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Published on: October 23, 2018
Compound A concentration in the circle absorber system during low-flow sevoflurane anesthesia: comparison of
Shunji Kobayashi1, Hiromichi Bito, Yukako Obata
1Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Japan. je2fbw@hama-med.ac.jp
Study Objective:
To determine compound A concentrations in a low-flow circuit containing Drägersorb Free (Dräger, Lübeck, Germany), Amsorb (Armstrong, Coleraine, Northern Ireland), and Sodasorb II (W. R. Grace, Lexington, MA).
Design:
Randomized study.
Setting:
Hamamatsu University Hospital.
Patients:
24 ASA physical status I and II patients scheduled for general anesthesia greater than 3 hours' duration.
Interventions:
Patients were allocated to three groups of eight patients each to receive either using either Drägersorb Free, Amsorb, or Sodasorb II. Immediately before anesthesia induction, 1 kg of fresh absorbent was placed in the anesthesia canister. Anesthesia was maintained with sevoflurane (end-tidal concentration 1% to 3%) in oxygen and nitrous oxide (FIO(2) > 0.3) at a total flow of 1 L/min.
Measurements:
Inspiratory compound A concentration in the circuit was measured once every hour.
Main Results:
Maximum compound A concentrations for Drägersorb Free, Amsorb, and Sodasorb II were 2.4 +/- 0.8 (mean +/- SD) ppm, 3.1 +/- 0.5 ppm, and 28.0 +/- 10.0 ppm (p < 0.01 vs. Drägersorb Free and Amsorb). Concentrations with Drägersorb Free and Amsorb remained at less than 4 ppm throughout the study.
Conclusions:
Because compound A concentrations in the circuit with Drägersorb Free and Amsorb were negligible, sevoflurane can be used at a fresh gas flow of 1 L/min with these two absorbents.
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