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.
RCT Entities:
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.