by Ian Douglas
The first option—capping off the flow—was faster and more certain if it worked, but those swarms of one-micron ’bots in there were up against an almost insurmountable problem—Joy’s blood pressure. The blood was still coming through her hepatic portal system so fast and hard that the nanobots simply couldn’t hold against that surging tide. Her heart was still beating—her heart rate was up to 190 now, trying to keep up with her rapidly falling blood pressure. As her BP continued to drop, the ’bots would be able to complete the pinch-off, but by then her pressure would be so low that she would be looking at serious brain damage on top of everything else.
And so I’d decided on the slightly longer option—rechanneling the flow through a nanobot bypass, literally growing a centimeter or so of artificial blood vessel to keep her blood flow contained.
Had I made the right choice? The ’bots were struggling, fighting the current as they tried to complete the linkup. This sort of work was a lot easier with smaller blood vessels.
Almost there . . . yes! The nanobots made the connection.
The latticework now formed a complete tube . . . and then I watched the structure dissolve again as a few tens of thousands of the ’bots lost their hold against the tide.
They were failing. Heart rate 205 . . . blood pressure 70 over 30.
I had one more option, one more thing to try, but it was hellishly dangerous.
“Doc!” It was Hancock again. “Doc, heads up! You’ve got bad guys moving toward your position!”
As if I didn’t have enough to worry about. “Where?”
“On your left. Fifteen meters!”
I looked. The body of the wrecked crane was there, providing some shelter but blocking my view. Well, if I couldn’t see them, maybe they couldn’t see me. . . .
I could hear the sounds of the firefight all around me, the lightning-bolt crack of lasers superheating tubes of air, creating miniature thunderclaps as the vacuums collapsed, the deeper whoosh-bang of plasma bolts. The Marines up on the ridgetop were firing at everything that was moving down on the spaceport, but they wouldn’t be able to keep it up for much longer. The Roc had been swept out of the sky, but more and more enemy troops were converging on the area, and before much longer the Marines would have to withdraw.
“Doc!” That was Baumgartner. “You need to get out of there. Now!”
“I can’t move my patient, sir,” I replied.
“Capture her then, and get her out of there!”
“Not fucking yet, damn it!” I shouted back.
Shouting obscenities at your commanding officer is never a good idea, not if you want a healthy career in the military illuminated by good quarterly reports and a lack of non-judicial punishment. On the other hand, he was up there, while I was down here.
A Qesh trooper came around the side of the ruined crane, coming straight toward me. I think he was more surprised than I was, because he came to an abrupt halt when he saw me, fumbling with his weapon.
Dropping the N-prog, I rolled half a meter to my right, scooping up Leighton’s plasma weapon and dropping it across her legs as I took aim and triggered it all in one motion.
The bolt of charged plasma slammed into the armored giant right at the level of his upper arm, shattering his weapon and peeling open his armor in a blossoming flower of raw energy and vaporizing plastic and metal. The Qesh tumbled to the side and collapsed, dirty smoke pouring from the charred crater punched into his plastron.
I left Joy’s weapon braced across her legs and went back to work on her wounds. Despite her falling blood pressure, I needed to further reduce her BP so that the nanobots in her side could finish their work. Short of letting her damn near bleed to death, there was only one way I could think of to do this quickly enough to make a difference. If I could just manage to switch off her heart . . .
Well, switch it half off, anyway.
The heart is an amazing organ. It keeps on beating completely independently of any and all nervous influences and hormone shifts with what cardiologists call intrinsic automaticity. Those heart-muscle cells with the fastest rate of electrical depolarization capture the depolarization rate of every other cell in the heart’s muscular walls, causing all of them to contract, relax, and contract again in perfect synch. The pacemaker for the entire system is the sinoatrial node, or SA, located in the right atrium. It’s this patch of cells that responds to signals from the autonomic nervous system or to certain drugs like adrenaline or halothane to change the rate of the beating heart.
I reached into my M-7 pack and pulled out a fresh vial of nano. I clipped it into the receiver on her left shoulder, snapped the panel shut, and fired it into her neck.
I keyed Program 5 into the N-prog, limiting the input to about half of the new nano. The rest I sent down to her liver to help out the ’bots still struggling to stem the bleeding.
Program 5 sent a few hundred thousand nanobots straight to Joy’s sinoatrial node, following the currents of bioelectricity playing across her heart membranes.
There were other tricks I could have tried. You can slow a patient’s heart drastically by stimulating the vagus nerve, which causes the heart rate to decrease, a condition called bradycardia. You can also suppress the signals coming from the sympathetic nervous system, which also induces bradycardia, or I could just wait for her blood volume to drop enough that it triggered her Bainbridge reflex, which drops the heart into bradycardia naturally.
Both of those would take too long, I feared, and both were harder to reverse. I needed to drastically slow her heartbeat only long enough for the nanobots in her liver to finish their work, then switch it back on again.
