Aviat Space Envir Md
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Aviat Space Envir Md · Feb 2008
Trait anxiety and salivary cortisol during free living and military stress.
Accumulating evidence suggests that negative affect is associated with elevated cortisol. Limited research has investigated this association in young, highly functioning, and stress-resilient populations. ⋯ These findings suggest that trait anxiety influences the diurnal cortisol pattern in young, apparently healthy men during free-living conditions, but does not predict the cortisol response to uncontrollable military stress.
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Aviat Space Envir Md · Feb 2008
Profound hypoxemia in pulmonary patients in airline-equivalent hypoxia: roles of VA/Q and shunt.
Airliners at cruise altitudes have cabin pressures of 84.3-75.2 kPa, equivalent to 5000-8000 ft. Supplementary oxygen in flight is generally advised for patients whose ground-level arterial oxygen saturation by pulse oximetry (SpO2) is < 92%. However, some pulmonary patients with values above that threshold nevertheless develop profound in-flight hypoxemia (SpO2 < or = 82%) as cabin pressure falls. This experiment measured the contributions of ventilation-perfusion ratio (VA/Q) and pulmonary shunt to that phenomenon. ⋯ In patients with similar ground-level SpO2, profound hypoxemia was more likely to develop in those with reduced VA/Q (< or = 0.69) as opposed to those with shunts of 20%. Measurement of VA/Q and shunt during hypoxic hypoxia improves prediction of patient need for supplementary oxygen on airline flights.