Hi Robert,
Thanks for sharing the good idea. While the maximum sounds like the right approach for your scenario, I can imagine the minimum being useful in others. I'll put this on our backlog.
One idea in the interim would be to choose a pressure threshold that you want to be alerted on, and use that for the "Use time when the trace first reaches". You could then set the outlier definition for the metric to be any value greater than 0. If the pressure never exceeds the value, the metric won't have a time value to plot. I know it's a bit convoluted, but it might let you experiment without delay.
Thanks,
Josh