Aviat Space Envir Md
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Aviat Space Envir Md · Aug 2008
Hypercapnia effect on core cooling and shivering threshold during snow burial.
Hypercapnia during avalanche burial may increase core temperature cooling rate by decreasing the temperature threshold for shivering or by increasing respiratory heat loss. ⋯ Hypercapnia significantly increased T(re) cooling rate by increasing respiratory heat loss but did not suppress shivering. Afterdrop may significantly contribute to hypothermia during rescue of avalanche burial victims.
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Aviat Space Envir Md · Aug 2008
Inspiratory impedance threshold device effects on hypotension in heat-stroked swine.
Heat stroke is still an epidemiologically relevant disease with overall mortality rates as high as 15-33%. In heat stroke, hypotension is caused by relative central hypovolemia. We performed a feasibility study to determine if an inspiratory impedance threshold valve (ITDTM) set to open at -12 cm H2O would reverse systemic hypotension by enhancing venous return in hyperthermic, hypotensive, but spontaneously breathing animals. ⋯ Use of an inspiratory impedance threshold device resulted in an immediate rise in blood pressure in animals in heat stroke and preserved blood pressure for at least 20 min prior to cooling and fluid replacement.
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Aviat Space Envir Md · Aug 2008
Blood platelet count and severity of decompression sickness in rats after a provocative dive.
Previous animal studies reported that platelet count (PC) is decreased following decompression. Adherence and aggregation of platelets to the bubble surface has been demonstrated in severe decompression sickness (DCS). The present study was designed to clarify the relationship between post-dive platelet levels and the severity of DCS in a rat model. ⋯ The present study highlighted a relationship between the post-dive decrease in PC and DCS severity in rats. Platelet consumption could offer a new index for evaluating decompression stress.
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Aviat Space Envir Md · Jul 2008
Comparative StudyNauseogenicity of off-vertical axis rotation vs. equivalent visual motion.
Off-vertical axis rotation (OVAR) provokes motion sickness. The visual motion equivalent to OVAR in simulators is also nauseogenic. Our experiment compared the nauseogenicity of OVAR vs. visual motion. ⋯ OVAR was twice as nauseogenic as visual motion. Headache during visual motion suggests mechanisms in common with migraine. We hypothesize that subjects who fared better in the light used visual cues to resolve sensory conflict, whereas subjects who were equally susceptible in light and dark made poor use of visual cues; perhaps a form of 'field dependency'. This may explain why some people prefer 'a view of the road ahead' to help against motion sickness whereas others shut their eyes.
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Aviat Space Envir Md · May 2008
Historical ArticleThis month in aerospace medicine history--May 2008.