There are two different terms that refer to priority in Healthcare. The first, Acuity, is assigned in the PCI. This number refers to the priority of a patient with respect to patient locations. This doesn't refer to Staff Requirements.
The second term is called Priority. This refers to Staff Requirements for patient activities. So if two patients are waiting to start an activity called Escort Patient>Process that requires a nurse, and both have a priority level for the activity of 150 then it's first come first serve. However, if you have different activities (within the same track or a different track) that are asking for the same Staff Resource and one activity has a higher priority value, the nurse will help that patient first. Click here for more information about priority levels.
If you want Staff Resources to treat patients with a higher acuity first, you might consider creating a separate patient track for that PCI and raise the Priority level for each activity within that track.