Flight safety risk assessment of self-medication among fighter pilots: a cross-sectional study

BACKGROUND

Fighter pilots are a specific population in which any adverse drug reaction can unpredictably interact with aeronautical constraints and thus compromise flight safety. This issue has not been evaluated in risk assessments.

AIM

To provide a semi-quantitative assessment of the risk to flight safety of self-medication in fighter pilots.

METHOD

A cross-sectional survey that aimed at identifying the determinants of self-medication in fighter pilots was conducted. All medications consumed within 8 h preceding a flight were listed. A modified Failure Mode and Effects Analysis was performed, and any adverse drug reaction reported in the French marketing authorization document of a drug was considered a failure mode. The frequency of occurrence and severity were evaluated using specific scales to assign each to three risk criticality categories: acceptable, tolerable, and unacceptable.

RESULTS

Between March and November 2020, the responses of 170 fighter pilots were analyzed, for an overall return rate of approximately 34%. Among them, 78 reported 140 self-medication events within 8 h preceding a flight. Thirty-nine drug trade names (48 different international nonproprietary names) were listed, from which 694 potential adverse drug reactions were identified. The risk criticality was considered unacceptable, tolerable and acceptable for 37, 325 and 332 adverse drug reactions, respectively. Thus, the risk criticality was considered unacceptable, tolerable and acceptable for 17, 17, and 5 drugs, respectively.

CONCLUSION

This analysis suggests that the overall risk to flight safety of the current practice of self-medication in fighter pilots may be considered at least tolerable, or even unacceptable.

Residual Sleepiness Risk in Aircrew Members with -Obstructive Sleep Apnea Syndrome

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is a major problem in aviation medicine because it is responsible for sleepiness and high cardiovascular risk, which could jeopardize flight safety. Residual sleepiness after the treatment is not a rare phenomenon and its management is not homogenous in aviation medicine. Thus, we decided to perform a study to describe this management and propose guidelines with the help of the literature.METHODS: This is a retrospective study including all aircrew members with a history of OSAS who visited our aeromedical center between 2011 and 2018. Residual sleepiness assessment was particularly studied.RESULTS: Our population was composed of 138 aircrew members (mean age 50.1 ± 9.6 yr, 76.8% civilians, 80.4% pilots); 65.4% of them had a severe OSAS with a mean Epworth Sleepiness Scale (ESS) at 8.5 ± 4.7 and a mean apnea hypopnea index of 36.2 ± 19.2/h. Of our population, 59.4% performed maintenance of wakefulness tests (MWT) and 10.1% had a residual excessive sleepiness. After the evaluation, 83.1% of our population was fit to fly.DISCUSSION: An evaluation of treatment efficiency is required in aircrew members with OSAS. Furthermore, it is important to have an objective proof of the absence of sleepiness. In this case, ESS is not sufficient and further evaluation is necessary. Many tests exist, but MWT are generally performed and the definition of a normal result in aeronautics is important. This evaluation should not be reserved to solo pilots only.Monin J, Rebiere E, Guiu G, Bisconte S, Perrier E, Manen O. Residual sleepiness risk in aircrew members with obstructive sleep apnea syndrome. Aerosp Med Hum Perform. 2023; 94(2):74-78.

Prevalence of sleep disorders in a large French cohort of aircrew members and risk of in-flight sleepiness

BACKGROUND

/objectives: Sleep disorders are a critical issue for flight safety. Previous studies have shown a high prevalence of sleep disorders and excessive sleepiness in the general population and some aircrews. The objectives of this study are to measure the prevalence of excessive daytime sleepiness and sleep disorders in aircrews, and to determine the risk factors of falling asleep during a flight.

METHODS

this is a monocentric study based on questionnaires, including all professional civilian and military aircrews examined in an aeromedical center between January and May 2021. The questionnaire, created for this study, included information about socio-demographic characteristics, aeronautical experience, lifestyle, sleep habits, an Epworth sleepiness scale, and screening tests for chronic insomnia, sleep apnea syndrome and restless legs syndrome.

