He has put tubes down the throats of many patients, but now he was experiencing it. (BIGSTOCK)

The nasogastric tube was killing me. It had been in place for 12 hours now, threading its way up my nose and down my throat into my stomach. Try as I might, I couldn’t swallow away the nasty lump stuck to the back of my throat. And every time I tried, it hurt.

Decades before, as a physician-in-training, I’d put in more nasogastric tubes than I could remember. At the time, I hadn’t regarded them as a big deal. Now I was having my first personal experience with this vile little snake, and it sucked — in every sense of the word.

Two days before, I had developed a viral gastroenteritis — stomach flu, as it’s often called. Twenty-four hours into my illness, the miserable feeling that some dead critter lay rotting inside me had yet to ease.

By midnight on Day 2, I found myself sitting up at the kitchen table with my head on a pillow, the only comfortable position I could find. My belly was distended, and I was into my seventh hour of nonstop hiccups. You didn’t need to be a board-certified internist, as I am, to know that something was wrong. This was not how gastroenteritis plays out.

Despite her protests, I convinced my wife that I could drive myself to our local hospital. No need for both of us to lose a night’s sleep. She could catch up with me in the morning.

At 1 a.m. Saturday, the ER was quiet. Within an hour, an intravenous line was started, blood was drawn for tests and medications for pain and hiccups were administered. X-rays of my abdomen showed a condition called an ileus. It meant that my intestines weren’t moving things along as they normally would.

The ER physician confirmed my suspicions: I had allowed myself to become dehydrated and depleted in potassium. As a result, my intestines had simply said, “We’re done.”

I thought of the innumerable times I’d admonished my patients about maintaining hydration. I hadn’t taken my own advice.

By midmorning, my internist was standing next to my ER gurney telling me that my distended abdomen, silent as a graveyard, needed to be decompressed. The only way to do that is by gradually suctioning out the fluids and gas via a tube in the stomach.

“There’s no way around it, my friend,” he said. “We have to stop putting off the inevitable.”

I made no protest as the tube was snaked through my nose and down into my stomach.

Now here I was, alone and awake in my hospital room in the middle of the night, trying not to swallow because it felt as if someone had shoved an umbrella handle down my throat. I ruminated on how we torture our patients in order to get them better. I couldn’t believe how blithely I’d done this to people in the past.

Not that empathy is a new concept to me. At the medical school, I teach students how to connect with patients. I’d repeated it countless times: “There is no better lesson for a doctor than to be a patient.” And yet, that night, empathy for my patients felt like a revelation. Why? Why was I relearning this for the hundredth time? And what exactly, I wondered, is the half-life of a lesson?

When my wife gets up in the morning, her first waking thought is “What can I do for others?” Me, not so much. But I’m trainable. With some gentle prodding, I can be put back in touch with the better angels of my nature, decide to play on their team for a while. I’m like most people. Life hands us little reminders and, if we’re lucky, we notice them.

At dawn, the day-shift nurse came in to do her clinical assessment of me.

“Good news. You’ve got bowel sounds,” she pronounced, lifting her stethoscope from my belly. Fabulous, I thought. Between that and the gas I’d passed during the night, it meant my gut had reawakened and was back on the job.

“Could you double-check those sounds?” I asked. “Just to make sure they’re there?”

She did, and they were.

My diagnosis? I no longer needed the tube. But I didn’t share this with the nurse, nor did I talk about my nighttime revelation regarding the power and fragility of empathy. I just said, “Thank you very much,” and waited for her to leave.

Sunday morning. It would be several hours before my physician came in to do rounds. I didn’t begrudge him the time with his family, but I had an umbrella handle in my throat.

I reached up and peeled the tape from my nose.

Once more, I had learned my lesson about pain and vulnerability — and empathy.

I know I’ll never forget this night, I told myself as my fingers tightened around my tube.

I began pulling and thought, “Who am I kidding? I’ll settle for hoping I never forget this.” I kept pulling until the tube was out.

Kagan, an internist in Los Angeles, is an associate clinical professor of medicine at the Keck School of Medicine of the University of Southern California and a contributing writer to Discover magazine. This is an edited version of a story that appeared in Pulse, Voices From the Heart of Medicine.