Please explain how to monitor the number of hours the soda lime has been used in the

CO2 canister. What changes would you expect to see in the soda lime once it is no

longer effective? Also explain why monitoring and tracking the soda lime consumption

is so important.

The soda needs to be changed when there is a color change.

Explanation:

In order to detect the rate of use or exhaustion of soda, the determination of the inspired carbon dioxide, CO₂ is a reliable method. The measurement is done by means of a capnograph. This is the plot of the amount of CO₂ against time. When the CO₂ reacts with the soda lime, heat and water are formed. This is also accompanied by a pH change. The pH change causes the indicator to change color from white to pink. This change in color indicates that the soda lime is nearing exhaustion. The soda lime is changes when about two-thirds of the canister changes color.