PROS AND CONS OF ADDING AN ACCESSORY BREA THING SYSTEM TO THE MAIN CIRCLE CIRCUIT - I - ARGUMENTS FOR THEIR USE

In addition to the circle breathing system, which represents the main circuit of the anaesthetic machine, the use of an accessory breathing system (ABS), either a partial rebreathing system according to Mapleso n's classification, or a system including a non-rebreathing valve, is appropriate for the anaesthetic management of many patients, depending on their physical status, age, indication and duration of surgery. Th e same safety rules, namely full checking procedure before use of the system and monitoring of inhaled gases and end-tidal CO, must be appli ed as for the main circle system. Potential complications resulting fr om non compliance with these rules cannot be considered valuable reaso ns for denying the use of breathing systems that have safely been used for decades in millions of patients. (C) 1998 Elsevier, Paris.