A comparison of postmortem coronary atherosclerosis findings in general aviation pilot fatalities

The autopsy reports of 710 pilots involved in fatal general aviation accidents were received by the FAA for the years 1980-82; they were reviewed to appraise the age-specific prevalence of coronary atherosclerosis among the autopsied group and to compare findings with those of an earlier study. Of the autopsies on pilots killed in aircraft accidents, 69% indicated some degree of coronary atherosclerosis, ranging from minimal to severe. This finding is higher than for a similar group of pilots studied for the years 1975-77. However, only about 2.5% of the 1980-82 study group were found to have severe coronary atherosclerosis, compared with 5% in the previous study. Prevalence of severe coronary atherosclerosis increased with age from 5.8 per 1,000 for ages less than 40 years to 73.9 for age 50 years and above, also reflecting lower age-specific rates for severe coronary atherosclerosis than were found in the previous study.     

Challenges in investigation of diabetes-related aviation fatalities—an analysis of 1491 subsequent aviation fatalities in USA during 2011–2016

Diabetes mellitus (DM) could cause pilot incapacitation and result in aviation fatalities. The mechanisms could be directly as a consequence of acute hypoglycemia/subacute diabetic ketoacidosis (DKA) or indirectly as an acute cardiovascular event by contributing to the development of atherosclerosis in coronary or carotid and cerebral arteries. In this study, DM-related fatal flight accidents in the US National Transport Bureau’s database between years 2011–2016 were analyzed with special emphasis on postmortem (PM) glucose levels and correlation of toxicological reports with anamnestic information on DM. Additionally, autopsy results on coronary arteries were reviewed. In 43 out of 1491 (~ 3%) fatal accidents pilots had DM. Postmortem glucose or glycated hemoglobin percentage (Hb1Ac) was measured in 12 of the 43 cases; while antidiabetic medication was found in 14 of the cases (only two of the cases had both glucose measurements and medication). With the increasing prevalence of DM, a possibility of pilot incapacitation due to DM or complications of DM should be actively studied, even if no anamnestic information of DM was available. While PM hypoglycemia is difficult to assess, we propose a systematic investigation based on measurement of glucose, Hb1Ac%, and ketone bodies, and documentation of atherosclerotic lesions in major arteries to identify or rule out DM as a cause of pilot incapacitation.

     

First-generation H1 antihistamines found in pilot fatalities of civil aviation accidents, 1990-2005

INTRODUCTION: First-generation H1-receptor antagonists are popularly used for alleviating allergy and cold symptoms, but these antihistaminics cause drowsiness and sedation. Such side effects could impair performance and, thus, could be the cause or a factor in accidents. Therefore, the prevalence of these antagonists was evaluated in aviation accident pilot fatalities. METHODS: The Civil Aerospace Medical Institute's (CAMI's) Toxicology Database was examined for the presence of the first-generation antihistamines in pilot fatalities of civil aircraft accidents that occurred during a 16-yr (1990-2005) period. RESULTS: Of 5383 fatal aviation accidents from which CAMI received specimens, there were 338 accidents wherein pilot fatalities (cases) were found to contain brompheniramine, chlorpheniramine, diphenhydramine, doxylamine, pheniramine, phenyltoloxamine, promethazine, and triprolidine. Of the 338 accidents, 304 were general aviation accidents, and 175 of the 338 pilots held private pilot airman certificates. Antihistamines were detected alone in 103 fatalities (1 antihistamine in 94 and 2 antihistamines in 9), while other drug(s) and/or ethanol were also present in an additional 235 fatalities. The antihistamines were found in approximately 4 and 11% of the fatalities/accidents in 1990 and in 2004, respectively. The use of antihistamine(s) was determined by the National Transportation Safety Board to be the cause of 13 and a factor in 50 of the 338 accidents. CONCLUSIONS: There was an overall increasing trend in the use of antihistamines by aviators during the 16-yr span. Blood levels of the antihistaminics were in the sub-therapeutic to toxic range. Findings from this study will be useful in investigating future accidents involving antihistamines.     