RESULTS

749 aircrew members were included (86.2% male, 58.9% civilian, 74.1% pilot, mean age 43.4 ± 9.6 years), 45.9% of the population had at least one sleep disorder (chronic insomnia 39.5%, sleep apnea syndrome 10.5%, restless legs syndrome 4.1%), 15.5% had an excessive daytime sleepiness, and 24.6% reported in-flight sleep while on duty. Chronic insomnia, screen use before bedtime, use of sleeping pills, inadequate recovery time after a flight, female gender and civilian status were found as risk factors of in-flight sleep in the multivariate analysis.

CONCLUSION

this study emphasizes the need to improve the screening and prevention of sleep disorders in this particular population.

Self-Medication Among Military Fighter Aircrews

BACKGROUND: The practice of self-medication among military fighter aircrew could compromise flight safety because of the adverse effects that can occur in flight. However, data on this subject is scarce. The aim of this study was to identify the determinants of the practice in this population.METHODS: A cross-sectional study was carried out among the French Air Force fighter aircrew based on an anonymous questionnaire distributed electronically. The questions included personal characteristics, opinions, and relations with the healthcare domain as well as the use of self-medication in general and before a flight.RESULTS: Between March and November 2020, 170 questionnaires were reviewed for an overall return rate of approximately 34%. Our data showed an absolute self-medication rate of 97.6%, but the frequency of its use was rare or nonexistent in 53.5% of cases. Factors associated with a more frequent use of self-medication were the function of pilot, age under 35, having a regular prescription, lacking intentionality toward getting enough sleep, having confidence in the medical profession, and some specific clinical situations. The consumption of 97 medications was recorded and 49 before a flight.DISCUSSION: Despite the limitations due to the design of this survey, results suggest that the use of self-medication in fighter aircrews is a reality, but that the frequency of its use is less common. This practice is probably the result of a complex interaction between many personal factors. However, its impact on flight safety remains uncertain.du Baret de Limé M, Monin J, Leschiera J, Duquet J, Manen O, Chiniard T. Self-medication among military fighter aircrews. Aerosp Med Hum Perform. 2022; 93(7):571–580.

Heart muscle disease management in aircrew

This manuscript focuses on the broad aviation medicine considerations that are required to optimally manage aircrew with suspected or confirmed heart muscle disease (both pilots and non-pilot aviation professionals). ECG abnormalities on aircrew periodic medical examination or presentation of a family member with a confirmed cardiomyopathy are the most common reason for investigation of heart muscle disease in aircrew. Holter monitoring and imaging, including cardiac MRI is recommended to confirm or exclude the presence of heart muscle disease and, if confirmed, management should be led by a subspecialist. Confirmed heart muscle disease often requires restriction toflying duties due to concerns regarding arrhythmia. Pericarditis and myocarditis usually require temporary restriction and return to flying duties is usually dependent on a lack of recurrent symptoms and acceptable imaging and electrophysiological investigations.

Management of established coronary artery disease in aircrew without myocardial infarction or revascularisation

This paper is part of a series of expert consensus documents covering all aspects of aviation cardiology. In this manuscript, we focus on the broad aviation medicine considerations that are required to optimally manage aircrew with established coronary artery disease in those without myocardial infarction or revascularisation (both pilots and non-pilot aviation professionals). We present expert consensus opinion and associated recommendations. It is recommended that in aircrew with non-obstructive coronary artery disease or obstructive coronary artery disease not deemed haemodynamically significant, nor meeting the criteria for excessive burden (based on plaque morphology and aggregate stenosis), a return to flying duties may be possible, although with restrictions. It is recommended that aircrew with haemodynamically significant coronary artery disease (defined by a decrease in fractional flow reserve) or a total burden of disease that exceeds an aggregated stenosis of 120% are grounded. With aggressive cardiac risk factor modification and, at a minimum, annual follow-up with routine non-invasive cardiac evaluation, the majority of aircrew with coronary artery disease can safely return to flight duties.

