Aeromedical Evaluation Research Articles

Upgradation of aircrew with minor musculoskeletal injuries in the operational bases: Need for a relook

Objectives: Musculoskeletal injuries (MSKI) have been one of the most common contributors to disabilities among aircrew. The existing policy mandates all cases of MSKI in aircrew of the Indian Air Force, including minor injuries such as a sprain of small joints and phalangeal fractures to be evaluated at the Institute of Aerospace Medicine (IAM), majority of which do not warrant a complete Human Engineering (HE) assessment. Hence, a need was felt to decentralize evaluation and empower other boarding centers/operational bases with local aerospace medicine specialists to carry out the evaluation. Material and Method: A retrospective analysis was carried out of a total of 930 cases of MSKI among serving aircrew who reported to IAM between Jan 2016 and Oct 2020. Results: About 27.68% of cases were of lower limb injuries and 16.52% of cases were of upper limb injuries. About 36.77% of cases of upper limb and 52.71% of cases of lower limb injuries were treated surgically while 63.23% upper limb and 47.29% lower limb injuries were managed conservatively. Full functional recovery within 12 weeks was seen in a significant number of conservatively treated distal upper and lower limb injuries not involving joints. Conclusion: HE assessment of MSKI at IAM is comprehensive including exposure to simulated aeromedical stressors. However, certain minor musculoskeletal disabilities did not require full HE evaluation and simulator facilities of IAM. Sending aircrew with such minor disabilities from field units to IAM amounts to an administrative obligation that can be avoided by empowering other medical boarding centers and local operational bases which have aerospace medicine specialists. This paper discusses the procedure of conduct and facilitation of aeromedical evaluation of aircrew in the non-flying medical category with certain minor MSKI in the field.

A case of low G-tolerance: An approach to aeromedical evaluation and disposal

Conventionally, aircrew who is not able to withstand +7 Gz, 15 s with an anti-G suit (AGS) and anti-G straining maneuver (AGSM) is considered to have low G-tolerance. Aircrew suspected to have low G-tolerance needs to be comprehensively evaluated. This paper highlights our approach to aeromedical evaluation and disposal of a suspected case of low G-tolerance in an under-trainee (U/T) fighter aircrew. A 21-year-old U/T fighter aircrew presented with multiple episodes of gray out/blackout while flying syllabus sorties on exposure to 4.5 G and was not able to pull beyond 5 G. A detailed history did not reveal any likely predisposing factors for reducing G-tolerance. A detailed clinical evaluation did not reveal any organic pathology. During high-performance human centrifuge evaluation, his baseline relaxed (R) and straining (S) GOR and rapid onset rate (ROR) tolerance were found to be 3.2 G (R); 6.3 G (S) and 3 G (R); 4.5 G (S), respectively. He was unable to sustain beyond 6 Gz for the 30 s even with AGS and supervised AGSM. He underwent a 12-week supervised physical conditioning program. Reassessment following 12 weeks revealed a significant improvement in physical strength parameters. However, the aircrew could not withstand 6 G for 30 s even with AGS and supervised AGSM. The aircrew was diagnosed as a case of low G-tolerance and was recommended unfit for fighter flying. Any episode of visual symptoms of loss of consciousness due to G forces is potentially incapacitating in the air. Hence, aircrew suspected to have low G-tolerance needs to comprehensively evaluated. The evaluation should include a careful history to rule out any pre-disposing factors and a detailed clinical assessment to exclude organic disability. Aircrew needs to be indoctrinated on correct AGSM technique and proper fitment of AGS must be ensured during centrifuge evaluation. Before labeling an aircrew as a case of low G-tolerance, he should be assessed for his physical fitness and undergo a supervised physical conditioning program.

Aeromedical Implications of Long-Term COVID-19 Sequelae.

