Proteinuria in fighter pilots after high +Gz exposure

Exposure to high gravitational forces acting along the body axis towards the feet (+Gz) causes considerable strain on several organ systems, including the kidneys. During +Gz tolerance studies without anti-G suits, significant amounts of protein and hyaline casts were found in 17 of 20 fighter pilots after centrifugation. The G load alternated between 3.5 and 5.5 G. Mean time in the centrifuge was 15 min. For comparison we examined another group of 19 fighter pilots after air combat maneuver training with anti-G suits. None showed proteinuria. The proteinuria most likely indicates a severely depressed renal blood flow during centrifugation.     

580例歼击机飞行员的基础+Gz耐力检查结果分析

目的 分析歼击机飞行员的基础+Gz耐力检查结果. 方法 对580例歼击机飞行员的基础+Gz耐力分布、平均+Gz耐力、检查合格率,以及检查结果与年龄、飞行时间的关系进行了分析.基础+Gz耐力的检查在六三型载人离心机上进行,采用SPSS 10.0软件对试验数据进行统计学分析. 结果 该组飞行员的平均基础+Gz耐力为4.26±0.43 G,离心机检查合格率为81.4%.27～31岁年龄组飞行员的合格人数最多,共184人;37～43岁年龄组飞行员的合格率最高,达90.5%.平均+Gz耐力、检查合格率与年龄及飞行时间具有相关性(P＜0.05). 结论 以+4.25 Gz持续10s(+Gz增长率1 G/s)作为基础+Gz耐力合格标准是合理的.通过增加监测飞行员用力情况的措施,可进一步完善检查方法.     

Isometric force production in experienced fighter pilots during +3 Gz centrifuge acceleration

INTRODUCTION: Previously, we have shown that na?ve subjects produce exaggerated isometric forces when exposed to increased acceleration (+Gz) for the first time. The present study investigates whether +G,-experienced PA-200 Tornado pilots show similar deficits. METHODS: Experiments were conducted in the stationary (+1 Gz) or rotating (+3 Gz) gondola of a human-rated centrifuge. With their dominant hand, seven pilots produced visually prescribed forces of specific direction and magnitude using an isometric joystick. In practice trials, subjects received continuous visual feedback about their performance, while in test trials they did not. RESULTS: Peak forces during test trials were significantly higher in +3 Gz than in +1 Gz, although this increase of about 25% referring to the +1 Gz value was somewhat smaller in pilots than in nonpilot controls (increase of about 36%). DISCUSSION: Since pilots' responses were exaggerated in +3 Gz, it seems that frequent exposure to varying +Gz levels is not sufficient for a profound adaptation of force-producing mechanisms to +3 Gz. In consequence, pilots' performance on isometric tasks could be compromised during flight maneuvers in +Gz.     

The effects of +Gz force on the bone mineral density of fighter pilots

HYPOTHESIS: Bone is a metabolically active tissue which responds to high strain loading. The purpose of this study was to examine the bone response to high +Gz force loading generated during high performance flying. METHODS: The bone response to +Gz force loading was monitored in 10 high performance RAAF pilots and 10 gender-, age-, height-, weight-matched control subjects. The pilots were stationed at the RAAF base at Pearce, Western Australia, all completing the 1-yr flight training course. The pilots flew the Pilatus PC-9 aircraft, routinely sustaining between 2.0 and 6.0 +Gz. Bone mineral density (BMD) and bone mineral content (BMC) were measured at baseline and 12 mo, using the Hologic QDR 2000+ bone densitometer. RESULTS: After controlling for change in total body weight and fat mass, the pilots experienced a significant increase in BMD and BMC for thoracic spine, pelvis, and total body, in the magnitude of 11.0%, 4.9%, and 3.7%, respectively. However, no significant changes in bone mineral were observed in the pilots lumbar spine, arms or legs. The control group experienced a significant decrease in pelvic BMC, with no other bone mineral changes observed at any site. CONCLUSIONS: These findings suggest that site specific BMD is increased in response to high +Gz forces generated during high performance flying in a PC-9.     

