They are the mothers who maintain loose-leaf notebooks so jammed with precise notations on drug dosages, monitor readings and feedings that they resemble hospital charts. The counter tops in their cramped kitchens bristle with medication vials, miniature syringes and special infant formulas. Their refrigerators are papered with instructions for performing cardiopulmonary resuscitation and lists of emergency telephone numbers. Green and silver oxygen tanks stand at the ready in the dining room.

These are the mothers who are rarely more than a few seconds away from their babies, who have been forced by circumstance to quit their jobs and to put their lives on indefinite hold, tethered to newborns too precarious to entrust to a babysitter, a day care center or even, in some cases, a close relative. Some have installed mini-hospital rooms in their nurseries to provide sophisticated care for babies born too soon, too small or with devastating birth defects.

As recently as 15 years ago, many of these infants probably would have died in the first days or weeks of life, some without leaving the hospitals where they were born. A number of those who did survive would have been placed in institutions skilled at caring for babies with specialized medical needs.

These days, because of technological advances and managed care, with its emphasis on moving patients out of hospitals and into less-expensive settings, babies such as these are going home to be cared for by their families. While fathers and other family members take care of these babies, most of the burden is shouldered by mothers, health experts say.

Although these parents routinely are taught how to use complicated, life-sustaining equipment and to take care of their babies' medical needs, the physical and psychological stress can be considerable for mothers who double as quasi-medical personnel.

"We're seeing premature infants [born three or four months premature] who'd never have made it 10 years ago," said Karen Ryalls, executive director of United Cerebral Palsy of Tampa. "We can provide the medicines and the machines, but they come with a price. These infants are likely to have problems that are going to be with them for a very long time. For the families I work with, it's a very harrowing experience."

Rising to the Challenge

It is also an experience that an increasing number of parents are engaged in as the locus of care has shifted from the hospital. According to statistics compiled by the U.S. Department of Health and Human Services, 4 million children have significant medical problems, including about 2 million with mental retardation or developmental disabilities and 400,000 who need long-term care. Most of these children are being cared for at home.

For families already reeling from the birth of a baby, the shock of learning that the child has life-threatening problems, even if they appear to be temporary, can be terrifying.

"Ten years ago, my pediatrician told me, my son probably would have been a SIDS death," said Kathy Hardy, of Springfield, whose son, Clayton, was diagnosed with apnea, a serious breathing problem, a week after his birth last May at Fairfax Hospital. "We were told never to be more than two to four seconds away from him."

Hardy says that after doctors told her the reason her son periodically turned blue and stopped breathing, one of her first thoughts was, "I don't even know how to be a mom yet; how am I doing to deal with a life-threatening condition?"

"When they told me what I needed to do, I told my husband, 'I can't do this,' " recalled Amy Menache, 33, of Germantown. Menache's daughter Sivan was born 9 1/2 weeks early last March weighing less than 3 pounds. Within hours of her birth, Sivan was diagnosed with esophageal atresia, a birth defect in which the stomach and esophagus are not connected. Babies with esophageal atresia often have complicated medical problems involving multiple organ systems. "The truth is," Menache said, "I didn't have a choice. If I ever wanted her to come home, I had to do it."

Sivan, who spent the first six months of her life in three hospitals, requires round-the-clock care. Her mother is on duty from 10 a.m. to 10 p.m., relieved by a nurse who arrives at 10 p.m. for the second 12-hour shift. The nurse's salary is paid by the Maryland Medicaid program under a waiver based on the child's need, not the family's income.

Joanne Schuyler, a nurse on the maternal-child team of Home Health Clinical Services, which provides home health services to patients discharged from Inova's three hospitals in Northern Virginia, said that despite the demands, most parents want to have their babies come home and rise to the considerable challenges of being parent-caregivers.

"Even the babies with complicated needs are much more comfortable at home," said Schuyler, who spent eight years as a nurse in the neonatal intensive care unit at Fairfax Hospital.

Providing High Tech Treatment

The level of medical care required to manage these high-risk babies at home would give pause to a well-trained physician or nurse.

Other than a continuous gurgling sound, 7-month-old Sivan Menache makes no noise. She can't cry audibly because she has a tracheostomy tube in her throat that enables her to breathe.

