Overseas Vitrification of Cryonics Patients
Shipping times for cryonics patients from overseas to the Cryonics Institute can be very long (rarely less than two days) and recent regulations have increased the delays associated with shipping human remains to the United States. Long cold ischemic time (time spent in ice) reduces the ability to perfuse effectively, causes increased edema upon perfusion, and is not associated with good tissue preservation. There is now good evidence that cryonics patients who have been well-perfused with a high concentration vitrification solution can be shipped at dry ice temperature. Concerns about the possibility of freezing (ice formation) at dry ice temperature have been excessive, although the prospect of freezing increases if perfusion with vitrification solution is poor. Efforts to ship a vitrified patient from overseas in liquid nitrogen have proven exceedingly difficult, but shipment in dry ice has been done many times.
Fast initial cooling after pronouncement of death is recommended for all cryonics patients. Placing a patient in a body bag filled with ice and nearly as much water as ice is a very effective and portable means of cooling when a portable ice bath is not available. Inexpensive body bags that can be used with a stretcher for transport are available from Emergency Medical Products. More expensive, more durable body bags will have handles for carrying — available from Crimescenes.com. Packages of five such durable body bags are available from DQE, Inc. DQE also sells a 4' X 8' collection pool which could be used for an ice bath. CardioPulmonary Support (CPS — CPR without the intent to resuscitate) helps sustain tissues during cooling and helps to accelerate cooling by heat conduction through circulating blood.
An outline of CI vitrification procedures can be found on the Cryonics Institute website, although a simplified approach can be taken overseas. Vitrification saturation of the brain when done in Michigan is typically monitored with a refractometer, but for overseas perfusion volumes of 5 liters of 10% ethylene glycol followed by 5 liters of 30% ethylene glycol and finally 20 liters of 70% VM−1 should vitrify the brain of any patient. All these cryoprotectants are in m−RPS−2 carrier solution (which is not an organ preservation solution, and is not very good as a washout solution).
The Cryonics Institute can sell perfusion solutions to overseas groups, or provide detailed instructions on how to produce the solution locally.
To arrange for perfusion formulas or notes, please contact us:
Phone: 1 (586) 791-5961
Toll-free: 1 (866) 288-2796 (North America)
For surgery prior to perfusion a funeral director will be required. (A funeral director will be legally required for all patient transport, anyway.) The funeral director gains access to the blood vessels by incisions just below the clavicle. Slits (incisions) are made in the arteries for the insertion of the cannulation tubes (blunt needle-like cannulas) required for perfusion. The vessels are clamped below the incisions. The cannula on the left side of the drawing (right side of the patient) perfuses both the vertebral and the carotid. The right side of the drawing (left side of the patient) illustrates that the carotid and vertebral can be independently cannulated and perfused, but the vertebral is too small to cannulate very effectively, and no incision should be made for the left vertebral in an overseas case (and perhaps any case). Flow through the right vertebral should be adequate to cause perfusate to flow through the circle of Willis. For drainage, simply cut the jugular veins and allow the effluent to flow. (This is open-circuit perfusion.)
Embalmer's cannulae are used to cannulate the blood vessels for the perfusion.
Embalmer's pumps generally create too much pressure for perfusion of cryonics patients. A peristaltic pump capable of achieving physiological perfusion pressures (or slightly greater) is preferred. Specifically, pressures should be at least 120 mmHg and could be up to 160 mmHg or more insofar as higher pressures have been shown to useful in counteracting the effects of ischemia. Embalmer's cannulae can add about 80 mmHg to the pressure required, so 80 mmHg should be added to the measured pressure to determine the pressure that the patient is receiving.
Inexpensive peristaltic pumps can be purchased on the eBay website. Entering "peristaltic pump" (include the quotes) in the search box will generally result in some bargains. Tubing will be required as well, quarter-inch or three-eights inch inner diameter tubing is generally the most suitable.
Perfusion with a gravity-based system (elevated perfusate reservoir) could be a low-cost alternative to a peristaltic pump. Means of measuring pressure (such as a pressure gauge on the line) is advisable in all cases. An online pressure converter can be used to eliminate the requisite height of a reservoir for gravity-based perfusion. For example, if 240 mmHg is desired (160 mmHg in the patient with 80 mmHg added by the cannula), the reservoir should be at a height of 3.3 meters.
Glycerol perfusion may be easier than perfusion with vitrification solution, and if body perfusion is desired, only glycerol should be used for the body (vitrification solution generally causes too much edema in the body, despite not having this effect in the brain). There was controversy over use of glycerol and dry ice as an alternative to shipping in ice for overseas patients before it was decided that vitrification solutions are stable enough in dry ice. Glycerol by itself does not vitrify, but it can reduce ice formation by up to 80%. With good dehydration, however, glycerol may be even more effective. Compared with the cold ischemia associated with shipping in ice, some amount of ice formation does not seem so bad.
Body perfusion should be avoided if possible. If the head is perfused first, it is difficult to cool the head immediately after perfusion — which results in excessive exposure time of the brain to cryoprotectant toxicity (toxicity decreases with temperature). Glycerol shrinks blood vessels, so perfusing the body first can make it difficult to perfuse the head.
Once perfusion is complete, the patient should be packed in dry ice as soon as possible for rapid cooling. Protective towels can be used between the patient and the dry ice, although this would only be for cosmetic purposes.