anesthesia breathing systems

1. BREATHING SYSTEMS
PRESENTOR: DR. V. SAI SRI CHARAN
MODERATOR:DR.A.M.KUTAPPA

2. DEFINITION
• A breathing system is defined as an assembly of
components,which connects the patient's airway to the
anesthetic machine through which controlled composition of
gas mixture is dispensed.
• The breathing system converts continous flow from
anesthesia machine to intermittent flow to the patient.

3. USES OF BREATHING SYSTEMS
• delivers oxygen and anesthetic mixture of gases to the
patient
• removes expired gases
• controls temperature and humidity of inspired mixture

4. CHARECTERISTICS OF AN IDEAL BREATHING
SYSTEM
• simple ,safe and inexpensive
• able to deliver intended inspired gas mixture
• should permit spontaneous,controlled and assisted
ventilation in all age groups
• effecient at low fresh gas flow
• able to protect from baro trauma
• sturdy,compact and light weight
• easy scavenging of waste gases

5. • warming and humidification of inspired gases
• low resistance
• less or minimal dead space
• effective elimination of co2

6. COMPONENTS
• breathing tubes
• APL valve
• reservoir bag
• connectors and adaptors

7. DRIPPS CLASSIFICATION
• It is based on rebreathing,presence or absence of
reservoir,co2 absorption and directional valves
1. insufflation system: gases are delivered directly into
patient's airways,no reservoir bag,no valves,no co2
absorber- open drop method.
2. open type: gases are directed from anesthesia machine
and valves direct exhaled gases to atmosphere-intermittent
flow machines with non rebreathing valves.

8. 3.semi open type: mixture of inspired and expired gases occur
and rebreathing depends on fresh gas flows.
4.no co2 absorbers: mapleson systems
5.semi closed type: part of the exhaled gases go out to the
atmosphere,part of it gets mixed with inspired gases and goes
to the patient,co2 absorber is present.

10. MAPLESON POSTULATES
• professor bill mapleson had
analysed the bidirectional flow
systems and made few
assumptions which are of
historical interest.
• gases move enbloc- they
maintain their identity as fresh
gas ,dead space gas and alveolar
gas. there is no mixing of these
gases.

11. • reservoir bag continues to fill up, without offering any
resistance till it is full.
• the expuratory valve opens as soon as the bag is full and
pressure inside the system goes above the atmospheric
pressure.
• the valve remains open throughout te expiratory phase
without offering resistance to gas flow andcloses at the start
of next inspiratory phase.

12. LETS MAKE IT EASY TO UNDERSTAND!!
• For functional analysis they have been classified as
1. afferent reservoir system(ARS)
2. enclosed afferent reservoir system
3. efferent reservoir system
4. combined system
the effeciency of the system is determined by the co2
elimination and FGF utilisation.

13. • AFFERENT LIMB: The part of the breathing system which
delivers the fresh gas to the patient from the anesthesia
machine.
• if the reservoir is placed in this limb as in mapleson A
,B,C,&Lack's system they are called as afferent reservoir
system
• EFFERENT SYTEM: Part of the breathing system which
collects the exhaled gas and vents it to the atmosphere
through the expiratory valve/port
• if the reservoir is placed in this limb as in D,E,F and Bain's
system it is called efferent system.

14. MAPLESON A/ MAGILL SYSTEM
• originally described by sir
ivan magill
• length of the breathing tube -
110 to180 cms
• FGF from the machine end
• APL -close to the patient
• sampling ports to be placed
between apl valve and the
tube.

15. FUNCTIONAL ANALYSIS
• SPONTANEOUS BREATHING
• 3 phases are identified
• inspiratory phase
• expiratory phase
• expiratory pause

16. • to prevent rebreathing FGF=
MV is advised
• FGF = 70 ml/kg/min is
advised this system is
extremely effecient for
spontaneous ventilation

17. CONTROLLED VENTILATION
• these systems are ineffecient for controlled ventilation
• FGF more than 20l/min are required to pevent rebreathing.
• it cannot be used in patients weighing less than 30 kgs.
• it becomes more effecient if the expiratory phase is
prolonged
• however this system should not be used for controlled
ventilation unless etco2 is monitored.

