Which Mapleson circuit is best for controlled ventilation?

Which Mapleson circuit is best for controlled ventilation?

• A. Mapleson A
• B. Mapleson D
• C. Jackson-Rees system
• D. Mapleson F

Answer: (B)

In controlled ventilation, the goal is to minimize rebreathing of exhaled CO2 while delivering a known tidal volume. Mapleson D achieves this best because its arrangement directs the fresh gas toward the lungs while providing an efficient expiratory path for exhaled gas, so CO2-rich gas is flushed out of the circuit rather than being rebreathed. This lets you maintain ventilation with a modest fresh gas flow and keeps inspired CO2 low. The other configurations either don’t separate fresh gas from exhaled gas as effectively under positive pressure (or lack an expiratory valve in the same way), making rebreathing more likely during controlled ventilation. The Bain version is a modern coaxial form of the same D setup, sharing these advantages.

In controlled ventilation, the goal is to minimize rebreathing of exhaled CO2 while delivering a known tidal volume. Mapleson D achieves this best because its arrangement directs the fresh gas toward the lungs while providing an efficient expiratory path for exhaled gas, so CO2-rich gas is flushed out of the circuit rather than being rebreathed. This lets you maintain ventilation with a modest fresh gas flow and keeps inspired CO2 low. The other configurations either don’t separate fresh gas from exhaled gas as effectively under positive pressure (or lack an expiratory valve in the same way), making rebreathing more likely during controlled ventilation. The Bain version is a modern coaxial form of the same D setup, sharing these advantages.