Maintaining patients at an intermediate temperature means keeping them warmer than liquid nitrogen, but cold enough to inhibit biological decay. For years we have wanted to provide this option. On June 14th, we came much closer to our goal.
Why Intermediate Temperature Storage is Necessary
If cryoprotective perfusion is performed successfully with a high terminal concentration, residual amounts of water in solution in the brain tend to solidify instead of forming ice crystals. When we use the vitrification solution which is now standard for all Alcor neuropatients, the entire brain should become a glassy solid as its temperature drops below the “glass transition point” around -125 degrees Celsius.
Traditionally, we have maintained our cryopatients at -196 degrees, the temperature of liquid nitrogen. We use liquid nitrogen because it is cheap, nontoxic, convenient, and requires no refrigeration equipment at our facility. The liquid is “precooled” when it is delivered. Unfortunately, it is colder than we would really like it to be.
When a cryopatient makes the long journey from -125 to -196 degrees, some portions of the brain inevitably tend to cool faster than others. This creates thermal stress which can result in fracturing. We use a “crackphone” to sense and record vibrations which we believe are an accurate indication of fracturing events.
Proponents of nanotechnology believe that fracturing will be relatively easy to repair in the future compared with cellular damage, but still we would like to prevent it. The problem probably can be minimized or even eliminated if the patient isn’t allowed to get so cold, and is held at a temperature just below the glass transition point. In other words, we would like our patients to be cold enough to vitrify, but not so cold that they start to fracture. Unfortunately the only easy way to achieve this has been by using an expensive laboratory freezer–until now.
A New Way to Maintain an Intermediate Temperature
On June 14th, in Rancho Cucamonga, California, biophysicist Brian Wowk of 21st Century Medicine gave a remarkable presentation attended by all Alcor board members and many staff members. Dr. Wowk has developed a simple, reliable design for an intermediate temperature storage device using a heavy-gauge metal container enclosed in a jacket of closed-cell insulating foam fitted with two 2-watt heaters. The insulating jacket is then immersed in liquid nitrogen, and the heaters are run variably by an external controller to maintain the desired temperature inside the metal liner, which conducts heat and minimizes the thermal gradient.
According to Dr. Wowk, seven of his storage devices will fit beside each other within the diameter of a typical “bigfoot” dewar of the design that Alcor uses. The initial cost of building each storage device will be around $2,000, but a greater expense will be incurred in the long term as the heating elements will increase the total boiloff of liquid nitrogen in the enclosing Dewar. Also, because of the foam insulating jacket, each intermediate temperature storage device will occupy a greater volume compared with a standard neuro container. However, we believe that many of our members may feel that a higher payment for longterm care is a very reasonable tradeoff if Dr. Wowk’s design minimizes or eliminates fracturing.
Alcor has purchased Dr. Wowk’s first prototype and will be testing it for reliability and boiloff. After we have the numbers, we will be able to offer intermediate temperature storage probably as an extra-cost option. We can’t estimate the precise cost at this time, but Alcor News will provide additional updates in the future.
This is the most exciting development in cryonics since the advent of vitrification, and we’re especially pleased by its simplicity. We believe there is an excellent chance that this will become the preferred method of patient care at Alcor.