18. LACK'S SYSTEM
• co-axial mapleson A system
• outer tube inspiratory inflow
with a diameter of 30 mm
• inner tube is expiratory
outflow with a diameter of 14
mm
• APL valve is at the patients
end

19. TESTING OF CIRCUITS- MAGILL AND LACK'S
• MAGILL - tested by closing the patients end and pressurising the
system
• Opening of apl valve will conform the proper functioning of the
components
• In addition the patient or user should breathe through the system to
tike out block
• LACK'S- along with the above check ,integrity of the inner tube should
be checked.

20. • Et tube is attached to the inner tube and valve is closed.Air is blown.if
leak os present then excursions will be seen in the reservoir bag.
• Occlude both the limbs with apl valve open.then squeeze the bag.if
leak is present air will be released from the apl valve.

21. MAPLESON B SYSTEM
• The circuit functions similarly in spontaneous and controlled
ventilation.
• Went out of practice due to requirement of high fresh gas flow to
prevent rebreathing.
• Fresh gas flow almost equal to peak inspiratory flow rate of 20-
25l/min are required
• Hence there was a lot of ot pollution.

22. MAPLESON C SYSTEM
• also called as west minister face piece.
• Now a days only use of this system is in emergency resuscitation.
• System is similar to MAPLESON B system ,expect for the fact of
absence of corrugated tubing.
• Functional analysis is similar to MAPLESON B .
• Requires high fresh gas flows to prevent rebreathing.

23. EFFERENT RESERVOIR SYSTEM
• MAPLESON D,E,F all have a t piece in common.
• It is a 3 way connector with following ports
• 1.to the patient
• 2. Expiratory port
• 3. Fresh gas flow.
• Fresh gas flow =PIFR has been used to prevent air dilution.

24. MAPLESON D SYSTEM
• Classic form of MAPLESON D system has a 6mm tube which delivers
fresh gas flow from the machine to the patient.
• It connects to the t piece at the patient end.
• The other end is connected to the corrugated tube to which a
reservoir bag is attached
• Expiratory valve is at the reservoir bag end.

25. BAIN'S MODIFICATION OF MAPLESON D
• Originally modified by bain and spoerel in 1972.
• It is a co-axial system.
• Length of 180 cms
• Outer tube carries expired gas .Has a diameter of 22mm
• Inner tube carries inspiratory gases and has a diameter of 7mm

26. SPONTANEOUS VENTILATION
• When the patient inspire fresh gas goes to the patient.
• During expiration, the expired gas gets mixed continuously with fresh
gas flow and flows back into corrugated tube and reservoir bag.
• During expiratory pause the fresh gas continues to flow and gilla the
proximal portion of the corrugated tube.
• During next inspiration the patient t breathes fresh gas as well as
mixed gas from the tube.
• FGF of 1.5 to 2 × MV is needed to prevent rebreathing.

27. CONTROLLED VENTILATION
• Most efficient for controlled ventilation aming MAPLESON systems.
• To facilitate controlled ventilation apl valve has to be partially
closed.when the system is filled with fresh gas the patient os
ventilated from the corrugated tube.
• During expiratory phase the expired gas flows down the corrugated
tube.
• During exp pause the fresh gas enters the tubing and pushes the
mixed gas towards the reservoir bag.

28. • As the bag is squeezed to ventilate ,the pressure in the system
increases and the valve opens and the contents of the reservoir bag
are discharged into atmosphere.
• It contains dead gas, alveolar gas and some fresh gas.
• Rebreathing can be avoided if FGF is 1.5 to 2 ×MVor if expiratory
pause is increased.

