O slideshow foi denunciado.
Utilizamos seu perfil e dados de atividades no LinkedIn para personalizar e exibir anúncios mais relevantes. Altere suas preferências de anúncios quando desejar.

Breathing systems open circuit- shoeib

  • Seja o primeiro a comentar

Breathing systems open circuit- shoeib

  2. 2. “NECESSITY IS MOTHER OF INVENTION” <br />Earlier circuits were simple, differing in the type of anesthetic agent administered.<br />The purpose of breathing systems that have evolved in anesthetic practice is to deliver Gas & Vapor to the patient in an appropriate, controlled & efficient manner. <br />
  3. 3. 1846 Sir W.T.G Morton did public demonstration with Ether.<br />
  4. 4. 1876  Clover`s Inhaler developed by J.T Clover.<br />
  5. 5. 1907 Barth used it to administer N₂O.<br />1909 Teter`s apparatus developed.<br />1909-13 F.W.Hewitts developed Hewitt`s apparatus.<br />
  6. 6. 1913 Gwathemy Apparatus developed.<br />1917 Boyle`s Apparatus developed.<br />1928 Magill`s Circuit was developed.<br />1937 Philip Ayre introduced T piece.<br />
  7. 7. 1972 J.A Bain & W.E Spoerel introduced Bain`s Circuit.<br />1975 Dr Gordon Jackson Rees developed Mapleson F system.<br />Humphrey Davy, Brock & Downing  developed combined ADE system.<br />
  8. 8. Definition<br />A breathing system is defined as an assembly of components, which connects the patient’s airway to the anesthetic machine creating an artificial atmosphere form and into which the patient breathes.<br />The breathing system converts a continuous flow from the anaesthesia machine to an intermittent flow; <br />
  9. 9. In practice the breathing system is usually regarded as extending from the point of fresh gas inlet to the point at which gas escapes to the atmosphere or a scavenging system.<br />Rebreathing: in anesthetic systems, it now conventionally refers to the breathing again of some or all of the previously exhaled gases including CO2 & water vapor.<br />
  10. 10. Components of breathing system: <br />Formally these were called breathing apparatus or breathing circuits. These names have been abandoned. <br />It primarily consists of<br />A fresh gas entry port/delivery tube through which gases are delivered from the machine to the systems.<br />A port to connect it to the patients airway.<br />A reservoir for a gas in the form of a bag or a corrugated tube to meet the peak inspiratory flow requirements<br />
  11. 11. d) An expiratory port/valve through which the expired gas is vented to the atmosphere.<br />e) Corrugated tubes for connecting these components.<br />f) Flow directing valves may or may not be used. <br />g) A CO2 absorber if total rebreathing is to be allowed.<br />
  12. 12. h) Connectors & adaptors <br /> A connector is a fitting that joins together 2 or more similar components. <br />An adaptor is a specialized connector that establishes functional continuity between otherwise disparate or incompatible components.<br />There sizes are universal & either male/female, 15/22mm connections. Some incorporate gas sampling ports.<br />
  13. 13. Bacterial filters- <br />they prevent transmission of infection to the patients or contamination of equipments.<br />Generally a new filter should be used for every patient or in the absence of filter, a disposable system should be used on every patient. <br />
  14. 14. j) Heat & Moisture Exchange (HME Filters)-<br />These humidify & warm the Anesthetic gases being delivered to the patients.<br />These devices also help to dehumidify the gases that are been sampled for analysis by the side stream devices<br />
  15. 15. RESERVOIR BAGS<br />Composition Rubber, synthetic latex, neoprene.<br />Ellipsoidal in shape.<br />Available in size ranging from 0.25L to 6L.<br />Types <br /><ul><li>Closed End.
  16. 16. Double end.
  17. 17. Kuhn`s bag.</li></li></ul><li>A normal size adult bag holds a volume exceeding the patients inspiratory capacity.<br />Functions <br />Reservoir<br />Provides PIF.<br />It provides a means whereby ventilation may be assisted or controlled.<br />It protects the patient from excessive pressure in the breathing system.<br />It can serve through visual & tactile observation as a monitor of patients spontaneous respiration.<br />