Every 15 minutes or so while Sivan is awake, someone must suction the tube to prevent it from becoming clogged with saliva or mucus; if it's not cleared, she could choke to death. Her caregivers are also kept busy washing off the filter top of the trach tube, which Sivan recently has learned to fling or stick in her mouth.

In addition to the tracheostomy tube, Sivan, a placid 15-pounder with a ready smile, has another surgically created hole in her neck, called a fistula, that drains saliva produced when she swallows. She is fed every 4 1/2 hours through a tube inserted in a surgically created buttonhole in her stomach covered by a surgical snap.

Sivan's medical problems were not detected before her premature birth last spring. Minutes after delivery, doctors at Shady Grove Adventist Hospital diagnosed esophageal atresia, a birth defect that occurs in one of every 3,000 to 5,000 births. The condition occurs very early in fetal development when the esophagus fails to develop properly.

Doctors have told Sivan's parents that she will need several more surgeries over the next few years to repair her vocal cords, to remove the tracheostomy tube and to connect her esophagus with her stomach, enabling her to eat and breathe without tubes.

Sivan has already undergone several operations. When she was 3 months old, a surgeon at Shady Grove attempted to repair her esophagus, but the operation failed and left the baby with paralyzed vocal cords, according to her mother. In June, after she developed breathing problems, a surgeon at Fairfax Hospital inserted the tracheostomy tube to help her breathe.

When Sivan sleeps, she must wear a device called a humidifier collar, which adds moisture to the air entering the trach tube. A pulse oximeter, a device that measures the level of oxygen in her blood, is attached to her toe; the device emits a piercing alarm if Sivan is receiving too little oxygen. The small, cheerful bedroom in the Menaches' town house that serves as a nursery is crowded with medical equipment; a chart on the wall lists the half-dozen medications Sivan takes every day and a bulging notebook near her crib contains daily reports compiled by the nurse.

Consuming Family Life

While the demands of caring for Sivan at home are extraordinary, many parents who take their babies home must be able to deliver a range of medical services such as giving shots, changing and cleaning various kinds of tubes, hooking up oxygen, administering frequent doses of medication and, if necessary, administering life-saving cardiopulmonary resuscitation on babies the size of small cats.

Parents who are taught at home to care for their babies remember more than those taught in the hospital, said Nancy Steinbuechler, clinical supervisor for maternal child health for Home Health Clinical Services of Northern Virginia. "In the hospital there's a real lack of confidence because [parents] are surrounded by medical personnel."

"In a home situation it's much less distracting and much more comfortable than in the hospital," nurse Joanne Schuyler agreed. "I've heard parents say they can't deal with it, but usually it means that they need some help. So you sit down with the family and you help them. We don't leave them deserted."

Regardless of the outside support, families bear the burdens--psychological, physical and financial--of caregiving. For parents like Amy Menache, caregiving consumes their lives.

Because someone must watch Sivan 24 hours a day, her mother can leave her as long as she watches a portable television monitor, its miniature camera trained on the crib.

Caring for her daughter "is a full-time job, and it's exhausting," Menache said. She would like to return to work as a paralegal, a job she left two years ago while she was undergoing infertility treatments, but doesn't see how it will be possible for the foreseeable future.

"We could certainly use the money," said Menache, 32, whose husband, Isaac, works as a photographer at a small newspaper in Reston and some days spends as much as two hours commuting one way from the couple's home in upper Montgomery County. "We're not rich, we're middle class, and we're living on one income."

Menache said the couple spent $12,000 of their savings on in vitro fertilization, and then more than $1,300 on a nurse for Sivan before they were approved for Medicaid. The baby's bills for in-home medical care total about $100,000 annually and are covered by Medicaid.

Because only she and her husband and a nurse are trained to care for Sivan, Amy Menache cannot leave the baby with a sitter, even her mother. "I love my family dearly, but it's a humongous responsibility," Menache said. "I have a hard enough time leaving her and going to bed when the nurse is here."

Running a simple errand like going to the nearby grocery store can be daunting.

In addition to a stroller and diaper bag--filled with diapers as well as medical supplies such as extra suction catheters--Amy Menache must lug a portable suction machine and an oxygen tank. She can't drive longer than 15 or 20 minutes because someone needs to be in the back seat with Sivan to suction her tracheostomy tube. "If I'm in a store and I need to do that, I have to find a private corner so everybody doesn't stare," Menache said.

These days Amy Menache's chief source of support outside her family is the Internet, which enables her to correspond with other parents whose children have esophageal problems.

