title: Disconnect alarm failure in detection of common gas outlet disconnection.
abstract: This laboratory study was prompted by two paediatric cases where low pressure alarms and capnography failed to detect common gas outlet disconnection when using a T-piece pump ventilator. A carbon dioxide producing model lung was ventilated using the Clare ventilator (a T-piece pump type ventilator) via an Ayres T-piece. The T-piece used has 3 mm diameter fresh gas tubing. Common gas outlet disconnects were carried out using varying fresh gas flows and ventilatory patterns. At fresh gas flows of less than 8 l/min, the low pressure alarm of the Clare ventilator failed to sound following common gas outlet disconnection. Oxygraphy showed a rapid rise in inspired oxygen. End-tidal CO2 rose, whilst inspired CO2 remained at zero. This experiment demonstrates that the Clare ventilator's low pressure alarm detects common gas outlet disconnection poorly when used with an Ayres T-piece with narrow fresh gas tubing. Graphical representation of airway oxygen content has merit as an alerting monitor for common gas outlet disconnection.
authors.affiliation: Department of Anaesthesia, Christchurch Hospital, New Zealand.
authors.forename: R A
authors.initials: RA
authors.lastname: French
authors.forename: R R
authors.initials: RR
authors.lastname: Kennedy
mesh_terms: D000776:Anesthesiology / Q000295:instrumentation*; D002675:Child, Preschool; D004868:Equipment Failure; D006801:Humans; D007223:Infant; D012122:Ventilators, Mechanical