Management of cardiac conduction abnormalities and arrhythmia in aircrew

Cardiovascular diseasesⁱ are the most common cause of loss of flying licence globally, and cardiac arrhythmia is the main disqualifier in a substantial proportion of aircrew. Aircrewⁱⁱ often operate within a demanding physiological environment, that potentially includes exposure to sustained acceleration (usually resulting in a positive gravitational force, from head to feet (+Gz)) in high performance aircraft. Aeromedical assessment is complicated further when trying to discriminate between benign and potentially significant rhythm abnormalities in aircrew, many of whom are young and fit, have a resultant high vagal tone, and among whom underlying cardiac disease has a low prevalence. In cases where a significant underlying aetiology is plausible, extensive investigation is often required and where appropriate should include review by an electrophysiologist. The decision regarding restriction of flying activity will be dependent on several factors including the underlying arrhythmia, associated pathology, risk of incapacitation and/or distraction, the type of aircraft operated, and the specific flight or mission criticality of the role performed by the individual aircrew.

Management of established coronary artery disease in aircrew with previous myocardial infarction or revascularisation

This manuscript focuses on the broad aviation medicine considerations that are required to optimally manage aircrew with established coronary artery disease (CAD) without myocardial infarction (MI) or revascularisation (both pilots and non-pilot aviation professionals). It presents expert consensus opinion and associated recommendations and is part of a series of expert consensus documents covering all aspects of aviation cardiology.Aircrew may present with MI (both ST elevation MI (STEMI) and non-ST elevation MI (NSTEMI)) as the initial presenting symptom of obstructive CAD requiring revascularisation. Management of these individuals should be conducted according to published guidelines, ideally with consultation between the cardiologist, surgeon and aviation medical examiner. Return to restricted flight duties is possible in the majority of aircrew; however, they must have normal cardiac function, acceptable residual disease burden and no residual ischaemia. They must also be treated with aggressive cardiac risk factor modification. Aircrew should be restricted to dual pilot operations in non-high-performance aircraft, with return to flying no sooner than 6 months after the event. At minimum, annual follow-up with routine non-invasive cardiac evaluation is recommended.

Epidemiology of Inflight Medical Events

Introduction: Since the 1950s, air travel has grown exponentially. In 2018, the number of international air passengers was estimated at 4.1 billion. Air travel exposes the passenger to a number of constraints (like physical constraints, stress) that can be correlated and lead to an inflight medical event, especially for passengers with chronic conditions or fragile health. Methods: In June 2017, a mini review of the literature was conducted in order to summarize the data on inflight medical events and their frequency, types, and consequences. Results: The most frequent inflight medical events are syncope and lipothymic discomfort, followed by digestive disorders, cardiorespiratory symptoms, neuropsychiatric disorders, and trauma. In almost two-thirds of all cases, these medical events are linked to a pre-existing pathology. There is no reliable register of inflight medical events, but their number is estimated to be between 120 to 350 each day throughout the world. Conclusion: The definition of an inflight medical event deserves to be specified, and the collection of these events needs to be standardized. This will help bring about a better understanding of the issue and maybe raise awareness among passengers with chronic diseases or fragile health and their general practitioners.

An introduction to aviation cardiology

The management of cardiovascular disease (CVD) has evolved significantly in the last 20 years; however, the last major publication to address a consensus on the management of CVD in aircrew was published in 1999, following the second European Society of Cardiology conference of aviation cardiology experts. This article outlines an introduction to aviation cardiology and focuses on the broad aviation medicine considerations that are required to manage aircrew appropriately and optimally (both pilots and non-pilot aviation professionals). This and the other articles in this series are born out of a 3 year collaborative working group between international military aviation cardiologists and aviation medicine specialists, many of whom also work with and advise civil aviation authorities, as part of a North Atlantic Treaty Organization (NATO) led initiative to address the occupational ramifications of CVD in aircrew (HFM-251). This article describes the types of aircrew employed in the civil and military aviation profession in the 21st century; the types of aircraft and aviation environment that must be understood when managing aircrew with CVD; the regulatory bodies involved in aircrew licensing and the risk assessment processes that are used in aviation medicine to determine the suitability of aircrew to fly with medical (and specifically cardiovascular) disease; and the ethical, occupational and clinical tensions that exist when managing patients with CVD who are also professional aircrew.

