The suicide bus-bombing victims who flooded Shaare Zedek Medical Center's emergency room on Feb. 25 represented the single most grisly incident this Jerusalem hospital has handled in recent years.

Concentrated pressure waves emanating from the blast ripped lungs open, burst stomachs, ruptured ear drums and popped blood vessels in eyes. Hot metal bus parts seared skin. Twenty-five were dead and another 50 suffered injuries.

When the injured began pouring into the emergency room 15 minutes after the explosion, the hospital's crisis plan was already in full swing. Fifty doctors and 100 nurses were waiting. An information center was assembling to answer the flood of phone calls in Hebrew, English, Russian, Ethiopian and Arabic. Mental health workers were amassing to assist grieving families.

The 500-bed hospital, in fact, is prepared to handle far worse incidents than the recent terror attacks.

"Unfortunately, we are very experienced," said Dr. Jonathan Halevy, the hospital's director general who was visiting the Bay Area this week to raise money via the American Committee for Shaare Zedek.

While American hospitals prepare for such catastrophes as earthquakes, Israel's 23 hospitals must go several steps further.

"All hospitals in Israel have to be prepared for war and for mass disasters as we call them during peace time," he said.

Terrorist attacks actually account for a "negligible" percentage of the hospital's 50,000 annual emergency room visits, he said. Car accidents, heart attacks and everyday injuries comprise the vast majority.

Still, everything from the medical center's physical layout to constant drills run by the military are designed to prepare the hospital to absorb up to 300 wounded civilians or soldiers in a few hours.

When the 94-year-old medical center moved in 1979 to its new campus next to Mount Herzl national cemetery, the hospital's main building was constructed in the side of the rocky hill.

The three bottom floors, which include the emergency room and general operating rooms, were built underground in order to function during wartime. These floors are designed to endure conventional bombings, chemical warfare and nuclear attacks.

The emergency room is larger than necessary for a typical medium-sized hospital, Halevy said. And three parking levels, also under the ground, double as a chemical decontamination center complete with high-pressure showers to wash off the toxins.

Halevy, a 48-year-old Israel Defense Force major who fought in the Six Day, Yom Kippur and Lebanon wars, spends part of his annual reserve duty outlining the hospital's emergency preparation to the military.

The IDF also drills the hospital staff every few months. The tests range from performing routine checks to find out how many off-duty hospital staff immediately respond to telephone calls in a crisis, to simulating full-fledged disasters with mock injuries.

Within two days after an emergency, including the recent terror attacks, the hospital and IDF officials meet to evaluate the hospital's minute-by-minute response. They follow up a week later.

"We investigate ourselves all the time," Halevy said.

Halevy's expertise also includes the detailed effects of various types of terrorist attacks on the human body.

The Feb. 25 bombing, for example, managed to instantly kill a relatively high percentage of the bus riders because the windows on the No. 18 were closed on the cold winter morning. This trapped the explosion's pressure waves into a small space, he noted.

Burst lungs — the most deadly injury that results from this type of attack — can kill a victim quickly. But if the air that leaks into the chest is drained soon enough and the victim is placed on a respirator in time, he said, the lung tissue can regenerate in a matter of days.

"Once you don't die on the spot, you have a very good chance," Halevy said.

The March 3 suicide bus-bombing in Jerusalem had a similar effect, killing 20 and wounding another seven.

On the other hand, the bomb outside Tel Aviv's Dizengoff Center on March 4 exploded in an open area. It spewed shrapnel and nails, wounding 130 but creating a relatively low rate of casualties. Fourteen were killed.

Nonetheless, Halevy added, even the victims whose bodies completely heal will deal with a plethora of psychological problems similar to wartime shell shock.

"I don't believe someone can undergo such an experience without residual effects."