38例冠状动脉心肌桥飞行员病例分析

目的：探讨冠脉心肌桥飞行员的临床特征以及飞行人员冠脉心肌桥与航空卫生安全的关系。方法：152例运动平板心电图为阳性或可疑阳性的飞行员经冠脉CTA检查,发现38例为冠状动脉心肌桥。将38例冠状动脉心肌桥的飞行员根据有无伴随症状、冠脉心肌桥变异位置、心电图有无异常、有无伴随心血管疾病易患因素及有无伴发冠脉粥样硬化病变作回顾性统计分析。将同在左前降支存在心肌桥变异的冠脉与无心肌桥变异的冠脉分组作对比,比较两组冠脉中出现冠状动脉粥样硬化的病例数,并作统计学分析。结果：38例冠脉心肌桥飞行员中,临床上无症状,其多数静息心电图正常,大多属Nobte分级Ⅰ级,且心肌桥均为表浅型;部分心肌桥合并存在冠心病危险因素;左前降支心肌桥所在动脉及其近端动脉出现动脉粥样硬化者占30.3%（A组）,左前降支无心肌桥冠脉出现动脉粥样硬化者占13.2%（B组）,两组存在显著性差异（P〈0.05）。结论：冠状动脉心肌桥的飞行员,目前多数无临床症状,心肌桥变异位置多数在左前降支中段,多为表浅型,Nobte分级为I,临床上无需治疗;对于存在冠心病危险因素的飞行员应积极预防及控制这些冠心病危险因素;但心肌桥可继发冠脉的粥样硬化,对于存在冠脉心肌桥的飞行员应引起足够的重视。     

Antiemetic and sedative levels found together in 26 civil aviation pilot fatalities, 2000-2006

INTRODUCTION: Antiemetics and sedatives are two drug classes that may have harmful side effects when mixed. This is especially dangerous for pilots. Although many of these compounds are considered disqualifying by the FAA, their use occurs. Some pilots may be unaware of the danger of combining compounds from these two drug classes. Our laboratory was interested in evaluating the circumstances surrounding accidents in which the pilot was found positive for drugs from each of these two classes. METHODS: Epidemiological, toxicological, and aeromedical findings from pilots involved in such accidents were collected for the 7-yr period from 2000 through 2006. Case histories, accident information, and the probable cause of the aviation accidents were obtained from the National Transportation Safety Board (NTSB). Toxicological information was obtained from the Civil Aerospace Medical Institute's (CAMI's) Forensic Toxicology Research Laboratory. RESULTS: Of the 2184 fatal aviation accidents over this time period, 26 were found positive for compounds from both the antiemetic and the sedative drug classes. All 26 aircraft were operated under 14 CFR Part 91 as general aviation. All pilots were male; 21 tested positive for a disqualifying substance that may have affected their ability to control the aircraft. CONCLUSION: Although the percentage of accidents in which the pilot tests positive for a compound from each class is small, it is important for all pilots to understand the dangers of self-medicating and concomitant use of such substances. Under-reporting of medications by pilots during their certification process occurs; education is the key to preventing inadvertent drug-drug interactions.     

Routine electroencephalograms of pilots later killed in crashes: a case-control study

BACKGROUND: The value of the electroencephalogram (EEG) as a screening tool in aviation medicine is subject to debate. We evaluated the use of periodic repetition of the EEG--after an initial EEG screening-in healthy, fully-licensed pilots to identify risk factors for fatal air crashes. METHODS: In a nested case-control study, we compared the EEG patterns of 33 pilots who died in military aviation accidents from 1990 to 2001 with the recordings of 66 controls. Cases and controls were matched for potentially confounding factors such as age, military membership, type of aircraft, and aeronautical experience. RESULTS: Both groups presented normal EEGs. EEG findings in cases and controls did not differ; nonspecific EEG abnormalities did not occur more frequently in those pilots who crashed. CONCLUSIONS: After an initial EEG screening, periodic repetition of the EEG is not a useful means to detect risk for fatal air crashes.     

通用航空的飞行安全与人的因素

目的 回顾分析国外通用航空飞行事故的概况,及其与飞行员性别、年龄、飞行经验等有关的人的因素在飞行事故中所起的相关作用,为我国通用航空飞行安全提供建设性意见. 资料来源与选择 国内外通用航空的飞行安全与人的因素研究领域相关文献. 资料引用 公开发表的文献38篇. 资料综合 介绍美国通用航空飞行事故概况和该领域开展的针对性预防研究工作,分析飞行员性别、年龄、飞行经验和综合因素在通用航空飞行事故发生中的作用,为我国通用航空飞行安全提出建议.通用航空飞行事故中人的因素占首位.男性飞行员的冒险本性,使其发生的致命事故要多于女性飞行员;年龄大的飞行员积累的飞行经验可部分补偿因生理、心理引起的工作能力降低的影响,但其所从事危险飞行任务增加,在飞行管理上需进行完善.此外,气象条件、事故环境、飞行员有酒精、药物滥用史等因素易诱发通用航空飞行事故. 结论 我国通用航空即将迎来飞速发展的阶段,充分借鉴国内外航空医学已有的研究成果和经验,规范通用航空飞行员的医学检查标准和机制,加强对通用航空飞行员的教育和培训,建立完善的事故报告分析体系,将有助于减少我国未来通用航空发展中由于人的因素所导致的飞行事故,提高飞行安全水平.     

