Any signs of bubbles from the mouth? If you can see that then yes I would say RI.
But as a note I have had a few BP's that "whistle" and it happens when they are about to shed. This is common. But none the less stressing when you hear it. Check for the bubbles from the mouth on larger snakes and some small I have a nice rubber bowl scraper ya know the kind that is a soft flimsey rubber. Then I very very gently open the mouth and look for the bubbles and check the mouth as well for any signs of problems. If the problem persists then a Vet visit can help you and your pet.. A good check up will clear your mind and insure your animal has a A-OK health.