A breathing circuit disconnection detected by anesthetic agent monitoring

Purpose: To describe a case involving a spontaneously breathing patient whe re a circuit disconnection was detected by a change in monitored anesthetic agent parameters. Clinical features: A patient undergoing shoulder surgery was breathing spon taneously from a circle type anesthesia circuit via a laryngeal mask. A dis connection occurred between the heat and moisture exchanger (HME) and the c ircle system's Y-piece. As the gas sampling port was integrated into the HM E a near normal pattern of CO2 continued to be displayed, The disconnection was noted because of a change in the graphical display of the volatile age nt concentration. Conclusions: Anesthetic circuit disconnection can be difficult to detect, e specially in the spontaneously breathing patient, Capnometry may not detect a disconnection on the machine side of the gas sampling port, Changes in o xygen and volatile agent concentrations may provide an early indication of these types of disconnection.