Non-coronary cardiac surgery and percutaneous cardiology procedures in aircrew

This manuscript focuses on the broad aviation medicine considerations that are required to optimally manage aircrew following non-coronary surgery or percutaneous cardiology interventions (both pilots and non-pilot aviation professionals). Aircrew may have pathology identified earlier than non-aircrew due to occupational cardiovascular screening and while aircrew should be treated using international guidelines, if several interventional approaches exist, surgeons/interventional cardiologists should consider which alternative is most appropriate for the aircrew role being undertaken; liaison with the aircrew medical examiner is strongly recommended prior to intervention to fully understand this. This is especially important in aircrew of high-performance aircraft or in aircrew who undertake aerobatics. Many postoperative aircrew can return to restricted flying duties, although aircrew should normally not return to flying for a minimum period of 6 months to allow for appropriate postoperative recuperation and assessment of cardiac function and electrophysiology.

Congenital heart disease in aircrew

This article focuses i on the broad aviation medicine considerations that are required to optimally manage aircrew ii with suspected or confirmed congenital heart disease (both pilots and non-pilot aviation professionals). It presents expert consensus opinion and associated recommendations and is part of a series of expert consensus documents covering all aspects of aviation cardiology. This expert opinion was born out of a 3 year collaborative working group between international military aviation cardiologists and aviation medicine specialists, as part of a North Atlantic Treaty Organization (NATO) led initiative to address the occupational ramifications of cardiovascular disease in aircrew (HFM-251) many of whom also work with and advise civil aviation authorities.

The challenge of asymptomatic coronary artery disease in aircrew; detecting plaque before the accident

Coronary events remain a major cause of sudden incapacitation, including death, in both the general population and among aviation personnel, and are an ongoing threat to flight safety and operations. The presentation is often unheralded, especially in younger adults, and is often due to rupture of a previously non-obstructive coronary atheromatous plaque. The challenge for aeromedical practitioners is to identify individuals at increased risk for such events. This paper presents the NATO Cardiology Working Group (HFM 251) consensus approach for screening and investigation of aircrew for asymptomatic coronary disease.A three-phased approach to coronary artery disease (CAD) risk assessment is recommended, beginning with initial risk-stratification using a population-appropriate risk calculator and resting ECG. For aircrew identified as being at increased risk, enhanced screening is recommended by means of Coronary Artery Calcium Score alone or combined with a CT coronary angiography investigation. Additional screening may include exercise testing, and vascular ultrasound imaging. Aircrew identified as being at high risk based on enhanced screening require secondary investigations, which may include functional ischaemia, and potentially invasive coronary angiography. Functional stress testing as a stand-alone investigation for significant CAD is not recommended in aircrew. Aircrew identified with coronary disease require further clinical and aeromedical evaluation before being reconsidered for flying status.

Assessing aeromedical risk: a three-dimensional risk matrix approach

Early aeromedical risk i was based on aeromedical standards designed to eliminate individuals ii from air operations with any identifiable medical risk, and led to frequent medical disqualification. The concept of considering aeromedical risk as part of the spectrum of risks that could lead to aircraft accidents (including mechanical risks and human factors) was first proposed in the 1980s and led to the development of the 1% rule which defines the maximum acceptable risk for an incapacitating medical event as 1% per year (or 1 in 100 person-years) to align with acceptable overall risk in aviation operations. Risk management has subsequently evolved as a formal discipline, incorporating risk assessment as an integral part of the process. Risk assessment is often visualised as a risk matrix, with the level of risk, urgency or action required defined for each cell, and colour-coded as red, amber or green depending on the overall combination of risk and consequence. This manuscript describes an approach to aeromedical risk management which incorporates risk matrices and how they can be used in aeromedical decision-making, while highlighting some of their shortcomings.

