The first thing Sidney L. Williams says he heard when he awoke in the operating room during open heart surgery two years ago was the insistent whine of a bone saw cleaving his sternum. As doctors began discussing his badly damaged heart, Williams wondered whether he was eavesdropping on his own death: The surgeon had warned him before surgery that there was a 50 percent chance he would die on the table. Seconds later, Williams said, he felt jolts of searing pain as the doctor shocked his heart, which had stopped. "I once almost severed two fingers with a table saw," Williams, 56, recalled. "This was much, much worse."

JCAHO's action was prompted in part by a trio of studies published earlier this year about the frequency of intraoperative awareness -- which is estimated to affect one or two of every 1,000 patients receiving general anesthesia -- and the ability of newer brain wave monitoring devices to detect it. The alert, which is advisory, means that JCAHO will begin collecting data on awareness cases from patients. In the future, the alert could become the basis for new requirements hospitals must meet to retain their accreditation, as have previous warnings about preventing wrong- site surgery.

Robert J. West, an Austin lawyer who is representing Williams in the malpractice case he filed against his anesthesiologist, said he does not know why his client was under-anesthetized, "but his condition certainly had some role." Williams, who was undergoing surgery for a defective mitral valve, has congestive heart failure. In court papers the anesthesiologist denied Williams's allegations.