An innovative anaesthesia machine: the closed system.
OBJECTIVE
Closed system anaesthesia allows economic use of medical gases and volatile anaesthetics, maintenance of airway climatization and reduction of anaesthetic gas loss into the environment. In this context we reviewed papers addressing recent technical and clinical advances of closed system anaesthesia.


RESULTS
New anaesthesia ventilators with computer-aided control of inspiratory oxygen, nitrous oxide and expiratory volatile anaesthetic concentrations have been developed. When compared with low flow or minimal flow techniques applied to classical anaesthesia ventilators with out-of-circle vaporizers these new ventilators provide fast and reliable achievement of the targeted volatile agent concentrations. The profile of desired end-tidal concentrations are stable with minimal or no operator intervention and the times to washout volatile anaesthetics are short.


CONCLUSIONS
Modern feedback controlled ventilators allow the application of closed system anaesthesia as a safe and economic technique for routine clinical practice.
Department of Anaesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany.
Patrick
P
Schober
Stephan A
SA
Loer