Anesthesia machines and breathing systems: An evolutionary success story

Abstract

The first anesthetists delivered ether and chloroform from handkerchiefs, towels or inhalers, and nitrous oxide from large reservoirs such as bladders. In 1847, Snow devised a temperature-compensated vaporizer that delivered fully saturated ether in air. Clover improved matters in 1877 by adding liquid chloroform to a large measured gas volume to produce a known concentration. Except for the French Ombrédanne ether inhaler, the United Kingdom provided most advances in vaporizer equipment. Delivered concentrations of anesthetic were usually inexact until 1951 when Morris introduced the Copper Kettle vaporizer to deliver a concentration that could be precisely calculated. In the mid-1950s, Cyprane produced the Fluotec, a variable bypass vaporizer that allowed the user to set any desired concentration, eliminating the calculations required with the Copper Kettle.