Pilot medical history and medications found in post mortem specimens from aviation accidents

INTRODUCTION: Federal Aviation Administration (FAA) regulations require pilots to report all medications and medical conditions for review and consideration as to the overall suitability of the pilot for flight activities. METHODS: Specimens were collected by local pathologists from aviation accidents and sent to the Bioaeronautical Sciences Research Laboratory for analysis. The results of such tests were entered into the Forensic Case Management System. This database was searched to identify all pilots found positive for medications used to treat cardiovascular, psychological, or neurological conditions over the period January 1, 1993, through December 31, 2003. RESULTS: Toxicological evaluations were performed on 4143 pilots. Psychotropic drugs were found in 223 pilots. Cardiovascular medications were found in 149 pilots. Neurological medications were found in 15 pilots. Pilots reported psychological conditions in 14 of the 223 pilots found positive for psychotropic drugs. Only 1 of the 14 pilots reporting a psychological condition to the FAA reported the psychotropic medication found after the accident. Cardiovascular disease was reported by 69 of the pilots found with cardiovascular drugs in their system. Cardiovascular medications found in the pilots were reported by 29 of the 69 pilots reporting a cardiovascular condition. Only 1 of the 15 pilots reported having a neurological condition to the FAA; none of the pilots found with neurological medications reported the medication. CONCLUSIONS: Toxicology successfully identified 93% of the medications reported by the pilots. Pilots involved in fatal accidents taking psychotropic or neurological medications rarely reported the medication or their underlying medical condition to the FAA.     

Selective serotonin reuptake inhibitors in pilot fatalities of civil aviation accidents, 1990-2001

INTRODUCTION: Selective serotonin reuptake inhibitors (SSRIs) are popularly prescribed for treating depression. With a few exceptions, these psychotropic medications are not approved by aeromedical regulatory authorities for use by aviators. Since SSRIs have the potential for impairing performance and causing drug-drug interactions, the prevalence of SSRIs in pilot fatalities of civil aviation accidents was evaluated. METHODS: Postmortem samples from pilots involved in fatal civil aircraft accidents are submitted to the Civil Aerospace Medical Institute (CAMI) for toxicological evaluation. Findings from such evaluations are maintained in the CAMI Toxicology Database. This database was examined for the presence of SSRIs in pilot fatalities of the accidents that occurred during 1990-2001. RESULTS: Out of 4,184 fatal civil aviation accidents from which CAMI received samples, there were 61 accidents in which pilot fatalities had SSRIs. Of these accidents, 56 were of the general aviation category, 2 were of the air taxi and commuter category, 2 were of the agricultural category, and 1 was of the ultralight category. Blood concentrations of SSRIs in the fatalities were 11-1121 ng x ml(-1) for fluoxetine; 47-13102 ng x ml(-1) for sertraline; 68-1441 ng x ml(-1) for paroxetine; and 314-462 ng x ml(-1) for citalopram. In 39 of the 61 pilots, other drugs--for example, analgesics, antihistaminics, benzodiazepines, narcotic analgesics, and/or sympathomimetics--and/or ethanol were also present. As determined by the National Transportation Safety Board, the use of an SSRI [with or without other drug(s) and/or ethanol] has been a contributory factor in at least 9 of the 61 accidents. CONCLUSIONS: Numbers of SSRI-involved accidents were low, and blood SSRI concentrations in the associated pilot fatalities ranged from subtherapeutic to toxic levels. However, the interactive effects of other drug(s), ethanol, and/or even altitude hypoxia in producing adverse effects in the pilots cannot be ruled out. Findings from this study should be useful in investigating SSRI and other substance-involved accidents and in making decisions concerning the use of SSRIs in aviation.     

Current role of alcohol as a factor in civil aircraft accidents.

Ethyl alcohol continues as a serious adverse factor in general aviation flight safety. According to FAA figures, the level of alcohol-associated general aviation fatal accidents has remained relatively static at a 16% general level since 1969. A recent survey of the attitudes of pilots toward alcohol and flying reveals a lack of appreciation among one-third of the pilots concerning the adverse effects of alcohol on safe flight. A renewed pilot education program on alcohol and flight safety appears indicated.     

