Create a running record of when your students leave the room, whether it's to use the restroom, go to the nurse, or to the office. Students fill in the correct date and time they leave the classroom, along with the subject currently being taught. The teacher quickly initials the form and that night, parents also initial the form. This provides communication between teachers and parents and informs parents if their child needed to see the nurse that day, or if they are missing significant portions of the lesson due to bathroom breaks. Since using this system I have seen far fewer students needing to use the restroom multiple times during the day and I've seen far fewer students needing to see the nurse. This allows for more time spent on learning.