The short version: an agreement was reached!
The long version: My proposed updated policy was passed around to all the nurses at our monthly nurse's meeting yesterday, along with position statements that I used to write the policy, including the one by the Public Health Department. There were uneasy glances exchanged as I described the major change from a no-nit to no-lice policy, but eventually, grumbling agreement. The coordinator, who had previously agreed with me about when to send kids home (taken directly from Public Health, my stance was the unpopular one, that they would be allowed to remain in class with lice; after immediate notification of the parents, they will be excluded by the end of the day at the latest) became a stellar politician and before my very eyes, flip-flopped on that agreement to the more popular one, which is to send them home (thereby humiliating the student) immediately. To say I was upset about this change of heart would be an understatement: she was my sole supporter of this whole project, and if I didn't have hers, I didn't have anybody's.
I knew I wouldn't rest at night unless I did all that I could, so I spoke up and provided my reasoning (again, reading directly from the official statements that we base all of our other practices on), only to be met with disgusted looks. But...stubborn people make change! I calmed my nerves and approached another nurse after the meeting, one I have had very little contact with ever, but knows her stuff. She is extremely "by the book," which I certainly can't claim to be, and I knew if I didn't win over her support, I wasn't going to get this approved. Conversely, I knew if I had her support, this would get approved: she can argue a point as well as I can, and if we aren't arguing the same position, we're at a stalemate forever.
Turns out I work well with people I don't think I get along with. She is actively involved in the union, school nurse organization, etc., and she commended my enthusiasm and perserverance on something so mundane to most people in education, as well as the fact that I was even involving myself in policy-writing. We worked together to re-write the sentence I was stuck on, adding in the phrase that she suggested: "or at the discretion of the school nurse or designee." Power to the nurses! It didn't take long for us to both be happy with it and given we are the two loudest nurses (who aren't flip-floppers) in regards to policies, I feel good that I've done what I can on this issue. There's no saying anything will become of it, because it still needs to be sent to the board, etc., which will take eons, but I can sleep well at night knowing I've done what I can to save my kids from unnecessary humiliation and needless absences. Phew.