Essential thrombocytosis and myocardial infarction in an aircrew member: aeromedical concerns

Of essential thrombocytosis (ET) cases, 25% occur in patients younger than 40 yr of age, and are often discovered as an incidental laboratory abnormality. However, the risk for thrombosis remains of concern and needs to be closely evaluated, especially in the aerospace environment. We report on the case of a 40-yr-old, female French military air traffic controller (ATC) admitted for an ST-elevation myocardial infarction. She was a smoker and had no previous medical history of ET. The coronary angiogram showed a thrombus of the left anterior descending coronary artery. She was treated medically with angioplasty and stent. Laboratory data revealed an elevated platelet count (495,000 x mm(-3)), confirmed 6 mo later (645,000 x mm(-3)). The diagnosis of ET was then established. No platelet-lowering therapy was prescribed, aspirin was continued, and this ATC was considered unfit for operational duties. Arterial thrombosis is more frequent than venous in ET, and can affect the whole arterial tree from the microscopic to the main arteries. Thrombosis is unpredictable and, due to abnormalities of the platelet functions and associated cardiovascular risk cofactors, may occur even with an almost normal platelet count. Risk-adjusted therapy is needed, including lifestyle modification to address vascular risk factors, antiplatelet drugs (aspirin), and platelet-lowering agents with their risk of leukomutagenesis. Furthermore, there is no consensus for the prevention of venous thrombosis. The decision for the aeromedical expert is difficult and depends on the specialty of the aircrew member, the type and duration of the mission, the therapeutics used, and the benefit-risk ratio of platelet-lowering agents.     

Transcatheter PFO closure in an aircrew member with cryptogenic stroke: aeromedical disposition

Stroke is an uncommon event among military aircrew, partly because that population tends to be younger and healthier than typical stroke victims. Aircrew members suffering stroke rarely have identifiable risk factors or etiology that can be treated or modified such that return to flying duties is a consideration. In this case, an aircrew member was found to have a patent foramen ovale (PFO) during his stroke evaluation. Several studies support the association between PFO and cryptogenic stroke, but literature clearly defining the need for PFO repair in the context of cryptogenic stroke is still incomplete. On clinical recommendation from his providers, this aircrew member underwent elective closure of his PFO with a transcatheter device. After complete recovery from his stroke and an apparently successful PFO closure, he requested return to flying duties. History of stroke and PFO closure with transcatheter device were both disqualifying conditions according to United States Air Force Instructions. This case is presented as an example of an aeromedical decision-making process when confronted with an unusual case such as this.     

The maintenance of wakefulness test as a predictor of alertness in aircrew members with idiopathic hypersomnia

Aviators are required to maintain a high level of alertness during their missions. Two conditions that may disrupt this alertness are fatigue and hypersomnia. Fatigue is a physiological state, while hypersomnia is a pathologic state, also termed excessive daytime sleepiness (EDS), which is manifested by the tendency to fall asleep in inappropriate places or situations, such as during flight or driving. Hypersomnolence may be diagnosed by subjective measurements, such as the Epworth sleepiness scale, but the diagnosis is established by two objective tests: the Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT). The first consists of four 20-min sessions used to determine the time it takes the patient to fall asleep when given the opportunity and is considered positive when the sleep latency time is shorter than 5 min, although some authors use 8 min as the cut-off for the diagnosis. The Maintenance of Wakefulness Test (MWT) consists of four 40-min sessions during which the patient attempts to maintain wakefulness while seated in a dark, quiet room during the day. Herein we report 2 cases of aviators who were returned to flying duty despite a pathologic MSLT. These aviators were waivered based on a normal MWT and safety history obtained from their commanders.     

High +Gz induced acute inguinal herniation in an F-16 aircrew member: case report and review

This paper describes previously unreported, acute inguinal herniation during high +Gz air combat maneuvers. The flight surgeon aircrew member involved incorrectly analyzed the etiology of the abdominal wall discomfort during and immediately after the mission. Several factors contributed to the delayed diagnosis. Surgical exploration and repair revealed larger than expected defects. An open, anterior "tension-free" repair using polypropylene mesh grafts adequately reinforced the muscular and fascial defects. Return to full flight status occurred 4 wk following surgery. Post-operatively, repeat exposures to both a high +Gz flight environment and exertionally induced increased intra-abdominal pressures were well tolerated. Minimal sequelae from the injury and repair resolved within 1 yr of the surgery and did not affect mission capability or lifestyle activities. This article includes a review of hernia repairs and their aeromedical implications, with a discussion of epidemiology, surgical techniques, risk factors, surgical complications and recovery times for return to full activity.     

Hyperventilation in aircrew: a review.

The causes and effects of hyperventilation, relevant to the flight environment, have been reviewed and one case history is presented. Methods of investigating in-flight hyperventilation are discussed.     

一起飞行事故的医疗救治

一、一般资料 1.事故经过:某部队执行某次飞行任务中,1架飞机在返回着陆时发生事故.1名机组人员牺牲,其余5名成功救治.     

The use of EEG in aircrew selection.

