[Considerations on the monitoring of soda lime. Consideration technique].

The choice of ethyl violet as a pH indicator in soda lime is not the best. Color change happens too late because pH alteration of the surface of soda lime is slower than in the core of the canister. Clinical and comparative measurement of wall temperature of two in series canisters is a good precaution. If the down stream canister is warmer than the upstream one, you must change the latter.