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The Cryonics Institute’s 70th Patient: By Ben Best

by System Administrator / Wednesday, 9 November 2005 /

The 70th patient of the Cryonics Institute was a 21-year-old man who died in an automobile accident. He was killed by a drunken driver. This is proof of the principle that your life is in the hands of any fool coming in the opposite direction who lacks the ability to stay on his or her side of the center-line.

In addition to suffering head injuries in the accident, the patient was autopsied. We were contacted after the autopsy, so we had no chance to intervene. Normally, we would not accept such a patient, but we were told it was a "light autopsy", that the patient was in refrigeration and there seemed to be no opposition in the family. Also we were believing that holding a person on dry ice post-mortem was not an option because of new airline requirements (this belief is now being re-evaluated). We make no guarantee of accepting such patients in the future.

Reportedly the patient had spoken of wanting to be cryopreserved, without anticipating that he would be deanimating so young. I urged that the patient be shipped as quickly as possible, but although the mother (who signed the forms) was apparently in agreement with this, there were evidently others in the family who insisted that a church service be held with the remains in a casket. A closed-casket funeral service was held, attended by hundreds of people, with the casket containing ice. I was assured that this was the compromise they had agreed upon and I didn't put up too much of a fight. I did not attempt to get involved in the family negotiations other than my urging, which I did not vigorously pursue. These matters can be sensitive.

There was no possibility of perfusing (infusing anything into blood vessels) this patient because of the time delay and blood clotting which would have occurred. So we did a "straight-freeze", meaning that no anti-freeze cryoprotectant was used to prevent ice formation because of the inability to perfuse. We used our old dry ice cooling box, which looks primitive, but is well-suited for this task.

Even in the case of straight-freezing there are more and less damaging ways to freeze. It is more damaging to cool so quickly that most ice forms inside of cells, damaging organelles. There is a higher concentration of nucleating agents (agents causing ice formation) outside of cells than inside of cells. Therefore if tissue is cooled slowly, water will freeze outside of cells and water will continue to migrate to the extracellular space where the ice has already nucleated to form ice. Slow cooling gives water time to cross the cell membranes and leave the cells. Cells become dehydrated and the remaining solution can even be vitrifying. Nonetheless, the extracellular ice tends to expand and to mechanically crush surrounding tissue.

Facilities Manager Andy Zawacki was on his annual November hunting vacation. If we had vitrified a patient we would have called him back to help get the patient into liquid nitrogen. But I decided to cool the patient in dry ice and keep him in dry ice until Andy returned from his vacation. I believe dry ice temperature is cold enough that little harm would be done by storing at this temperature for a couple of weeks.

Upon receiving the patient we placed him in the dry ice cooling box with 100 pounds of dry ice. Cooling was reasonably slow at first, just what I wanted. The next day (12 hours later) I ordered and added another 300 pounds of dry ice. This additional dry ice caused the patient to cool somewhat rapidly from -50ºC to about -70º, which should have been after the time that extracellular ice had formed.

Oddly, the dry ice cooled the patient to about -90ºC, about 10ºC below the sublimation temperature of dry ice. I thought that we must have had a calibration problem, but I got a similar result when I measured the temperature with another thermocouple. The only explanation that I can think of is that dry ice is manufactured and distributed at a temperature well below the sublimation temperature.

The patient was kept on dry ice from November 19 to December 1st in the dry ice cooling box, which encapsulates the patient in about a foot-and-a-half of foam board. I used 1,000 pounds of dry ice. On December 1st we moved the patient to our computer-controlled, liquid nitrogen cooling box. We cooled from dry ice temperature to liquid nitrogen temperature in about 8 hours. Cracking is not much of a concern at low temperature with a straight-frozen patient because thermal stress does not easily arise in frozen tissue.