Rewarming hypothermic piglets with 915 MHz microwave radiation

Microwave radiation (MWR), with its ability to penetrate tissue, can provide an efficient means of generating heat within the body. A first trial determined a safe and efficient rate of rewarming using a 915 MHz microwave (MW) unit. Hypothermia was induced in 46 neonatal piglets. Their rectal temperatures were reduced to 25$\sp\circ$C. Piglets were randomly assigned to be rewarmed at the rate of 0.5, 0.75, or 1.0$\sp\circ$C min$\sp{-1}$ using 915 MHz MWR. After being rewarmed to 38$\sp\circ$C, the piglets were returned to the sow and allowed to suckle. It was concluded that the rewarming rate of 1.0$\sp\circ$C min$\sp{-1}$ was the most time efficient and provided a safe and effective treatment for hypothermic piglets. A second trial compared rewarming of hypothermic piglets with MWR vs. infrared radiation (IRR). It was concluded that 915 MHz MW rewarming is a safe and more efficient method for rewarming hypothermic piglets than using the conventional IR lamp. The third trial was performed to evaluate the short-term biological effects following the established rewarming procedures. Blood samples were taken from 16 experimental piglets at birth, after cooling, after rewarming, and at sacrifice. Neither plasma cortisol or glucose levels showed significant differences ($P >$ 0.05) between treatments at any of the four sampling times. However, differences were significant ($P <$ 0.05) within treatments between times. Rewarming treatment did not influence liver glucose or glycogen levels. The percentage are of the adrenal gland zones showed no significant difference ($P <$ 0.05) between treatment groups. It was concluded that rewarming hypothermic piglets with 915 MHz MWR does not appear to cause any detrimental effects to these variables assessed. (Abstract shortened by UMI.).