Contemporaneous management of valvular heart disease and aortopathy in aircrew

Valvular heart disease (VHD) is highly relevant in the aircrew population as it may limit appropriate augmentation of cardiac output in high-performance flying and predispose to arrhythmia. Aircrew with VHD require careful long-term follow-up to ensure that they can fly if it is safe and appropriate for them to do so. Anything greater than mild stenotic valve disease and/or moderate or greater regurgitation is usually associated with flight restrictions. Associated features of arrhythmia, systolic dysfunction, thromboembolism and chamber dilatation indicate additional risk and will usually require more stringent restrictions. The use of appropriate cardiac imaging, along with routine ambulatory cardiac monitoring, is mandatory in aircrew with VHD.Aortopathy in aircrew may be found in isolation or, more commonly, associated with bicuspid aortic valve disease. Progression rates are unpredictable, but as the diameter of the vessel increases, the associated risk of dissection also increases. Restrictions on aircrew duties, particularly in the context of high-performance or solo flying, are usually required in those with progressive dilation of the aorta.

Epidemiology of Airmen Treated with Immunosuppressive Drugs and Vaccination Concerns

BACKGROUND

Immunosuppressive treatments are increasingly prescribed in a variety of diseases. This issue concerns airmen.

METHODS

To assess the problem, we conducted an observational retrospective study in the aircrew population examined in 2014 at the Aeromedical Center of Percy Military Hospital.

RESULTS

Airmen treated with immunosuppressive drugs accounted for 0.5% of the total population (N = 13,326). Rheumatic and digestive diseases were the main etiologies, respectively 43% and 35% of cases. One-third of airmen took such medications during at least 3 yr and three-quarters of airmen were declared fit to fly, with some limitations.

DISCUSSION

Due to their working conditions, airmen are exposed to a real infectious risk, which is, however, difficult to evaluate. The risk is obviously increased by immunosuppressive drugs and may affect flight safety. Aeromedical evaluation should consider this problem. Vaccination plays a central role in the prevention of infectious risk. Based on French recommendations, we propose a vaccination schedule for these particular patients.Guiu G, Monin J, Hamm-Hornez A-P, Manen O, Perrier E. Epidemiology of airmen treated with immunosuppressive drugs and vaccination concerns. Aerosp Med Hum Perform. 2018; 89(4):377-382.

Progression of early repolarization patterns at a four year follow-up in a female flight crew population: Implications for aviation medicine

BACKGROUND

To assess the prevalence, the appearance, and the distribution, as well as the fluctuation over time of early repolarization patterns after four years in a female population derived from the French aviation sector.

METHODS

This was a retrospective longitudinal study from 1998 to 2010 of a population of female employees who received a full clinical examination and an electrocardiogram (ECG) upon their recruitment and after a period of four years.

RESULTS

A total of 306 women were included (average of 25.87 ± 3.3 years of age). The prevalence of early repolarization was 9.2%. The most common appearance was J-point slurring for 64.3% (i.e. 20/28 subjects) that occurred in the inferior leads for 28.6% (i.e. 8/28 subjects). After four years, the prevalence was 7.5%, with a regression of this aspect in five of the subjects. There were no changes in the ECG in terms of the distribution and the appearance among the 23 subjects for whom the aspect persisted. Over the course of this four year period all of the subjects remained asymptomatic.

CONCLUSIONS

Early repolarization in this largely physically inactive female population was common, and it fluctuated over time. At present, no particular restrictions can be placed on asymptomatic flight crew who exhibit this feature in the absence of a prior medical history for heart disease.

Prevalence of Intraventricular Conduction Disturbances in a Large French Population

BACKGROUND

Recommendations for the interpretation of electrocardiogram have been published in 2009. The aim of this study was to define the prevalence of intraventricular conduction disturbances (ICoDs) in a large population, using these recommendations.