  18. 18. ASTM Standards specifies –<br />For bags < 1.5L, min pressure 30cms. & max pressure 50cms of water.<br />For bags > 1.5L, min pressure more than 35cms & max pressure not exceeding 60cms of water. <br />
  19. 19. Breathing Tubes<br />Made of rubber or plastic or silicone.<br />Can be impregnated with silver to add antimicrobial effect.<br />Length is variable.<br />Internal diameter <br /><ul><li>Adults – 22mm.
  20. 20. Pediatric – 15mm.</li></ul>Internal volume  400-500ml/m.<br />Distensibility 0-5ml/m/mmHg.<br />
  21. 21. Resistance to gas flow  <1mm of H₂O/litre/min of flow<br />Corrugations prevent kinking & increased flexibility.<br />Backlash  seen during spontaneous breathing.<br />Wasted ventilation  seen during controlled breathing.<br />Functions<br />Act as reservoir in certain systems.<br />They provide connection from 1part of system to another.<br />
  22. 22. Adjustable Pressure Limiting Valve (APL Valve)<br /> Also called as expiratory valve, pressure relief valve, pop off valve, Heidbrink valve, Dump valve, Exhaust valve, Spill valve etc<br />
  23. 23. TYPES OF APL VALVES<br />Spring Loaded Disc<br /><ul><li>Most commonly used type.
  24. 24. Has 3 ports –</li></ul>Inlet, <br />The Patient & <br />Exhaust Port.<br /><ul><li>Exhaust port may be open to atmosphere or scavenging system.</li></li></ul><li>Stem & Seat type<br />Control Knob type<br />Collection Device & Exhaust Port<br />
  25. 25. Humphrey Type valve.<br /> APL Valves with Inbuilt<br />Overpressure Safety devices<br />
  26. 26. Uses of APL valves in spontaneous & controlled ventilation.<br />Spontaneous<br /><ul><li>Valve is kept fully opened.
  27. 27. Partial closing will result in PEEP.
  28. 28. Pressure <1cm H₂O needed to open valve.
  29. 29. Should have pressure drop 1-3cm of H₂O for airflow of 3L/min & 1-5cms of water at 30L/min.</li></ul>Controlled<br /><ul><li>Valve is partially left open.</li></li></ul><li>Essential/ Principle Criteria<br />The breathing system must<br />Deliver the gases from the machine to the alveoli in the same concentration as set and in the shortest possible time.<br />b) Effectively eliminate carbon-dioxide.<br />c) Have minimal apparatus dead space.<br />d) Have low resistance.<br />
  30. 30. Desirable/Secondary Criteria<br />The desirable requirements are<br />economy of fresh gas.<br />b) conservation of heat.<br />c) adequate humidification of inspired gas.<br />d) light weight<br />
  31. 31. e) Convenience during use.<br />f) Efficiency during spontaneous as well as controlled ventilation (efficiency is determined in terms of CO2 elimination and fresh gas utilization)<br />g) Adaptability for adults, children and mechanical ventilators<br />h) Provision to reduce theatre pollution<br />
  32. 32. Dripps classification<br />It is based on rebreathing, presence or absence of reservoir, CO2 absorption & directional valves. <br />Insufflation system – gases are delivered directly into the patient’s airways, no reservoir bag, no valves, no CO2 absorber – open drop method<br />Open type – gases are directed to the patient from anesthesia machine, and valves direct exhaled gases to the atmosphere – intermittent flow machines, systems with non rebreathing valves<br />
  33. 33. Semiopen type – mixing of inspired and expired gases occur and rebreathing depends on fresh gas flow. <br />No CO2 absorber – Mapleson systems<br />Semiclosed system – part of the exhaled gases go out to the atmosphere, part of it gets mixed with inspired gases and is rebreathed. CO2 absorber is present<br />Closed system – complete rebreathing of expired gas. CO2 absorber is present.<br />
  34. 34.
  35. 35. Breathing systems without CO2 absorber<br />1) Unidirectional flow<br />non rebreathing system<br />They make use of non-rebreathing valves.<br />To prevent rebreathing FGF =MV. <br />
