Hotel rooms have occupancy limits, as do elevators, and even taxi cabs in New York City, but few laws in the United States regulate or even monitor the number of patients that any one hospital nurse can be responsible for at a given time. This hit home for me after the publication of my book The Shift: One Nurse, Twelve Hours, Four Patients’ Lives. Many nurses reacted by reminding me that four patients is a cakewalk, not worth writing a book about—their usual load is eight patients or more.

I don’t think the general public understands how having so many patients added to nurses’ workloads can severely compromise the quality of care in hospitals. This misunderstanding results from how society views nurses—to many, they are basically glorified wait staff. But even in the busiest restaurant, the serving of food and clearing of tables will get done despite low staffing. Some patrons will wait longer than they want to for service. Some will stiff on their tip. But they will all eat, and no one will die because there are too few servers working that day.

That’s right. Die. Hospital patients die when the number of patients under each nurse’s care rises above an established safe maximum (which varies according to how sick patients are). Linda Aiken at the University of Pennsylvania and Jack Needleman at the University of California in Los Angeles are two of the most prominent researchers who have—separately—documented a consistent correlation between decreases in nurse staffing in hospitals and subsequent increases in patient mortality. Their work, along with research done by others, has transformed the phrase “safe staffing” from a slogan to a call to arms: When there aren’t enough nurses in hospitals, patients may die.

Of course, correlation is not causation—it’s hard to prove that adding more nurses would definitely decrease patient deaths. Plus, nursing is by far the largest labor cost for any hospital, since nursing care is not billed separately but included in the “room charge.” Reducing the number of nurses working each shift is an easy way for hospitals to cut room charge expenses.

But consider what a nurse does: dispense medication; monitor IVs; dress wounds; translate between patients and physicians; respond to immediate needs for relief of pain or vomiting; and serve as a first alert system when a patient becomes dangerously unstable. It’s that last duty listed above that is most affected by nurse staffing. Like food and drink in a busy restaurant, medications can often be delayed, dressing a wound can wait, pain and even vomiting won’t kill a patient in the short term. But if a patient develops a serious problem and no one notices, by the time someone does it may be too late.

I saw this almost happen as a nursing student. My one patient for the day had escalating pain and received increasing doses of pain medication all morning. When I carefully counted her breaths per minute while taking her vital signs, the number was low enough that she met the standard for respiratory depression (a possible side effect of narcotics). I asked her nurse whether narcan—a reversal agent for narcotics—was needed.

That day—and every day—my patient’s nurse had eight patients under her care. Eight patients with their own unique set of complex and ongoing health care needs. “Narcan?” the nurse said, “I don’t have time for that. She’s fine.”

I got pulled away for a meeting with our instructor, and when I returned 30 minutes later they were running a code on the patient. She got Narcan. She also got an emergency intubation and went to the ICU. I held her hand while they stuck the endotracheal tube down her throat and then walked with her stretcher to intensive care, feeling alternately guilty and angry.

I never asked but that’s probably how the patient’s nurse felt, too. It was a bad outcome, but a calculation I understood: The patient going into respiratory arrest was a possibility but the known needs of the nurse’s seven other patients were immediate and pressing. Her choice to focus on them was completely appropriate—until it suddenly wasn’t.

We’re currently in the middle of National Nurses Week, meaning nurses all over the country will receive recognition in the form of pizza parties, tote bags, and travel mugs. The better way to honor us, though, would be to help ensure safe staffing. The way to do that is legislation. California has had success with mandated RN-staffing ratios in hospitals. Other states, including my home state of Pennsylvania, are taking a different approach by instead asking that the number of patients each hospital nurse cares for be made public. The advantage of transparency is that it allows members of the community to clearly see which hospitals are most committed to patient safety vis-a-vis nurse staffing. Because many hospitals now view patients as customers, publishing staffing numbers creates commercial pressure not to overload nurses, even if doing so saves hospitals money.

Another option for correcting the problem would be to pull nursing care fees out of the hospital room charge and into a separate category. Minimum safe standards of nurse staffing could be set for each hospital floor, and when the number of patients in any nurse’s care rises above that minimum, the reimbursements received from insurance companies would precipitously drop. Linking staffing explicitly with reimbursement is an almost guaranteed way to make hospitals take the issue seriously.

A nurse recently tweeted at me, “Just 4?” referring to the four patients in my book’s subtitle. “Lucky nurse,” she clarified. It is lucky for me—but it’s luckier for my patients. And when it comes to life or death, we shouldn’t be relying on luck.