After being separated from my family, I became a darling of the military region thanks to my medical

In the second hour after Xiaoman was taken to the ICU, she was scheduled for a color Doppler ultrasound, which Ye Zhen performed personally. The child lay on the monitoring bed with electrodes attached to her chest, and the waveform on the electrocardiogram monitor was fast and shallow. Gao Haiping followed behind, holding Xiaoman's medical record in his hand.

"The noise from Shiao Village was coming from the third or fourth intercostal space on the left side of the sternum. I had previously estimated that the ventricular septal defect was no more than 0.8 centimeters," Ye Zhen said to Gao Haiping while adjusting the probe frequency. "But the degree of clubbing of the child's fingers and the depth of cyanosis have always made me feel something was wrong."

Gao Haiping stood at the foot of the bed, his hands in the pockets of his white coat.

"You suspect the actual defect is larger than determined by auscultation?"

"Um."

Ye Zhen squeezed the coupling agent onto the probe and gently placed it on Xiaoman's chest wall.

The screen lit up, and the black-and-white ultrasound images began to flow.

Ye Zhen slightly turned her wrist, adjusting the angle of the probe little by little, and the four chambers of the heart gradually became clear on the screen.

Gao Haiping leaned closer to the screen, looked at it for two seconds, and his expression changed.

"This defect..."

Ye Zhen didn't speak, but tapped a few times on the keyboard, and a measuring scale appeared on the screen.

Two white dotted lines block the two ends of the defect, and the numbers pop up.

0.9 centimeters.

Gao Haiping took half a step back.

"It's bigger than what you judged from the mountains."

Ye Zhen continued to adjust the angle, and the probe swept across from another cut.

This time, the scene on the screen made Gao Haiping pull his hand out of his pocket.

The edges of the defect are not smooth, but rather a sac-like bulge protruding towards the left ventricle. The tissue is so thin that the blood flow signal from the opposite side can almost be seen through it on ultrasound.

"A tumor-like bulge," Gao Haiping said in a low voice. "How thick is this membrane?"

Ye Zhen fixed the probe at that angle, magnified the image, and used a vernier to measure the thickness of the thinnest part of the bulge.

0.8 millimeters.

Gao Haiping took a breath, turned around with his back to the hospital bed, and braced his hands on the windowsill.

"Xiao Ye, if you use a regular patch in this situation, the stitches won't hold the edge tissue during suturing. When the blood flow and shear force come up, the patch will tear at the junction with the tissue."

Ye Zhen turned off the ultrasound machine, put the probe back on the stand, and wiped the coupling gel off Xiaoman's chest with a tissue.

"I know."

"So how do you plan to replenish it?"

Ye Zhen printed out the ultrasound images, tucked them into her medical record folder, and turned to walk towards the door.

"Back to the office, I need to calculate some data."

Gao Haiping followed in her footsteps.

"What data?"

"Nickel-titanium alloy."

Gao Haiping was stunned for a moment, then he understood.

"You want to use that thing? It's still in the experimental stage; it hasn't even completed the full cycle of animal testing."

Ye Zhen pushed open the ICU door, and the cold wind from the corridor rushed in.

"I saw the fax Hans sent last month. It showed a ten-year fatigue test—no breakage, no deformation. Just because it passes on paper doesn't mean the child can pass it too."

"But that's an in vitro simulation, not the human body."

Ye Zhen stopped and turned to look at Gao Haiping.

"Conventional patches can't cover that edge, and when the stitches are strained, the joint opens first. The superelasticity of nickel-titanium alloy allows it to deform synchronously with the surrounding tissue, preventing stress from being pushed out at the edge."

Gao Haiping followed behind in silence for a long time, until the two entered the office, at which point he finally spoke.

"Are you sure Hans can make it?"

"We can do it." Ye Zhen opened the drawer and pulled out a stack of papers filled with data from the bottom. It was a parameter table of nickel-titanium alloy materials that she had kept during her negotiations with Hans. "The problem isn't whether we can do it, it's whether we have enough time."

Gao Haiping watched as she spread the parameter table on the table, then took out a pencil from the pen holder and began to write out equations on the draft paper.

"How much time do you need to calculate?"

"tonight."

Gao Haiping nodded, then turned back as he walked to the door.

"I'll go to the ICU to keep an eye on Xiaoman. You do your own thing. I'll call you if anything happens."

Ye Zhen was already engrossed in the numbers and only hummed in response.

I used seventeen sheets of draft paper and sharpened the pencil three times.

