The 600 gram CO2 absorption canister: an experimental study.

Abstract

Model investigations were performed on a canister containing 600 g of Sodasorb indicator soda lime in a transparent lime compartment used in the Hafnia circle. The CO2 input was 300 ml per min. Carbon dioxide will be efficiently eliminated from the gas mixture conveyed to the patient connection in this system for at least 4 h, irrespective of the rate of fresh gas flow. There was proportionality between the fresh gas inflow and the duration of effective CO2 elimination. The relative efficacy of the CO2 absorption was investigated at different levels in the canister. The temperature in the axis of the lime compartment was 43-52 degrees C, and the temperature of the gas mixture conveyed to the patient attachment 30-35 degrees C. The colour shift in the lime charge was a reliable indicator of the efficiency of CO2 elimination. The canister should be replaced when the colour shift has progressed to 2/3 of the lime charge. The canister contains no disposable parts except for the lime charge. All the components of the circle system should be taken apart and cleaned after each anaesthesia.