The Reflector: a new method for saving anaesthetic vapours

Anaesthesia systems that minimize the use of volatile anaesthetics to reduce cost and pollution are of interest. Closed circuit anaesthesia is the ideal solution, but requires continuous adjustment of fresh gas flow and composition and thus is demanding in routine practice. We describe an alternative system, the Reflector system, which is open in regard to oxygen, nitrogen and N2O, and semiclosed in regard to volatile anaesthetics. The Reflector system is a circle system with a carbon dioxide absorber and an automatic vapour delivery device placed in the inspiratory limb of the circle. A zeolite filter, the Reflector, is placed between the ventilator and the circle. The Reflector functions as a molecular sieve, preventing the volatile anaesthetic from leaving the circle. Isoflurane consumption using the Reflector system in bench tests and an animal study was compared with that of an open system. In bench tests consumption was reduced by 79% and 82%, at a respiratory frequency of 10 and 20 min-1, respectively. The corresponding mean figures from the animal experiment were 65% and 77%.