When someone in my family does not get pre-approved for care, I write a letter and and ask my physician to sign, and ask the other doctors at his practice to sign a letter that goes like this:

"I beleive this procedure _____________ is medically necessary for __________. Time is of the essence, and this procedure should be performed as close to immediately as possible."

In the signature block, I include the degree, specialty and medical school of the doctor. I then fax the letter in, and within 30-40 minutes, I have a phone call apologizing for rejecting and giving me pre-approval for the care. I learned about this when my (at the time) 15 year old was rejected for a cardiac procedure and the billing person pulled out a pre-printed deck of letters that was pre-signed by every department head at the hospital. The one thing the insurance people fear most is risk.