Freezing Times, Rewarming Times, and Lowest Temperatures in Experimental Frostbite of Hanford Miniature Swine

摘要

Frostbite was produced in the skin of five Hanford Miniature Swine exposed to chilled air (-75 C) for 1, 3, 5, 10, or 20 minutes. A hypodermic probe with a copper-constantan thermocouple was inserted into the skin to monitor the temperature. Average freezing time - the time to reach 0 C or lower - was approximately 2 minutes. The average lowest temperature for 1 minute freezes ranged from -8.3 to -9.2 C and for the 3 minute freezes ranged from -13.0 to -18.2 C. Excluding pig 5, the 5, 10, and 20 minute freezes had a smaller range, from -18.9 to -24.3. Average rewarming times were shortest for 1 minute freezes and longest for 20 minute freezes. The ranges within freezes were minimal: 2.8- 3.8, 4.0-4.9, 5.0-6.3, 6.2-7.2, and 7.6-8.9 minutes (+ .5 min.) for the 1, 3, 5, 10, and 20 minute freezes respectively.