歼击机飞行员颈椎X线表现调查

目的　探讨高 G加速度对飞行员颈椎可能产生的影响及其临床意义。　方法　对一组正常歼击机飞行员的颈椎 X线摄片分析 ,同样对一组正常地面人员的摄片 ,就常见的异常 X线征像结合临床情况进行讨论分析比较。　结果　飞行员组颈椎“切凹征”的出现率较对照组明显增高 ;颈曲变直、反向或侧弯程度都比对照组要显著 ;颈椎椎间隙狭窄情况两组无明显差异。对照组颈椎既往症状发生率显著增高于飞行员组。　结论　加速度负荷可能是加速颈椎退变主要因素之一 ,但 X线所示的颈椎退行性改变并不一定意味着临床症状的出现 ;飞行员常规保持体育运动对颈椎临床症状的预防具有重要的临床意义。     

战斗机飞行员颈椎退变研究

目的 了解战斗机飞行人员颈椎退变情况。方法对5年前作过MRI检查的战斗机飞行员（甲组,平均年龄47岁,平均累计飞行时间2100h,乙组,平均年龄27岁,平均累计飞行时间830h）。和无飞行经验年龄相仿的对照组人员（丙组）进行复查。结果与5年前MRI结果比较,每组的椎间盘突出数增加,但丙组的骨赘、老飞行员的椎管狭窄数明显增加。与5年前比较,老飞行人员与丙组间的MRI差别降低。结论战斗机飞行员的椎间盘退行性病变的发展可能较早。但是,随着年龄的增加,与对照组的差别逐渐缩小。     

MRI cervical spine findings in asymptomatic fighter pilots

MRI of the cervical spine for evaluation concerning degenerative lesions was performed on asymptomatic experienced military high performance aircraft pilots (mean age 42 yr with mean accumulated flying time of 2600 h), and for comparison on age-matched controls without military flying experience. Young military high performance aircraft pilots (mean age 23 yr with 220 h of flying per person) were also examined. There were significantly more osteophytes, disk protrusions, compressions of the spinal cord and foraminal stenoses in the experienced pilots than in the age-matched controls. Low frequency of low grade degenerative lesions was found in the young and inexperienced pilots.     

Central spinal cord lesions in stenosis of the cervical canal

Summary 34 patients suffering from cervical spondylotic myelopathy confirmed by myelography were examined by delayed CT 6–10 h after myelography. Twelve patients showed bilateral intramedullary collections of contrast medium, predominantly cranial to the stenosis. In these patients males predominated, the duration of clinical symptoms lasted longer although their age was lower. There was no correlation to the degree and the extension of the narrowing of the cervical spinal canal. Half of 20 patients undergoing consecutive decompressive surgery showed intramedullary contrast enhancement, and this was shown again by postoperative MRI in eight. The postoperative clinical and neurophysiological results revealed no change in the majority of patients, but three patients showing intramedullary contrast medium deteriorated in neurophysiological outcome, while only one of the patients in whom intramedullary contrast medium was not noticed got worse.     

歼击机飞行员颈椎X线平片分析

为了解飞行对颈椎的影响，我们自2001年5月至2003年5月，从健康疗养的歼击机飞行员中进行了颈椎X线摄片检查，并与地面无症状人群对照比较，结果如下。     

Upper cervical spinal cord compression due to bony stenosis of the spinal canal

Compression of the upper cervical spinal cord due to stenosis of the bony spinal canal is infrequent. In the first case reported here, stenosis was due to acquired extensive, unilateral osteophytes centered on the left apophyseal joints of C1–C2 in an elderly professional violinist. In the second case, stenosis was secondary to isolated congenital hypertrophy of the laminae of C1 and C2.     

Further aspects of MR-signal enhancements in stenosis of the cervical spinal canal

Summary The validity and anatomical basis of increased MR-signal intensity of the cord in cervical canal stenosis is discussed with respect to our own data of 32 patients (including results of clinical, CSF and other imaging technique findings) and previous reports. A shear-stress hypothesis with edematous tissue changes is favoured.     

歼击机飞行员垂直半规管功能的检测及其特征

目的　建立垂直半规管功能的测量方法 ,对我军部分战斗机飞行员和地面人员的垂直半规管功能进行检测 ,初步确定战斗机飞行员垂直半规管功能的特征。　方法　对 35名男性现役歼击机飞行员和 2 0名地面人员进行检测。在暗室中将受试者在转椅上通过特制头托头后仰 6 0° ,同时头左倾或右倾 4 5°,使两侧前、后垂直半规管分别位于水平面 ,采取 90°/s恒速旋转后急停刺激模式 ,记录旋转后眼震电图 ,分别对两侧前垂直半规管、两侧后垂直半规管受刺激引起的垂直眼震的持续时间、最大慢相速度、慢相速度衰减时间常数及各参数间的两侧不对称比进行计算分析 ,建立垂直半规管功能的测量方法。　结果　同地面人员相比 ,飞行员垂直眼震的最大慢相速度降低 (P <0 0 5 ) ,慢相速度衰减时间常数延长 (P <0 0 5 )。　结论　我军战斗机飞行员垂直眼震功能同地面人员存在一定差别 ,长期飞行对飞行员垂直半规管功能可能产生一定影响。     

Tolerance of +Gz acceleration in pilots with health problems

Fighter pilots with health abnormalities were examined for their tolerance to +Gz acceleration. It was found that pilots with psychoneurological disorders and cardiac arrhythmias showed a lower acceleration tolerance. Pilots with arterial hypertension displayed a markedly higher tolerance as compared to the average pilot population. Other health disturbances produced no effect on +Gz acceleration tolerance.     

