Anesthesia machine basics

The anesthesia machine is that component of the anesthesia delivery system that receives medical gases (oxygen, nitrous oxide, air, heliox) under pressure and controls the flow of each gas individually. It creates a gas mixture of known composition at a known flow rate and delivers it to the common gas outlet of the machine. From here, the fresh gas flow is conducted to the anesthesia circle breathing system. This review will discuss the storage of compressed oxygen and nitrous oxide and how these gases arrive to a generic anesthesia machine. The paths taken by these gases as they flow through the generic machine will be described. The important components used to create the precisely controlled fresh gas mixture, as well as the safety features of the machine will also be described. The reader should gain an understanding of the machine basics that he/she can use to understand his/her particular model of machine.