  36. 36. Though it satisfies all the 4 essential requirements, still not very popular because<br />Fresh gas flow has to be constantly adjusted and is not economical.<br />2) There is no humidification of inspired gases.<br />3) There is no conservation of heat<br />
  37. 37. 4) The valve is bulky and has to be placed close to the patient.<br />5) Malfunctioning of the valve can occur due to condensation of moisture.<br />6) Can be noisy at times.<br />7) Cleaning and sterilization is somewhat difficult<br />
  38. 38. Bidirectional flow<br />E.g. Water`s canister<br />These are obsolete in current anesthetic practice.<br />
  39. 39. MAPLESON BREATHING SYSTEM<br />In 1954 – on advice of William Mushin, Mapleson reported on functional analysis of Breathing systems.<br />
  40. 40. For better understanding of functional analysis they have been classified as<br />Afferent Reservoir System (ARS)<br />2) Enclosed Afferent Reservoir System<br />3) Efferent Reservoir System<br />4) Combined System<br />The efficiency of a system is determined in terms of CO₂ elimination & FGF utilization.<br />
  41. 41. Afferent limb is that part of the breathing system which delivers the fresh gas from the machine to the patient. <br />If the reservoir is placed in this limb as in Mapleson A, B, C and Lack’s systems they are called as afferent reservoir system.<br />Efferent limb is that part of the breathing system which carries the expired gas from the patient and vents it to the atmosphere through the expiratory valve/port. <br />If the reservoir is placed in this limb as in Mapleson D, E, F and Bain systems they are called efferent reservoir system<br />
  42. 42. For spontaneous ventilation in the order of efficiency – ADCB (All Dogs Can Bite).<br />For controlled ventilation – DBCA (Dead Bodies Can’t Argue)<br />Here D includes E, F and Bain`s system<br />
  43. 43. Mapleson postulates (1954)<br />Mapleson has analyzed these bi-directional flow systems & few basic assumptions have been made which are of historical interest. <br />Gases move En-bloc i.e they maintain their identity as fresh gas, dead space gas & alveolar gas. There is no mixing of these gases. <br />
  44. 44. Reservoir bags continues to fill up, without offering any resistance till it is full.<br />The expiratory valve opens as soon as the reservoir bag is full & pressure inside the system goes above the atmospheric pressure.<br />The valve remains open throughout the expiratory phase without offering any resistance to gas flow & closes at the start of next inspiration.<br />
  45. 45. Mapleson A/Magill’s system<br />Originally described by Evan Magill.<br />Length of breathing tube  110-180 cms.<br />FGF  from machine end.<br />APL  close to patient.<br />Sampling ports to be placed between APL valve & the tube. <br />
  46. 46. Spontaneous Breathing<br />3 phases identified <br />Inspiratory<br />Expiratory<br />Expiratory Pause.<br />
  47. 47. Function<br />To prevent rebreathing FGF=MV is advised.<br />FGF = 70 ml/kg/min is recommended.<br />Extremely efficient system for spontaneous ventilation. <br />
  48. 48. mapelsonA.swf<br />
  49. 49. Controlled Ventilation<br />These systems are inneficient for controlled ventilation.<br />FGF >20L/min required for CO₂ elimination.<br />This system cannot be used in patients less than 30kgs.<br />
  50. 50. Function<br />Lack system<br />Co-axial Mapleson A.<br />Outer tube 30mm in diameter.<br />Inner tube 14mm in diameter.<br />APL valve placed near patients end.<br />
  51. 51. Testing for Leaks in Magills & Lacks <br />Magill – tested for leaks by occluding the patient end & closing valve & pressurizing the system.<br /> Opening the APL valve will conform proper functioning of the component.<br />In addition the user or patient should breathe through the system to rule out block.<br />
  52. 52. Lack – tested same as for Mapleson A with testing integrity of inner tube. <br />ET tube is attached to inner tube & valve is closed. Air is blown. If leak is present, excursions will be seen in the reservoir bag.<br />Occlude both the limbs with APL valve open, squeeze the bag. Any leak is confirmed by release of gas from APL valve. <br />
