Breathing Systems

2011 ◽  
Author(s):  
Patrick Magee ◽  
Mark Tooley
Keyword(s):  
Gas Flow ◽  
Anaesthetic Machine ◽  
Breathing System ◽  
Gas Flows ◽  
Co2 Absorption ◽  
Volatile Agent ◽  
Expiratory Valve ◽  
And Function ◽  
Expiratory Limb

An anaesthetic breathing system is a means of transferring the breathing gas mixture from the anaesthetic machine common gas outlet to the patient. It is also the means of transferring the exhaled gas from the patient to the outside world, usually via a scavenging system. Alternatively, after the carbon dioxide is absorbed from the exhaled gas, the unused fresh gas components of the exhaled gas are recirculated back to the patient. In general, a breathing system consists of a fresh gas limb, an inspiratory and expiratory limb, an expiratory valve, a reservoir bag and it may also consist of one or more unidirectional valves and a CO2 absorber. The simpler devices have fewer components and usually involve some rebreathing of expiratory gas, depending on the level of fresh gas flow. The ability to minimise rebreathing at as economical a fresh gas flow as possible is a measure of the breathing system’s efficiency. Depending on the precise design of the breathing system, such efficiency will vary depending on whether the patient is breathing spontaneously or is undergoing controlled artificial ventilation (see Chapter 26). The more complex systems ensure minimum rebreathing by the use of unidirectional valves and CO2 absorption systems; in this way, the additional complexity allows more economical use of fresh gas and volatile agent. The systems that use higher fresh gas flows (FGF) and involve some rebreathing were classified in 1954 by Professor Mapleson, according to their behaviour in terms of the FGF requirement to prevent CO2 rebreathing [Mapleson 1954]. At the time and for three decades beyond, they were the most popular breathing systems in UK anaesthetic practice. The Mapleson Classification of rebreathing systems is shown in Figure 25.1. Their design lends their structure and function to mathematical analysis [Dorrington 1989]. The Magill breathing system was invented by Sir Ivan Whiteside Magill in the early twentieth century. As shown in Figure 25.1A and Figure 25.2, the system is characterised by having the expiratory valve close to the patient and the fresh gas inflow at a distance from the patient, but close to the reservoir bag. Because of this particular configuration, the system is very economical in spontaneous breathing.

Detoxification of Heterophase Wastes Using Controlled Gas-Contact Technologies

2019 ◽  
Vol 23 (2) ◽  
pp. 4-9
Author(s):  
K.L. Chertes ◽  
D.V. Zelentsov ◽  
O.V. Tupitsyna ◽  
V.N. Pystin ◽  
O.I. Kondratyev
Keyword(s):  
Contaminated Soils ◽  
Gas Flow ◽  
Main Element ◽  
Gas Flows ◽  
Natural Conditions ◽  
Aeration System ◽  
Scope Of Application ◽  
Water Saturated ◽  
Artificial Pressure

The methods of natural and forced supply and removal of gases in arrays of heterophase wastes of various nature used in controlled gas-contact detoxification technologies are considered. The classification of the main parameters of the waste is divided into groups – mechanical, filtration, temperature, chemical and biological. Based on the analysis of the parameters, generalized criteria for determining the scope of application of gas-contact technologies are proposed. The implementation of gas flow control technology is described, an example of which are complexes biothermal treatment of oil-contaminated soils. The main element of this complex is the combined aeration system, which is necessary to increase the rate of biochemical decomposition of hardly decomposable hydrocarbons in oil waste. The results of the experiment conducted in the framework of the calculation and design of the aeration system due to the insufficiency of the initial data are presented. Shown the need to create a general theoretical model of controlled gas flows in porous, water-saturated, hard plastic media, both in natural conditions and under the action of an artificial pressure drop.

scholarly journals In vitro performance evaluation of AnaConDaTM-100 and AnaConDaTM-50 compared to a circle breathing system for control and consumption of volatile anaesthetics

2020 ◽  
Author(s):  
Martin Bellgardt ◽  
Dominik Drees ◽  
Vladimir Vinnikov ◽  
Adrian I. Georgevici ◽  
Livia Procopiuc ◽  
...  
Keyword(s):  
Gas Flow ◽  
Care Setting ◽  
Lung Model ◽  
Breathing System ◽  
Gas Flows ◽  
Test Lung ◽  
In Vitro Performance ◽  
Volume Controlled ◽  
Circle Breathing System

