 342 mi) above Earth's surface, contains the ionosphere . The temperature of the thermosphere gradually increases with height and can rise as high as 1500 °C (2700 °F), though

7735-429: The thermosphere. The exosphere contains many of the artificial satellites that orbit Earth. The thermosphere is the second-highest layer of Earth's atmosphere. It extends from the mesopause (which separates it from the mesosphere) at an altitude of about 80 km (50 mi; 260,000 ft) up to the thermopause at an altitude range of 500–1000 km (310–620 mi; 1,600,000–3,300,000 ft). The height of

7826-419: The total mass of the atmosphere is located in the lower 5.6 km (3.5 mi; 18,000 ft) of the troposphere. Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place. It has basically all the weather-associated cloud genus types generated by active wind circulation, although very tall cumulonimbus thunder clouds can penetrate

7917-430: The tropopause from below and rise into the lower part of the stratosphere. Most conventional aviation activity takes place in the troposphere, and it is the only layer accessible by propeller-driven aircraft . Within the five principal layers above, which are largely determined by temperature, several secondary layers may be distinguished by other properties: The average temperature of the atmosphere at Earth's surface

8008-487: The twentieth century after the introduction of the "Drinker respirator" in 1928, improvements introduced by John Haven Emerson in 1931, and the Both respirator in 1937. Other forms of noninvasive ventilators, also used widely for polio patients, include Biphasic Cuirass Ventilation , the rocking bed, and rather primitive positive pressure machines. In 1949, John Haven Emerson developed a mechanical assister for anaesthesia with

8099-509: The ventilator business. The Bennett MA-1 ventilator was a volume-cycled, constant flow generator that had three adjustable modes: assist, control, or assist-control. This model was the most commonly used ventilators in clinical practice. Oldest devices utilised for intermittent positive-pressure breathing (IPPB) therapy. These models were used in WW2 because the units were small, compact and easy to use. Mechanical ventilator A ventilator

8190-451: Was developed in a very short time and approved on April 15, 2020, by the FDA , only 30 days after conception. The mechanical ventilator is designed for use by trained medical professionals in intensive care units and easy to operate. It has a compact design and is relatively inexpensive to manufacture and distribute. The cost is only about 4% of a normal ventilator. In addition, this device does not require pressurized oxygen or air supply, as

8281-408: Was used to lift a weighted bellows unit, which fell intermittently under gravity, forcing breathing gases into the patient's lungs. The inflation pressure could be varied by sliding the movable weight on top of the bellows. The volume of gas delivered was adjustable using a curved slider, which restricted bellows excursion. Residual pressure after the completion of expiration was also configurable, using

#663336