mapleson circuits used in anesthesia practice, are in their way out but it is as important to know the mechanism with which the gases flow to and fro through them.

1. MAPLESON CIRCUITS
By,
Dr. Arun Kumar
Dept of Anesthesiology
Columbia Asia Referral Hospital,
Bangalore.

3. DEFINITION
 Circuit: a round course.
 Breathing circuit: a pathway in which volatile
agents and oxygen is delivered and Co2 is
removed, 2types non-circle, circle.
 Co Axial: it is where these is two coduits for
inhaled and exhaled gases, where one coduit is
inside the other.
 Magills circuit: a circuit in which has reservoir
bag a corrugated tube and spring loaded
expiratory valve, rebreathing prevented by
keeping fresh gas flow more than the patients
minute respiratory volume.

4.  Mapleson circuits: a circuit in which the fresh
gas flow is used to remove the exhaled Co2 .

5. ADVANTAGES/NEED
 Simple, inexpensive and rugged, parts easy to
dismantle and sterilize.
 Variation in minute volume affects end tidal co2
less than in circle systems.
 In co axial, warm expired gas heats the
inspiratory limb.
 Resistance low at flows in practice.
 Lightweight, easy to position.
 Compression and compliance loss less.
 Change in FGF, rapid change in ins., gas
composition.
 No co2 abs, possible toxic byproducts not formed.

6. HISTORY
 1954 Mapleson studied and described 5 different
semiclosed anesthetic breathing systems.
 These are refered as mapleson systems A-E.
 Later on Willis et al, added one more system
Mapleson F.

7. MAPLESON A(MAGILL
MODIFICATION)

8. MAPLESON A
 Differs from other circuits, fresh gas flow is not
at the patient’s end but on the other side.
 At the reservoir bag, a corrugated rubber tubing
connects the bag to the patient’s end where there
is a adjustable pressure valve.
 Lacks modification: in this he has added a
expiratory limb in the tube.
 makes adjusting gases easy but increases the
work of breathing.

9. MAPLESON A
 technique of use:
 For spontaneous breathing, the apl valve is left
open.
 For controlled ventilation the valve is half closed,
so that when given positive pressure adequate
expansion of lungs is achieved.
 Spontaneous respiration:
 As the patient exhales, first dead space gas then
alveolar gas flows towards the bag, the same
time fresh gas flows into the bag.
 When bag pressure is full APL valve opens.

11. MAPLESON A
 Fresh gas flow reverses the direction of exhaled
gas which vents out through the APL valve.
 In the inspiration end, first gas is alveolar gas,
then dead space gas, finally fresh gas flow.
 Controlled ventilation: during exhalation the
pressure in the system is low and no gas escapes
through APL valve, unless bag distends, all
exhaled gas remains in the tubing.
 at inspiration most of the gases are re breathed
into the system.

12. MAPLESON B

13. MAPLESON B
 The fresh gas inlet and APL valve is near
patient’s end.
 Technique of use: for spontanoeus APL valve is
left open.
 in controlled ventilation APL is closed
sufficiently to allow inflation of lungs.
 Spontaneous: as Pt exhales the gas moves
through the corrugated tube with FGF, when bag
fills up, APL valve open exits exhaled gas with
little FGF. On inspiration valve closes, FGF and
gas from the tubing is taken in.

14. MAPLESON B
 To prevent rebreathing FGF must be equal to
peak inspiratory flow(20-25l/min).
 Controlled : similar to Mapleson A but more
efficient since FGF is near patient end.
 a fresh gas flow of 2- 2.5 times minute volume is
recommended.

15. MAPLESON C

16. MAPLESON C
 Similar to Mapleson B, but without the
corrugated tubing.
 Technique is similar to the B system.

17. MAPLESON D

18. MAPLESON D
 Mapleson D,E,F all have T piece at the patient
end, all function similiarly.
 classic form: a length of tubing connects T
piece to the APL valve and reservoir bag next to
it.
 Bain modification: fresh gas supply runs
coaxially inside the corrugated tubing, and ends
at a point where the fresh gas would have flown
if classic mapleson D was used.
 The outer tubing is clear so the inner tube can be
inspected.

19. MAPLESON D
 technique of use:
 spontaneous: the APL valve is left open and the
gas is vented.
 Assisted: the valve is partially closed, and the
bag squeezed.
 Mech of use:
 Spontanoeous: pt., exhaled gas chanelled back to
reservoir where it gets mixed with fresh gas flow.
 FGF required is 150-200ml/kg/min. 1.5-2 times
alveolar minute volume.
 Inefficient and uneconomical.

20.  Controlled ventilation: efficient flow of 70-
100ml/kg/min maintains normocapnia.
 Exhalation gas flows from pt to tubing, even
fresh gas enters tubing.
 Inspiration: fresh gas and tubing air flows, if
FGF is low then exhaled gas may be inhaled.
 Can be connected to ventilator.

22. MAPLESON E (AYRE’S T- PIECE)

23. MAPLESON E
 This is used in children upto 25-30kg body
weight.
 A T shaped tubing with 3 open ports, one fresh
gas, second patient end, third reservoir tubing.
 Designed to provide spontaneous ventilation,
since there is almost no resistance to expiration.
 Not popular as there is no scope for cotrol of gas
flows.

24. MAPLESON E
 Advantage: lightweight.
 minimal resistance to flow
 can be used for spont/ controlled
vent.
 simple design.
 Disadvantage: exhaust gas not easy to scavenge.
 obs to expiratory limb : high
pressure to patient.
 no scope to artificially ventilate
pts.

25. MAPLESON F (JACKSON REES MOD)

26. MAPLESON F
 It is mapleson E with a reservoir bag added at
the expiratory limb.
 Hence monitoring patient’s breathing was
possible.
 reservoir bag has a valve outlet at the end.
 Using which for spontaneous vent can be kept
open,
 While for controlled can be partially closed.

28. DISADVANTAGES.
 Requires high gas flows.
 Due to this inspired heat and humidity tends to
be low.
 In mapleson A,B,C Apl valve is in the pt’s end:
inaccessible.
 In mapleson E,F difficult to scavenge.

29. REFERENCES
 Dorsch, understanding of anaesthetic
equipments. Seventh edition.
 Whylie, a practice of Anesthesia. Seventh edition.
 Al- shaikh, Stacey, essentials of Anesthetic
equipments. Third edition.
 World wide web.