title: A breathing circuit disconnection detected by anesthetic agent monitoring.
abstract: OBJECTIVE
  To describe a case involving a spontaneously breathing patient where a circuit disconnection was detected by a change in monitored anesthetic agent parameters.
  
  
  METHODS
  A patient undergoing shoulder surgery was breathing spontaneously from a circle type anesthesia circuit via a laryngeal mask. A disconnection occurred between the heat and moisture exchanger (HME) and the circle system's Y-piece. As the gas sampling port was integrated into the HME 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 agent concentration.
  
  
  CONCLUSIONS
  Anesthetic circuit disconnection can be difficult to detect, especially in the spontaneously breathing patient. Capnometry may not detect a disconnection on the machine side of the gas sampling port. Changes in oxygen and volatile agent concentrations may provide an early indication of these types of disconnection.
authors.affiliation: Department of Anesthesia, Christchurch Hospital, Christchurch, New Zealand.
authors.forename: R R
authors.initials: RR
authors.lastname: Kennedy
authors.forename: R A
authors.initials: RA
authors.lastname: French
mesh_terms: D000776:Anesthesiology / Q000295:instrumentation*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D017214:Laryngeal Masks; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D012119:Respiration