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  • alveoli
  • Lung alveoli are the ends of the respiratory tree, branching from either alveolar sacs or alveolar ducts, which like alveoli are both sites of gas exchange with the blood as well. (wikipedia.org)
  • Type I cells are thin and flat and form the structure of the alveoli Type II cells secrete surfactant to lower the surface tension of water and allows the membrane to separate, therefore increasing its capability to exchange gases. (wikipedia.org)
  • Reinflation of the alveoli following exhalation is made easier by pulmonary surfactant, which is a phospholipid and protein mixture that reduces surface tension in the thin fluid coating within all alveoli. (wikipedia.org)
  • At the dependent region smaller volumes mean the alveoli are more compliant (more distensible) and so capable of wider oxygen exchanges with the external environment. (wikipedia.org)
  • However, in most larger organisms, which have a small surface-area to volume ratios, specialised structures with convoluted surfaces such as gills, pulmonary alveoli and spongy mesophyll provide the large area needed for effective gas exchange. (wikipedia.org)
  • The test gas is held in the lung for about 10 seconds during which time the CO (but not the tracer gas) continuously moves from the alveoli into the blood. (wikipedia.org)
  • lung
  • Regional ventilation per unit of lung volume (spVr) was assessed with a positron camera during the washout of the tracer isotope 13NN from the lungs of 12 supine dogs. (biomedsearch.com)
  • A mathematical model of gas transport in a nonhomogeneous lung that exhibits such behavior is presented. (biomedsearch.com)
  • Measurement of inequality of ventilation and blood flow in the lung by using short-lived radioactive gases. (wikipedia.org)
  • Nahum A, Shapiro RS, Ravenscraft SA, Adams AB, Marini JJ (1995) Efficacy of expiratory tracheal gas insufflation in a canine model of lung injury. (springer.com)
  • Imanaka H, Kacmarek RM, Riggi V, Ritz R, Hess D (1998) Expiratory phase and volume-adjusted tracheal gas insufflation: A lung model study. (springer.com)
  • Kirmse M, Fujino Y, Hromi J, Mang H, Hess D, Kacmarek RM (1999) Pressure release tracheal gas insufflation reduces airway pressures in lung-injured sheep maintaining eucapnia. (springer.com)
  • This matching may be assessed in the lung as a whole, or in individual or in sub-groups of gas-exchanging units in the lung. (wikipedia.org)
  • A lower V/Q ratio (with respect to the expected value for a particular lung area in a defined position) impairs pulmonary gas exchange and is a cause of low arterial partial pressure of oxygen (paO2). (wikipedia.org)
  • To reduce symptoms To improve knowledge of lung condition and promote self-management To increase muscle strength and endurance (peripheral and respiratory) To increase the exercise tolerance To reduce length of hospital stay To help to function better in day-to-day life To help in managing anxiety and depression Reduction in number of days spent in hospital one year following pulmonary rehabilitation. (wikipedia.org)
  • A pulmonary contusion, also known as lung contusion, is a bruise of the lung, caused by chest trauma. (wikipedia.org)
  • Unlike pulmonary laceration, another type of lung injury, pulmonary contusion does not involve a cut or tear of the lung tissue. (wikipedia.org)
  • Pulmonary contusion and laceration are injuries to the lung tissue. (wikipedia.org)
  • Pulmonary laceration, in which lung tissue is torn or cut, differs from pulmonary contusion in that the former involves disruption of the macroscopic architecture of the lung, while the latter does not. (wikipedia.org)
  • When lacerations fill with blood, the result is pulmonary hematoma, a collection of blood within the lung tissue. (wikipedia.org)
  • However, pulmonary contusion is frequently associated with signs (objective indications) and symptoms (subjective states), including those indicative of the lung injury itself and of accompanying injuries. (wikipedia.org)
  • Diffusing capacity of the lung (DL) measures the transfer of gas from air in the lung, to the red blood cells in lung blood vessels. (wikipedia.org)
  • It is part of a comprehensive series of pulmonary function tests to determine the overall ability of the lung to transport gas into and out of the blood. (wikipedia.org)
  • Thus, the higher the diffusing capacity D L {\displaystyle D_{L}} , the more gas will be transferred into the lung per unit time for a given gradient in partial pressure (or concentration) of the gas. (wikipedia.org)
