Tan Wenfei decided to never apply for medical school when he saw his father's hair around his temples turn white overnight after a fatal accident during a surgery he was involved with in 1993.

Today, Tan is an anesthesiologist at the First Hospital of China Medical University in Shenyang, Liaoning province.

In 2019, the 20th year since he entered the field, Tan wrote a letter for his father, who passed away over two decades ago.

The son recalled his dad's final words. He told his son that, despite all the difficulties he'd faced as a surgeon, he hoped his boy would become an anesthesiologist.

"If you have a choice when you graduate, become an anesthesiologist. Surgeons can't work without anesthesiologists. The risk of anesthesia is high, and no one wants to do it. You are my son. And I hope you can carry this burden with courage,"Tan's father had told him.

In the letter, Tan recounts several events that shaped both of their careers.

Although his father was respected for his surgical expertise, two fatal medical incidents in the 1970s and the '90s changed his life.

Tan also experienced two events when his patients nearly died during surgery. But both were saved, thanks to advances in the field.

He wonders if contemporary technology could have saved his father's patients. And, if so, he wonders if he might have been more willing to pursue medical school after seeing what his dad went through emotionally.

The 45-year-old's biggest regret is that he could not work alongside his father.

"Improved anesthesiology means the distance between us as father and son is dissolving a little more,"Tan writes in the letter.

The letter won him the 2019 Wakley-Wu Lien Teh Prize, which aims to give a voice to Chinese doctors to tell their own stories and express their concerns. The Lancet, one of the world's leading medical journals, launched the honor.

It only took Tan an hour to finish the 1,800-word letter because all of the memories are so vivid.

The Lancet comments that Tan's essay demonstrates a powerful voice to tell clinical truths that inform, engage and encourage.

The award-winning letter went viral so quickly that Tan received greetings from one of his patients when he walked into the ward the next day.

"He told me he hadn't realized the importance of anesthesiologists' work," Tan says.

Tan earned his doctorate in anesthesiology at China Medical University and was a visiting scholar at the department of anesthesiology of the University of California, Los Angeles, in 2011.

"It's just a normal job, like any other," Tan says.

"There are more than 100 anesthesiologists in our hospital (in Shenyang). I'm just one of them. The hospital performs around 70,000 surgeries each year. Every single one requires an anesthesiologist."