CHI St. Luke's back in network for Blue Cross Blue Shield FacebookTwitterEmail The break between one of Houston’s largest hospital systems and a major insurance carrier comes just 10 days before the start of open enrollment on the Affordable Care Act marketplace exchange on Nov. 1.CHI St. Luke's Health - The Woodlands Hospital / CHI St. Luke's Health - The Woodlands Hospital Three weeks after 65,000 Blue Cross Blue Shield of Texas patients fell out of network at CHI St. Luke's and its sister hospitals, the health system said Friday night that they can return to visiting their doctors and emergency rooms at in-network rates.