  53. 53. Mapleson B system<br />This circuit functions similarly during both spontaneous & controlled ventilation.<br />FGF > 2x Min Volume used for both spontaneous & controlled ventilation.<br />
  54. 54. Mapleson C system<br />Also called as Westminster face piece<br />FGF > 2 x Min Volume for both Spontaneous & controlled.<br />Used for short periods during transportation of patient.<br />
  55. 55. Enclosed Afferent Reservoir System<br />Described by Miller & Miller.<br />Consists of Mapleson A system enclosed within a non-distensible structure<br />Spontaneous ventilation  variable orifice kept open, behaves like Mapleson A.<br />Controlled ventilation  variable orifice partially closed.<br />It is more efficient than Bain`s system when FG is > than Alveolar Ventilation.<br />
  56. 56. Efferent Reservoir System<br />Mapleson D,E,& F systems, all have a T piece in common. <br />T piece is 3 way tubular connector, 1cm in diameter & 5cm in length. <br />It has 3 ports <br />To Patient<br />The expiratory Port.<br />Fresh Gas Port.<br />FGF = PIFR has been used to prevent air dilution.<br />
  57. 57. Bain modification of Mapleson D system<br />Originally modified by Bain & Sporel in 1972.<br />Is co-axial system.<br />Usual length is 180cm.<br />Outer tube  <br />Diameter -22mm.<br />Carries exhaled gas.<br />Inner tube <br />Diameter-7mm.<br />Carries fresh gas.<br />
  58. 58. Spontaneous Ventilation<br />FGF of atleast 1.5-3 times MV is advised to prevent rebreathing.<br />Based on body wt. 200 ml/kg/min flow has been recommended.<br />
  59. 59. Controlled Ventilation<br />FGF to maintain normocarbia is advised to be around 70ml/kg/min.<br />Most efficient among the Mapleson Systems.<br />
  60. 60. Recommendations by Bain & Sporel<br />2L/min FGF in patients <10kg.<br />3.5L/min FGF in patients between 10-50 kg.<br />70ml/kg/min FGF in patients more than 60kg.<br />Tidal volume to be set at 10ml/kg.<br />Respiratory rate at 12-16 breaths/min. <br />
  61. 61. Advantages of Bains circuit<br />1) light weight<br />2) convenient to use<br />3) easily sterilized and reusable<br />4) scavenging of exhaled gases is facilitated<br />5) exhaled gases in the outer tubing add warmth to<br />the inspired gases<br />6) a long corrugated tubing with an aluminium APL valve may be used to ventilate a patient undergoing MRI<br />
  62. 62. Testing – <br />For the integrity of the inner tube<br />Set a low flow of O2 on the flow meter and occluding the inner tube (with a finger or the barren of a small syringe) at the patient end while observing the flowmeter indicator. <br />If the inner tube is intact and correctly connected, the indicator will fall.<br />
  63. 63. 2) Pethick’s test –<br />High flow O2 is fed into the circuit while the patient end is occluded until the bag is filled.<br />The patient end is opened and simultaneously ‘O2 flush’ is activated. <br />If the inner tube is intact, the Venturi effect occurring at the patient end, causes a decrease in pressure within the circuit and the reservoir bag deflates. <br />Conversely if there is a leak in the inner tube, gas escapes into the outer tube and the reservoir bag remains inflated<br />
  64. 64. Mapleson E system<br />Modification of Ayre`s T Piece.<br />Used initially for pediatric patients undergoing palate repair & intracranial surgery.<br />Minimal dead space, no valves, v.little resistance.<br />Volume of expiratory limb > Pts tidal volume to prevent air dilution. <br />
  65. 65. Used in children weighing 25-30kg.<br />Sampling port is between expiratory port & tubing.<br />FGF > 3 times min. volume<br />
  66. 66. Problems with this system are <br />Air dilution of the expiratory limb is short.<br />2) High fresh gas flow is required to prevent rebreathing and air dilution.<br />3) During controlled ventilation feel of the bag is not there and hence hazard of ‘barotrauma’ is a possibility.<br />Used to administer O₂ for spontaneously breathing patients in ICU.<br />