METHODS

From 01/31/1996 to 09/22/2010, an electrocardiogram was performed at each visit for all aircrew members examined for fitness assessment in an aeromedical center. The prevalence of left bundle branch block (LBBB), right bundle branch block (RBBB), incomplete LBBB, incomplete RBBB, nonspecific intraventricular disturbance (NIVCD), left anterior fascicular block (LAFB), and left posterior fascicular block (LPFB) was measured and compared by age and gender.

RESULTS

The global prevalence of ICoD was 3.09% in our population of 69,186 patients. The most frequent types of ventricular blocks were IRBBB (1.25%) and LAFB (1.10%), whereas RBBB (0.46%), LBBB (0.08%), ILBBB (0.03%), NIVCD (0.05%), and LPFB (0.13%) were rare findings. ICoDs are more frequent for males and older age groups (P < 0.001).

DISCUSSION

Our results are comparable to studies concerning low cardiovascular risks populations. The association between ICoD and cardiovascular diseases needs to be studied in this population.

Limitations of stroke volume estimation by non-invasive blood pressure monitoring in hypergravity

Background

Altitude and gravity changes during aeromedical evacuations induce exacerbated cardiovascular responses in unstable patients. Non-invasive cardiac output monitoring is difficult to perform in this environment with limited access to the patient. We evaluated the feasibility and accuracy of stroke volume estimation by finger photoplethysmography (SVp) in hypergravity.

Methods

Finger arterial blood pressure (ABP) waveforms were recorded continuously in ten healthy subjects before, during and after exposure to +Gz accelerations in a human centrifuge. The protocol consisted of a 2-min and 8-min exposure up to +4 Gz. SVp was computed from ABP using Liljestrand, systolic area, and Windkessel algorithms, and compared with reference values measured by echocardiography (SVe) before and after the centrifuge runs.

Results

The ABP signal could be used in 83.3% of cases. After calibration with echocardiography, SVp changes did not differ from SVe and values were linearly correlated (p<0.001). The three algorithms gave comparable SVp. Reproducibility between SVp and SVe was the best with the systolic area algorithm (limits of agreement −20.5 and +38.3 ml).

Conclusions

Non-invasive ABP photoplethysmographic monitoring is an interesting technique to estimate relative stroke volume changes in moderate and sustained hypergravity. This method may aid physicians for aeronautic patient monitoring.

Spine injuries related to high-performance aircraft ejections: a 9-year retrospective study

BACKGROUND

During an aircraft ejection, the pilot is exposed to accelerations to the point of human tolerance, which may cause spinal injuries. Many nations have reported a spinal trauma rate of about 20-30%, with plain radiography as the first-line exam. Insofar as ejection seats and diagnostic imaging have improved, the objectives of this study are to describe the spine injuries among recently ejected French aircrew, to analyze the spinal imaging used, and, if necessary, to propose a better standardized radiological procedure.

METHODS

A retrospective cohort study included all aircrews of the French forces who ejected from 2000 to 2008, with an authorized access to the technical reports of the investigations.

RESULTS

There were 36 ejections collected, 75% with an MK-10 seat and an arrival on dry land. All pilots were alive, but 42% of them sustained 24 spinal fractures, most of the time with a simple compression of the thoracic segment, but also 4 ligamentous or discal lesions. Computed tomography or RMI was used in 64% of cases and four fractures were missed or underestimated on X-ray. One complex fracture required surgical treatment. A return to flying duties was frequently possible within a period of 6 mo.

CONCLUSIONS

New generation ejection seats remain highly traumatic for the spine. It is recommended that all ejected aircrews be assessed with computed tomography to improve the sensitivity of the screening for fractures. The risk of asymptomatic lesions makes necessary the systematic use of a stretcher for initial evacuation when possible.

