Aviat Space Envir Md
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High altitude (HA) living produces physiological changes for adaptation to chronic hypobaric-hypoxemic conditions. Although much is known about these physiologic adaptations, no clear separation has been made regarding what is "native" or "genetic" adaptation and what is "acquired." In this review, we describe the genetic vs. acquired adaptation and only include studies performed in a population native to HA and not in an acclimatized population or trekkers. The changes encountered in animals and humans living at HA in terms of hematology, muscular, respiratory, cerebral, cardiovascular, hormonal, fluid and electrolytes and reproduction, strongly suggest that genetics play a very important role in HA adaptation. ⋯ Once the parameters are established, we can compare non-native populations exposed to HA that must emulate the HA physiology for a definite adaptation to be present. With measurable parameters, especially in the management of fluids and electrolytes, we can define how long it will take for a sea level native to adapt to an HA altitude. Until these studies are performed, speculation will continue and no rational medical intervention can be offered to HA newcomers who may experience HA difficulties.
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As we move into the next Millennium, increasing numbers of people will travel into space. Psychological screening methods will be relaxed on near-Earth missions, such as might occur on a space station or a lunar colony. Crewmembers on interplanetary missions such as a trip to Mars will have to deal with psychiatric problems themselves with no possibility of evacuating an affected individual. For these reasons, it is important for support personnel on Earth and crewmembers in space to be knowledgeable about psychiatric difficulties that might occur and their appropriate treatments. ⋯ Although much is known about psychiatric issues related to long duration manned space travel, more empirical work needs to be done during actual space missions.
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Exercise performance data of numerous altitude research studies and competitive sporting events of the last four decades are reviewed. ⋯ By assessing the performance of elite athletes, who are performing at an "all-out" effort in precisely timed events for which they are trained, it is determined that: a) the magnitude of submaximal exercise impairment is proportional to both the elevation and exercise duration at a given altitude; and b) submaximal exercise performance at altitude can improve with continued exposure without an increase in VO2max. Muscle strength, maximal muscle power, and anaerobic performance at altitude are not affected as long as muscle mass is maintained. In addition, performance is not impaired in athletic activities that have a minimal aerobic component and can be performed at high velocity (e.g., sprints).
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Aviat Space Envir Md · Dec 1995
Review Comparative StudyConvulsive syncope in the aviation environment.
Syncope in the aviation environment can be a very difficult problem to assess. Even more difficult is the differential diagnosis between convulsive syncope and epilepsy after the first event. This paper discusses syncope in general and the differential diagnosis between vasovagal syncope and other forms of syncope. ⋯ The other 35% are due to a variety of causes. We found no good algorithm to differentiate convulsive syncope from epilepsy. We reviewed the literature to develop a differential diagnostic table, focusing on: age, awake status, position, emotional/physiologic stressors, onset, aura, appearance, injury on falling, seizure characteristics, automatism, length of unconsciousness and subsequent confusion, pulse characteristics, blood pressure, urinary incontinence, seizure duration, recovery time post-event, post-seizure sequelae, amnesia, posture vs. recovery, EEG characteristics, and the value of sophisticated diagnostic procedures.
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Aviat Space Envir Md · Oct 1995
ReviewIncreased flight surgeon role in military aeromedical evacuation.
Physicians were involved in the development of aeromedical evacuation (medevac) and flight surgeons flew as crewmembers on the first U.S. military medevac flights. However, since World War II flight surgeons have not been routinely assigned to operational medevac units. The aeromedical literature addressing the role of physicians in medevac is controversial. Recent contingencies involving the U.S. Air Force (USAF) have required the augmentation of medevac units with flight surgeons. ⋯ Dedicated medevac flight surgeons fill a unique and valuable role in medevac systems. Agencies with medevac units should consider assigning flight surgeons to these units.