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Isoflurane concentrations using uncompensated vaporisers within circle systems
Author(s) -
Brosnan S.,
Royston B.,
White D.
Publication year - 1998
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1046/j.1365-2044.1998.00366.x
Subject(s) - medicine , isoflurane , anesthesia
In a series of studies designed to investigate the need for a temperature‐compensated vaporiser for use in a circle system, we first studied temperature changes within and isoflurane concentration delivered by a Komesaroff vaporiser during bench tests using different gas flows. Agent temperature and vapour concentration decreased as predicted by the Antoine equation. Using the vaporiser within a circle system during clinical anaesthesia, we then studied 20 patients breathing spontaneously and a further 10 patients receiving controlled ventilation, measuring the temperature of the agent within the vaporiser and the concentration of agent inspired by the patient. In clinical use with the fresh gas flows of 1–3 l.min −1 , the inspired agent concentration did not decrease despite the decrease in temperature of the liquid isoflurane in the vaporiser.