Luke dug deep. Judging by dated material, Donatello had spent the better part of a year working on this chapter alone, devising theories on the drugs and their negative effects. As he read further it became increasingly clear that conventional medicine was a route to steer clear from. Their physiology was similar to a human, but lacked some basic biological components which made them vulnerable to the effects of normal medicine.
His theories kept circling around the success of his Sensei's natural remedies in dealing with them, and upon one such remedy, he focused primarily - Niacin. After reading a couple of paragraphs about it, Luke looked up towards Splinter.
"Master Splinter, what can you tell me about Niacin?"
"It has certain...purging qualities. I have used it for all of them at one time or another, to help flush their system of an impurity. But as far as cleansing blood...it is not strong enough."
"Yes, I understand that, but Donatello was playing with the idea of using it in combination with a liquid base, and amplifying its basic properties to boost the effectiveness. It would be used intravenously to make the most impact."
"I know how to prepare herbs, but I am not a chemist, Doctor Barrows. I don't know how to change the properties of them. This is knowledge you have?"
"I do, though I'm not extremely familiar with this particular herb. Your son has some ideas down here, and experimentation he already completed. This gives us a major jumping off point, and it's something I feel we could try. Can you explain more about Niacin on its own?"
"I can tell you that it has some serious side effects when it's taken in large quantities," Splinter said immediately.
"Donatello wrote about the need to build up a tolerance. At this point I'm just concerned with getting the remedy in place. Then we can decide how quickly to increase the levels, according to how well and how long he's holding up without it."
Splinter closed his eyes with a sigh. "There is not much strength left in him. If you have hope in this, then seek after it hard, because it is the only remedy you may have time to pursue."
"You have the herb on hand I hope."
Splinter nodded. "Donatello mentioned making a large purchase of Niacin- I assume now because of the tests he was trying to run. Everything you require is probably already in this room. I will ask Michelangelo."

Mike did happen to know where it was, and showed Splinter to supplies at once.

As Luke got to work using the formula Donatello had already devised, Mike stopped by his brother for another look. He was silent for a few seconds, and then looked at his Master.
"He's getting worse, isn't he?"
"Yes, but that is why Dr. Barrows is here. Do not lose faith, Michelangelo. Go back to your brothers...and give them no reason to fear. Try to rest. I will not fail to tell you if something drastic changes."
Hesitantly, he bowed his head to the rat and obeyed.

Splinter sat back down to continue his vigil, feeling nowhere near as confident as he had assured his youngest son. Donatello was steadily growing worse, struggling more and more to breathe, and his temperature plummeting.

But Splinter had to shake his head at Luke's unflagging energy. The young man looked like he was getting closer to results, and it seemed to spur him on even stronger.
Around 5am, Luke let out a shaky breath as he held up a test-tube to the light. "I think...the reproduction is sound. I can't guarantee this will be flawless."
"His pulse barely resonates in my grip. We try this, or we let him die," Splinter said bluntly.
Luke carefully bagged up a portion of the formula, and set up the first transfusion through the IV. As he watched it start to flow, he let out another breath. "Here goes nothing."
"That is not nothing," Splinter countered. "It is his only hope."

The pair watched and waited together for several minutes, and Luke made a couple of adjustments on the IV flow. The doctor wanted to gradually build the levels of Niacin to avoid shocking his system worse, but he would do whatever was necessary to keep him alive at this point. In an hour's time, there had been no real change, yet it didn't really discourage Luke.
"He's been steadily declining for hours now. I think he has to level off a bit before he can start getting better...and I'll keep increasing the Niacin. I believe no change is a good sign," Luke told him.
"Do you never get tired?" Splinter asked.
Luke smiled for the first time in hours. "I keep weird hours because of when I work. This is my normal alive time. Why don't you take a quick break, or get some sleep if you feel like you can. I'm capable of keeping an eye on him."

Splinter left the room about ten minutes later to check on the others. Most of them had never left the living area. Leonardo and Raphael were sound asleep on the floor, and April was curled up unmoving on the couch. Mike, however. was wide awake and sitting rigidly in an arm chair. Splinter beckoned to him without speaking, and he eagerly followed him into the Lab.
"Have you slept at all?" his Master asked him.
"No, I couldn't." Michelangelo gazed past him at Don. "What's happening?"
"He's grown steadily worse overnight, but Dr. Barrows has recreated a formula from Donatello's own experimentation. He believes it shows promise for cleansing the sedative from his blood stream. He has been receiving the remedy only for about an hour. All we can do now is wait...and you need some sleep."
"What about you, Sensei?"
Splinter smiled thinly, and pointed at the other bed across the room. "Go. If you will rest, you may stay close by."
"Really?"
Splinter nodded willingly, and left him alone with Donatello for another moment while he returned to check on the others one more time.

Luke smiled at the turtle reassuringly from across the room, prompting gratitude.

"For what it's worth...thank you for doing this, Doc."
"I can't take credit for a lot of it, Mike. If I didn't have your brother's findings and his formula...I couldn't have churned out any type of remedy in time. And you've been a big help."
"Yeah, sure." He scoffed. "Because I'm the brightest crayon in the box."
"You know a lot about his Lab. You paid attention, regardless of how much you understood. I couldn't have done all this without your guidance, and I'm going to make sure he knows it. Then he can be as proud as your Sensei is."
Mike looked down for a moment without speaking, and glanced back up at him. "Thanks."
"Go get some sleep. You'll be the first to know when something changes," Luke encouraged him.

Mike ambled across the room to the empty bed. His eyes were so heavy with the toll weariness and stress had taken, that he was asleep in mere moments.

Splinter retreated out of his own necessity, leaving trust of Donatello with Luke. The young doctor had never felt such adrenaline in his entire life. He'd felt a life return to his veins that night which he didn't know was still possible.

Luke glanced at the screen monitoring the turtle, noticing instantly that his temperature had started rising. He smiled at the small sign that the Niacin was really working, and lightly rested a hand on his arm.
"We're going to be good friends you and me..." he said aloud. "But you gotta take to your meds, okay?"

Over the course of morning and early afternoon Donatello's vitals started leveling off even more, as the downward-spiral was replaced with a slight increase. Luke gradually upped the levels of Niacin to stronger doses, but continued with the slow drip to prevent worse side-effects. By 5pm, he felt good enough about his progress that he agreed to get some rest of his own.
Luke had met Jenna with some surprise earlier that day, and now greeted the young woman again as she joined Mike in the Lab, who was taking the first watch.

She hadn't seen Donatello since they first arrived, and now entered with some trepidation.
"It's okay," Mike told her gently. "C'mon in."
"He looks rough. Is he really going to be all right now?" she asked timidly.
"Dr. Barrows seems to think so. His vitals are better, and so is his breathing. The meds are being administered slowly enough that they shouldn't hurt him much either," Mike tried to sound positive.
"Has he come around at all?"

"No. We just have to wait...and trust."
"I wish I could have thanked him better. If it weren't for me, none of this would have happened in the first place."
He shook his head firmly at that. "Don't blame yourself, Jenna. Donnie knew what he was doing, he understood the risk involved. And for the record...nobody here is blaming you either."