Laboratory bench testing of six new anaesthesia ventilators

Objective: To assess the pneumatic performances of six new anaesthesia vent ilators. Study design: Bench test study. Material: The study included one ventilator operated by an electric motor: ABT 5300(TM) (Kontron); four ventilators of "bellows-in-bottle" category: A DU(TM) version 97 (Datex-Ohmeda); Aestiva 3000(TM) (Datex-Ohmeda), Kion(TM) (Siemens), the two versions of Julian(TM) (Drager); and an original ventil ator devised for quantitative, or self-regulating target controlled inhalat ion anaesthesia, with a totally closed circuit, made of four ventilating ch ambers: PhysioFlex(TM) (Drager). Methods: The bench test included a passive lung model with adjustable compl iance and resistances, and flow and pressure gauges. The accuracy of volume and pressure measurements was tested in various conditions of resistance a nd compliance. Results: Pneumatic performance and accuracy were satisfactory, even in seve re ventilatory conditions. All the ventilators, except ABT 5300(TM) and Jul ian(TM) 1, have a compliance compensation system permitting to deliver and to maintain a constant tidal volume under various conditions of downstream load, particulary under maximal load condition. Variations of tidal volume with the increase of the fresh gas flow are negligible. Conclusion: Recent technological progress has improved pneumatic performanc es of anaesthesia ventilators and the marketed models are more homogeneous at present. Ergonomics and training for the use of the machine are becoming major criteria for the global assessment and the choice of a ventilator. ( C) 2000 Editions scientifiques et medicates Elsevier SAS.