Figure 9-17 Halothane output of a North American Dräger Vapor 19.1 vaporizer with different carrier gases. The initial output concentration is approximately 4% halothane when oxygen is the carrier gas at flows of 6 L/min (A). When the carrier gas is quickly switched to 100% nitrous oxide (B), the halothane concentration decreases to 3% within 8 to 10 seconds. Then, a new steady-state concentration of approximately 3.5% is attained within 1 minute (C). (Modified from Gould DB, Lampert BA, MacKrell TN: Effect of nitrous oxide solubility on vaporizer aberrance. Anesth Analg 61:939, 1982.)