FIRST, DO NO HARM:

3) Getting health care is dangerous, so use the health-care system as little as possible

Medical errors kill more people than car crashes or new disease outbreaks. They kill more people annually than breast cancer, AIDS, plane crashes, or drug overdoses. Depending on which estimate you use, medical errors are either the third or ninth leading cause of death in the United States. Those left dead as a result of their medical care could fill an average-size Major League Baseball stadium -- sometimes twice over.

We typically think of hospitals as places where we go to get better. And that's definitely true; we've seen lifespans extended and diseases cured as a direct result of advances in modern medicine.

At the same time, hospitals are dangerous places. This is something I've learned a lot about in the past six months, as I've been working on a yearlong series about fatal medical harm. I've come to understand that every trip we take to the doctor's office and every stay in the hospital comes with the risk of something going wrong.

In many cases, screening doesn't help people -- it turns healthy people into patients unnecessarily

The doctor could prescribe us the wrong drug, or the wrong dose of the right drug (this happens about 1.5 million times each year). Improper hygiene practices -- a nurse who forgets to wash her hands before accessing a central line catheter, for example -- could lead to a deadly blood infection. This happens about 30,000 times each year.

This is not to say health-care professionals are trying to harm patients. Quite the opposite -- every doctor I've ever met is trying to do his or her absolute best to help patients. That is, after all, why they went into medicine in the first place.

Medical harm reflects the fact that medicine is complicated and humans are fallible. Doctors will make mistakes if their hospitals don't set up the proper systems to safeguard against harm -- if they don't, for example, create a checklist that reminds a nurse to wash her hands before accessing a central line, or switch to a digital prescribing system that makes it way harder for a pharmacist to misread a doctor's scribbled drug prescription.

Modern medicine can do incredible things, and the work providers do day in and day out is humbling. But each trip to the hospital is a chance for something to go wrong, too -- something I keep in mind thinking about my own care decisions.

-Sarah Kliff

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