BACKGROUND: While many COVID-19 studies focus on acute effects of the infection, few examine the intermediate and long-term sequelae of the illness. Studies have shown that a good portion of patients have chronic effects in several body systems for several months or longer. Such effects can potentially adversely impact pilot performance in flight. We sought to determine the long-term effects of COVID-19 infection, how such effects can affect pilot performance, and how to best evaluate pilots for aeromedical flight clearance.METHODS: We used the PubMed literature search engine to review peer-reviewed articles that focused on the intermediate and long-term effects of COVID-19 infection. Chronic signs and symptoms were subdivided based on the particular body organ system affected. Merging information obtained from case reviews, article reviews, and aeromedical standards, we created a risk stratification guide to assist with the aeromedical disposition of affected pilots.RESULTS: Long-term effects of COVID-19 infection can last for several months or longer. The most common effects are fatigue, weakness, pulmonary diffusion defects, depression, and anxiety.DISCUSSION: This review article focuses on the most common intermediate- and long-term COVID-19 conditions of aeromedical significance and the corresponding course of actions recommended for the aeromedical examiner. Aeromedical evaluation should take into consideration factors related to the pilot, aircraft type, and specific aviation environment. Such evaluation may include diagnostic testing, medical specialist consultation, preflight simulation in an altitude chamber, human centrifuge testing, and/or a flight simulator checkride.Ko SY, Nguyen NK, Lee CL, Lee LA, Nguyen KUT, Lee EC. Aeromedical implications of long-term COVID-19 sequelae. Aerosp Med Hum Perform. 2021; 92(11):898-907.

Establishment of a normative data for cervical and lumbar spine movements using spinal column analysis system

Introduction: The current assessment of spine movements during aeromedical evaluation of aircrew is performed using the CMS 20 spinal column analysis system. However, in the present configuration, the normal ranges of cervical and lumbar spine motions depicted by the equipment are based on normative data of German population measured by goniometric method. The study was conducted to generate normative values of cervical and lumbar spine movements with respect to age-specific Indian male population. Material and Methods: The study included a total of 225 healthy male Indian volunteers, divided into three age groups; <25 years, 25–35 years, and above 35 years, with 75 subjects in each age group. In each participant, ten cervical spine movements and six lumbar spine movements were recorded using CMS 20 S spinal column analysis system. The data were statistically analyzed to establish normative data for each of the cervical and lumbar spine movements for three age groups (<25 years, 25–35 years, and >35 years). Results: The mean age, height & weight of the participants were 21.2, 28.3 and 39.4 years, 173.1, 171.6 and 170.6 cm, 65.9, 68.7 and 70.2 kg respectively for the three different age groups - <25 years, 25-35 years and >35 years. The mean values along with standard deviation of the ten cervical and eight lumbar spine movements were derived and presented for the three different age groups. Conclusion: The normative data generated in the present study as per the three age groups may be used as reference values for male Indian personnel for that specific age groups for the assessment of cervical and lumbar spine movements using spinal column analysis system. The data may also be used as baseline data for aeromedical evaluation and future aviation research involving the same equipment.

Analysis of cardiovascular responses to head-up tilt testing

Introduction: Head-up tilt (HUT) testing is a widely accepted tool in the clinical evaluation of patients presenting with episodic loss of consciousness. The test has assumed its importance in aviation environment, where a single episode of unconsciousness in-flight may have a catastrophic outcome. To rule out this, HUT is carried out in all cases of syncope as a part of aeromedical evaluation. The present study was undertaken to analyze the CVS response to HUT conducted over a period of 11 years at the Department of Space and Environmental Physiology at the Institute of Aerospace Medicine. Material and Methods: A total of 168 subjects had undergone HUT testing from 2002 to 2012. The testing equipment was a standard tilt table with a foot board support for the feet and restraint system at the level of chest, waist, and ankle to support the body during tilting. The testing protocol consisted of passive tilting to an angle of 70° from the horizontal position for 45 min in all the cases. The physiological parameters consisting of heart rate (HR) and blood pressure from the database were analyzed to understand the CVS response to HUT. Results: Out of the total 168 patients, 147 (88.5%) cases showed normal response. Twenty-one (12.5%) cases showed abnormal response. Out of the cases showing abnormal response, 14 cases had syncope with frank loss of consciousness and could not maintain the postural tone. The remaining seven cases showed postural orthostatic tachycardia syndrome (POTS), where the HR increased by more than 30 beats per minute. Conclusion: A retrospective analysis of 168 cases with history of syncope, in a period of 11 years, revealed an abnormal cardiovascular response to HUT in 12.5% of cases. The abnormal physiological responses were mostly consistent with syncope and POTS.

