Aviat Space Envir Md
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Aviat Space Envir Md · Apr 2006
Controlled Clinical TrialCranial-neck and inhalation rewarming failed to improve recovery from mild hypothermia.
Rewarming from hypothermia in a field setting is a challenge due to the typical lack of significant power or heat source, making the targeted application of available heat critical. The highly vascular area of the head and neck may allow heat to be rapidly transferred to the core via blood circulation. At the same time, the warming of only a small skin surface may minimize the rapid rise in skin temperature proposed to attenuate shivering and endogenous heat production. Therefore, we investigated the efficacy of targeting the head and neck for rewarming from mild hypothermia. ⋯ In summary, neither cranial-neck nor cranial-neck and inhalation rewarming combined have an advantage in reducing the magnitude and duration of after-drop or increasing the rewarming rate over passive rewarming.
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Aviat Space Envir Md · Feb 2006
Controlled Clinical TrialCardio-respiratory responses evoked by transient linear acceleration.
Predictive control of the responses to re-orientating stimuli and its interaction with vestibular signals may be an important factor in protecting against spatial disorientation. Here we evaluated the influence of stimulus predictability on the cardio-respiratory responses to transient fore-aft linear accelerations. ⋯ A vestibulo-cardiac response is evoked by transient linear acceleration, independently from the phase of the breathing cycle and from the predictability of the stimulus. A vestibular signal of motion appears to be required to produce a prolonged increase in heart rate.
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Aviat Space Envir Md · Feb 2006
Randomized Controlled TrialCerebral blood flow velocity and psychomotor performance during acute hypoxia.
The physiological effects of hypoxic environments can help determine safe limits for workers where cognitive and motor performance is important. We investigated the effects of a PIO2 of 15 kPa and 10 kPa on medial cerebral artery blood flow velocity (CBFV) and psychomotor performance. ⋯ A PIo2 of 15 kPa did not affect subject performance, and should not cause operational risk. At 10 kPa PIO2, accuracy and vigilance were slightly affected; however, the reduction in oxygenation was not great enough to cause major decrements. CBFV was not a good indicator of mental stress during hypoxia.
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Aviat Space Envir Md · Jan 2006
Hearing in military pilots: one-time audiometry in pilots of fighters, transports, and helicopters.
Pilots are exposed to potentially harmful levels of noise, the actual consequences of which are still poorly documented. We have determined the audiometric profiles of pilots as a function of age and type of aircraft (i.e., fighter, transport, helicopter) and have searched for risk factors of deafness other than noise in a pilot population. ⋯ Pilots flying fighter and helicopter aircraft are at a higher risk of hearing loss compared with pilots flying transport aircraft. Improvements in ear protection seem particularly needed for the left ear. Hearing losses can potentially compromise speech communication in helicopter pilots.