What is an impaired nurse? What would you do if you

What is an impaired nurse? What would you do if you

What is an impaired nurse? What would you do if you encounter an impaired nurse while on-duty?
I need at least 2 references including
-Westrick, S. J., &Dempski, K. (2008). Essentials of nursing law and ethics. Sudbury, MA: Jones and Bartlett Learning