The deal that would bring a state-of-the-art academic children's hospital to the San Antonio Medical Center has collapsed. The University of Texas Health Science Center and the Baptist Health System were to work with the Children's Hospital of Philadelphia (CHOP) to build a new pediatric research and teaching hospital. But word came late Tuesday that CHOP will no longer be participating in the consortium because of competition in Philadelphia between CHOP and another company. "That caught us all by surprise," said Bexar County Judge Nelson Wolff. He said pediatricians at UTHSC are now in limbo.