Program 5 switched off the sinoatrial node, which meant the heart muscle’s pacemaking duties would be picked up by atrioventricular or AV node. The heart’s ventricles will keep on beating with their own inherent and much slower rhythm. This rhythm, called nodal or junctional rhythm, usually comes in at a rate of around thirty to fifty beats per minute.
Almost at once, the numbers for her heart rate and blood pressure began plummeting. I had two main questions at that point: Was the drop in time, and was it going to be too much?
The fresh nano reaching her belly was reinforcing the original ’bots now. The framework of artificial blood vessel walls was reforming, knitting itself together, first as an open framework, then filling in the spaces between until they created a solid tube anchored deep within the natural vessel walls.
Heart rate 35 . . . deep in nodal rhythm. Blood pressure . . . shit, I wasn’t getting any blood pressure. Zero over zero.
At this point, Joy’s brain was being starved of blood; we had about three minutes before irreversible damage set in. Some of that might be corrected through surgery, including transplants of newly grown brain tissue, but when parts of the brain die off and are replaced, the new brain is different.
The person is changed, usually forever.
I looked up at Joy’s face through her transparent visor, so I could see it, her eyes still closed, her skin a pasty, scary white.
I was thinking about Paula Barton, damn it.
You see, for the past year, ever since she’d suffered that stroke off the Mount Desert glacier, I’d been thinking of Paula as dead. It was easier that way. . . .
The truth was a lot tougher to deal with.
Paula had been dead when the med-rescue lifter had hauled her body up out of that sailboat and flew her back to Portland Medical. They’d hooked her to an artificial heart during the flight, but by that time she’d been dead for a good twelve to fifteen minutes. Life support, yeah, but no life to support.
But what that really meant was that the brain had started starving when her heart stopped. By the time blood flow had again been restored, large areas of her brain were dead, some from the direct effects of the stroke, some from the inevitable results of no heartbeat.
At Portland M
edical, they’d used surgical nano to carve out huge, dead chunks of her brain, and they’d filled them in with new tissue grown from Paula’s own stem cells. A few months of physical therapy and heavy reprogramming of her in-head hardware had gotten her walking and talking and thinking again. They’d brought Paula Barton back from the dead.
Only . . . she didn’t remember me. She didn’t remember the years we’d had together. She was perfectly healthy . . . and she was a different person.
I’d met with her once. She didn’t want to have anything to do with me—a common-enough response when the doctors are telling you that this stranger beside your bed is the guy with whom you spent several years of your life.
Having a stroke can change a person’s personality, change the way she feels about others, even rewrite memories.
And it’s even worse when half of your brain has been regrown.
You can see why it was easier for me to think of her as dead.
Three men came around the side of the wrecked crane, and for just an instant I thought they were three Marines. Then I saw the clumsy leather armor, the bug-faced goggles and breather masks, and I knew they were Salvationists. My immediate question—were they from the faction that was with us, or the one that was with the Qesh?—was answered immediately when one of them raised his cable-bound laser to his shoulder and fired at me.
The pulse of coherent light was absorbed by my armor, and I rolled back into place behind Joy’s plasma gun. They were almost on top of me, so close, I hardly even needed to aim; I squeezed the trigger and the blast of white-hot plasma burned through the leader’s center of mass and kicked him back off his feet and squarely into the two behind him. I triggered the weapon twice more; all three Salvationists were down, portions of their leather on fire.
I could hear the comm chatter of the Marines over the combat channel as they tracked targets and brought them down.
“Over there. On the right. Two Impies!”
“Tracking . . . firing . . .”
“Good shot!”
“There’s another. Twenty degrees west of the first!”
“Got him!”
“Bring that cannon around! Give him some cover!”
“Aye, aye, sir!”
“Range two-five-oh! On the way!”
Something slammed into the other side of the crane body, sending metal fragments hurtling into the sky, then raining back to the ground in plinks, clanks, and thumps.
I kept monitoring Joy. The restructuring of her hepatic portal vein was complete now, and the repair on her hepatic artery very nearly done as well. Fifty seconds had passed since her blood pressure had dropped to nothing. She probably had more than the three minutes of the deadline I’d given her; her heart was beating, and blood was flowing to her brain. But I didn’t know how to calculate a safety margin for this procedure. Hell, I’d never done it before, not even in simulation. I’d read about it in one of my Hospital Corps download texts, but I’d never slowed anyone’s heart before, not like this. There were so freaking many variables and danger points—the problems of too much pressure, of too little, of nanostruction in a high-volume flow, of shock, of exsanguination, of renal failure, of stroke, of cardiac arrest . . .
The list seemed to go on forever.
But the vessel repair was complete. It was time to bring her heart rate back up to speed.
If I could.
I reprogrammed the nanobots clustered over a particular spot on the wall of her right atrium, giving them the signal to fire a minute electrical charge into the tissue and trigger her SA node. I saw the feedback from the jolt, but nothing happened. I reset, then fired it again. And yet once again . . .
Her SA node responded, firing her heart muscles in unison, and then her heart was beating harder and faster as her SA node took over from her atrioventricular node, her heart rate swiftly rising from thirty-five to fifty . . . to seventy . . . to ninety . . .