Ground vasovagal presyncopes and fighter pilot fitness: aeromedical concerns

BACKGROUND

Vasovagal episodes are common events but may have consequences for flight safety, particularly in high-performance aircrafts, where the autonomic nervous system is impacted during +G(z) accelerations. However, the risk is difficult to assess in the case of ground presyncopes.

CASE REPORT

A 27-yr-old fighter pilot experienced a feeling of faintness at a daily briefing. He had previously shown no medical history except for a single episode. The initial physical examination was normal. During vagal maneuvers, the pilot developed a cardiac pause and a tilt-table test was positive. Other investigations were normal.The pilot lost consciousness twice in centrifuge testing while previous tests had shown a good cardiovascular tolerance. He was declared unfit to fly fast jets but fit as a multicrew transport pilot with a waiver.

DISCUSSION

The epidemiology of vasovagal reactions is difficult to estimate in aircrew. A late occurrence in the career can be explained by either a newly acquired hypervagotonia, or an old predisposition with specific triggering factors in which psychosocial aspects are important. In such circumstances three steps are necessary to assess fitness: 1) to check for other etiologies; 2) to look for vasovagal predisposition; and 3) to check psychiatric condition. The studies about the predictive value of the tilt-test must be taken into account.

CONCLUSION

In the case of vasovagal presyncope in a fighter pilot, the aeromedical decision should consider the medical history of the pilot, the results of investigations, and the experience and motivation of the individual under review. Centrifuge testing may be useful in difficult situations.

[Treatment specifics for spontaneous pneumothorax in flight personnel]

Spontaneous pneumothorax is one cause of aeronautical unfitness in flight personnel, because of the risk of recurrence in flight, making it an issue of flight safety. Specific treatment is required for fighter pilots, pilots flying single-pilot and pilots in professional training: surgical synthesis via video-thoracoscopy is obligatory from the first episode. Considering the exposure to an accumulation of aeronautical factors that are likely to encourage pneumothorax recurrence in flight, it is apical pleurectomy together with abrasion of the remaining pleura and resection of bullae/blebs that is required for fighter pilots to allow them to recover aeronautical fitness unrestrictedly. For all other categories of flight personnel, treatment is no different from that of the common patient. Knowledge of these treatment specifics is essential, to avoid unnecessary systematic surgical indication for all flight personnel, or jeopardise professional fitness in some of them due to inappropriate treatment.

LBBB in aircrew with low cardiac risk: diagnostic application of multislice CT

INTRODUCTION

Because of its excellent negative predictive value for diagnosing coronary stenoses, multislice computed tomography (MSCT) may be a way to assess the absence of significant coronary stenosis. We discussed its place in aeromedical decision-making for aircrew members with a low level of cardiovascular risk factors and acquired left bundle branch block (LBBB).

METHODS AND RESULTS

During the period 2002-2004, 12 male aircrew members (mean age: 42.9 yr) with acquired LBBB were admitted to our cardiovascular and aeronautical department. The exploration of LBBB was classical, including an electrophysiological study, the usual coronary angiography, and MSCT. All the morphological explorations of the coronary tree were normal.

DISCUSSION

In addition to complex electrophysiological mechanisms, coronary artery disease (CAD) is suspected, but remains infrequent in some EKG findings such as acquired LBBB, especially for patients with low cardiovascular risk factors as demonstrated with our aircrew members. However, in aerospace medicine the expert needs to prove the absence of CAD. The use of standard examinations (exercise stress test, stress myocardial scintigraphy, etc.) is controversial because of artifacts and a conventional coronary angiography is necessary. According to previous studies, including using a validated technique in our department (with 16-slice computed tomography), the excellent negative predictive value of MSCT (97 to 99%) may be a way to avoid invasive exploration during the investigation of a newly acquired LBBB in aviators with low cardiovascular risk.

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.