"I have good days and bad days," Menache said. "Some days I just sit here and cry and say I can't do this. But you just keep reminding yourself that there are families out there who have it so much worse."

Once-Fearful Mother Masters Medical Devices

Giselle Simpson was born 15 weeks early and weighing just over two pounds. When she came home from the neonatal intensive care unit of Fairfax Hospital to her family's apartment in North Arlington, her mother, Sandy Simpson, remembers being "so scared I wanted to die."

"Here I was, bringing her home from the hospital and there was no nurse, there was just nobody around," recalled Simpson, 33, a preschool teacher whose daughter had spent nearly three months in the hospital. When she was discharged, Giselle's weight hovered around five pounds and her parents were given an apnea monitor to check her breathing, an oxygen tank and instructions for administering several medications, interspersed with feedings every three hours around the clock.

They had learned the special way Giselle needed to be fed: five sips of formula from a bottle, then a rest to enable her to breathe. They knew she had to be hooked up to the oxygen tank while she ate--she couldn't suck and breathe on her own simultaneously--and she couldn't eat too much at any one feeding because her immature digestive system couldn't handle the strain.

What scared Simpson most at the time, she said, was the possibility that the apnea monitor that measured Giselle's breathing would go off. In the hospital she and the baby's father, Jose Ozuna, had been taught what to do if that happened: how to distinguish the frequent false alarms from a real emergency and the steps to take before administering cardiopulmonary resuscitation. Simpson wasn't sure she could remember how to do CPR.

"I was just praying the whole time, 'Don't go off, don't go off,' " Simpson said.

When Ozuna told Simpson he had to leave for his job later that day, she lost it. "I began crying and saying, 'Don't leave me, please don't leave.' "

But he did, she coped, and the alarm never went off. A week after that awful day in late August, she said, she began to feel more confident that she could take care of her fragile daughter.

Now, three months later, she knows she can handle the monitor, which has gone off numerous times. She feels bolstered by the support of her mother, who lives nearby, and her employer, who calls to see how she's doing and asks--without pressuring her--when she's going to return to work. Giselle, who weighs just over 10 pounds, has never been sick or needed to be rehospitalized.

Equally important, Simpson said, is the knowledge that a home health team consisting of pediatric nurse Joanne Schuyler and her supervisor, Nancy Steinbuechler, will come to her apartment three times a week to check on the baby. Simpson knows that the home health agency is available by telephone 24 hours a day and on weekends.

Earlier this fall during a routine visit, Steinbuechler examined Giselle as her parents watched attentively. As Giselle lay nestled dozing in her infant seat, Steinbuechler snapped her fingers near each tiny shell-like ear to test the baby's hearing. She asked Simpson how much formula Giselle was drinking, whether she seemed to be tracking objects with her eyes, what had happened at recent doctors' appointments, and whether Giselle was still spitting up, probably a sign that she had reflux.

Schuyler weighed Giselle on a portable scale and approvingly noted her weight gain, then checked the baby's diaper rash, which was much improved. But when she looked in Giselle's mouth she thought she saw thrush, a yeast infection, and recommended that Simpson call her pediatrician for anti-fungal medication.

"See that white stuff?" she said to Simpson. "If it wipes off on your finger, it's formula. If it doesn't, it's thrush."

After Schuyler administered a shot of Epogen, a thrice-weekly injection the baby receives to treat newborn anemia, she asked Simpson if anything had happened since her last visit. Simpson reported that on one occasion, the baby's hands turned purple.

"What action did you take?" Steinbuechler asked.

"I started rubbing her hands together and her normal color returned," Simpson replied.

"It could be that she needs oxygen," Steinbuechler replied, making a note in the chart.

She then advised Simpson to make sure she washed her hands before touching the baby, to stop giving Giselle water for hiccups and substitute sips of fortified formula and to change her clothes before touching the baby after she comes home after being outside, especially if she's been to the school her 6-year-old son, Cody, attends.

"She's doing good," Schuyler said approvingly.

After she left, Simpson acknowledged that she feels much more confident, although she still worries about her ability to perform CPR.

"When it comes down to saving my daughter," she said, "I'm pretty sure it would come back to me."

CAPTION: Sandy Simpson turns on oxygen while preparing to feed her daughter Giselle, as her son Cody, 6, looks on.