I don't think there are any guidelines that I am aware of but this is the way they used to do it back in the day. However I think its dangerous, especially for long procedures. Every time you give positive pressure, you risk opening the LES and insufflating the belly with air. Over time this can potentially build up and cause regurg->aspiration. I've done it once for a D&C and it is a pain in the arse. Unless you can position the pt perfectly with the mask straps, your gonna have to sacrifice a hand thrusting the jaw and sealing the mask. LMA's are much easier to use, so why not just use an LMA? True, LMA can be malpositioned in the esophagus and cause regurg but I think the incidence is much lower (although I have no scientific proof).
A much safer way is to not provide PPV. Just have patient breath spontaneous with maybe a little support with a CPAP of 5ish. Thats how we did all our ear tube cases in peds, mainly because the rapid turnover with no IV access. But again if you wanted to use for longer term, I would still LMA especially if I had access to an IV.