Performance characteristics of a 'to and fro' disposable soda lime canister

The performance of the Intersurgical disposable soda lime canister was compared to British Pharmacopoeia standards for carbon dioxide absorption and to other carbon dioxide absorber systems. This canister system more than adequately fulfilled the equivalent of the British Pharmacopoeia standard for CO2 absorption. It performed efficiently for over 3 h of continuous use, absorbing 200 ml.min-1 at varying combinations of tidal volume and ventilation rate. Efficiency was not dependent on close matching of tidal volume with canister volume and there was no channelling of gases. Heat was generated by the reaction between soda lime and CO2 and the maximum temperature recorded in the system was 42.1 degrees C. Under clinical conditions this should pose no threat of thermal injury to the patient.