Sleeping dragon wont wake up

Question
Hi I have a 4 year old  female bearded dragon. Last night I think she got too cold from the air-conditioning. At 5 o'clock this morning I thought she was dead. I rushed her to the emergency clinic..  They said they found a faint heartbeat .  At 8:20 AM my regular vet gave her fluids put her on oxygen and a catheter. About 1230 she said her heart stopped beating. I went back to my vets to get her and I brought her home so my other animals including my male bearded dragon  could say goodbye . I had wizzy sitting on her bed  in the sun at the patio screen door. My mother and I both could tell she was breathing. You could also put your hand on her back right past her head  and feel her breathing going up-and-down. At this point it's about 5:30 PM. I have had rescue  Bearded dragons  in the past who did not make it and there rigor mortis set in not too long after they passed. Whittey has no signs of remorse, her eyes are not sunken in,  and she has no foul odor coming from her.  In fact every now and then she kind of peaks her I open a little bit and then shuts it. I took her back to the vets and my vet said she cannot hear   A heartbeat. She even  did an ultrasound. It's 8:10 PM now she still breathing still no signs of rigor mortis and she's not under a heat lamp I just have her wrapped up in her blankets and she still has a little warmth to her.
My question is what should I do?  I have one that saying to keep her in the cool part of her tank. And another vet that I know saying hibernation is not normal for them and I should put her in a warm bath.
Wizzy will be 4 in May
She is very healthy and has check ups  with her vet regular
She has UVA UVB basking bulb,
And a UBB long tube light.
Please help me!! What should I do???

Answer
Hello Brady,

I have to admit that this is a new one by me!  They cannot hear a heartbeat but couldn't determine that she was breathing??  If so, then I would say for sure that it is time to find another vet.  During brumation their heart rates can actually slow down to the rate of 1-3 beats per minute so it may be hard to detect.  Why didn't they try doing an EKG on her to pick up electrical activity?
She is most definitely alive, if she is breathing & opening her eyes.  Geez.  Do you have any pictures of her you could post for me just so I can see her physical condition?  Is she intermittently opening her mouth, gasping like in the agonal breathing of the final death cycle?
How long has she brumated or slept for?  Brumation is extremely normal for them & done routinely in the wild!
Which UVB light are you using, is it a long tube or a compact/coil light?  How often do you supplement her with calcium & what types of food do you feed her?
For now, if she has been sleeping/brumating, try to go ahead & bring her out of it & get her to bask & started eating.  What are the temperatures that you keep her tank at?

Let me know how things are going.

Tracie