Related Experiment Videos
Sevoflurane degradation by soda lime in a circle breathing system
I T Munday1, P M Ward, N D Foden
1Academic Department of Anaesthetics, St Mary's Hospital Medical School, Imperial College of Science, London.
Anaesthesia
|July 1, 1996
Summary
Sevoflurane anesthesia can produce Compound A, a vinyl ether, when degraded by soda lime. Higher sevoflurane levels and soda lime temperatures increase Compound A concentrations in breathing systems.
Area of Science:
- Anesthesiology
- Chemical Engineering
- Toxicology
Background:
- Sevoflurane is a widely used inhalation anesthetic.
- Degradation of sevoflurane by soda lime generates Compound A, a vinyl ether.
- Compound A has demonstrated nephrotoxicity in animal studies.
Purpose of the Study:
- To quantify Compound A concentrations in a clinical setting.
- To investigate the relationship between sevoflurane exposure and Compound A generation.
- To determine the influence of soda lime temperature on Compound A levels.
Main Methods:
- Gas chromatography and flame ionization detection were used for analysis.
- Compound A concentrations were measured in the inspiratory and expiratory limbs of the circle breathing system.
- End-tidal sevoflurane concentration and soda lime temperature were recorded in 31 patients.
Main Results:
- Peak Compound A concentrations ranged from 10 to 32 ppm (inspiratory) and 7 to 26 ppm (expiratory).
- A significant positive correlation was found between peak Compound A concentration and end-tidal sevoflurane concentration (r2 = 0.545, p < 0.0001).
- A significant positive correlation was also observed between peak Compound A concentration and soda lime temperature (r2 = 0.301, p = 0.0014).
Conclusions:
- End-tidal sevoflurane concentration is a key determinant of Compound A generation.
- Soda lime temperature significantly influences Compound A production.
- Clinical monitoring of these factors may help minimize Compound A exposure.