Is PD Adequest compatible with Windows 8.1?
No, the software does not run in Windows 8.1 because there is no version released for this operating system at all. I have checked the official website, and although there is some data about PD ADEQUEST, it's not enough to say if it actually works.
There is a General Support page with details you can use to get in touch with developers. This way you will get the official answer: http://www.baxter.com/contact-and-support/technical-services-support.page