I had a BP on her again!
Correction: I had her systole, the first number in a BP reading, but I wasn’t picking up the second number, the diastole.
Systole is a measure of the highest pressure inside the arteries, at the moment the heart contracts and forces blood out into the body. Diastole is the lowest pressure, measured between the heart’s contractions. I was getting a systole of thirty and a diastole of nil. Not good, not good by several hundred light years, but a hell of a lot better than a flatline zero over zero. At least I had something to work with now.
And the pressure was coming up. Heart rate at 103, BP 45 over 20. Come on!
I wasn’t sure what to shoot for as an endpoint. Joy had lost a hell of a lot of blood, and I might not be able to get her pressure much above, say, 100 over 50. But if I could at least get it stable, that would be something.
While I was waiting, I engaged the CAPTR software in her armor, uploading the data to the Marine network, essentially giving it into the care of the platoon AI. If Joy died in the next hour or two, at least something might be recovered.
I also did something I should have done earlier—upload the data I’d pulled from the Salvation computer to the platoon net as well. That was to ensure its survival in case something happened to me, a distinct possibility with the firefight swirling closer and closer around me.
And then something slammed into my left side, knocking me away from the Marine. What the hell . . . ?
A Qesh warrior had emerged from the ruins fifty meters away, to my left and behind me. His plasma bolt had struck rock directly beside me, the shock slamming into my armor and kicking me to the side. I couldn’t reach the plasma gun; my laser carbine was on the ground where I’d dropped it, just within reach. I scooped it up, twisted around, dragging the targeting cursor projected into my in-head display across the Qesh’s body and triggered three quick rounds.
I hit him below the helmet and just above the upper arm, saw the bolts, with all of the explosive power of a firecracker’s snap, absorbed. Damn!
The Qesh fired again; I managed to not be where the bolt was by rolling to my left, and when I brought the laser up again, I tried to target the enemy’s optical sensor strip. Again and again, I mashed down the trigger button, slamming pulses of coherent light into that walking tank as fast as I could. I couldn’t tell if I was hitting anything vital or not, and shifted my aim to the Jacker’s weapon, hoping to buy myself some time by disarming him.
His helmet blossomed open, metal and ceramic torn and half melted. But a second Qesh was emerging from behind the crane’s fallen cab, and my carbine was warning me that I’d drained its capacitors, that it would be a few seconds before the battery packs could recharge.
I tossed the carbine aside and scrambled back to Joy and the plasma gun resting across her thighs. An enemy shot grazed my left leg, a savage shock. I ignored it and grabbed the weapon, swinging it around and opening fire. The second Qesh ducked back behind the crane wreckage.
It looked like sheet metal, crumpled and propped up by a part of the crane’s framework. I took a guess at where the Qesh might be hiding and put a bolt through the sheet. A half centimeter or so of corrugated iron offered about the same resistance to hot plasma as silk to a Marine nanoknife. The sheet sagged, glowing red-hot around the hole melting through the center, and the Jacker behind twisted and fell with the impact.
Joy’s heart rate was at 120, her blood pressure 90 over 30. The hepatic vessel repairs seemed to be holding, and her heart was solidly back into its normal sinoatrial rhythm.
I took a close look at her spine, sending some of the remaining free nanobots into her back to outline the broken bones and tissues on my N-prog display. It was clear that the T-11 and T-12 vertebrae had been displaced far enough that her spinal cord was torn apart, and that alone was damage that I couldn’t even think about addressing here. Maybe, back on board a ship with a decent surgical suite . . .
The most seri
ous problem that I could do anything about was the possibility of doing more damage. I had to move her, and when I did, those bone fragments—especially those jagged lengths of broken rib—might puncture something else. It looked like another rib fragment was pressing up against her diaphragm; if it shifted, it might punch right through that thin sheet of muscle, and go on to puncture her right lung.
Programming the nano from my N-prog, I directed them to form ligatures—slender but tough threads insinuating themselves through damaged tissue, binding bone to bone, holding the fragments in place. I was tempted to try doing the same for the two severed sections of her backbone, but the damage was too severe. Instead, I popped open her suit controls and keyed in some coded instructions. The torso of her combat armor was damaged but still functional enough that the central torso section could tighten around her waist, then lock itself into rigid immobility.
Her combat armor would serve as a kind of rough-and-ready body cast, immobilizing her spine while I tried to move her.
Tried to move her. That was the operative phrase.
I was up against a major logistical problem now.
Joy massed 64 kilos; her armor massed 25. That was what they would weigh on Earth. Here, together, they weighed nearly 165 kilograms.
My normal weight on Earth comes in at around 90 kilos; here, and wearing full armor, I weighed almost 213 kilos.
I was faced with hauling a total of over 378 kilograms across 200 meters of open ground, much of it rugged, broken, and uphill.
I would have been hard-pressed to pull off that kind of feat back on Earth. Even on Mars our combined weights would have been only a little less than 80 kilos. Combat armor compensates somewhat, of course, and the exoskeleton bracing, legs, back, and arms would have let me get away with it.
