Mapleson Circuit [exclusive] -

Introduction Before the advent of modern, sophisticated anesthesia workstations with integrated circle systems, the Mapleson circuit was the workhorse of inhalational anesthesia. Even today, these simple, lightweight, and efficient breathing systems remain indispensable for emergency rooms, MRI suites, veterinary medicine, transport ventilators, and as a backup system in operating theaters.

Invented by the British anesthetist Dr. William Mapleson (who also contributed significantly to the physics of heat and moisture exchangers), the is a classification system for non-rebreathing semi-open anesthesia circuits. This article explores the anatomy, physics, clinical applications, and advantages of each of the original Mapleson systems (A through E). The Fundamental Problem: Rebreathing All anesthesia circuits aim to deliver oxygen and anesthetic agents to the patient while removing carbon dioxide (CO₂). In a circle system, CO₂ is removed by a soda lime canister. In Mapleson circuits, there is no absorbent . Instead, fresh gas flow (FGF) is used to wash exhaled CO₂ out of the circuit before the patient takes the next breath. mapleson circuit

If FGF is too low, the patient rebreathes their own CO₂, leading to hypercapnia, tachycardia, and hypertension. If FGF is too high, we waste expensive volatile agents and pollute the operating room. The key to mastering Mapleson circuits is understanding which system is efficient for versus controlled ventilation (CV) . The Classification (Mapleson A through E) In 1954, Mapleson analyzed five basic configurations (later a sixth was added). They differ only by the position of the fresh gas inlet, the reservoir bag, the patient connection, and the adjustable pressure-limiting (APL) valve. William Mapleson (who also contributed significantly to the