心脏瓣膜手术前行冠状动脉造影及同期行冠状动脉旁路移植术分析

目的探讨心脏瓣膜病患者术前选择性行冠状动脉造影及同期施行冠状动脉旁路移植术的效果及经验。方法对211例50岁以上行心脏瓣膜手术的患者进行统计,其中男104人,女107人,年龄50~75岁(60±3·5岁)。术前对有心绞痛等相关症状、糖尿病、高脂血症、心电图存在缺血等冠心病高危因素的患者行冠状动脉造影,冠状动脉狭窄超过50%为阳性,狭窄超过75%(左主干超过50%)者同期行冠状动脉旁路移植术。结果211例患者中行冠状动脉造影术128例(60·7%,其余患者无症状及相关危险因素未造影),其中30例冠状动脉存在单支或多支病变,狭窄程度>50%,造影阳性率23·4%。同期行冠状动脉旁路移植术24例(80·0%),手术死亡1例,其余患者随诊4~38个月,效果良好。结论50岁以上瓣膜病患者术前行冠状动脉造影可为术前诊断和排除冠心病、选择术式提供帮助。     

民航飞行人员冠心病19例临床特点分析

目的 通过回顾分析19例民航飞行人员冠心病的临床特点和医学鉴定情况,为飞行人员冠心病医学鉴定和航卫保障工作提供参考. 方法回顾分析我国南方航空公司2002～2006年5年间19例新发冠心病飞行人员的临床和医学鉴定资料,总结其特点. 结果对象均为男性,发病年龄40～57(52.9±3.9)岁,平均飞行时间18 210 h,其中驾驶员12例,机械师7例;2002～2006年年均发病率为2.64‰,各年之间发病率比较无显著差异(x2=1.251,P>0.05);深圳分公司发病例数最多,为9例,年均发病率为9.50‰,与广州、武汉和郑州分公司比较,深圳分公司飞行人员冠心病的发病率明显偏高(P<0.05),其他地区之间冠心病发病率比较无显著差异(P>0.05);冠状动脉造影显示病变血管以中重度狭窄为主,其中单支病变8例,双支病变10例,3支病变1例.4例获特许飞行合格,至今最长安全飞行时间>2000 h. 结论加强心血管病危险因素干预是预防冠心病的根本,冠心病介入治疗为飞行人员冠心病后重获飞行资格创造了条件.     

Glider accidents: an analysis of 143 cases, 2001-2005

INTRODUCTION: The majority of aviation crashes and casualties take place in general and sport aviation. Although gliding has gained popularity in recent decades, we could find no systematic analysis of glider accidents. This study determined factors associated with both non-fatal and fatal glider accidents to document their position within sport and general aviation accidents, and to suggest preventive measures and improvements. METHODS: We performed a retrospective review of glider accidents for the period 2001-2005 in the database maintained by the U.S. National Transportation Safety Board (NTSB). RESULTS: A total of 117 non-fatal and 26 fatal glider accidents were reported for the 5-yr period. Adverse weather was the cause in 20% of all non-fatal accidents, 60% of which occurred in the cruise phase. Logistic regression revealed that fatal accidents were predicted by pilot error, flight phase, and home-built aircraft. DISCUSSION: Factors contributing to glider crashes are specific to this type of sport aviation. Owners of home-built gliders should pay particular attention to the aircraft's specifications and design limits.     

Coronary to pulmonary artery fistula associated with significant coronary atherosclerosis and severe aortic valve stenosis: A Case Report

Coronary artery fistulas are anomalous connections between one or two coronary arteries with either a cardiac chamber or any major blood vessels (coronary sinus, superior vena cava, pulmonary veins and pulmonary artery). It is rarely reported, occurring only in 0.1%-0.2% of patients who undergo coronary angiography. We report a very rare case where myocardial ischaemia may have resulted from the presence of coronary artery fistula, significant coronary artery stenosis and severe aortic valve stenosis. Transthoracic echocardiography showed severe aortic stenosis, while coronary angiography showed a tortuous coronary artery fistula originating from the proximal left anterior descending artery, with a single opening in the main pulmonary artery. Angiography also showed significant stenosis in the middle of the left anterior descending artery. Coronary artery fistula with concomitant significant coronary atherosclerosis and severe aortic stenosis requires optimal therapeutic planning.     

