12 replies to this topic

[jordansparks]

I believe I have come up with a better approach to the initial response phase of cryonics than has been used in the past. I'm probably going to establish some pages on one of my websites fleshing out the details, but here's the outline:
1. Use liquid ventilation to provide all or most cooling. We're talking about a cooling rate of 1 degree C per minute, which is very very fast.
http://www.anl.gov/M...5/ET051028.html
2. Use water or water ice slurry rather than perfluorocarbon (PFC). The only advantage of PFC is that it removes CO2 a little faster. That's irrelevant in our situation. An ice slurry is more efficient at cooling than PFC.
http://en.wikipedia....iquid_breathing
3. The trick to getting the ice particles to flow into the lungs is to make them very small and very smooth. I will initially explore a standard slushie machine which will certainly make the ice particles smooth enough. What I'm not sure of yet is how to get the particles small enough.
4. The cooled blood must be circulated, but the circulation doesn't have to be very good, and it doesn't have to go on for more than about 20 minutes. Use a mechanical chest compression device with a power source that will hold up for just a few minutes. The rest of the time, it can be plugged into a vehicle or a wall outlet.
5. Oxygen not needed. There will be some O2 in the water, but the cooling rate is fast enough that additional O2 is unnecessary.
6. Cart can be a standard gurney since no need for an ice bath. This also makes it more manageable.
7. Liquid ventilation equipment can be on a separate cart since it can easily be disconnected for short periods of time.

I think that this is a very important topic. I've already been working on such a chest compression device, and I will probably work on a liquid ventilation device later. I know Dr. Harris has been doing this for years, but mine will be different because it will need no oxygenation, and the cooling will be performed by ice particles in the liquid rather than by a more complicated heat exchanger. This device will obviously have no application in emergency medicine, but will be very specific to cryonics.

Edited by jordansparks, 08 December 2006 - 06:58 PM.

[bgwowk]

Use water or water ice slurry rather than perfluorocarbon (PFC). The only advantage of PFC is that it removes CO2 a little faster.

That is not correct. Water carries much less oxygen than PFC at the same temperature. Saline liquid breathing animal tests were conducted in hyperbaric chambers. Also I think you have the CO2 solubility backwards. CO2 is removed better by water than by PFC.

The cooled blood must be circulated, but the circulation doesn't have to be very good...

The circulation does have to be good. If the cooling rate is 1 degC/minute with a heart beating, it will be half that during external cardiopulmonary support (CPS).

...and it doesn't have to go on for more than about 20 minutes.

It does, because cooling during external CPS is slow, and because of what Steve Harris calls the "baked Alaska" effect. Well-perfused core organs cool faster than peripheral tissues, so if you stop the process when a target core temperature is reached, the periphery will warm things back up again. It takes a long time to get everything down and stay down.

Oxygen not needed.

It is, because cooling takes a long time. Unfortunately even if you have oxygen, saline cannot adequately deliver it. What you propose is better than external cooling without CPS, but is probably not as good as external cooling with good CPS and oxygen ventilation, and is definitely not as good as fluorocarbon cooling with CPS and oxygen ventilation.

In terms of this Argonne work, it's unlikely that saline ice slurries will ever be used clinically for liquid ventilation cooling. Not only is gas exchange poor, but the treatment would leave lungs in very bad condition afterward. I don't think those experiments were ever performed with long-term survival as endpoint.

[jordansparks]

OK, your explanations are all quite reasonable. I'll just slink off now and hope nobody noticed my post. Of course, now my pet project is cancelled, so I'll have to find something else to do. It's just frustrating to sit here and not be able to get my hands on anything.

I'm still very excited about Dr. Harris's work. I consider internal cooling to be much more important than external cooling. It sort of surprises me that this didn't happen sooner. I hope he brings a working prototype with him to Florida.

[bgwowk]

Both SA and Alcor have field-deployable fluorocarbon liquid ventilation cooling units in development. After languishing for a decade, there is now intense interest in deploying this technology for cryonics.

With all the engineering development now going on at these companies, and your enthusiasm, Jordan, I wonder if there is some way they could use you?

[jaydfox]

It's just frustrating to sit here and not be able to get my hands on anything.

I know the feeling. If you have the time and skills to get stuff done, consider networking with others you meet here with similar interests, and you may yet find a way to put your talents to work. One example is as Brian points out: maybe one of these companies can use your help? Even if not, I'm sure someone here can.

[jordansparks]

They need people who can move to where the organization is. They also need people for standby situations. But those are very disruptive and time consuming for most people as well due to jobs and families. But I do know one thing they need that they don't have which I might be able to make: a better CPS device. I'll just start another thread regarding the design.

[jaydfox]

A collaboration directly with their engineers might be more fruitful. However, I wouldn't know how to go about setting something like that in motion. I'm not that well connected.

It's important to know what they're doing, why they're doing it that way, what else they've tried, and why they didn't stick with those other designs/ideas. It may save you a lot of work.

[garethnelsonuk]

Why is removing CO2 irrelevant?

[jordansparks]

The idea was that the brain would be cooled so quickly that it simply would not be generating a significant amount of CO2. If the cooling rate could be achieved that is shown on the Argonne website, the cellular metabolism would drop off very quickly. That's the same reason that I was hoping to get away with not supplying O2. Brian feels that the cooling rate will only be about half of the one shown in the graph, which would then require supporting the metabolism.

[garethnelsonuk]

I would remain on the side of caution with such matters when possible. It is an intriguing idea though if an icebath could be eliminated for local standby. As jaydfox has stated, a collaboration with the people at SA (who I am aware have been working on liquid ventilation for the purposes of cooling) could be quite fruitful. Perhaps animal testing is a very good idea - the criteria should be that you can keep the brain viable and if possible capable of recusitation as long as possible up to cryoprotective perfusion and deep cooling down towards cryogenic temperatures. If the current 4 or 5 hour period for reversible short-term suspended animation can be lengthened it would benefit not just cryonics but medicine in general.

[garethnelsonuk]

Both SA and Alcor have field-deployable fluorocarbon liquid ventilation cooling units in development.  After languishing for a decade, there is now intense interest in deploying this technology for cryonics.

With all the engineering development now going on at these companies, and your enthusiasm, Jordan, I wonder if there is some way they could use you?

I am curious what Alcor's current status with liquid ventilation cooling is - are techniques in this area even taught to those undergoing standby training?

[bgwowk]

Presumably it will be taught when there is field equipment ready to do it.

[garethnelsonuk]

Both SA and Alcor have field-deployable fluorocarbon liquid ventilation cooling units in development.  After languishing for a decade, there is now intense interest in deploying this technology for cryonics.

With all the engineering development now going on at these companies, and your enthusiasm, Jordan, I wonder if there is some way they could use you?

What is wrong with this equipment?