If your ICU has patients from multiple departments, consider using the "Color of Background" option to have an easy visual for which department a patient is from.
For example, your hospital can decide on specific colors for each department, like:
Blue = Internal Medicine
Pink = Cardiology
Purple = Emergency
Green = Dentistry
Orange = Surgery
That way when the pet is physically in ICU, the whiteboard can still indicate from which department they originated:
Some clinics find it helpful to create a "legend" of these colors and post it around the clinic at first until the team is used to what each color means.