The anesthesia machine: current design and alternatives

The anesthesia machine is a major component in an integrated anesthesia care system. It can be considered in terms of the functional subsystems responsible for gas proportioning, anesthetic vapor delivery, patient ventilation, and waste gas scavenging. Alternative technologies for these functional units should be examined in light of the disadvantages inherent in present machines. Safety features, often added on an ad hoc basis, should instead be designed into the machine itself. The anesthesia delivery system should include feedback about the patient status and device performance, as well as provide for the delivery of anesthetic and pharmacologic agents. Improvements in performance and provisions for automation of some functions should be considered as future design criteria.