Inside a tent in the terminal at Louis Armstrong International Airport, they were trying to find a good vein in the arm of a woman with sickle cell anemia. Next to her was a 12-year-old with a rare blood disease. Down the row of green Army stretchers, a man was sucking on an asthma inhaler.

The woman with sickle cell, Yolanda Sherman, was shivering. "I'm just freezing, ma'am," she said.

"We don't have blankets, darlin'; we just have the paper gowns," said registered nurse Nan Nealy, gently draping the woman with a second paper dressing gown.

The light was oddly beautiful inside the white medic tent, filtered and soft, a surreal MASH unit illuminated by the skylight inside New Orleans's main airport, now the main field hospital for victims of Hurricane Katrina. On Saturday, about 800 patients arrived each hour from various shelters and evacuation centers, less than Friday's flow of nearly 2,000 an hour but still staggering. More help also arrived Saturday: more doctors, medics, nurses, supplies, choppers and evacuation planes.

A week ago, the airport, its long driveway lined with gas lanterns to evoke the French Quarter, was a place where the delights and delays of air travel occurred. A place for a po' boy and a cold beer before departure. It has since turned into a spontaneous field hospital of suffering, improvisation and lifesaving. The familiar sights of the airport could still be seen -- ticket counters, luggage belts -- but they were transformed by their new, desperate purposes. A bar was now a makeshift pharmacy, the liquor bottles replaced by tall stacks of Tylenol, Ensure, Aciphlex and alcohol preps, all under a glowing Miller Lite neon sign.

The smell was sour and fetid. Flies circled trash cans. Litter was piled in corners. Bio-hazard bags contained soiled diapers, soiled clothing, dirty gauze and discarded disposable gloves.

The tents where patients were being treated were scattered around the terminal near the ticket counters. Each had a sign on the door. Red for critical. Yellow for semi-acute. Green for primary care. A newly arriving doctor in Army fatigues from Kansas scribbled this on the inside of her forearm to remember. Inside the semi-acute tent, 11 patients were lined up on the floor.

This was Col. Richard Newbold's tent. The tall doctor with the Nevada Air National Guard gave the orders. He went over to a frail man on a stretcher. "Mr. Kenner, we're gonna fly you to a hospital," he said. "Put you on a helicopter. That sound all right to you?"

The 80-year-old man barely responded.

Most medical personnel have been working 12-hour shifts, crashing on cots in darkened parts of the airport. They have lived largely on canned chicken salad with pop-tops, cookies, cheese and crackers. Ice was scarces, nothing cold, and sometimes the bottled water shipped in was often warm. Lacking blankets, nurses gave patients paper dressing gowns, some in layers of three. The sick were everywhere: sitting, lying, sprawling, leaning. They seemed to be the weakest of the weak. Elderly. Children. Invalids. The mentally handicapped. The frail. Many who arrived here came with preexisting medical conditions such as hypertension, kidney problems and respiratory troubles that were exacerbated by the stress and physical hardship caused by Hurricane Katrina.

They arrived by helicopter or ambulance and were brought from the tarmac inside the triage unit, otherwise known as the Delta baggage claim area. They came on stretchers, loaded with their belongings: a bag of clothes, a pair of shoes, a pocketbook, a hat, a wig, a Bible. One woman brought her bird, and it chirped in its cage beside her stretcher. Some were moaning, and others seemed to be lost in a vacant state of resignation. They were assessed and then shipped off to various medical tents.

In Newbold's tent for semi-acute patients, Arnette Taylor, 59, sat beside her son, Ron Taylor, a 34-year-old paraplegic who had been carried up eight flights of stairs darkened stairs at New Orleans's Charity Hospital and evacuated to the airport field hospital. Inside the medic tent, Mrs. Taylor stroked her son's forehead. His arms were curled to his chest. Mrs. Taylor took a towel from her bag of belongings and placed it over his arms so he wouldn't get cold. "I'm not letting him out of my sight," she said.

But in the effort to evacuate patients quickly to hospitals, families were getting separated. Outside the tent, Shirley Kenner sat on a chair patiently outside Newbold's tent. She wore the same clothes she had worn since she and her husband were evacuated. Wherever he was going, she was going. "We've been married 50 years," she said, holding her Bible. "He's never been on an airplane. He needs me." But somehow in the confusion, Joseph Kenner was prepared for transport. He was lifted. He was taken, off to the chopper and a hospital in Lafayette.

A Federal Emergency Management Agency official, Elizabeth Nealy, whose sister, Nan, was a nurse inside the Kenner's medic tent, had to explain to Mrs. Kenner that her husband was gone. "He'll be scared without me," Mrs. Kenner said, clutching a bag of Cheez-Its and her Bible.

"We are going to find where he went," Nealy promised.

Hours later, Mrs. Kenner was put on a plane to Lafayette to join her husband.

Back inside the tent, Nan Nealy was trying to get a patient's intravenous link working. Without the right gauge needle, they had to use a butterfly clip and tape it up with adhesive and gauze to hold the line in place.

Nealy has not seen her own children for five days. They were evacuated to north Mississippi with their father, and she has been unable to reach them. "I come here to keep my mind off it," she said. "I just make my way through the roadblocks, trying to help."

"Nurse," someone called across the light-filled tent, and she was gone.

Hurricane survivor Javann Green is treated by Scott Warner, a doctor from Alabama, at the field hospital set up at the airport. Most of the medical personnel helping the evacuees have been working 12-hour shifts.