Ye Zhen repeatedly deduced the thickness of the patch. 0.15 mm was too thin and it would be easily punctured by the needle tip during suturing; 0.25 mm was too thick and the shape memory recovery force would put extra pressure on the thin edge tissue.

She eventually drew a circle at a position of 0.2 millimeters.

Elastic modulus, shape memory temperature threshold, surface roughness—each parameter corresponds to a specific process requirement.

The next day, Ye Zhen copied the final parameter table, folded it, and put it in her shirt pocket.

She glanced at the clock on the wall; it was 6 a.m. Beijing time, which was 11 p.m. the previous night in Munich.

Hans should still be in the lab.

Ye Zhen picked up the phone and dialed the international long-distance hotline.

"Connect to Siemens Medical Devices Research and Development Center in Munich, West Germany, extension number 4207."

The dial tone sounded four times before the call was answered.

"Hallo? Wer ist da?" Hans's voice was hoarse from staying up all night.

"Hans, it's me."

There was a moment of silence on the other end of the phone, followed by the sound of a chair leg scraping against the floor; Hans had clearly jumped up from his seat.

"Ye, I was just looking for you. The first batch of six patches have all passed the final heat treatment and the ten-year fatigue test is also complete."

"What I need now is not celebration, but a patch that can reach the child's heart."

"explain."

"I have a five-year-old boy here with a ventricular septal defect that is 0.9 cm in diameter and has a tumor-like bulge at the edge, with the thinnest part being 0.8 mm. I need a custom-made pediatric patch that is 0.2 mm thick, 1.9 cm in diameter, with a shape memory recovery temperature set at 35 degrees Celsius, and a microporous surface treatment to promote endothelial overlap."

The sound of a pen tip frantically slicing across paper came from the other end of the phone.

"Wait, let me write this down: 1.9 centimeters in diameter, 0.2 millimeters in thickness, 35-degree rotation... Ye, are you planning to use this for the first human trial?"

"right."

"first?"

"first."

Hans was silent for three seconds, then burst into a trembling laugh.

"God, I've waited six months for this day. Ye, give me forty-eight hours. No, thirty-six hours. I'll drag the team out of bed right now!"

"Forty-eight hours is the minimum. The window of opportunity for surgery for children is only five to seven days. I need to allow time for preoperative preparation."

"That's enough. Twelve hours of heat treatment, four hours of fine grinding, two hours of quality inspection, and I'll use the rest of the time to fly!"

Ye Zhen heard Hans yelling at the other people in the lab in German on the other end of the phone.

"Hans".

"exist!"

"Bring this patch here yourself. Don't send it by freight or have someone else deliver it."

"Nonsense! This is the first nickel-titanium alloy patch in human history to be implanted in the heart. Even if the sky falls, I'll personally deliver it to you. I'll book my plane ticket right now!"

"There's one more thing."

"explain!"

"Bring your complete set of material testing reports and raw data from in vitro fatigue tests; I need to keep them on file."

"No problem, bring them all. Ye, may I observe the operation?"

Ye Zhen thought for a moment.

"Okay, but you can only stay in the observation area and are not allowed to enter the sterile area."

"Deal! I'm hanging up now, I need to go get my backup!"

After hanging up the phone, Ye Zhen put the receiver back on the landline.

The office quieted down, the sky outside the window was already bright, and the sound of nurses' footsteps changing shifts could be heard in the corridor.

Ye Zhen leaned back in her chair and closed her eyes for a while.

The door was pushed open, and Gu Zheng walked in carrying a bowl of hot porridge, followed by the guard Xiao Wang carrying a thermos.

"I didn't sleep all night." Gu Zheng placed the porridge in front of her; it wasn't a question, but a statement.

"I'm done." Ye Zhen opened her eyes and looked at the bowl of steaming white porridge.

"Eat first, then tell me when you're done."

Ye Zhen picked up the spoon and took a sip. It was so hot that it made her tongue numb, but the warm feeling in her stomach made her feel a little more relaxed.

"Xiaoman's condition is more serious than I expected. Regular patches won't work, so I need to use a nickel-titanium alloy."

Gu Zheng sat down opposite her, stretching his long legs under the table.

"What did Hans say?"

"Arriving within 48 hours."

"What else do you want me to do?"

Ye Zhen finished half a bowl of porridge and put down the spoon.

"Please make an appointment with Dean Zhou Hai for me this morning, the earlier the better."

Gu Zheng stood up.

"See you in his office in half an hour."

Ye Zhen nodded, finished the rest of the porridge, and got up to wash her face.

The person in the mirror has obvious bluish discoloration under their eyes, but their gaze is clear.

Forty-eight hours is enough.