Going around in circles. Is there a continuing need to use the T-piece circuit in the practice of pediatric anesthesia?

Anesthetic equipment, including breathing circuits, has evolved over time. The T-piece circuit, in its various forms, was designed to meet the needs of its time. As equipment and techniques have moved on, it is timely to consider the place of the T-piece in modern pediatric anesthetic practice. Today the circle system is a ubiquitous part of anesthesia. When integrated with a modern anesthetic machine it offers precise control of ventilation together with continuous monitoring of airway pressure and flow: but at the cost of complexity. In comparison the T-piece offers a simple cheap lightweight design, so ergonomic in use that it almost becomes part of the anesthetist: but lacks the control and the barriers to unsafe use of more sophisticated systems. In addition, it requires high fresh gas flow adding to cost and environmental pollution. This pro-con debate discusses whether there remains a case for continuing to use the T-piece circuit in preference over other options. Possible indications for the T-Piece are discussed together with alternative strategies. The limitations of the circle system, the T-piece, and other alternative (such as self-inflating resuscitator bag) are discussed with respect to pediatric anesthetic practice.