"It was quite tiresome and the fingers get numb, but the minute you ease off, even a little bit, the patient might die," Zhang says. "In this instance, the patient was only in his 50s, he is still young."

When they finally got the patient intubated, they were all soaked with sweat.

"We always said we were on a battlefield since we arrived in Wuhan, and in that moment I realized that the doctors next to me were indeed my comrades in arms," Zhang says.

Noticing that some of the ICU patients were, naturally, anxious and fearful, he tried his best to offer comfort by talking with them or helping them to make video calls with family.

"Imagine being one of the patients? You wake up in a ward that is full of people in protective equipment, you cannot see their faces clearly, and you are intubated and cannot talk. How scary is that?" Zhang says.