Mapelson circuits in anaesthesia mnemonic

Hey!

So I've faced a lot of problems trying to remember the various Mapelson semiopen circuits for inhalational anaesthesia and sadly they have been asked in exams so I tried to identify them using these simple points.

Firstly, remember, the circuits are semi open so part of the gases will be exhaled and part of them will be re inhaled.

Basic parts of any circuit are
-an inlet for fresh gases
-an outlet valve for exhalation
-the patient end
-the distal end usually with a bag to control rise and fall of the chest.

1) Mapelson A
The only circuit where fresh gases come in from the distal end. The exhaling valve is near the patient. It is suitable for spontaneous ventilation so rate of flow of gases = minute volume.

2) Mapelson B
Remember, B for both. So both inlet and outlet are together at the patient end. Otherwise it's the same as A.

3) Mapelson type C
C for closed and C for corrugationless. It's a closed circuit and the only one which has no corrugations.

4) Mapelson D
It is the exact opposite of A. Inlet for fresh gases is near the pt, outlet is far away. It is suitable for controlled ventilation.

5)Mapelson E
This is a valveless circuit and also has no bag (the only one without a bag). Since the arrangement is in the form of a T, it is also called Ayre's T piece.

6) Mapelson F
It is the same as E, valveless, but it has a bag to control the rise and fall of chest. It is mainly used in infants and neonates.

Summary:

Fresh gases distally ➡A

Inlet outlet both together➡B

No corrugation➡C

Opposite of A➡D

No exhaling valve ➡ E and F

No bag ➡ E

Same as E but with bag ➡F

Submitted by Aditi