Millenbaugh Nancy J, Kiel Johnathan L, Ryan Kathy L, Blystone Robert V, Kalns John E, Brott Becky J, Cerna Cesario Z, Lawrence William S, Soza Laura L, Mason Patrick A
General Dynamics, San Antonio, TX 78235, USA.
Shock. 2006 Jun;25(6):625-32. doi: 10.1097/01.shk.0000209550.11087.fd.
Electromagnetic fields at millimeter wave lengths are being developed for commercial and military use at power levels that can cause temperature increases in the skin. Previous work suggests that sustained exposure to millimeter waves causes greater heating of skin, leading to faster induction of circulatory failure than exposure to environmental heat (EH). We tested this hypothesis in three separate experiments by comparing temperature changes in skin, subcutis, and colon, and the time to reach circulatory collapse (mean arterial blood pressure, 20 mmHg) in male Sprague-Dawley rats exposed to the following conditions that produced similar rates of body core heating within each experiment: (1) EH at 42 degrees C, 35 GHz at 75 mW/cm, or 94 GHz at 75 mW/cm under ketamine and xylazine anesthesia; (2) EH at 43 degrees C, 35 GHz at 90 mW/cm, or 94 GHz at 90 mW/cm under ketamine and xylazine anesthesia; and (3) EH at 42 degrees C, 35 GHz at 90 mW/cm, or 94 GHz at 75 mW/cm under isoflurane anesthesia. In all three experiments, the rate and amount of temperature increase at the subcutis and skin surface differed significantly in the rank order of 94 GHz more than 35 GHz more than EH. The time to reach circulatory collapse was significantly less only for rats exposed to 94 GHz at 90 mW/cm, the group with the greatest rate of skin and subcutis heating of all groups in this study, compared with both the 35 GHz at 90 mW/cm and the EH at 43 degrees C groups. These data indicate that body core heating is the major determinant of induction of hemodynamic collapse, and the influence of heating of the skin and subcutis becomes significant only when a certain threshold rate of heating of these tissues is exceeded.
毫米波波长的电磁场正被开发用于商业和军事用途，其功率水平可导致皮肤温度升高。先前的研究表明，持续暴露于毫米波会使皮肤产生更大程度的发热，导致循环衰竭的诱导速度比暴露于环境热（EH）更快。我们通过比较雄性Sprague-Dawley大鼠在以下条件下皮肤、皮下组织和结肠的温度变化，以及达到循环衰竭（平均动脉血压，20 mmHg）的时间，在三个独立实验中验证了这一假设。在每个实验中，这些条件会使体核产生相似的发热速率：（1）在氯胺酮和赛拉嗪麻醉下，42摄氏度的环境热、75 mW/cm的35 GHz毫米波或75 mW/cm的94 GHz毫米波；（2）在氯胺酮和赛拉嗪麻醉下，43摄氏度的环境热、90 mW/cm的35 GHz毫米波或90 mW/cm的94 GHz毫米波；以及（3）在异氟烷麻醉下，42摄氏度的环境热、90 mW/cm的35 GHz毫米波或75 mW/cm的94 GHz毫米波。在所有三个实验中，皮下组织和皮肤表面温度升高的速率和幅度在排序上存在显著差异，顺序为94 GHz大于35 GHz大于环境热。与90 mW/cm的35 GHz组和43摄氏度的环境热组相比，仅在暴露于90 mW/cm的94 GHz的大鼠中，达到循环衰竭的时间显著更短，该组是本研究中所有组中皮肤和皮下组织发热速率最高的组。这些数据表明，体核发热是诱导血流动力学衰竭的主要决定因素，只有当这些组织的发热速率超过一定阈值时，皮肤和皮下组织发热的影响才会变得显著。
