INDIANAPOLIS -- Indiana's lieutenant governor assumed the duties of acting governor as Gov. Frank O'Bannon lay in critical condition Tuesday after a stroke.

Doctors on Tuesday said that O'Bannon, 73, had evidence of brain damage and that it was too soon to say whether he would pull through. They said he would probably remain in an induced coma for several days.

State officials decided, for now, not to invoke the process spelled out in the Indiana Constitution for formally transferring authority to Lt. Gov. Joe Kernan.

O'Bannon, a Democrat in his second term, was found unconscious and near death on the floor of his Chicago hotel room Monday morning.

Kernan became acting governor under a provision in the state constitution that allows him to temporarily carry on business without a formal transfer of power. A formal transfer requires a petition from legislative leaders and state Supreme Court approval.

The acting governor met with Tim Joyce, the governor's chief of staff, who said they had discussed how to carry on the office's day-to-day duties -- everything from reviewing agency vacancies to issuing proclamations.

Nothing on O'Bannon's previous schedule required immediate action on Kernan's part.