Figure 70-13 Performance of an anesthetic vaporizer system at increased ambient pressure. A, Flow characteristics of a rotameter system as shown. At 4 ATA the actual delivered flow is less than 60% of the flow indicated by the rotameter. B, Fluotec vaporizer output in partial pressure of halothane as a function of ambient pressure. Only small increases in delivered partial pressure are evident at 3 ATA, at the 2% and 3% settings. (From Committee on Hyperbaric Oxygenation: Fundamentals of Hyperbaric Medicine [Publication No. 1298]. Washington, DC, National Academy Press, 1966.)