Soda lime circuit (closed circuit)For efficient CO2 absorption the common absorber used is soda lime. Exhaled gas is passed through the soda lime granules (which is a mixture of 94% Ca (OH2)2 + 5% NaOH + 1% KOH) some silicates are also added to prevent powdering
- Moisture 14-19% is also needed for efficient CO2 absorption.
- It absorbs CO2 & produces H2O + heat thereby humidify & warms inspired gases.
- 1 gm of soda lime absorbs 88m1 of CO2 & temp within the canister may increases up to 60oC.
- Anesthetic gases to be avoided in Soda lime - : Trichloroethylene & sevoflurane at higher temperature.