“A very interesting article by PAULINE W. CHEN, M.D.”

Tall, in her 50s and sporting a perfectly coiffed salt-and-pepper pixie cut, the woman was one of the most respected nurses in the hospital. She had nearly three decades of clinical experience, so older nurses and doctors valued her insight, younger ones sought her approval, and those of us in between tried to stand a little straighter in her presence.

One morning, however, she arrived at work to find that the hospital was full and her unit understaffed. It wasn’t the first time she had to cover for more patients because of staffing issues, but by the end of this 12-hour shift, she noticed a slight twinge in her lower back — a minor muscle sprain, she thought, from helping one of the other nurses lift a patient.

A week later, the slight twinge turned into debilitating back pain.

But she continued to work through the pain. “What else could I do?” she said one afternoon, pointing out all the patients who would suffer without the additional nurse. “I thought I was going to be lucky and make it to retirement without getting hurt, but now I just want to be able to put in a few more years so I can retire.”

When she rubbed the heel of her palm against her back, I saw her lower lip begin to quiver slightly.

“How terrible is it that we do everything to care for the health of others,” she whispered, “but we cannot care for ourselves.”

Nurses make up the largest group of health care providers in the United States, working in venues as varied as doctors’ offices and biotech firms, governmental agencies and private insurers. Trusted more than almost any other professional, nurses exert a wide-ranging influence on how health care is delivered and defined.

But nurses’ work is not easy, particularly in the hospital setting, where they must deal with intense intellectual and significant physical demands over three or more grueling 12-hour shifts each week. Not surprisingly, nursing ranks among the worst occupations in terms of work-related injuries, and studies have shown that in a given year, nearly half of all nurses will have struggled with lower back pain.

The obvious question, then, is this: If the nurses are grappling at work with all these injuries, what is happening to patients?

Recent research published in two journals, The American Journal of Nursing and Clinical Nurse Specialist, reveals that when nurses suffer, so do their patients.

Researchers developed a questionnaire for registered nurses working at hospitals, asking them about their own health and the extent to which their injuries or illnesses might affect their work. Analyzing more than 1,000 responses, the researchers found that almost 20 percent of the nurses questioned had symptoms of depression, an incidence twice as high as for the general population. In addition, roughly three-quarters of the nurses experienced some level of physical pain from a muscle sprain or strain while at work.

The researchers then looked at the quality of the nurses’ work. A small percentage of nurses reported that they had made a recent medication error or that a patient had fallen while under their care. Adjusting the analysis to take into account how the nurses were feeling, researchers discovered that the risks of a patient fall or medication mistake increased significantly – by about 20 percent – the more a nurse was in pain or depressed.

Extrapolating the individual costs of these lapses in care to a national level, the researchers estimate that medication errors and patient falls that occurred as a result of nurses’ health issues incurred as much as $2 billion annually on the health care system.

“We have money bleeding out the back door because we don’t have a healthy work force,” said Susan Letvak, the study’s lead author and a registered nurse who is an associate professor of nursing at the University of North Carolina at Greensboro.

Nurses work in an increasingly stressful work environment, particularly within hospitals. Patients are sicker than before, and nurse-to-patient staffing ratios are not always standardized. Over the course of a 12-hour shift, nurses can find themselves in the potentially devastating situation of caring for more patients than is comfortable. When ill, many nurses feel pressure to show up for work because their absence means even more work for their colleagues and even spottier care for their patients.

They may also feel compelled to work because of an ethos that pervades the profession. “Nothing is supposed to stop a nurse,” Dr. Letvak noted. “We are supposed to care for everyone else and soldier on.”

Unfortunately, there are few work-based resources for nurses who are ill or depressed. Few hospitals have preventive programs that mandate, for example, safe patient lifting practices or policies that support nurses who may be temporarily disabled. Nurse managers often have little training in how to handle nurses with health problems, and many staff nurses themselves are unaware of how they might recognize and help a colleague whose work is impaired by illness.

Some nurses are also hesitant to disclose how they feel for fear of losing their jobs. “We have a system of penalizing nurses instead of early recognition and treatment,” Dr. Letvak said.

While the predicted nursing shortage will likely exacerbate many of these issues, Dr. Letvak believes there are several initiatives that could strengthen the current work force. These include measures like standardizing the nurse staffing ratios, providing the option of working shifts shorter than 12 hours and creating more health screening programs. She and her colleagues already have plans to study how helping nurses who are in pain and making shift lengths more flexible might improve patient outcomes and help experienced nurses practice for as long as they can.

“The only way to ensure the best quality for our patients is to have an expert staff of qualified nurses who are healthy enough to offer that kind of care,” Dr. Letvak said. “We can’t ignore nurses’ health anymore.”