Document Type
Thesis
Date of Award
5-31-1989
Degree Name
Master of Science in Biomedical Engineering - (M.S.)
Department
Biomedical Engineering Committee
First Advisor
Peter Engler
Second Advisor
David S. Kristol
Third Advisor
Stanley S. Reisman
Abstract
In search for a more effective treatment for rewarming of profound accidental hypothermia, a comparative survival rate study was conducted of intrashock versus postshock microwave rewarming in rats subjected to hemorrhagic shock. In an anechoic chamber, rats were illuminated with 50 Watts of continuous microwave power supplied by a 915 MHz microwave generator. This frequency corresponds to a free-space wavelength of about 33 cm. The incident-power density was calculated to be about 8.5 mW/cm2, and the whole-body specific absorption rate (SAR) was calculated to be 14.5 W/kg.
The microwave postshock group showed a significantly higher post shock survival rate than the microwave intrashock group (P<0.001, Fischer's exact test) or the control group (P<0.001, Fischer's exact test). Each group consisted of 10 animals. From the microwave postshock group, 30 % of the animals survived for more than 72 hrs post shock. The microwave intrashock group had no long-term survivors (>72 hrs post shock), and only 10 % of the animals in the control group (allowed to maintain their own body temperatures without any external intervention) survived hemorrhagic shock. This significantly higher survival rate in the microwave postshock group indicates a clinical potential for utilizing microwave energy for active rewarming of profound accidental hypothermia victims.
The high mortality rate of the microwave intrashock group confirms the premature vasodilation phenomenon. It is believed that intrashock rewarming is detrimental to long-term survival of the laboratory animals. It is suggested that animals should be allowed to autoregulate their own body temperatures during shock, and that rewarming techniques should be restricted to the post shock period.
The pattern of core temperature increases in the two experimental groups strongly suggests the presence of centrally located thermal receptors elsewhere in the body than just the hypothalamus.
Recommended Citation
Patel, Hani M., "Survival rate study of intrashock versus postshock microwave rewarming in rats subjected to hemorrhagic shock" (1989). Theses. 2863.
https://digitalcommons.njit.edu/theses/2863