  • For this reason, CO is generally the test gas used to measure the diffusing capacity and the D L {\displaystyle D_{L}} equation simplifies to: The single-breath diffusing capacity test is the most common way to determine D L {\displaystyle D_{L}} . The test is performed by having the subject blow out all of the air that he/she can, leaving only the residual lung volume of gas. (wikipedia.org)
  • The person then inhales a test gas mixture rapidly and completely, reaching the total lung capacity as nearly as possible. (wikipedia.org)
  • In contrast, partial liquid ventilation (PLV) is a technique in which a PFC is instilled into the lung to a volume approximating functional residual capacity (approximately 40% of total lung capacity). (wikipedia.org)
  • If PFC liquid is not maintained in the lung, PLV can not effectively protect the lung from biophysical forces associated with the gas ventilator. (wikipedia.org)
  • In PLV, the lungs are filled with the liquid, the patient is then ventilated with a conventional ventilator using a protective lung ventilation strategy. (wikipedia.org)
  • Vaporization of perfluorohexane with two anesthetic vaporizers calibrated for perfluorohexane has been shown to improve gas exchange in oleic acid-induced lung injury in sheep. (wikipedia.org)
  • dead space venti
  • Because of the increased dead space ventilation, the PaO2 is reduced and thus also the peripheral oxygen saturation is lower than normal, leading to tachypnea and dyspnea. (wikipedia.org)
  • Ventilatory limitationIncreased dead space ventilation Impaired gas exchange Increased ventilatory demands due to peripheral muscle dysfunction Gas exchange limitationCompromised functional inspiratory muscle strength Compromised inspiratory muscle endurance Cardiac dysfunctionIncrease in right ventricular afterload due to increased peripheral vascular resistance. (wikipedia.org)
  • Physiology
  • In respiratory physiology, the diffusing capacity has a long history of great utility, representing conductance of gas across the alveolar-capillary membrane and also takes into account factors affecting the behaviour of a given gas with hemoglobin[citation needed]. (wikipedia.org)
  • In respiratory physiology, it is convenient to express the transport of gas molecules as changes in volume, since V O 2 ∝ n O 2 {\displaystyle {V_{O_{2}}}\propto {n_{O_{2}}}} (i.e., in a gas, a volume is proportional to the number of molecules in it). (wikipedia.org)
  • positive-pressure ve
  • This person must be capable of initiating resuscitation, including administration of positive-pressure ventilation and chest compressions. (ahajournals.org)
  • The 1856 works of English physician and physiologist Marshall Hall recommended against using any type of bellows/positive pressure ventilation, views that held sway for several decades. (wikipedia.org)
  • membrane
  • The alveolar membrane is the gas exchange surface. (wikipedia.org)
  • In these creatures the gas exchange membrane is typically the cell membrane. (wikipedia.org)
  • Other gas-exchange processes are important in less familiar organisms: e.g. carbon dioxide, methane and hydrogen are exchanged across the cell membrane of methanogenic archaea. (wikipedia.org)
  • D is the diffusion coefficient, which will differ from gas to gas, and from membrane to membrane, according to the size of the gas molecule in question, and the nature of the membrane itself (particularly its viscosity, temperature and hydrophobicity). (wikipedia.org)
  • If the two compartments are individually well-mixed, then this is simplifies to the difference in concentration of the gas between the inside and outside compartments divided by the thickness of the membrane. (wikipedia.org)
  • Fick's Law for gas-exchange surface Gases must first dissolve in a liquid in order to diffuse across a membrane, so all biological gas exchange systems require a moist environment. (wikipedia.org)
  • This test gas mixture contains a small amount of carbon monoxide (usually 0.3%) and a tracer gas that is freely distributed throughout the alveolar space but which doesn't cross the alveolar-capillary membrane. (wikipedia.org)
  • inert
  • METHODS: In patients with MVD (n = 12) or with CAD (n = 12), VA/Q distribution was determined using the multiple inert gas elimination technique. (biomedsearch.com)
  • 100 [% of VE]) were calculated from the retention/excretion data of the inert gases. (biomedsearch.com)
  • Stated mathematically: R = λ λ + V A / Q {\displaystyle R={\frac {\lambda }{\lambda +VA/Q}}} From this equation, we can measure the levels of each inert gas retained in the blood. (wikipedia.org)
  • Beyond this, however, it is possible to measure the concentrations of the inert gases in the expired gas from the subject. (wikipedia.org)
  • Preterm
  • Poulton DA, Schmölzer GM, Morley CJ, Davis PG (2011) Assessment of chest rise during mask ventilation of preterm infants in the delivery room. (springer.com)
