For doctors, self-doubt is a hard habit to break. That’s a good thing.

Working in a cardiac surgical intensive-care unit, caring for some of the sickest patients in the hospital, every decision matters.

After surgery, for instance, keeping a patient’s breathing tube in too long can delay recovery and cause extra discomfort. Remove it too early, the patient may struggle to breathe.

One afternoon, I went to see a patient who had open-heart surgery that morning. She seemed to be doing well, so our team decided to take out the breathing tube.

Several hours later, a nurse stopped me as I was preparing to head home. “She looks exhausted,” she said, clearly concerned. “I don’t know, maybe she wasn’t quite ready?”

Had we missed something? Should we have left the tube in place? Would her condition worsen?

I felt guilty about leaving, even though I knew she was in excellent hands with my colleagues on the overnight shift.

Emotionally, though, I never left. Uncertainty ruled over me. I stayed up late, texting colleagues to see whether she was okay. Thankfully, she ended up doing just fine. The tube came out at the right time. She was tired at the end of the day because, like so many people, she wasn’t in great condition when she went into surgery.

Still, I couldn’t sleep. My worries about my patient were replaced by a new set of fears.

Why could I not leave work worries at work? How could I have a medical career if I was gripped by such uncertainty?

As a junior resident, there is not a day in which I fully understand everything that happens at work. Especially as I take on more clinical responsibilities, I am always second-guessing myself.

Did I choose the right medication? Did I miss subtle signs of an infection or a stroke? Should I have examined the patient more carefully?

Taking home these uncertainties can feel like a heavy burden. I reassured myself that as time goes on and I see more patients and develop my expertise, I will worry less.

One recent night at work, an overhead announcement directed me to pick up the phone: “Jason, line 2.” It was 10 p.m.

When I answered, I was surprised to hear the voice of one of our senior surgeons.

“Is the patient from earlier doing OK?”

I told him that he was.

“Okay, good. Please call me if anything changes,” he said, and then hung up.

Initially, I was perplexed by the encounter. He is one of the most experienced surgeons I know. He could have no doubt that we would call him immediately if his patient ran into trouble. Yet he made the call.

Had he also taken home some of his own uncertainties?

That’s when I realized that perhaps I had been thinking about all this the wrong way.

Uncertainty cannot always be overcome with experience. Medicine is an inexact science. No matter how strong our grasp of the subject, no matter how far along we might be in our careers, there will always be bigger questions or bigger mysteries that continue to humble us.

So, the goal is not to overcome uncertainty or to shake it off. It is to harness it throughout our lives in a way that leads us to better versions of ourselves. It does not imply weakness. It shows that we care.

I used to believe that the opposite of uncertainty is certainty. But I now recognize that it is apathy. If uncertainty pushes me to help a patient more, or learn about something I do not know, it becomes a strength. Embracing uncertainty — even if it means anxiety — makes us better doctors.

As I advance in my training, there will always be bigger challenges. I’ll continue to bring them home.

Jason Han, M.D., is a resident in cardiothoracic surgery in the Perelman School of Medicine at the University of Pennsylvania.