Indiana's lieutenant governor assumed the duties of acting governor as Gov. Frank O'Bannon (searchlay in critical condition Tuesday following 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 recover. They said he would probably remain in an induced coma for several days.

State lawmakers on Tuesday held off invoking a process spelled out in the state constitution for formally transferring authority to Lt. Gov. Joe Kernan (search).

Kernan said he believed he could conduct the state's business without a formal transfer, but Republican Sen. President Pro Tem Robert Garton said he and Democratic House Speaker Patrick Bauer (searchcould initiate the process, perhaps as early as Wednesday.

They would need to send a petition to the Indiana Supreme Court for its approval.

The legislative leaders have asked for a written statement outlining O'Bannon's condition from his attending physician. They said they also want the O'Bannon family's approval before proceeding.

O'Bannon, a Democrat in his second term, was found in his pajamas, unconscious and near death, on the floor of his Chicago hotel room Monday morning. He had suffered a type of stroke that involves bleeding in the brain.

In Chicago, Northwestern Memorial Hospital spokeswoman Kelly Sullivan said doctors saw evidence of brain damage, but the extent of it was not yet clear. The effects of such damage could range from slurred speech to paralysis.

O'Bannon is expected to remain under sedation for at least several days. Patients with such injuries are often placed in drug-induced comas to help relieve the pressure on the brain and allow it to rest and heal.

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.

"I think all of us are in state of disbelief that this could happen to someone who is so vital, who has so much energy," Kernan said. "But at the same time, we've got to realize, in his absence, it is our responsibility -- and it is exactly what he would tell us -- that we need to step up."

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.