  • Uptake
  • Conversely, in oxygenic photosynthetic organisms such as most land plants, uptake of carbon dioxide and release of both oxygen and water vapour are the main gas-exchange processes occurring during the day. (wikipedia.org)
  • blood
  • Streseman E and Sattler FP (1969) Effects of washout of anatomical deadspace on ventilation, pH, and blood gas composition in anesthetized dogs. (springer.com)
  • The fluid coating is produced by the body in order to facilitate the transfer of gases between blood and alveolar air. (wikipedia.org)
  • Ideally, the oxygen provided via ventilation would be just enough to saturate the blood fully. (wikipedia.org)
  • Moreover, a similar understanding exists for the relationship between the distribution of blood flow and the distribution of ventilation. (wikipedia.org)
  • Thus, it is critical to choose the appropriate PFC for a specific biomedical application, such as liquid ventilation, drug delivery or blood substitutes. (wikipedia.org)
  • Breath gas concentration can then be related to blood concentrations via mathematical modeling as for example in blood alcohol testing. (wikipedia.org)
  • The simplest model relating breath gas concentration to blood concentrations was developed by Farhi C A = C v ¯ λ b:air + V ˙ A / Q ˙ c , {\displaystyle C_{A}={\frac {C_{\bar {v}}}{\lambda _{\text{b:air}}+{\dot {V}}_{A}/{\dot {Q}}_{c}}},} where C A {\displaystyle C_{A}} denotes the alveolar concentration which is assumed to be equal to the measured concentration. (wikipedia.org)
  • Chest
  • The severity ranges from mild to severe: small contusions may have little or no impact on health, yet pulmonary contusion is the most common type of potentially lethal chest trauma. (wikipedia.org)
  • invasive
  • Breath gas analysis is a method for gaining non-invasive information on the clinical state of an individual by monitoring volatile organic compounds present in the exhaled breath. (wikipedia.org)
  • diffusion
  • Gas exchange is the biological process by which gases move passively by diffusion across a surface. (wikipedia.org)
  • The exchange of gases occurs as a result of diffusion down a concentration gradient. (wikipedia.org)
  • The negative sign indicates that the diffusion is always in the direction that - over time - will destroy the concentration gradient, i.e. the gas moves from high concentration to low concentration until eventually the inside and outside compartments reach equilibrium. (wikipedia.org)
  • In general, the higher the concentration gradient across the gas-exchanging surface, the faster the rate of diffusion across it. (wikipedia.org)
  • mechanisms
  • [11,Given these discrepant results and because improvement of oxygenation is the major aim of IRV, a better understanding of the mechanisms underlying the effects of IRV on pulmonary gas exchange is warranted. (asahq.org)
  • displaystyle
  • This is because the amount of gas diffusing per unit time (dq/dt) is the product of J and the area of the gas-exchanging surface, A: d q d t = J A {\displaystyle {\frac {dq}{dt}}=JA} Single-celled organisms such as bacteria and amoebae do not have specialised gas exchange surfaces, because they can take advantage of the high surface area they have relative to their volume. (wikipedia.org)
  • Dogs
  • Nahum A, Ravenscraft SA, Nakos G, Adams AB, Burke WC, Marini JJ (1993) Effect of catheter flow direction on CO 2 removal during tracheal gas insufflation in dogs. (springer.com)
  • Comparison of continuous and phase-specific gas injection in normal dogs. (springer.com)
  • high
  • In calibration experiments using a gas-mixing technique a high degree of linearity was found, both in the determination of the fraction of oxygen and carbon dioxide (r equal to 0.9996). (biomedsearch.com)
  • Effects of respiratory variables on regional gas transport during high-frequency ventilation. (biomedsearch.com)
  • Gas molecules move from a region in which they are at high concentration to one in which they are at low concentration. (wikipedia.org)
  • Those individuals with the lowest initial partial pressure of end-tidal pCO2 (the lowest concentration of carbon dioxide at the end of the respiratory cycle, a measure of a higher alveolar ventilation) and corresponding high oxygen saturation levels tend to have a lower incidence of acute mountain sickness than those with high end-tidal pCO2 and low oxygen saturation levels. (wikipedia.org)
  • normally
  • Sends stimulatory impulses to the inspiratory area - activates and prolongs inhalations Overridden by pneumotaxic control from the apneustic area to end inhalation Ventilation is normally unconscious and automatic, but can be overridden by conscious alternative patterns. (wikipedia.org)
  • carbon
