1. BREATHING SYSTEMS
MODERATOR:
DR RAJNI MATHUR
ASSO. PROFESSOR,DEPARTMENT OF
ANAESTHESIOLOGY,SMS MEDICAL
COLLEGE,JAIPUR
Presented by:
DR. KAUSHLESH SHARMA

2. DEFINITION
• A Breathing system is defined as an assembly
of components which connects the patients
airway to the anaesthetic machine creating an
artificial atmosphere ,from and into which the
patient breathes.

3. It primarily consists of
• a) A fresh gas entry port/delivery tube through which
gases are delivered from machine to the systems;
• b) A port to connect it to patient’s airway;
• C) A reservoir for gas ,in the form of bag or a
corrugated tubing to meet the peek inspiratory flow
requirements;
• d) An expiratory port/valve through which the expired
gas is vented to the atmosphere.
• e) A carbon dioxide absorber if total rebreathing is to
be allowed and
• f) Corrugated tubes for connecting these components
.F low directing valves may or may not be used.

4. REQUIREMENTS OF A BREATHING
SYSTEM
Essential:
• The breathing system must
• a) deliver the gases from the machine to the
alveoli in the same concentration as set and in
the shortest possible time .
• b) Effectively eliminate carbon dioxide.
• c) Have minimal apparatus dead space ; and
• d) Have low resistance.

5. Desirable
The desirable requirements are :-
• a) Economy of fresh gas.
• b)Conservation of heat
• c) Adequate humidification of inspired gas
• d) Light weight& convenient during use
• E)Efficiency during spontaneous and controlled
ventilation
• f) Adaptability for adults , children and
mechanical ventilators
• g) Provision to reduce theatre pollution.

6. Classification
OPEN NO BOUNDRY AND NO OXYGEN TUBING NEAR
DEAD SPACE PATIENT
SEMI OPEN PARTIAL BOUNDRY SCHIMMELBUCH MASK
BETWEEN AIRWAY AND
ATMOSPHERE
SEMI closed FULLY BOUNDED .Prevents MAPLESON SYTEM
entry of atmsph. Air but
vents excess fresh gas
Closed No Venting Of Excess Gas Circle system at low flows

7. Many Configurations
NO SODA LIME SODA LIME
Unidirect Non Breathing circle system Circle System
ional
Bidirecti a) Afferent reservoir systems. Waters Canister
onal Mapleson A , B ,& C
b) Enclosed afferent reservoir systems
Miller’s
c) Efferent reservoir systems
Mapleson D , E & F
Bain ‘s system
d) Combined Systems
Humphery ADE

8. Components of a Breathing System
• Adjustable Pressure Limiting Valve
• Reservoir Bag
• Tubing

9. Adjustable Pressure Limiting Valve
 Spill valve, pop – off valve, expiratory valve.
 Designed to vent gas during Positive Pressure.
 Pressure of less than 0.1 kPa activates the valve when
open.
Components:- 3 Ports
• Inlet, patient & exhaust port-later can be open to
atmosphere or connected to scavenging system
• Lightweight disc sits on a knife edge seating held in
place by a spring
• TENSION in the spring and therefore the valve’s
opening pressure is controlled by the valve dial.

10. Mechanism of Action
• One way , adjustable , spring loaded valve
• Valve allows gases to escape when pressure in
the breathing system exceeds the valve's
pressure.
• During spontaneous ventilation: the patient
generates a positive pressure during expiration ,
causing the valve to open
• During positive pressure ventilation, a
controlled leak is produced in the inspiration by
adjusting the valve dial ,allowing control of the
patient’s airway pressure.

11. Connector and adaptor
• A connector is a fitting device intended to join together
two or more similar components .
• An Adaptor is a specialized connector that establishes
functional continuity between otherwise disparate or
incompatible components.
They can be used to:-
• 1. Extend the distance b/w patient & breathing system esp.
in head and neck surgeries.
• 2. Change the angle of connection b/w patient and
breathing system.
• 3. Allow a More Flexible and Less kink able connection b/w
patient and breathing system .
• 4. They increase the Dead space.

13. RESERVOIR BAG
• Also known as Respiratory ,Breathing or sometimes
called Rebreathing bag. Standard size is 2l(range from
0.5 to 6l) .
• Made up of Rubber and Plastic ,ellipsoid in shape. It has
following functions .:-
• 1. It allows gas to accumulate during exhalation &
provides gas for next inspiration and permits rebreathing.
• 2. It provides a means whereby ventilation may be
assisted or controlled.
• 3. It can serve through visual and tactile observation as
a monitor of spontaneous respiration .
4. It protects patient from excessive pressure in breathing
system.

