Anesthesia Machine Evaporator Application

Anesthesia Machine Evaporator Application

      Due to the application of highly efficient volatile inhalation anesthetics in anesthesia machines, the design of evaporators tends to be specialized, that is, based on the evaporation characteristics of a certain volatile inhalation anesthetic, an evaporator that is only used for that drug is calibrated. For example, specialized evaporators for halothane, methoxyflurane, enflurane, isoflurane, and sevoflurane. The design and manufacturing process of these evaporators are completely the same, but they are specifically handled during calibration. In addition to being labeled with special drug fonts, some manufacturers also attach eye-catching color labels to the evaporators of various anesthesia machines, such as red for halothane, dry yellow for enflurane, light purple for isoflurane, and light green for sevoflurane.

      When volatile inhalation anesthetics with different vapor pressures share the same evaporator, the output concentration varies greatly: therefore, if the vapor pressures of two volatile anesthetics are similar, the output concentration should seem to be the same when using the same evaporator. However, the research results found that the output concentrations were not the same. Under normal circumstances, the vapor pressure of isoflurane is similar to that of fluoroalkane. When isoflurane borrows a fluoroalkane evaporator, within a certain range, the output concentration matches the calibrated concentration. On the contrary, if halothane is used with an isoflurane evaporator, the output concentration can be 25% higher than the calibrated concentration. Therefore, it is best not to mix the evaporator for general anesthesia machines.