The value of the electroencephalograph (EEG) as a screening device in aviation medicine is questioned, because few subjects are disqualified on grounds of an EEG exam. At the Netherlands Aeromedical Institute, pilot applicants are rejected with a diagnosis of epilepsy or with severe EEG abnormalities (including epileptiform patterns where epilepsy is highly suspected). Although several studies have shown a low incidence of epileptiform EEG abnormalities in candidate pilots, subjects with an epileptiform EEG have a substantially increased risk of sudden incapacitation during their flying careers. In this review, we calculate the probability that a candidate with epileptiform EEG, but no history of epileptic seizures, will develop seizures during his flying career. This probability is about 25%, more than 12 times higher than for subjects with normal EEG and no history of epileptic seizures (2%). Subjects with epileptiform EEGs not only have increased risk of future epileptic seizures, but additionally it is recognized that epileptiform EEG discharges may be associated with episodic functional impairment, which can be a danger when a subject is flying. Taking this into account, one should consider rejecting all candidates with epileptiform EEGs in the future. This is at the expense of a small group of subjects with false-positive EEGs, but we believe that concern for public safety must override other considerations in these rare cases. To improve the understanding of the usefulness of the EEG in pilot screening procedures, an international classification and coding system should be developed, so that data from different countries can be compared.     

Low back pain in Norwegian helicopter aircrew

The size and consequences of low back pain (LBP) in Norwegian helicopter aircrew has been investigated in a retrospective and prospective survey. With 50.5% reporting such pain in a 2-yr period, and Sea King aircrew reporting LBP on on almost half (49.3%) of the missions flown, the magnitude of the problem equals that reported from other air forces. Pilots reported LBP six times more often than other crewmembers and almost half (48.6%) felt the pain influenced the quality of work. This could have flight safety implications. Crewmembers with total flying time over 2,000 h have a significantly higher incidence of sick leave than those with less than 2,000 h. Only 1 pilot out of 10 with total flying time under 500 h had had flight-related LBP.     

Association of aircraft noise stress to periodontal disease in aircrew members.

A review of the literature reveals a multitude of effects that noise may contribute to periodontal disease, including cardiovascular disease, angiospasm of peripheral vessels, hypertension, and an increase in inflammatory cells with concurrent inhibition of healing. Three groups of 25 men were selected from the Pennsylvania Air National Guard for study. Group 1 consisted of F-102 jet fighter pilots; Group 2, pilots and crew of a four-engine, propeller-driven C-121 aircraft; and Group 3, enlisted men not exposed to aircraft noise, as a control. The degree of alveolar, intraceptal bone loss for each subject was measured from full-mouth radiographs of all groups. The greatest amount of bone loss occurred in crew members of propeller-driven aircraft. Jet pilots had considerably less bone loss while the average number of millimeters of bone lost per tooth revealed a difference between the three groups to the 0.01 significance level (F=24.7). The data suggests there is a degree of alveolar bone loss over a period of years associated with exposure to propeller aircraft noise and vibration, and negligible loss for jet aircraft noise.     

飞行人员代谢综合征研究进展

目的 综述飞行人员代谢综合征（metabolic syndrome,MS）的研究进展,为飞行人员MS的防治提供参考. 资料来源与选择 国内外有关MS的研究论文. 资料引用 引用国内外公开发表的文献资料63篇. 资料综合 根据现有的国内外关于飞行人员MS的相关研究,简要概述了飞行人员MS的流行病学、发病机制、诊断及防治情况.飞行人员MS的流行病学特征与普通人群一致,随着年龄的增长患病率逐渐增高.发达国家MS患病率相对较高.飞行人员MS的患病率低于普通人群,其发病为多种因素相互作用的结果,包括有遗传因素、环境因素,核心为胰岛素抵抗.WHO、国际糖尿病联盟、中华医学会糖尿病学分会等分别制定了MS的诊断标准,各标准侧重点不同.飞行人员MS的防治主要包括生活方式改变和药物治疗. 结论 飞行人员作为一个被普遍认为健康状况良好的特殊群体,其MS的患病率并不低,且以高脂血症和中心性肥胖为主要临床特点.应重视飞行人员MS,大力加强对MS多种异常组分的预防和矫治,全面防治飞行人员MS.     

Cancer incidence in Republic of Bulgaria aircrew, 1964-1994.

BACKGROUND: This study includes all cases of cancer among Republic of Bulgaria Air Force and civil aviation aircrew. Cancer incidence, Standardized Incidence Ratios (SIRs) and 95% confidential intervals were calculated for the pilots, using data about cancer incidence in the same age groups of the male population of the Republic of Bulgaria for the same period of time, taken from the National Cancer Register. RESULTS: The results show a considerable difference in the structure of cancer among males in Bulgaria, as compared to male pilots (r<0.0001). While cancer of the respiratory system has the greatest incidence among the civil population, cancer of the bladder has the greatest incidence among pilots, followed by testicular and skin cancer. For the period under consideration there is a lower risk of malignant diseases in pilots as compared to the rest of the population. There is a higher risk of testicular cancer only in civil aviation pilots. For Air Force aircrew there is a 10-fold higher risk of bladder cancer as compared to the rest of the population. CONCLUSION: We established an interdependence between age and cancer incidence, cancer incidence being higher among pilots in the age group from 20-40 yr. For the remaining age groups, cancer incidence among the civil population is approximately 2.5 times higher. Of the pilots with cancer, 73.53% returned to a flying career after an average of 7 mo treatment.     