Pilot behaviors in the face of adverse weather: A new look at an old problem

INTRODUCTION: Weather-related general aviation accidents remain one of the most significant causes for concern in aviation safety. Previous studies have typically compared accident and non-accident cases. In contrast, the current study does not concentrate on occurrence outcome. Instead, the emphasis is on the different behaviors that pilots exhibit in the face of adverse weather and, by inference, on the decision-making processes that underlie those behaviors. METHODS: This study compares three weather-related behaviors that reflect different levels of risk: visual flight rules flight into instrument meteorological conditions ('VFR into IMC'); precautionary landing; and other significant weather avoidance actions. Occurrence data (n=491) were drawn from the Australian Transport Safety Bureau database of aviation occurrences, and included weather-related accidents, incidents, and 'normal operationsd.' RESULTS: There were few significant differences between the three weather-related behavior groups in terms of pilot demographics, aircraft characteristics, geographic or environmental factors, or absolute flight distances. The pattern of relative flight distances (a psychological construct) was markedly different for the three groups, with pilots in the weather avoidance group being distinguished by taking timely action. DISCUSSION: The relative distance results suggest that the mid-point of the flight can be a 'psychological turning point' for pilots, irrespective of the absolute flight distance involved. Hence, pilots' behavior was sometimes influenced by psychological factors not related to any particular operational aspect of the flight. The results of the weather avoidance group indicate that a safe pilot is a proactive pilot. Dealing with adverse weather is not a one-off decision but a continually evolving process. This aspect is discussed in terms of the concept of 'mindfulness'.     

Toxicological findings in fatal civil aviation accidents, fiscal years 1968-1974.

Toxicological findings in 1,345 fatal general aviation accidents from fiscal year 1968 through 1974 are summarized. Methods used in examination of specimens for alcohol, drugs, carbon monoxide, cyanide, and cholinesterase activity are described. Blood ethanol levels in excess of 0.050% were found in 117 of the 1,345 pilots (8.7%). Drugs were found in 16 cases (1.2%). These and other toxicological findings indicate that in more than 40% of the cases, information worthy of consideration in developing the human-factors history of an accident or the cause of death from survivable crashes was obtained.     

MRI detects increased coronary wall thickness in asymptomatic individuals: the multi-ethnic study of atherosclerosis (MESA)

PURPOSE: To evaluate the use of coronary wall MRI as a measure of atherosclerotic disease burden in an asymptomatic population free of clinical cardiovascular disease. Coronary wall magnetic resonance imaging (MRI) is a noninvasive method for evaluation of arterial wall remodeling associated with atherosclerosis. MATERIALS AND METHODS: Asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis (MESA) study were studied using black blood MRI. MRI-assessed coronary wall thickness was compared with computed tomography calcium score, carotid intimal-medial thickness, and risk factors for coronary artery disease. RESULTS: Eighty-eight arterial segments were evaluated in 38 MESA participants (mean age, 61.3+/-8.7 years). The maximum coronary wall thickness was greater for participants with two or more cardiovascular risk factors than for those with one or no risk factors (2.59+/-0.33 mm vs. 2.36+/-0.30 mm, respectively, P=0.05.) For participants with zero calcium score, the mean and maximum coronary wall thickness for subjects with two or more risk factors for coronary artery disease were greater than the wall thickness for subjects with one or no risk factors (mean thickness: 1.95+/-0.17 mm vs. 1.7+/-0.19 mm; maximum thickness: 2.67+/-0.24 mm vs. 2.32+/-0.27 mm, respectively, P<0.05). Subjects with increased carotid intimal-medial thickness also had increased coronary artery wall thickness (P<0.05). CONCLUSION: Coronary artery wall MRI detects increased coronary wall thickness in asymptomatic individuals with subclinical markers of atherosclerotic disease and in individuals with zero calcium score.     

Debates in cardiac CT: Coronary CT angiography is the best test in asymptomatic patients

Cardiovascular disease remains a major cause of mortality, accounting for a third of all global deaths annually. Although there have been major improvements in our ability to detect and to treat patients with coronary heart disease, most myocardial infarctions occur in previously asymptomatic individuals. Identification of individuals at risk of myocardial infarction remains challenging and primary prevention guidelines rely on the use of cardiovascular risk scores that can be supplemented by coronary artery calcium scores. Coronary artery calcium scores provide a simple surrogate late marker of atherosclerosis but is unable to identify the early high risk non-calcified plaque which can be particularly problematic in younger individuals. Coronary computed tomography angiography is increasingly being used as the imaging strategy of choice in patients with symptoms of coronary heart disease. As an anatomical test, it can non-invasively detect the presence of coronary atherosclerosis, providing clinicians with a strong mandate to commence symptom relieving and preventative therapies. For asymptomatic individuals, it allows precise targeting of therapies to those with coronary heart disease rather than those “at risk” of disease. Moreover, our ability to calculate risk using coronary computed tomography angiography is rapidly improving with the use of techniques, such as plaque quantification and characterisation. These techniques have the potential to provide clinicians with tools to target cardiovascular disease prevention in a precision medicine approach. We here debate the ways in which coronary computed tomography angiography could improve the selection of asymptomatic individuals for preventative therapies over and above risk calculators and calcium scoring.