Abstract: An apparatus and method for identifying one anesthetic agent contained in an anesthetic gas sample as the primary anesthetic agent and for identifying a second anesthetic agent as the secondary anesthetic agent is based on the use of minimum alveolar concentration (MAC). The primary agent is identified as the anesthetic agent which has the highest percent of its MAC at its measured volume concentration. The secondary agent is identified as the anesthetic agent which has the second highest percentage of its MAC at its measured volume concentration. Certain minimum threshold levels must be met before an anesthetic agent is identified either as the primary or secondary agent.

Abstract: The twice scaled waveform display apparatus combines a twice scaled factor indication with the autoscaled waveform display so that an input data quality indication is produced based on factors such as signal strength, wherein the twice scaled factor is used to modulate the size of the display that is presented to the user. Thus, the generated waveform occupies a predetermined portion of the display when the signal strength and/or other input data qualities are at an acceptable level. The size of the waveform presented to the user on the display is reduced in magnitude when there is a degradation in the input signal magnitude or other quality factors.