Jersey Sean L, Hundemer Gregory L, Stuart Rory P, West Kelly N, Michaelson Robert S, Pilmanis Andrew A
David Grant USAF Medical Center, 60 MDTS/SGQX, 101 Bodin Circle, Travis AFB, CA 94535, USA.
Aviat Space Environ Med. 2011 Jul;82(7):673-82. doi: 10.3357/asem.2851.2011.
Compared to the previous 47 yr, U-2 pilots reported an increased number of altitude decompression sickness (DCS) incidents with central nervous system (CNS) manifestations during 2002-2009. Due to increasing incident severity during military operations, the U.S. Air Force initiated an investigation to prevent future mishaps.
We retrospectively examined all neurological DCS cases observed among U-2 pilots during 2002-2009. Urgency to prevent further pilot losses limited this study to using existing, often incomplete data sources.
During 2002-2009, 16 confirmed incidents of CNS DCS occurred with 13 pilots, plus 4 possible incidents with 4 pilots. Significantly, 12 of 16 confirmed incidents occurred at 1 operating location, including 4 of 5 life-threatening cases. This series of cases were of a type and severity rarely found in flight operations and correlated temporally with increased sortie frequency/duration associated with combat operations. Multiple investigations confirmed no defects in aircraft, support equipment, or oxygen supplies. Nor were significant trends observed with age, habitus, environmental exposure, medication use, or cardiac defects. In 11 cases, symptom recognition occurred well after the 4-h point where clinical experience indicated risk should stabilize. Symptoms also recurred days later and responded to repeat hyperbaric oxygen therapy in three of four cases. Finally, neuropsychiatric symptoms persisted in six pilots for years and may represent permanent injury.
An increase in U-2 CNS DCS cases probably resulted from more cockpit activity combined with longer, more frequent high-altitude exposures. Adjustments in preoxygenation, cabin altitude, exercise at altitude, and frequency of flights may reduce incidence.
与此前的47年相比，U - 2飞行员报告在2002年至2009年期间出现中枢神经系统（CNS）表现的高空减压病（DCS）事件有所增加。由于军事行动中事件严重程度不断上升，美国空军展开了一项调查以预防未来的事故。
我们回顾性研究了2002年至2009年期间在U - 2飞行员中观察到的所有神经型DCS病例。防止进一步飞行员损失的紧迫性使本研究限于使用现有的、通常不完整的数据源。
在2002年至2009年期间，13名飞行员发生了16起确诊的中枢神经系统DCS事件，另有4名飞行员发生了4起可能的事件。值得注意的是，16起确诊事件中有12起发生在1个作业地点，包括5起危及生命的病例中的4起。这一系列病例的类型和严重程度在飞行作业中很少见，并且在时间上与作战行动相关的 sortie频率/持续时间增加相关。多次调查证实飞机、支持设备或氧气供应没有缺陷。在年龄、体型、环境暴露、药物使用或心脏缺陷方面也未观察到显著趋势。在11例病例中，症状识别在4小时时间点之后很久才出现，而临床经验表明风险在此时间点应已稳定。症状也在数天后复发，4例中有3例对重复高压氧治疗有反应。最后，6名飞行员的神经精神症状持续了数年，可能代表永久性损伤。
U - 2中枢神经系统DCS病例增加可能是由于驾驶舱活动增多以及高空暴露时间更长、频率更高。调整预充氧、座舱高度、高空运动和飞行频率可能会降低发病率。
