The plans have been drawn up to give doctors specific guidelines for extreme circumstances, and they include procedures under which patients who weren’t improving would be removed from life support with or without permission of their families.

The plans are designed to go into effect if the U.S. were struck by a severe flu pandemic comparable to the 1918 outbreak that killed an estimated 50 million people worldwide. State and federal health officials have concluded that such a pandemic would sicken far more people needing ventilators than could be treated by the available supplies.

Many of the draft guidelines, including those drawn up by the Veterans Health Administration, are based in part on a draft plan New York officials posted on a state web site two years ago and subsequently published in an academic journal. The New York protocol, which is still being finalized, also calls for hospitals to withhold ventilators from patients with serious chronic conditions such as kidney failure, cancers that have spread and have a poor prognosis, or "severe, irreversible neurological" conditions that are likely to be deadly.

New York officials are studying possible legal grounds under which the governor could suspend a state law that bars doctors from removing patients from life support without the express consent of the patient or his or her authorized health agent.

State and federal officials involved with drafting the plans say they have been disquieted by this summer’s uproar over whether Medicare should pay for end-of-life consultations with families. They acknowledged that the measures under discussion go far beyond anything the public understands about how hospitals might handle a severe pandemic.

By every indication, state and federal officials expect to weather this year’s flu season without having to ration ventilators. That assumes that the H1N1 virus will not mutate into a more serious killer, the vaccines against it and the other seasonal flus will continue to prove effective, and any dramatic surges in the number of patients in need of ventilators will occur in different parts of the U.S. at different times.

In recent months, New York officials have met three times with physicians, respiratory therapists and administrators to rehearse how their plan might play out in hospitals in a severe epidemic. In one of those “tabletop exercises,” participants suggested that the names of triage officers charged with making life and death choices among patients at each hospital should be kept secret. The secrecy would be needed, participants said in interviews, to avoid pressure and blame from colleagues caring for patients who were selected to be taken off life support.