14. RESERVOIR BAG

15. Tubing
• Corrugated or smooth
• Different lengths depending on system being
used
• Allow humidification of inspired air
• Parallel and coaxial arrangements available

16. Mapleson systems
Afferent systems
• Mapleson A
• Mapleson B
• Mapleson C
• Lack Modification
Efferent sytems
• Mapleson D
• Mapleson E
• Mapleson F

18. Mapleson A
• Corrugated rubber or plastic tubing: 110-130
cm in length
• Reservoir Bag at Machine end
• APL valve at the patient end.
• Tube volume > Tidal volume

19. Mapleson A : Functional Analysis
• Spontaneous breathing: The system is filled
fresh gas before connecting to the patient .
When the patient inspires, the fresh gas from
the machine and the reservoir bag flows to
the patient , and as a result the reservoir bag
collapses.

20. • The expired gas , initial part of which is the
dead space gas , pushes the FG from the
corrugated tube into the reservoir bag and
collects inside the corrugated tube.
• Expiratory pause- Fresh gas washes the
expired gas of the reservoir ,filling it with fresh
gas for the next inspiration.

21. Controlled Ventilation:
• To facilitate IPPV the expiratory valve has to be
partly closed.
• During inspiration the patients gets ventilated
with FG and part of the FG is vented through
the valve after sufficient pressure has
developed to open the valve.

22. • During expiration , the FG from the machine
flows into the reservoir bag and all the expired
gas ( i.e. dead space and alveolar gas flows
back into the corrugated tube till the system is
full.

23. • During the next inspiration the alveolar gas is
pushed back into the alveoli followed by the
fresh gas. When sufficient pressure is
developed, part of the expired gas and part of
the FG escape through the valve.
• This leads to considerable rebreathing as well
as excessive wastage of fresh gas . Hence
these system are inefficient for controlled
ventilation.

24. Mapleson A – Lack Modification
• Coaxial modification of Magill Mapleson A.
• 1.5 m in length
• FGF through outside tube ( 30mm), exhaled
gases from inner tube.
• Inner tube wide in diameter (14 mm) to
reduce resistance to expiration(1.6 cm H2O).
• Reservoir bag at machine end
• APL valve at machine end.
• Better for spontaneous ventilation.

25. • This system functions like Mapleson A both
during spontaneous & controlled ventilation.
• The only difference is that expired gas instead
of getting vented through the valve near the
patient ,is carried by an afferent tube placed
coaxially and vented through the valve placed
near the machine end. This facilitates easy
scavenging of expired gases.

26. Function of Lack modification

27. Mapleson B System
• The FG inlet is near the patient, distal to the
expiratory valve.
• The expiratory valve open when pressure in
the circuit rises,and a mixture of retained
fresh gas and alveolar gas is inhaled.
• Rebreathing is avoided with fresh gas flow
rates of greater than twice the minute
ventilation for both spontaneous and
controlled ventilation.

28. Mapleson C system
• This circuit is also known as Water’s circuit.
• It is similar in construction to the Mapleson B ,
but the main tube is shorter.
• A FGF equal to twice the to twice the minute
ventilation is required to prevent rebreathing.
Carbondioxide builds up slowly with this circuit.
• Mapleson B &C : In order to reduce rebreathing
of alveolar gas FG entry was shifted to near the
patient.
• This allows a complete mixing of FG and expired
gas.
• The end result is that these system are neither
efficient during spontaneous nor during
controlled ventilation.

30. Ayre’s T- PIECE
• Introduced by Phillips Arye in 1937.
• Belongs to Mapleson E.
• Available as meatllic / plastic.
• Length – 2 inches.
• Parts – inlet, outlet, side tube.
• Inlet size-10 mm, outlet size-10mm metallic
&15 mm plastic

31. Advantages
• Simple to use , Light weight .
• No dead space , no resistance.
• For pediatric pts. Less than 20 kgs.
• Expiratory limb is attached to the outlet of T piece.-
• -It should accommodate air space equal to 1/3 rd of TV.
• - If too short – air dilution in spont. Breathing patients
& pts become light.
• 1 inch of expiratory tube can accommodate 2-3 ml of
gas.
• Gas Flows – 2- 3 times MV

32. Dis advantages:
• High flow rates are required.
• Loss of heat & humidity.
• Risk of accidental occlusion of expiratory limb-
risk of increased airway pressure &
barotrauma to lungs.

33. Mapleson D System
• It consists of fresh gas inlet nearer the patient
end , a corrugated rubber tubing one end which
is connected with expiratory valve and then
reservoir bag.
• It is mainly used for assisted or controlled vent
• During the controlled ventilation there is little
chance of rebreathing.
• The FGF which enters during expiratory pause
accumulates in the patient end is forced during
the inflation.

34. • In spontaneous breathing during inspiration the
patient will inhale the fresh gas & gas in
corrugated tube depending on FGF, TV, length of
expiratory pause & volume of corrugated tube.
• Rebreathing can be minimized by increasing FGF
2-3 times the MV.
• For an adult 15L/min FGF which seems
uneconomical is required.
• In some cases 250 ml/kg/minrequired to prevent
rebreqthing.

