intestinal blockage

My 2 year old Westie is at the vet right now b/c he began throwing up about 36 hours ago.  I took him in after about 8 hours of that and he examined him and felt his pancreas was sensitive and my pup was given thorazine, but the vet kept him to observe him.  When I spoke w/ the dr. about 8 hours later he said the dog was still gagging and he was going to try to give more fluids and laxatol to try to flush out his system.  When I called this morning the dr. said he felt the best option was to open him and see if there was an obstruction b/c my pup couldn't keep anything down.  What do you think could be the problem?

[Jaybay]

I'm glad to hear your vet is going to do the surgery.  Obviously something is stopping the flow of food, water and waste and tests can only determine so much.  If a section of intestine is twisted like a kinked water hose, it can kill the affected tissue.  That calls for a resection.  The same thing can happen if the dog eats something that simply can't pass through.  

Please let us know how the surgery goes and what your vet discovers.  Praying that the surgery will take care of everything.  :-)