29. BAIN AND SPOREL RECOMMENDATIONS
• 2L/min FGF in patients weighing less than 10kg
• 3.5L/min FGF in patients between 10-50 kg
• 70ml/kg/min in patients more than 60 kg
• Tidal volume to bet set at 10 ml/kg
• Respiratory rate at 12 -14breaths/min.

30. ADVANTAGES OF BAIN'S SYSTEM
• Light weight and simple to use
• Easily sterilised and reusable.
• Scavenging of exhaled gases is facilitated
• Exhaled gases in outer tubing add humidification to inspired gases
• Can be used in ventilation of patients in MRI suites with a long
corrugated tubing and aluminium apl valve.

31. TESTING OF THE COMPONENTS
.Outer tube- outer tubing is checked for cracks or leaks.
Outer surface is wiped with spirit and air is blown down the tube.if
leaks are present it produces chillness in the hands of the che king
personnel.
Inner tube- set a low flow of 02 in the flow meter and occlude the
inner tube with little finger or a occluder at the patient end while
observing the flow meter
If the inner tube is intact and correctly connected the ik indicator will
fall.

32. Pethicks test
• High flow oxygen is fed into the circuit while the bag is filled by
occluding the patient end.
• Simultaneously o2flush is activated and patient end is opened
• If the inner tube is intact ,due to venturi effect the reservoir bag
deflates
• If there is a leak in the inner tube the reservoir bag continues to
inflates as the gas escapes into outer tube.

33. MAPLESON E SYSYTEM
• Modification of ayre's t piece.
• Used initially for pediatric patients undergoing cleft lip and paalte
surgeries and intracranial surgeries.
• Minimal dead space with no valves and with little resistance
• The initial ayre t piece was a metal tube of 1cm length and 5mm
diameter with aside port.
• Later on there were modifications with plastic corrugated tubing
• Length of the expiratory Lomb is increased to decrease air dilution.

34. • Used in children weighing less than 25-30 kg
• Sampling port is between expiratory port and tubing.
• FGF 2.5 to 3 times MV in spontaneous ventilation and 1.5 to 2 times
MV in controlled ventilation to prevent rebreathing.

35. PROBLEMS WITH THIS SYSTEM
• Air dilution risk if the expiratory limb is short.
• High fresh gas fLows are required to prevent rebreathing
• Risk of barotrauma is more in children as there is no reservoir bag
during ventilation

36. MAPLESON F SYSTEM
• Also known as jackson -rees modification of ayre's t piece.
• Out of the various modifications of t piece ,this system gained
popularity for use in pediatric population.
• T piece arrangement with a reservoir bag
• Apl valve is present at the end of the bag or side wall of the bag(Kuhn
bag)
• FGF =2-3×MV in spontaneous respiration

37. ADVANTAGES
• Light weight
• Simple construction
• Easy to assemble
• Minimal resistance
• Minimal dead space
• Controlled ventilation is easy due to reservoir bag
• Scavenging is easily facilitated.

38. HAZARDS
• Lack of humidification
• Need for high fresh gas flows
• Risk of barotrauma is a possibility due to occlusion of relief valve.

39. ADVANTAGES OF MAPLESON SYSTEMS
• Simple , inexpensive and rugged
• Easy to disassemble and sterilise
• Resistance is within recommended ranges
• Rebreathing causes retention of heat and moisture
• Light weightand does not cause drag on ET tube
• Easy to position conveniently
• Can be used in remote places and out of ot anesthesia purposes

40. DISADVANTAGES
• Requires high fresh gas flows and results in ot pollution.
• Optimal fresh gas flow may be difficult to determine
• In MAPLESON A,B,C, apl valve is bear to patient and may be
inaccessible.
• MAPLESON E and F are difficult to scavenge.

41. COMBINED SYSTEMS
• Designed by Humphrey D ,brock and downing.
• Has two reservoir- afferent and efferent
• Only one reservoir functions while in use.
• Lever helps in switch over function.
• Can be used in both adults and children.

42. REFERENCES