飞行员在高+Gz暴露后的肺功能变化

目的 研究不同水平高＋Gz暴露后对人体肺功能的后效应.方法 95名现役男性歼击机飞行员,分别接受＋7 Gz和＋9 Gz离心机检查,于＋Gz暴露前1 d和暴露后12～65 min内测定肺容量、肺通气功能和弥散功能指标.结果 ＋7 Gz暴露后,飞行员肺弥散功能减退和轻度小气道功能异常,＋9 Gz暴露后程度加重,并出现肺活量降低.但＋7 Gz和＋9 Gz之间,各项指标无明显差异.结论 高G暴露可导致小气道功能和弥散功能减低的后效应,其持续时间和对飞行员肺功能有无长期影响有待进一步研究.     

Chiari-I malformation in two fighter pilots

This report describes two cases of Chiari Malformation Type I (Chiari-I) in fighter pilots of the Turkish Air Force. Chiari-I is a congenital malformation characterized by herniation of cerebellar tonsils through the foramen magnum. Patients have symptoms and signs related to dysfunction of the brainstem, spinal cord, and cerebellum. They generally are symptomatic in the earlier years of life. However, asymptomatic cases can eventually become symptomatic in later years. Symptoms can be provoked by increasing intracranial pressure (Valsalva or straining). We report on two pilots with Chiari-I malformation who had no symptoms or signs in their daily activities. Furthermore, these pilots had successfully completed physiological training, including centrifuge training, without any symptoms. However, they suffered from headache, neck spasms, and/or disequilibrium under +Gz during flight training sorties. The clinical presentation, diagnosis, treatment, possibility of acquired cases, and aeromedical disposition of Chiari malformations are discussed.     

不同水平+GZ暴露后飞行员心脏功能的变化

目的　研究不同水平 Gz 暴露及高G训练对人体心脏功能的后效应。　方法　 2 4名歼击机飞行员接受基础 Gz 耐力测查 (最高暴露于 4 2 5～ 4 5Gz)、 7 0Gz 或 8 0Gz 高G训练 ,观察 Gz 暴露后 2h心电图、心脏彩超和次日心肌酶 (AST、LDH、CK)的变化。　结果　接受基础 Gz 耐力测查和 7 0Gz 高G训练后 2h的心电图无明显变化。心脏彩超检查示 :基础 Gz 耐力测查后 2h ,升主动脉和肺动脉主干内径、左心房和右心房内径、右心室内径、左心室舒张末内径、左心室短轴缩短率均减小 (P <0 0 5或P <0 0 1 ) ;采取抗荷措施进行 7 0Gz 高G训练后 2h ,这种变化无明显加重或有减轻趋势。左心室舒张末内径差值、收缩末内径差值和射血分数 Gz 暴露后无明显变化。接受 8 0Gz高G训练后次日 ,血液中心肌酶无明显升高。　结论　较高水平的 Gz 暴露可在短时间内对心脏收缩和舒张功能造成轻度不利影响 ,但左心室泵血功能和心电图无明显变化。在高G训练中采取抗荷措施对心脏功能具有保护作用     

超声检查飞行员反复正加速度暴露后心脏功能的变化

目的观察中等强度反复正加速度( Gz)暴露是否会对飞行员心脏功能产生不利影响。方法38名歼击机飞行员接受离心机检查, Gz暴露峰值从 2.5Gz/10s开始。通过后,每次再递增 0.5Gz~ 1.0Gz,达到最高加速度暴露强度 4.5Gz/10s后结束检查。观察飞行员 Gz暴露前后心脏超声多项心功能指标的变化。结果飞行员 Gz暴露后2~4h,左室射血分数(EF)、短轴缩短率(ΔD)、主动脉血流速度、肺动脉血流速度和二尖瓣E峰速度,以及左心房收缩末前后径、左心室收缩末前后径、左右径和左心室舒张末左右径与暴露前比较变化不明显(P>0.05)。二尖瓣A峰速度轻度增加(P<0.01),左心室舒张末前后径和E/A峰速比值有所减小(P<0.05)。其中12名飞行员 Gz暴露后24h,EF、ΔD和二尖瓣A峰速度较暴露前轻度增加(P<0.05),E/A峰速比值仍有所减小(P<0.05)。结论中等强度反复 Gz暴露对飞行员心脏收缩功能无明显影响,但对心脏舒张晚期功能可造成暂时轻度不利影响,24h后趋向恢复,提示应重视 Gz暴露后飞行员心脏功能的保护。