Fred Henretig is intimately familiar with the unique anatomy of children. He knows how elusive their threadlike veins can be, how they defy all but expert attempts to pierce them with an intravenous line. He knows the way their airways, narrow as a piece of penne, can be hard to open with a lifesaving breathing tube.

These physiological characteristics , said the Children's Hospital of Philadelphia emergency physician, mean that it's "nerve-wracking to deal with even a single critical child."

As Henretig ponders the terrorist threats facing the United States, he sees what he calls a "nightmare" scenario: not a single critical child, but dozens, felled by an attack on a school, a sporting event or an ice show. He sees children separated from parents, wailing as other-worldly rescuers clad in frightening yellow suits attempt to provide first aid.

And he sees these same emergency workers hampered not just by their bulky protective clothing, but by the tools they would be likely to use: adult-size IV lines, face masks and doses of medicine.

Henretig was among nearly 70 of the country's top pediatric and emergency medicine experts who met in Washington last week to discuss something they say has been woefully unexplored during the preparations for acts of terrorism: the unique challenges the youngest patients and those who treat them will face if catastrophe strikes.

The three-day conference, organized by the Children's Health Fund and the Children's Hospital at Montefiore in New York , was funded by the U.S. Department of Health and Human Services.

On Sept. 11, 2001, the Children's Health Fund sent two mobile medical units to Ground Zero. Later that month, the group's president, Irwin Redlener, attended a meeting of hospital leaders and federal officials. Said Redlener: "At the end I raised the question, 'So what special provisions are we taking to make sure that emergency planning incorporates the unique needs of children?' "

He wasn't satisfied with the answer. While federal bioterrorism legislation passed last year orders states to include pediatric preparedness in their disaster plans, funds are only slowly finding their way to hospitals. Redlener said each hospital in New York received an additional $40,000 for disaster preparedness. That's a fraction of what it would cost to address what he sees as the most pressing need: building a pediatric triage unit in every American hospital. Also desperately needed, he said: materials outlining standards of treatment and appropriate dosages for children and programs to train emergency personnel.

Most hospitals that specialize in pediatric patients are have incorporated pediatric planning into their disaster scenarios. Children's National Medical Center revamped its disaster plan after the Sept. 11 attacks, said chief medical officer Peter Holbrook, when the hospital's leaders realized their old worst-case scenario -- the arrival of 25 to 50 patients after a school bus crash -- required updating.

A terrorist attack involving hundreds of children would create a cascading series of challenges, starting with how many patients Children's could safely accommodate, Holbrook said. The hospital could treat more victims from certain kinds of attacks, he said, since the ratios of those who would need to be admitted vs. those who could be treated and released, would differ. Holbrook said the hospital also has to prepare for an influx of family members.

While hospitals that generally serve adults have also been forced to plan for catastrophe, they are less likely to think much about children, Redlener said. Suburban Hospital's extensive disaster plan "has no special provisions for pediatric patients," said spokeswoman Ronna Borenstein-Levy. "That isn't our primary target patient."

Southern Maryland Hospital Center in Clinton has a pediatric unit, so it stocks child-size masks and other appropriate equipment. But spokesman David DeClark said the hospital's disaster preparedness program has no specific guidelines for responding to an influx of young victims.

What Redlener and others find especially troubling is the lack of pediatric experience among most "first responders." It's understandable, since children rarely have strokes, heart attacks or any of the other health problems that paramedics and EMTs are most familiar with. As Holbrook puts it: "It could be argued that children are too healthy for their own good."

They are also disturbingly vulnerable targets for a terrorist strike with chemical, biological or radiological weapons. In the words of Theodore Cieslak, an Army pediatrician and bioterrorism expert who traveled from San Antonio for the conference, they "live closer to the ground," which means their "breathing zone" is at the level where heavier-than-air chemical agents may settle. Children breathe faster than adults, so they would take in toxins more rapidly. And their skin is more permeable than that of grown-ups, another reason they're likely to get sicker quicker. Symptoms such as diarrhea and vomiting, while harmful to adults, can be fatal to youngsters.

Many of the treatments for chemical, biological and radiological attacks were devised with adults in mind. Auto-injectors for atropine and other nerve-gas antidotes were designed for military use and so contain adult dosages.

But more than medicine will have to be changed, Redlener said. The standard procedure for patients exposed to dangerous chemicals starts with stripping them naked outside the emergency room and dousing them with a hose. Do that to a child, said Redlener, and "you run the risk of having kids become hypothermic and going into shock." You need contained showers, with warm water, he said. "And they must be built in such a way that a parent can be there, too."

Lost on none of the conference participants was the eerie coincidence of meeting just after the Department of Homeland Security raised the terror threat level from yellow to orange. As anxiety increased last week, several attendees were summoned back to their jobs.

Conference organizers are rushing out an executive summary of their conclusions within the week. Soon after that, the full report will be sent to hospitals, health professionals, state and local emergency planners and government officials.

"We have to get together and have a single plan," said Redlener. "What we don't want in a disaster is people doing Internet research and trying to figure out treatment."