Premium
Molecular sieves: an alternative method of carbon dioxide removal which does not generate compound A during simulated low‐flow sevoflurane anaesthesia
Author(s) -
FEE J. P. H.,
MURRAY J. M.,
LUNEY S. R.
Publication year - 1995
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1111/j.1365-2044.1995.tb05847.x
Subject(s) - molecular sieve , carbon dioxide , soda lime , sevoflurane , anesthesia , chromatography , medicine , adsorption , chemistry , organic chemistry
Summary Molecular sieves are used in industry to 'scrub’ industrial gases. We examined, during simulated low‐flow closed system anaesthesia, (1) the carbon dioxide adsorbing potential of molecular sieves and (2) the reactivity of the sieves compared to soda lime using sevoflurane as an indicator. A low‐flow anaesthetic system containing 13X molecular sieves was connected to a model lung. End‐tidal concentrations of CO 2 were measured continuously at an O ‐2 flow of 800 ml.min ‐1 and a CO 2 flow of 200 ml.min ‐1 . In the second study, sevoflurane (FE'sevo 1.7%) was added to the system after which samples were taken from the inspiratory limb of the anaesthetic system. This experiment was performed both during carbon dioxide removal with soda lime and with the molecular sieves. The samples were stored in gas‐tight syringes and analysed by gas chromatography. The temperature of both absorbents was measured throughout the study. The molecular sieves adsorbed carbon dioxide (20 %) efficiently for a period of 5h. There was a gradual increase from the baseline of 4.4% to 4.5, 5.4, and 6.0% at 90, 180, and 300 min, respectively. When sevoflurane was added to the system, compound A was detected at the start of both experiments. However, when soda lime was used the concentrations of compound A increased 10‐fold after 2.5 h compared with baseline values. No increase in compound A was observed when molecular sieves were used for carbon dioxide removal. The highest mean (SD) temperature of the molecular sieves was 41.5 (3.2)° C. Molecular sieves are effective adsorbents of carbon dioxide when used in a simulated low‐flow, closed anaesthetic system. Compound A is not formed when sevoflurane is added to the system.