Mapleson's classification of anaesthetic breathing systems

Option A: Describes four systems, A, B, C and D
Option B: Classifies the Bain system as maples on D
Option C: Describes the T-piece as mapleson D
Option D: Describes the T-piece as requiring a fresh gas-flow of 1.5-2 times

The Correct answer is B. Anaesthetic gas exits the anaesthesia machine (via the common gas outlet) and then enters a breathing circuit. The function of the circuit is to deliver oxygen and anaesthetic gases to the patient and to eliminate CO2. The CO2 may be eliminated by gas inflow or by soda lime absorption. Various classification systems have been developed to aid understanding of how breathing systems operate.

• Open, semi-open, semi-closed and closed
• Non-rebreathing and rebreathing systems
• Mapleson systems
• Adjustable pressure-limiting valve (APL valve)

Mapleson described five different arrangements of breathing circuits. He classifed these circuits and they are now known as the Mapleson systems, termed A-E. This classification does not include systems with CO2 absorption.