35. Bain circuit
• Introduced by Bain & spoerel in 1972.
• It is a modification of Mapleson D system.
• It is a coaxial system in which fresh gas flows
through a narrow inner tube within outer
corrugated tubing
• It functions like T-piece except that tube
supplying FG to the patient is located inside
the reservoir tube.

36. Specifications:-
• Length-1.8 meters.
• Diameter of tube-22mm(transparent,carries expiratory
gases)
• Diameter of inner tubing-7 mm(inspiratory)
• Resistance-Less than0.7 cmH2O
• Dead space-Outer tube upto expiratory valve( around
500ml=TV)
• Flow rates-100-150 ml/kg/min for controlled
ventilation. Average 300 ml/kg/min for spontaneous
ventilation

37. Bain system (Mapleson D)- Functional
Analysis
• Spontaneous respiration: The breathing system
should be filled with FG before connecting to the
patient. When. the patient takes an inspiration,
the FG from the machine , the reservoir bag and
the corrugated tube flow to the patient.
• During the expiration there is a continuous FGF
into the system at the patients end .The expired
gas gets continuously mixed with the FG as it
flows back into corrugated tubing and the
reservoir bag

38. • Once the system is full the excess gas is vented to
the atmosphere through the valve situated at the
end of the corrugated tube near the reservoir
bag. During the expiratory pause the FG
continues to flow and fill the proximal portion of
the corrugated tube while mix gas is vented
through valve.
• During the next inspiration , the patient breathes
FG as well as mixed gas from the corrugated tube.
• It is calculated and clinically prove that FGF
should at least 1.5- 2 times the patient’s MV

39. • Controlled ventilation : To facilitate intermittent positive
pressure ventilation, the expiratory valve has to be partly
closed so that it opens only after sufficient pressure has
developed in the system. When the system is filled with
fresh gas, the patient gets ventilated with the FGF from the
machine, corrugated tubing and the reservoir bag.
• During expiration expired gas continuously gets mixed with
FG that is flowing into the system at the patient end. During
the expiratory pause the FG continues to enter the system
and pushes the mixed towards the reservoir.
• When next inspiration is initiated , the patient gets
ventilated with the gas in the corrugated tube i.e.a mixture
of FG, alveolar gas and dead space gas. As the pressure in
the system increases,APL valve open and the contents of
reservoir bag are discharged into the atmosphere.

40. BAIN CIRCUIT AND IT’ FUNCTION

41. Mapleson E and F
• Valveless breathing system used for children upto
30 kg.
• Suitable for spontaneous and controlled
ventilation
• Components:-
• - T shaped tubing with 3 ports.
• -FGF delivered to one port
• -2 nd port goes to patient & 3rd to reservoir tube.

42. Mapleson E AND F

43. Maoleson F
• The most commonly used T –piece system is
the Jackson-Rees’ modification of Ayre’s T-
piece (sometimes known as the Mapleson F).
• This system connects a two ended bag to the
expiratory limb of the circuit;gas escapes via
the tail of the bag.

44. It comprise of-
• Plastic angle mount
• Plastic Ayre’s T-piece
• Corrugated rubber hose.
• Reservoir bag of 0.5- 1 lit capacity.
• Green PVC 1.5 meter long tube with plug that fits into
the fresh gas outlet of the Boyle’s apparatus.
• Gas flows required -2-3 times MV.
• Dead spce-1 ml/lb( 1KG=2.2LBS)
• Tidal volume- 3 times dead space.
• FGF flushes expiratory limb during the pause.
• Expiratory limb should be more than TV to prevent air
dilution & rebreathing in spon. Breathing child.

45. • This allows respiratory movements to be more easily
seen and permits intermittent positive ventilation if
necessary.The bag is however not essential to the
functioning of the circuit.
• IPPV may be performed by occluding the tail of the bag
b/w a finger and a thumb and squeezing bag.
• Alternatively , a ‘bag-tail valve’,which employs an
adjustable resistance to gas flow, may be attached to
the bag tail. This causes the bag to remain partially
inflated and so facilitates one handed performance of
IPPV.
• Another aid to IPPV is Kuhn bag which has gas outlet
on side of bag.
• To prevent rebreathing , system requires a minimal
flow of 4 litre/minute,with a FGF of 2.5 to 3 times the
patient MV.

46. Advantages:
• Compact,lightweight,no drag to ETT.
• Inexpensive,easy to use and sterlize.
• No valves.
• Minimal dead space
• Minimal resistance to breathing
• Economical for controlled ventilation
• Dis advantages:- kuhn bag
• The bag may get twisted and impede breathing.
• High gas flow requirement.
• Lack of humidification
• USES:
• Children under 20 kg weight.

47. THANK YOU