X-Message-Number: 2855 Date: 06 Jul 94 17:38:59 EDT From: Mike Darwin <> Subject: CRYONICS Small Groups More on Robert Cardwell's post and the situation of the Australian group. After thinking about the Australian Group's situation in light of what Robert has said about their capabilities I would like to add the following thoughts. If you have a blood pump or other acceptable pump and a simple circuit with a 40 micron alterial filter AND you have the capability to mix and filter perfusate (again a pump capable of generating enough head to push the perfusate through the 0.2 micron filter is needed) AND you feel confident about setting up a flush circuit and doing cannulation (with or without assistance from a mortician) I think you would be FAR better off to go ahead and carry out cryoprotective perfusion and freezing locally. How would you do that? 1) Start out with a single pass batch of 10% glycerol in MHP (consult Mike Perry's paper for the volumes you'll need -- or better still consult Mike Perry). You will probably need about 20 liters for a neuro -- this presumes using both carotids and both jugulars (i.e., perfusing just the head) -- this may be contraindicated in some patients due to atherosclerosis, etc. 2) Make your next batch 25% -- again about 20 liters for a neuro. Keep your pressures to between 40 and 60 mmHg. You can place venous cannulae to act as stents and put a connector with port on each one so you can draw venous effluent samples for later analysis. 3) Your final pass can be with 30 liters of 6.5 M (about 50% glycerol). Surgically isolate the head using an electric carving knife and hacksaw (I use a Black and Decker knife and a Satterlee amputation saw) and place the patient in two plastic bags and submerge in n-propyl alcohol for dry ice cooling. A whole body simply requires you to have a metal tank (standard metal air shipper will work -- this is what we used at Alcor for the first couple whole bodies) and 55 gallons of n-propanol. N-propanol is about $150 per 55 gallons in the US -- it will probably cost more in Australia because petrol prices are about 2-4 fold higher. The point here is simple: for a modest expenditure of funds and acquisition of a modest additional amount of equipment you can easily do CPA perfusion on-site. Given the time-delays and logistic difficulties you will likely encounter this is probably a worthwhile tradeoff IF you have mastered open-circuit bypass. Oh yes, and of course you'll need some whole body plastic bags to protect from the alcohol -- Alcor has LOTS of these and they are not expensive. As to delays, keep in mind that long delays have resulted in both cases of shipping from outside the US in which I had involvement (I am excepting Canada here) because of bureacratic red tape. In one instance the US consulate was shut down for the weekend (normal practice) and it was impossible to even get the permitting process *started * until Monday. These people are NOT in a rush to get permitting going fast and all of Carlos' efforts (which were herculean) to get them in over the weekend were, as I recall, to no avail. Additionally, holidays (Australian *and* American -- I now believe that it is a holiday at some where on earth EVERY DAY of the year) and vagaries of cargo can cause massive delays. I am currently doing some consulting for a person in Australia who wishes to have his/her large dog frozen in Australia. I made a call or two about cargo and found out that there was NO cargo space (even for emergencies) available for three days -- on any airline that serviced Sydney to LAX and I made it a point to ask about shipping both medical perishables and cadavers! Look at what sometimes happens inside the US: Alcor was almost unable to take delivery on their last patient for another day or two because the Scottsdale Airport airfreight terminals were closed for the weekend! Also by way of example, I recently found it IMPOSSIBLE to move personnel (even with an MD's statement that it was a medical emergency) between the Bay Area and LAX -- and we had a horrible time even getting a charter flight (air ambulance to move the patient/personnel) because of icing and bad weather at Ontario Airport here in Southern California in MAY!!!!! Thus, if you really have the people/capability I would urge you to go with cryoprotective perfusion/freezing in Australia. Also, as I understand it (perhaps I am mistaken) you are using a Pall 40 micron filter in-line with a gravity flush system. This is extremely dangerous and absolutely contrary to the manufactuer's recommendations -- and safe practice. Normally, extracorporeal filters are primed with carbon dioxide gas before wet priming and are then extensively circulated with liquid prime under high-flow conditions (with a pump) to deaerate them (the CO2 is used to displace air because it dissolves better in the prime than nitrogen and/or oxygen in the air). Unless this is done the filter becomes a SOURCE for air rather than a trap for it (its only function when perfusing open circuit since the perfusate will have been pre-filtered through a 0.2 micron filter and will not accumulate particulates such as clumps of RBCs, clots, platelet aggregates, etc. during the course of perfusion -- these are a problem only if you close the circuit). Thus, unless you can recirculate your prime and THOROUGHLY debubble your filter by tapping on it (use a rubber exam hammer), repeatedly inverting it, and recirculating fluid through it you are BETTER OFF WITHOUT ONE. Indeed, a few cardiothoracic surgery groups DO NOT RUN FILTERS at all! (I emphasize here that this is minority practice in the US -- it is routine in third world countries where the cost of the filter is prohibitive). Anyway, I hope this is some of help to you and the other Australians. Good luck. Mike Darwin Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=2855