Aviat Space Envir Md
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Aviat Space Envir Md · Nov 2014
Simulated flying altitude and performance of continuous positive airway pressure devices.
Continuous positive airway pressure (CPAP) is used in air ambulances to treat patients with impaired oxygenation. Differences in mechanical principles between CPAP devices may affect their performance at different ambient air pressures, as will occur in an air ambulance during flight. ⋯ The velocity of airflow through the flow resistor CPAP device is strongly influenced by reduced ambient air pressure, leading to a higher delivered CPAP effect than the preset CPAP level. Threshold resistor CPAP devices seem to have robust performance regardless of altitude. Thus, the threshold resistor CPAP device is probably more appropriate for CPAP treatment in an air ambulance cabin, where ambient pressure will vary during patient transport.
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Aviat Space Envir Md · Nov 2014
A retrospective study of acute mountain sickness on Mt. Kilimanjaro using trekking company data.
High altitude illnesses (HAI) are a risk factor for any individual who is exposed to a significant increase in altitude. To learn more about the epidemiology of HAI, we sought to determine if health records from a commercial trekking company could provide novel data on the prevalence of HAI, as well as efficacy data regarding common HAI therapeutics. ⋯ The prevalence of AMS symptoms was not reduced by taking 2 extra days to reach the summit of Mt. Kilimanjaro. Prophylactic acetazolamide modestly improved oxygen saturation; however, it did not reduce symptoms. Therapeutic dexamethasone, especially at higher altitudes, was effective at reducing symptoms. We conclude that meaningful high altitude physiological data can be obtained from private trekking companies.
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We evaluated ocular outcomes in a 14-d head-down tilt (HDT) bed rest (BR) study designed to simulate the effects of microgravity on the human body. ⋯ A few functional and structural changes were detected after 14-d HDTBR, notably an improved BCVA possibly due to learning effect and RNFL thickening without signs of optic disc edema. In general, 6° HDTBR determined a small nonprogressive IOP elevation, which returned to baseline levels post-BR. Further studies with different BR duration and/or tilt angle are warranted to investigate microgravity-induced ophthalmological changes.
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Aviat Space Envir Md · Oct 2014
United Kingdom military aeromedical evacuation in the post-9/11 era.
Recent UK military operations in support of the fight against terrorism have resulted in UK military casualties. Movement of these casualties through the military medical chain requires a highly sophisticated aeromedical evacuation capability with worldwide reach. Recognition of the determinants of evacuation allows development to ensure optimal future configurations of military aeromedical evacuation services. ⋯ The UK aeromedical evacuation system must have the capacity to evacuate large numbers of patients with nontraumatic diagnoses, but also the flexibility to accommodate smaller, more variable numbers of higher dependency trauma patients. The military medical chain must continually review the differing requirements of civilian patients transferred within their aeromedical system.
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Aviat Space Envir Md · Oct 2014
Case ReportsCentral serous chorioretinopathy following hypobaric chamber exposure.
Hypobaric hypoxic exposures are associated with a number of risks, most notably decompression sickness and various ophthalmologic disorders, including high altitude retinopathy. Central serous chorioretinopathy (CSCR) is an idiopathic condition that typically affects young males and is associated with several comorbidities and medications; however, an association with hypoxia or high altitude has not been identified. We present a case of CSCR in an aviator following a simulated flight in a hypobaric chamber. ⋯ Complaints of visual symptoms immediately following hypobaric exposure should primarily trigger suspicion of decompression sickness; however, once ruled out, patients should be referred to an eye specialist for detailed ocular examination. This case suggests a possible link between CSCR and hypobaric hypoxia as a topic of further investigation.