Anaesthetics machine circle absorber, 1934. This device consists of uni-directional valves and a canister containing a substance such as soda lime. The system of valves directs the exhaled air from an anaesthetised patient through the soda lime. The soda lime absorbs the carbon dioxide exhaled by the patient. The exhaled air can then be re-breathed mixed with air drawn from a fresh gas supply. Introduction of carbon dioxide absorbers allowed a reduction in the amount of anesthetic gas required to anesthetize patients, a reduction in the amount of gas that leaked into the air of the operating room, better humidity of delivered gases, and reduced loss of body heat. This model was designed by Charles King.