AbstractTo identify the better volatile anaesthetic delivery system in an intensive care setting, we compared the circle breathing system and two models of reflection systems (AnaConDa™ with a dead space of 100 ml (ACD-100) or 50 ml (ACD-50)). These systems were analysed for the parameters like wash-in, consumption, and wash-out of isoflurane and sevoflurane utilising a test lung model. The test lung was connected to a respirator (circle breathing system: Aisys CS™; ACD-100/50: Puriton Bennett 840). Set parameters were volume-controlled mode, tidal volume-500 ml, respiratory rate-10/min, inspiration time-2 sec, PEEP-5 mbar, and oxygen-21%. Wash-in, consumption, and wash-out were investigated at fresh gas flows of 0.5, 1.0, 2.5, and 5.0 l/min. Anaesthetic target concentrations were 0.5, 1.0, 1.5, 2.0, and 2.5%.  Wash-in was slower in ACD-100/-50 compared to the circle breathing system, except for fresh gas flows of 0.5 and 1.0 l/min. The consumption of isoflurane and sevoflurane in ACD-100 and ACD-50 corresponded to the fresh gas flow of 0.5-1.0 l/min in the circle breathing system. Consumption with ACD-50 was higher in comparison to ACD-100, especially at gas concentrations > 1.5%. Wash-out was quicker in ACD-100/-50 than in the circle breathing system at a fresh gas flow of 0.5 l/min, however, it was longer at all the other flow rates. Wash-out was comparable in ACD-100 and ACD-50. Wash-in and wash-out were generally quicker with the circle breathing system than in ACD-100/-50. However, consumption at 0.5 minimum alveolar concentration was comparable at flows of 0.5 and 1.0 l/min.

scholarly journals Simulation of the kinematics and gas dynamics of the centrifugal dispersion stand

2021 ◽  
Vol 2094 (4) ◽  
pp. 042046
Author(s):  
A E Zverovshchikov ◽  
G S Bolshakov
Keyword(s):  
Powder Material ◽  
Gas Dynamics ◽  
Gas Flow ◽  
Heterogeneous Medium ◽  
Deposition Process ◽  
Gas Flows ◽  
Working Chamber ◽  
Operational Analysis ◽  
Centrifugal Dispersion

Abstract The article studies the kinematics and gas dynamics of the centrifugal dispersion stand for spheroidizing hard alloy materials. When studying the process of centrifugal spraying on an experimental setup, it was found that the behavior of particles in the volume of the dispersion chamber is determined by the aerodynamics of gas flows formed in the working chamber. It is assumed that under the influence of gas flows, a spontaneous classification of the particles of the medium occurs, determined by the size of the latter. To study the trajectory of movement of particles of powder material in the working chamber and the deposition process, a gas-dynamic model of a centrifugal dispersion unit in the SolidWorks FlowSimulation application is proposed. The developed model of the centrifugal dispersion unit showed the possibility of operational analysis of the behavior of the gas flow, the trajectory of the particles of the powder material and the temperature of the obtained powder material, depending on the design and technological factors. The simulation results allow one to determine the principles of separation of a heterogeneous medium of particles into fractions, directly at the installation for the implementation of the method.

scholarly journals Classification of bulk material from the gas flow in a device with coaxially arranged pipes

2020 ◽  
Vol 193 ◽  
pp. 01056
Author(s):  
V. E. Zinurov ◽  
A. V. Dmitriev ◽  
M. A. Ruzanova ◽  
O. S. Dmitrieva
Keyword(s):  
Silica Gel ◽  
Gas Flow ◽  
Bulk Material ◽  
Gas Flows ◽  
Dusty Gas

The paper deals with the problem of classification of bulk material, based on silica gel, larger than 30 µm, from dusty gas flow. In order to solve this problem, the design of a classifier with coaxially arranged pipes is proposed. According to the conducted studies, it is more efficient to use a classifier with an inner conical pipe to solve the problems of separating the particles from the gas flows of various sizes, since a greater value is achieved for the centrifugal, inertial, gravitational and other forces acting on the dusty flow, that contribute to knocking the particles out of its structure, than in a classifier with a cylindrical inner pipe. On average, the efficiency of a classifier with a conical inner pipe is by 35.3% higher than that of a classifier with a cylindrical inner pipe. Classification of particles of bulk material, based on silica gel, larger than 30 µm from the dusty gas flows is solved most effectively by using a classifier with a conical inner pipe and hd parameter of 50 mm and a classifier with a cylindrical inner pipe and hd parameter of –10 mm.

