Ayre's T piece (Mapleson E system) is selected for a spontaneously breathing infant. Which statement about this system is correct?
- A It contains an adjustable pressure limiting valve and a reservoir bag
- B It is valveless and bagless, requiring a fresh gas flow of roughly two to three times the minute volume to prevent rebreathing ✓
- C It is the most efficient Mapleson system for spontaneous ventilation at one times minute volume
- D It must be connected to the scavenging interface to function
Correct answer: B. It is valveless and bagless, requiring a fresh gas flow of roughly two to three times the minute volume to prevent rebreathing
Explanation
The classic Ayre's T piece is a simple T shaped metal connector with no valves and no bag, which keeps apparatus dead space and resistance minimal, ideal for neonates and infants. Rebreathing is prevented by washout of the expiratory limb, requiring fresh gas flow of about two to three times minute volume during spontaneous breathing. Adding an open ended reservoir bag converts it to the Jackson Rees modification, which also permits assisted ventilation.
Reference: Morgan and Mikhail's Clinical Anesthesiology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.