A rare case of “coronary slow-flow phenomena” in an aviator: An approach to aeromedical disposition – A case report

Introduction: Coronary slow-flow phenomenon (CSFP) is a frequent angiographic finding with obscure pathophysiology. Although recognized for decades, the incidence of such a clinical entity is rare in aviation environment and poses unique aeromedical challenges in disposition of the aircrew. Case Details: A 53-year-old asymptomatic pilot from a helicopter stream was detected to have ECG abnormality during a routine medical examination. His treadmill test was borderline positive for inducible myocardial ischemia, whereas angiography revealed proximal ectasia with a slow flow. He was diagnosed as a case of “Coronary Slow-Flow Phenomenon,” started on antiplatelets and was observed on ground for 36 weeks. A comprehensive cardiological evaluation following that revealed an asymptomatic status, controlled modifiable risk factors and no progression of ECG changes. Echocardiography, 24 h Holter, and stress MPI were essentially normal. Based on an evidence-based approach, the aircrew were reflighted back to flying in a multicrew aircraft. Discussion: This case study discusses our approach to aeromedical evaluation and disposition of a helicopter pilot with CSFP, which is unique, yet rarely encountered disability among aircrew.

The Effect of Using the Lower Limit of Normal 2.5 in Pulmonary Aeromedical Assessments.

INTRODUCTION: Many regulations for aeromedical assessments state that a ratio between forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of < 0.7 should be evaluated by a pulmonary specialist. The Global Lung Initiative (GLI) reference values introduced the lower limit of normal (LLN 2.5), in which the lowest 2.5% of the population is regarded as abnormal, instead of a fixed ratio. This study assesses the impact of adopting GLI reference values on aeromedical evaluation and referrals.METHODS: The Royal Netherlands Air Force performed 7492 aeromedical assessments between February 2012 and April 2017. Cases with FEV1/FVC < 0.7 from three groups were selected: 1) men < 25 yr; 2) men > 40 yr; and 3) women, with twice as many matched controls. Pearson's Chi-squared and Fisher's exact tests were used to analyze the data.RESULTS: From the database, 23 (group 1), 62 (group 2), and 7 (group 3) cases were selected, with 184 controls. Respectively, 17%, 84%, and 29% would not be referred using the GLI. In the controls, this would lead to one additional referral (group 1). Qualitative analysis of the cases who would not be referred using the GLI showed that no significant diagnoses would have been missed.DISCUSSION: Using the GLI LLN 2.5 reference values for pulmonary function tests leads to significantly fewer referrals to a pulmonary specialist without missing relevant pulmonary pathology in our aircrew. This would reduce resources spent on the assessment of aircrew without compromising flight safety.Wingelaar-Jagt YQ, Wingelaar TT, Bülbül M, vd Bergh PP, Frijters E, Staudt E. The effect of using the lower limit of normal 2.5 in pulmonary aeromedical assessments. Aerosp Med Hum Perform. 2020; 91(8):636-640.

A paradigm approach toward predicting barotrauma

Barotrauma is one of the most common medical problems associated with aviation and has been a causal factor for significant loss of trained aircrew hours. The occurrence of barotrauma has been reported not only in flight but also during simulated exposures to changing pressures as a part of aeromedical evaluation and training. This occurrence is despite the screening of individuals by otoscopy and tympanometry before exposure to barometric changes. In such cases, baro-challenge-induced eustachian tube (ET) dysfunction has been identified as the most probable cause, leading to decreased ability to equalize pressures across the middle ear. This paper describes a paradigm approach to the prediction of baro-challenge-induced ET dysfunction using the nine-step test and ET dysfunction questionnaire. The inclusion of the test as a screening tool before exposure of aircrew to baro-challenge after recovery from their ear, nose, and throat ailments is recommended to prevent occurrence/ reoccurrence of barotrauma.

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.

Epidemiology of Airmen Treated with Immunosuppressive Drugs and Vaccination Concerns.