飞行人员生殖健康教育调查

为了解飞行人员生殖健康教育现状和服务需求,我们于2003年12月对空军某部飞行人员进行了问卷调查,并在所到部队召开座谈会和开展咨询调研等活动,现将结果报告如下.     

Heat strain in Royal Navy helicopter aircrew

A review of the literature on heat strain and aircrew and a questionnaire survey of Royal Navy aircrew have been completed. Aircrew appreciate, some 50% from first hand experience, that heat strain can reduce their operational endurance and performance. They are at greatest risk of developing it in the pre-flight period, especially when wearing Nuclear, Biological, or Chemical (NBC) protective equipment. Several techniques they use to reduce this risk are described. Some may be of particular assistance in the field should air conditioned facilities be unavailable. However, opportunities to improve the thermal environment within the aircraft on the ground and in flight are limited as the heat generated within it and high levels of solar radiation impinging on it severely challenge air conditioning units, themselves constrained by weight and size. Other demands placed on protective clothing offer little potential to increase the rate at which aircrew can lose accumulated heat. It is concluded that an appropriate micro-climate cooling system worn next to the skin may be required to achieve truly significant reductions in heat strain. Research at the Institute of Naval Medicine has identified liquid cooling techniques which may be suitable for aircrew in all but the smallest helicopters. Any views expressed are those of the author and do not necessarily represent those of the Department.     

Peacetime U.S. Army aircrew rescue and factors delaying rescue.

Despite strict flight discipline, U.S. Army aircraft infrequently suffer inflight mishaps. This is a retrospective study of aircrew survival and rescue in 97 mishaps investigated by the U.S. Army Safety Center from October 1988 to June 1990. To identify factors delaying rescue, recent mishaps are compared with 37 mishaps where the time to reach the mishap site exceeded 2 h. The average time to reach a mishap site was 2.2 h, but over 90% were reached within 2 h. There were two or more survivors at 82% of the sites and 98% of the downed aircrew had at least personal survival equipment available. Adverse operational and environmental factors were more common in delayed rescue mishaps. Sudden aircraft failure was three times more common in prolonged rescue mishaps, while night or instrument meteorologic conditions contributed eight times and four times greater risk of delay, respectively. Rescues in mountainous terrain or overwater were seven times more likely to be delayed. While fatalities were more common with prolonged rescue, there were no mishaps where a delay in reaching the crash site resulted in the loss of an airman.     

Techniques to enhance safety in acceleration research and fighter aircrew training.

Acceleration (+Gz) research and aircrew training using human centrifuges involves considerable stress that can alter normal cardiovascular and neurologic function even in completely healthy individuals. It is clear that electrocardiographic rate, rhythm, and conduction disturbances are frequently associated with +Gz exposures. These cardiac changes can result in altered perfusion of the central nervous system (CNS) to an extent which exceeds that induced by the +Gz stress alone. Although centrifuge-based research and training have a proven record of overall safety, there is finite risk associated with such stressful exposures, and adverse events have been observed. It is, therefore, extremely important to continually develop improved avenues to enhance human safety during centrifuge exposure. We have implemented techniques that can be immediately employed by centrifuge medical personnel to reduce the potential for significant CNS embarrassment and possible injury. These include techniques to 1) reduce excessive parasympathetic tone that may result in marked bradycardia and transient asystole post +Gz stress, and 2) manually controlled inflation and pulsation of the anti-G suit to enhance CNS perfusion post +Gz stress.     

Confidentiality and the psychological treatment of U.S. Army aircrew members

The present article addresses the issue of confidentiality in U.S. Army psychological services and the special considerations affecting the confidentiality afforded to Army aviation personnel receiving such services. The author reviews Army regulations and American Psychological Association ethical standards relevant to the issue of confidentiality for aircrew members. Recommendations are offered for mental health professionals who provide services to Army aviation personnel, and a hypothetical clinical case is presented to illustrate the concepts discussed.     

Idiopathic multicentric osteolysis.

A 59 year old while female with striking carpal and tarsal osteolysis is reported. The process primarily involves the carpals and tarsals but includes other sites. The pertinent literature is reviewed and a simplified classification of idiopathic multicentric osteolysis is presented. Idiopathic multicentric osteolysis may be sporadic but can demonstrate either dominant or recessive inheritance. There may or may not be associated nephropathy. The underlying mechanism appears similar in all variations of this condition. Gorham's disease, the Winchester syndrome, and other osteolytic conditions which may predominantly affect the tarsal and carpal bones most likely are totally different processes, unrelated to idiopathic multicentric osteolysis.