Aviat Space Envir Md
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Aviat Space Envir Md · Nov 2013
Randomized Controlled TrialCognition at altitude: impairment in executive and memory processes under hypoxic conditions.
The negative effect of hypoxia on cognitive function has been well described. However, less has been published regarding cognitive dysfunction resulting from hypoxia produced by exposure to different altitudes. ⋯ The results of this study suggest that electronic versions of these tests may be useful in screening for acute symptoms of hypoxia and could provide insight into how discrete cognitive processes become impaired with oxygen deprivation at various altitudes. Given that these tests also assess neuropsychological functioning, our results allow for inferences to be made about the effects of hypoxia on human brain functioning.
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Aviat Space Envir Md · Oct 2013
Suction-modified needle biopsy technique for the human soleus muscle.
The needle biopsy technique for the soleus muscle is of particular interest because of the muscle's unique fiber type distribution, contractile properties, and sensitivity to unloading. Unlike other commonly biopsied muscles, the soleus is not fully superficial and is in close proximity to neurovascular structures, resulting in a more challenging biopsy. Because of this, a standardized protocol for performing needle biopsies on the human soleus muscle that is safe, reliable, and repeatable is presented. ⋯ The procedure presented consists of a detailed protocol to accurately and consistently obtain muscle biopsy samples from the human soleus muscle. We have demonstrated that the human soleus biopsy is a safe, reliable, and repeatable procedure providing ample tissue for multiple types of analyses.
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Aviat Space Envir Md · Sep 2013
Intracranial pressure and optic nerve sheath diameter as cephalic venous pressure increases in swine.
Nontraumatic, nonhydrocephalic increases in intracranial pressure (ICP) are often difficult to diagnose and may underlie spaceflight-related visual changes. This study looked at the utility of a porcine animal model of increasing cephalic venous pressure to mimic acute changes in ICP and optic nerve sheath diameter (ONSD) from cephalic venous fluid shifts observed during spaceflight. ⋯ Increases in SVCP result in ICP changes that are well correlated with alteration in ONSD. These changes are consistent with observed ONSD changes monitored during spaceflight.
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Aviat Space Envir Md · Sep 2013
Sensorineural hearing loss incidence among U.S. military aviators between 1997 and 2011.
Noise-induced hearing loss is the most common cause of sensorineural hearing loss (SNHL) in military aviation. Few published studies compare SNHL rates between fixed and rotary-wing military pilots. The study's objective was to determine whether a difference in mean annual SNHL incidence rate exists between fixed and rotary wing aviators in the U.S. Army, Navy, Air Force, and Marines. ⋯ The average annual incidence rate of SNHL between 1997-2011 was higher for fixed than for rotary-wing aviators, and higher for U.S. Army and Air Force than Navy and Marine aviators. An examination of hearing conservation programs and engineering controls may be warranted.
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The major causes of in-flight fatal incapacitation in civil pilots are acute coronary events, new onset idiopathic epilepsy, and physiological problems. Less than 1% of all air accidents are due to sudden incapacitaion. The problem with acute coronary disease is very serious when occurring during critical stages of the flight, such as takeoff or landing, rather than during the cruising phase. ⋯ The normal aorta contains collagen, elastin, and smooth muscle cells that form the vessel wall. Degenerative changes lead to breakdown of the collagen, elastin, and smooth muscle, and an increase in basophillic ground substance with the formation of cysts and accumulation of mucopolysaccharide. Medical incapacitation in the cockpit is rare. The leading causes of fatal in-flight incapacitation are myocardial infarction, cardiac arrhythmias, and epileptic seizures; cystic medial necrosis is very rare and no similar cases were found in the aviation literature.