Modeling Affordances and Functioning for Personalized Robotic Assistance

2020 ◽  
Author(s):  
Alessandro Umbrico ◽  
Gabriella Cortellessa ◽  
Andrea Orlandini ◽  
Amedeo Cesta
Keyword(s):  
Domain Knowledge ◽  
Experimental Tests ◽  
International Classification Of Functioning ◽  
Knowledge Representation And Reasoning ◽  
Health State ◽  
Knowledge Reasoning ◽  
Cognitive Assistance ◽  
Ontological Model ◽  
And Function

A key aspect of robotic assistants is their ability to contextualize their behavior according to different needs of assistive scenarios. This work presents an ontology-based knowledge representation and reasoning approach supporting the synthesis of personalized behavior of robotic assistants. It introduces an ontological model of health state and functioning of persons based on the International Classification of Functioning, Disability and Health. Moreover, it borrows the concepts of affordance and function from the literature of robotics and manufacturing and adapts them to robotic (physical and cognitive) assistance domain. Knowledge reasoning mechanisms are developed on top of the resulting ontological model to reason about stimulation capabilities of a robot and health state of a person in order to identify action opportunities and achieve personalized assistance. Experimental tests assess the performance of the proposed approach and its capability of dealing with different profiles and stimuli.

Co-Current and Countercurrent Migration of Gas Kicks in “Horizontal” Wells

1999 ◽  
Vol 121 (2) ◽  
pp. 96-101 ◽  
Author(s):  
H. Baca ◽  
J. Smith ◽  
A. T. Bourgoyne ◽  
D. E. Nikitopoulos
Keyword(s):  
Test Section ◽  
Gas Flow ◽  
Gas Injection ◽  
Horizontal Wells ◽  
Gas Flows ◽  
Countercurrent Flow ◽  
Drilling Operations ◽  
Operating Window ◽  
Annular Pipes ◽  
Injection Rates

Results from experiments conducted in downward liquid-gas flows in inclined, eccentric annular pipes, with water and air as the working fluids, are presented. The gas was injected in the middle of the test section length. The operating window, in terms of liquid and gas superficial velocities, within which countercurrent gas flow occurs at two low-dip angles, has been determined experimentally. The countercurrent flow observed was in the slug regime, while the co-current one was stratified. Countercurrent flow fraction and void fraction measurements were carried out at various liquid superficial velocities and gas injection rates and correlated to visual observations through a full-scale transparent test section. Our results indicate that countercurrent flow can be easily generated at small downward dip angles, within the practical range of liquid superficial velocity for drilling operations. Such flow is also favored by low gas injection rates.

Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column

2019 ◽  
Vol 41 (5) ◽  
pp. 820-820
Author(s):  
Pongayi Ponnusamy Selvi and Rajoo Baskar Pongayi Ponnusamy Selvi and Rajoo Baskar
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Aqueous Ammonia ◽  
Volume Flow Rate ◽  
Packed Column ◽  
Operating Conditions ◽  
Co2 Absorption ◽  
Absorption Column

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.

Effects of the Water Content of Soda Lime on Compound A Concentration in the Anesthesia Circuit in Sevoflurane Anesthesia 

1998 ◽  
Vol 88 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Hiromichi Bito ◽  
Yukako Ikeuchi ◽  
Kazuyuki Ikeda
Keyword(s):  
Gas Flow ◽  
Soda Lime ◽  
Absorption Capacity ◽  
Low Flow ◽  
Co2 Absorption ◽  
Sevoflurane Anesthesia ◽  
Compound A ◽  
Carbon Dioxide Co2 ◽  
End Tidal ◽  
Co2 Elimination

Background Sevoflurane anesthesia is usually performed with fresh gas flow rates greater than 2 l/min due to the toxicity of compound A in rats and limited clinical experience with sevoflurane in low-flow systems. However, to reduce costs, it would be useful to identify ways to reduce compound A concentrations in low-flow sevoflurane anesthesia. This goal of this study was to determine if compound A concentrations can be reduced by using soda lime with water added. Methods Low-flow sevoflurane anesthesia (fresh gas flow of 1 l/min) was performed in 37 patients using soda lime with water added (perhydrated soda lime) or standard soda lime as the carbon dioxide (CO2) absorbent. The soda lime was not changed between patients, but rather was used until CO2 rebreathing occurred. The perhydrated soda lime was prepared by spraying 100 ml distilled water onto 1 kg fresh soda lime, and water was added only when a new bag of soda lime was placed into the canister. Compound A concentrations in the circle system, soda lime temperatures, inspired and end-tidal CO2 and end-tidal sevoflurane concentrations, and CO2 elimination by the patient were measured during anesthesia. Results Compound A concentrations were significantly lower for the perhydrated soda lime (1.9 +/- 1.8 ppm; means +/- SD) than for the standard soda lime (13.9 +/- 8.2 ppm). No differences were seen between the two types of soda lime with regard to the temperature of the soda lime, end-tidal sevoflurane concentrations, or CO2 elimination. Compound A concentration decreased with the total time of soda lime use for both types of soda lime. The CO2 absorption capacity was significantly less for perhydrated soda lime than for standard soda lime. Conclusions Compound A concentrations in the circuit can be reduced by using soda lime with water added. The CO2 absorption capacity of the soda lime is reduced by adding water to it, but this should not be clinically significant.

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