New O.R. Table – 80L H20 Cooldown Test with Blanket

Based on our findings last month that the mylar cooldown blanket significantly reduced the LN2 usage of our automated perfusion and cooldown table with an empty patient pod, Steve Graber decided to conduct a more rigorous cooldown test utilizing four 20L water bladders in the pod cavity and a target cooling temperature of -80C. Note that this test was initiated with H2O at room temperature and is in no way intended to accurately convey an actual patient cooldown scenario. Steve filled all four bladders with room temperature H2O and placed them into the table. Each bladder weighed approximately 20Kg. He inserted thermocouples into the head and leg bladders via their fill tubes and located the probes approximately within the center of each bladder. The torso area comprised two stacked bladders with a single thermocouple probe sandwiched between them.

The table was connected to the Cooldown computer system and the initialization file was modified to perform only cooldown functions. The test was started with both atmospheric and cold stages set to exactly -80C and the mylar blanket in place and was cooled sequentially with two LR-40 dewars. The data collection continued for an additional day to record the warmup segment. A quick review of the test data showed that the table was not cooling evenly from end to end and needed some tuning to correct this. For this reason the table was designed to allow tuning corrections.

The photo above displays the table at hour number 5 running at -80C. The interior is LED lighting.