[Right bundle branch block: electrocardiographic and prognostic features]

The electrocardiographic appearances and the significance of right bundle branch block were described at the beginning of the 20th century. Typical appearances include prolongation > 0.12 s of the QRS complex, RR' or rR' or Rr' appearances in V1 and widened S waves in the leads exploring the left ventricle (SI, aVL, V5 and V6). A delay in the appearance of the intrinsic deflection > 0.08 s may also be observed in the right precordial leads and negative T waves with ST depression may be seen in V1 and sometimes in V2. Left axis deviation of the QRS complex greater than - 45 degrees suggests associated left anterior hemiblock. Right axis deviation beyond + 120 degrees is equivocal. The principal differential ECG diagnosis is the Brugada syndrome, a familial arrhythmogenic autosomal dominant cardiomyopathy of variable penetration. This diagnosis is suggested when ECG abnormalities are observed in patients with a personal or family history of sudden death. Right bundle branch block only seems to have haemodynamic consequences in cardiac failure with associated asynchrony of the left ventricle or in certain cases of right ventricular dilatation encountered in congenital heart disease. The prognosis of right bundle branch block in the absence of underlying cardiac disease is good but it may be poor in other cases, particularly coronary artery disease. Moreover, the prognosis of right bundle branch block to complete atrioventricular block is rare in the absence of associated cardiac disease.

[Multislice computed tomography to detect coronary stenosis among asymptomatic patients with cardiovascular risk factors and equivocal prior stress test: preliminary study]

Multislice computed tomography (MSCT) is a non-invasive and validated technique to detect coronary stenoses. Some questions remain about its accuracy to detect coronary stenoses (CS), especially for asymptomatic patients (P) when a prior stress test isn't conclusive.

METHODS

MSCT was performed among 45 asymptomatic men (mean age: 58,3 +/- 16), with a high ten year risk of fatal cardiovascular disease (SCORE 2003 data for low-risk regions of Europe), without any previous coronary history and with previous non conclusive exercise testing. When significant (> 50%) CS was suspected at MSCT, an angiocoronarography (AC) was done.

RESULTS

Eighteen MSCT were normal, unsignificant CS (< 50%) were detected on 14 MSCT and significant coronary stenoses (SCS) for 13 P. Among this 13 P, 19 SCS were identified: 2 SCS of left main coronary artery (CA), 9 of the left descending CA, 6 of the right CA and 2 of the left circumflex CA. 13 CS were confirmed at AC. Finally, because of critical angiographic lesions +/- ischemia at nuclear tomoscintigraphy (NT), 9 P had coronary revascularization (7 catheter based, 2 surgical bypass), 4 P had medical treatment.

DISCUSSION

Benefits of this preliminary study are obvious: 9 coronary revascularization/45 P. However, the place of MSCT for the screening of CS is uncertain, but may be usefull as a complement for the screening of coronary arterial disease.

[The heart and aerobatics]

Aerobatics is an aerial sport which has many physiological constraints, principally cardiovascular, with a risk if not adapted of sudden mid-air incapacity which could jeopardise aviation safety, and thus justifies the selection and surveillance of pilots. The aeronautical constraints during flight are multiple, related to the environment traversed, how the aircraft functions and its movements. Those which cause accelerations (+G in particular) pose the problem of haemodynamic tolerance because they can induce loss of consciousness due to cerebral hypoxia. Tolerance of acceleration varies among individuals; it can be improved with training, certain protective manoeuvres, and is reduced by hypoxia, certain medications, dehydration and heat. Moreover, in aerobatics certain tricks require manoeuvres which reduce this tolerance to +G accelerations. This is the "push-pull" effect (_G acceleration immediately followed by +G acceleration). This leads to a risk of sudden loss of consciousness with a load factor much lower than that which the pilot knows he is capable of tolerating. Besides the haemodynamic effects, the existence of an actual acceleration cardiomyopathy has been suggested but has not been proven in man. Finally, while changes in cardiac rhythm during accelerations are usual and relate to changes in vaso-sympathetic balance, ventricular and supra-ventricular rhythm disturbances are rare and are related to the intensity and duration of the acceleration.