By the time I performed my first surgery, I was 32 years old. That might sound old, but in medicine years, I was just coming out of the minor leagues. I was told that I should start my career by doing some simple lumbar surgeries like the one Tiger Woods had, or maybe some basic operations on the brain.

That wasn’t the case.

On my first day, my cell phone rang. When I picked it up, I was told that there was a 35-year-old man in the emergency room, dying. He had a mass on the back of his brain. They didn’t know exactly what it was, but it was blocking the flow of spinal fluid throughout his body. As a result of the blockage, the fluid didn’t have any outflow, and water was beginning to fill up rapidly in his brain. The patient only had only a few hours to live, six at the most.

With the aid of my assistant and a nurse, we positioned the man on his stomach and I made a small incision in the back of his head, at the top of his neck.

I opened up the patient’s brain-lining and began to operate in his cerebellum. I thought I’d be able to find the tumor easily.

But things never work out like that.

Have you ever been golfing and hit the ball in the rough? Often, you’ll know that your ball is in a certain area, but oddly enough you still can’t find it under the thick grass. This was my dilemma. I tried to use an ultrasound to locate the tumor, but I still had difficulty finding it. Beads of sweat began to build on my forehead.

I tried my best to stay calm. I kept telling myself to follow his anatomy. This is what I had trained for as a resident. But after 45 minutes had gone by, I was thinking doom and gloom. I was deep inside the patient’s brain, in a place where a slip could cost him his mobility. I was thinking catastrophe. I admit it: I made the mistake of letting my mind run. As I operated through white membranes, I was terrified by the thought that I’d accidentally entered the patient’s brainstem and had paralyzed him permanently. I knew I needed to get back on track or this man would die.

So, I did what I always do when I am in trouble. I came back to my breathing.

Inhale. Exhale.

Sure enough, after some more searching, I saw this brownish hue. No joke, it looked like a dirty golf ball. I took a long, grasping instrument, and carefully grabbed the growth and shimmied it out of the patient’s brain. Hoisting it in the air, I yelled, “Oh, yes, I can do this!”

I know: It’s cheesy. But that’s how I felt at the moment. And I felt even better a couple of days later, seeing the patient walking out of the hospital on his own two legs, his spinal fluid levels back to normal.

As I wrote the prescription for his anti-fungal medications, I couldn’t help but think about the life I had saved. It was my first.

I’ve had many blissful moments of profound gratitude since. I’ve also had dark moments of losing patients; Every surgeon, the saying goes, has their own graveyard they visit on occasion. But it’s all part of my job. And when I’m not sure if I can go on anymore, I remember one simple thing:

Inhale. Exhale. You hardly need to be a neurosurgeon to understand how it works. And you hardly need to be a neurosurgeon to apply it in your own life, either. Whoever you are, whatever you do, the principle is the same: A negative mindset only makes situations worse, and poise and composure frequently carry the day.

How to describe the perfect state of mind to be in if you’re about to tackle a complicated and potentially unsettling task? I made up the word “gritflowness”—a combination of grit, flow, and mindfulness—to describe my desired state-of-mind.

At its core is finding my flow state, which is the place where I think without thinking, operating on autopilot and trusting my training and my instincts. It’s where I do my best work, and where I need to be if I want to save lives without my mind and my anxiety getting in the way. The principle applies regardless of one’s profession: Think, for example, of a baseball player getting ready for his at-bat. He’s swung a million times. He’s run the bases more than he can remember. He can go through the motions in his sleep. But there’s nothing in the world you can do to prepare him for the wave of emotion that’s going to hit him when he steps on the field. When he walks into the batter’s box, he has two choices: step up, or don’t.

The same is true for everyone. So next time you face a task you find daunting, just stop, breathe, and find your flow. The rest will follow.

John Boockvar, MD (Vice Chair, Neurosurgery Lenox Hill Hospital)