The Reflector: a new method for saving anaesthetic vapours

Abstract

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%.

Influence of two different ventilation modes on the function of an anaesthetic conserving device in sevoflurane anaesthetized piglets

“…To the authors’ knowledge, no reports are available about factors, which may increase anaesthetic agent breakthrough with the AnaConDa device. It has been shown that isoflurane breakthrough through zeolite filters, was more pronounced at higher (Perhag et al. 2000).…”

“…Originally, a filter containing hydrophobic zeolite was used, reducing the isoflurane consumption by 50–70% compared with a conventional open system (Thomasson et al. 1989; Perhag et al. 2000).…”

“…both delivery and conservation of the anaesthetic. It has been demonstrated that isoflurane retention by a zeolite filter was less efficient at higher (Perhag et al. 2000).…”

A review of the practice of sedation with inhalational anaesthetics in the intensive care unit with the AnaConDa® device

“…Initial attempts at conserving anaesthetic vapours using an open system involved the development of a reflector which incorporated zeolite crystals. [1516] However, this was subsequently abandoned due to the possibility of zeolite inhalation causing pulmonary toxicity.…”

Sedierung mit volatilen Anästhetika auf der Intensivstation

“…Alternativ sind auch die Bezeichnungen Anästhesiegasreflektorsystem oder Anästhesiegaskonservierungsfil-ter gebräuchlich [32]. Der aktuelle Wissenstand der Anwendung volatiler Substanzen unter intensivmedizinischen und organprotektiven Gesichtspunkten wird dargestellt.…”