  • Takahashi T, Bugedo G, Adams AB, Bliss PL, Marini JJ (1999) Effects of tracheal gas insufflation and tracheal gas exsufflation on intrinsic positive end-expiratory pressure and carbon dioxide elimination. (springer.com)
  • Excretion of carbon dioxide is also impaired, but a rise in the arterial partial pressure of carbon dioxide (paCO2) is very uncommon because this leads to respiratory stimulation and the resultant increase in alveolar ventilation returns paCO2 to within the normal range. (wikipedia.org)
  • Tracheal
  • Kacmarek RM (2001) Complications of tracheal gas insufflation. (springer.com)
  • Imanaka H, Kirmse M, Mang H, Hess D, Kacmarek RM (1999) Expiratory phase tracheal gas insufflation and pressure control in sheep with permissive hypercapnia. (springer.com)
  • Burke WC, Nahum A, Ravenscraft SA, et al (1993) Modes of tracheal gas insufflation. (springer.com)
  • Gowski DT, Delgado E, Miro AM, Tasota FJ, Hoffman LA, Pinsky MR (1997) Tracheal gas insufflation during pressure-control ventilation: effect of using a pressure relief valve. (springer.com)
  • mixtures
  • While at NEDU, Thalmann created a number of unique and innovative underwater exercise devices, still in use today, intended to assist in gauging the underwater endurance of divers using various gas mixtures while performing physically demanding tasks. (wikipedia.org)
  • The Thalmann Algorithm was the basis for a new set of decompression tables that provided more flexibility for diving time, depth, gas mixtures and pressures. (wikipedia.org)
  • breath
  • This dilution factor can be calculated once the CO2 in the exhaled breath is determined (either by electronically monitoring the exhaled breath or by collecting the exhaled breath in a gas impermeant bag (a Douglas bag) and then measuring the mixed gas in the collection bag). (wikipedia.org)
  • chlorine gas
  • The National Institute for Occupational Safety and Health recommends that a person wear splash proof goggles, a face shield and a respirator mask when working in the vicinity of chlorine gas. (wikipedia.org)
  • A recent chlorine gas leak in Pune, India, landed 20 individuals in the hospital. (wikipedia.org)
  • Though that was an accidental exposure, chlorine gas has been used as a weapon of warfare since World War I, most recently in 2007 in Iraq. (wikipedia.org)
  • Prolonged exposure to low concentration of the gas may have lethal effects, as can short-term exposure to high concentrations like chlorine gas poisoning. (wikipedia.org)
  • Measures
  • Because of safety issues, phosgene is almost always produced and consumed within the same plant and extraordinary measures are made to contain this gas. (wikipedia.org)
  • function
  • The standards also based on the concentration of nitrogen dioxide that show a significant and profound effects on the function of the pulmonary of asthmatic patients. (wikipedia.org)
  • occurs
  • Because chlorine is a gas at room temperature, most exposure occurs via inhalation. (wikipedia.org)
  • It usually occurs after the inhalation of the gas beyond the threshold limit value. (wikipedia.org)
  • tissues
  • Based on scientific studies of gas exchange in human tissues, further informed by his supervision of hundreds of experimental dives, Thalmann developed his namesake mathematical algorithm to protect divers from decompression sickness. (wikipedia.org)
  • dissolve
  • Once the sample is obtained, care is taken to eliminate visible gas bubbles, as these bubbles can dissolve into the sample and cause inaccurate results. (wikipedia.org)
  • heart
  • Individual and races may differ in nitrogen dioxide tolerance level and individual tolerance level for the gas may be altered by several factors, such as metabolic rate, barometric pressure, and hematological disorders but significant exposure may result in fatal conditions that could lead to shorter lifespan due to heart failure. (wikipedia.org)
  • known
  • Type II cells in the alveolar wall contain secretory granular organelles known as lamellar bodies that fuse with the cell membranes and secrete pulmonary surfactant. (wikipedia.org)
  • Known sources of nitrogen dioxide gas poisoning include automobile exhaust and power stations. (wikipedia.org)
  • current
  • April 3, 1945 - July 24, 2004) was an American hyperbaric medicine specialist who was principally responsible for developing the current United States Navy dive tables for mixed-gas diving, which are based on his eponymous Thalmann Algorithm (VVAL18). (wikipedia.org)
  • products
  • The relative stabilities of the V-substituted products were assessed in both solution and gas phases. (jove.com)
  • Care
  • Respir Care 22:491-500, 1977 Suwa K, Geffin B, Pontoppidan H, et al: A nomogram for deadspace requirement during prolonged artificial ventilation. (wikipedia.org)