[Performance studies of 6 new anesthesia ventilators: bench tests].

OBJECTIVE: To assess the pneumatic performances of six new anaesthesia ventilators.

STUDY DESIGN: Bench test study.

MATERIAL: The study included one ventilator operated by an electric motor: ABT 5300 (Kontron); four ventilators of "bellows-in-bottle" category: ADU version 97 (Datex-Ohmeda); Aestiva 3000 (Datex-Ohmeda), Kion (Siemens), the two versions of Julian (Dräger); and an original ventilator devised for quantitative, or self-regulating target controlled inhalation anaesthesia, with a totally closed circuit, made of four ventilating chambers: PhysioFlex (Dräger).

METHODS: The bench test included a passive lung model with adjustable compliance and resistances, and flow and pressure gauges. The accuracy of volume and pressure measurements was tested in various conditions of resistance and compliance.

RESULTS: Pneumatic performance and accuracy were satisfactory, even in severe ventilatory conditions. All the ventilators, except ABT 5300 and Julian 1, have a compliance compensation system permitting to deliver and to maintain a constant tidal volume under various conditions of downstream load, particularly 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 performance 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.