A 20-year old spontaneous breathing patient undergoing incision and drainage under GA, which of the following is the breathing circuit of choice for spontaneous ventilation?

Ans. a. Mapleson A (Ref: Miller s Anesthesia 8/e p692-695)Mapleson A is the breathing circuit of choice for spontaneous ventilation.'Mapleson A, also called as McGill circuit, is the circuit of choice for spontaneous ventilation, while for controlled ventilation the circuit of choice is Mapleson D.'Breathing CircuitsMapleson A (Magill circuit):Circuit of choice for spontaneous breathingQFlow rate = Minute volumeQ (5 liters/min)Mapleson B:Not in common clinical useMapleson C (Waters circuit):Circuit of choice in post operative recovery roomQMapleson D (Bain coaxial system):Bain circuit is most commonly used circuit in anaesthesiaQCircuit of choice for controlled ventilationQMapleson E (Ayre's T tube):For infants and young childrenQFlow rate = 2-3 times of minute volumeQMapleson F (Jackson and Rees circuit):Used for children <6 years of age or less than 20 kgQ.Flow rate = 1.6 times of minute volume for controlled ventilationQFlow rate = 2.5 times of minute volume for spontaneous ventilationQType E and Type F circuits do not have valve (valveless circuits) and this is to decrease the resistanceQ.