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

Horizontal canal benign paroxysmal positional vertigo in a fighter pilot

Benign paroxysmal positional vertigo (BPPV) is the most common disorder of the peripheral vestibular system, characterized by intense, positional provoked vertigo. BPPV is thought to occur due to canalithiasis of the posterior semicircular canal. Recently, a new entity of BPPV, known as horizontal canal (HC)-BPPV, has been recognized. Although only 3 to 8% of BPPV is due to horizontal canal involvement, HC-BPPV is not rare. We present a case of a naval fighter pilot who had an incident of HC-BPPV on the ground. The pilot aeromedical evaluation and considerations are discussed.

Disaster Management and Response

1. The Changing Face of Nursing Practice: Homeland Security Challenges to Health Care Delivery (Boatright, McGlown) 2. Disaster Nursing Competencies (Bond, Beaton) 3. Care of the Victim of Bioterrorism During Aeromedical Evaluation (Cieslak, Herrold) 4. Historical Lessons Learned from Third World Disasters (Davies) 5. The Impact of the Disaster Experience on Culture, Self and Identity: A Need for Increased Awareness Among Healthcare Professionals (Deeny, McFetridge) 6. Mass Casualty Triage: Field Considerations in WMD Events (Hembree) 7. Antidote Therapy for Hazardous Materials (Lehmann, Weber) 8. Care of the Patient Exposed to Biological Agents (Ricciardi) 9. Role of Public Health Nurses in Emergency Preparedness and Response (Rowney) 10. Competency Development and How Competencies can be Integrated into the Basic Nursing Curriculum (Stanley) 11. Preparing Hospital-Based Nurses for Radiation Emergencies: Clinical Response and Systems Preparedness (Veenema) 12. A National Curriculum in Emergency Preparedness for Nurses (Weiner) 13. Pediatrics in Disasters (Hohenhaus)

The Effects of Air Pollution on the Lipid Balance of Traffic Police Personnel

The purpose of our study was to evaluate the effects of urban pollution on the lipid balance of members of a municipal police force in a big city. Our case-control study comprised 118 male members of the police force performing traffic duties, and 118 blood donors who perform office work, and was paired by age and length of service. Total cholesterol, HDL and triglycerides were studied. The comparison of the average values of HDL cholesterol and triglycerides between the exposed traffic police group and the control group showed significant differences. The difference in the frequency distributions of HDL cholesterol and triglycerides between the exposed group and control group was significant as well. The results suggest the possibility of an alteration in the lipid balance among asymptomatic people who are exposed to air pollution. The results suggest that some chemical agents (such as carbon dioxide) contained in the urban pollution of a big city could cause dyslipidemia among people exposed to such air pollution.

Dysrhythmia comparison in apparently healthy males during and after treadmill and acceleration stress testing

Maximal treadmill exercise stress testing and centrifuge +G z-acceleration stress testing are both known to be dysrhythmogenic. A comparison of the effects of these two stresses on 60 healthy men was performed. The 60 individuals were divided into three groups of 20 each. One group was made up of healthy volunteer members from the United States Air Force School of Aerospace Medicine acceleration stress panel. The other two groups were asymptomatic USAF aircrewmen undergoing aeromedical evaluation for newly discovered dysrhythmias (dysrhythmia group) and for other aeromedical abnormalities (nondysrhythmia group). The effect of these two stresses on the poststress cardiac rate and rhythm were also evaluated by means of 24-hour Holter monitoring. Both stresses were observed to induce dysrhythmias with approximately the same frequency in the two patient groups; but, with the panel members who experienced higher +G z stress, the centrifuge stress induced more dysrhythmias than did treadmill exercise stress. The stress-induced changes were limited to the period of stress and did not significantly affect cardiac rate or rhythm in the poststress 24-hour period. Certain dysrhythmias were more commonly associated with centrifuge stress. Centrifuge acceleration stress testing apparently is as safe as maximal treadmill exercise testing. For USAF high-performance fighter pilots who are routinely exposed to repeated high sustained +G z stress during aerial combat, it is imperative to assure that they are not predisposed to +G z-induced dysrhythmias which could cause sudden inflight incapacitation. Centrifuge stress testing is therefore a valuable tool in the aeromedical evaluation of these aircrewmen.