  67. 67. Mapleson F system(JACKSON-REES)<br />T piece arrangement with a reservoir bag.<br />Relief mechanism is either an adjustable valve at end of bag or a hole on side of Bag.<br />Newer modification incorporates APL valve before the reservoir bag. <br />Pressure relief is actuated at 30cms of water.<br />FGF = 2-3 x MV for spontaneous respiration.<br />FGF = Bain`s for controlled respiration.<br />
  68. 68. 1) light weight <br />2) simple construction<br />3) inexpensive<br />4) minimal resistance<br />5) minimal dead space<br />6) controlled ventilation is easily done<br />7) scavenging is easily facilitated.<br />
  69. 69. Hazards<br />1) lack of humidification<br />2) need for high fresh gas flows<br />3) occlusion of relief valve can increase the airway pressure, producing barotraumas<br />
  70. 70.
  71. 71. Advantages of Mapleson systems<br />the equipment is simple, inexpensive and rugged.<br />2) components can be easily disassembled and can be sterilized.<br />3) the systems provide buffering effect so that variations in minute volume affect end tidal CO2 less than in a circle system<br />4) rebreathing will result in retention of heat and moisture<br />5) resistance is within the recommended ranges<br />
  72. 72. 6) light weight and not bulky<br />7) do not cause excessive drag on ET tube<br />8) easy to position conveniently.<br />9) compression & compliance losses are less with these systems than with circle systems.<br />10) Changes in fresh gas concentration result in rapid changes in inspiratory gas composition<br />
  73. 73. Disadvantages<br />require high gas flows, higher costs, increased atmospheric pollution.<br />2) optimal fresh gas flow may be difficult to determine. Necessary to change fresh gas flows when changing from spontaneous to controlled mode.<br />3) anything that causes decreased fresh gas flow can produce dangerous rebreathing<br />
  74. 74. 4) in Mapleson A, B and C system the APL valve is close to the patient end and may be inaccessible.<br />5) Mapleson E and F are difficult to scavenge.<br />6) These are not suitable for patients with Malignant Hyperthermia because it may not be possible to increase the fresh gas flow enough to remove the increased CO2 load.<br />
  75. 75. Combined systems<br />Designed by Humphrey D, Brock & Downing.<br />Has 2 reservoirs, <br />Afferent<br />Efferent.<br />While in use, only 1 reservoir functions.<br />Lever helps in switch over function.<br />Can be used in adults as well as in children.<br />Not yet widely used. <br />
  76. 76. REFERENCES:<br />Dorsch J.A, Dorsch S.E. Understanding Anesthesia Equipment; 4th edition<br />Ward C S. Anaesthetic Equipment; 2nd edition.<br />Eisenkraft JB, Ehrenwerth J. Anesthesia Equipment. 1st edition<br />Ravishankar M. Man and the Machine – Anesthetic Breathing Systems<br />Barasch PG, Cullen BF, Stoelting RK. Clinical Anesthesia. 5th edition.<br />Wylie and Churchill Davidsons. A practice of anesthesia. 5th edition.<br />RACE 2008- Breathing Circuits by Dr M R Shankar.<br />
  77. 77. THANK YOU<br />

    Seja o primeiro a comentar

    Entre para ver os comentários

  • ChahatArya1

    Jan. 3, 2019
  • HarsimranSingh115

    Jan. 23, 2019
  • Abdelrahmanalshawadf

    Mar. 17, 2019
  • Ndhikh

    Apr. 25, 2019
  • AnitaSingh136

    May. 12, 2019
  • shantisushma

    Jun. 12, 2019
  • rajmohan1840070

    Nov. 12, 2019
  • abhikishore1

    Nov. 16, 2019
  • KrishnaReddy429

    Feb. 19, 2020
  • arunmedico

    Mar. 1, 2020
  • RupaliTiwari8

    May. 4, 2020
  • ankitagupta410

    May. 26, 2020
  • AnandLikhithaReddy

    Jul. 30, 2020
  • PradnyaShinde32

    Sep. 17, 2020
  • SurajGhosh20

    Dec. 10, 2020
  • NarendraSingh544

    Jan. 3, 2021
  • DipeshBK

    Feb. 11, 2021
  • FatimaOjabo

    Jun. 4, 2021
  • MubeshirAli1

    Jul. 14, 2021
  • VivekPatange1

    Jul. 22, 2021


Vistos totais


No Slideshare


De incorporações


Número de incorporações