INTRODUCTION: To ensure flight safety military aircrew undergo regular clinical and occupational assessment. Coronary artery calcium scoring (CACS) has been established as an imaging modality to noninvasively assess coronary artery disease (CAD). CT coronary angiography (CTCA) potentially offers a more accurate assessment of CAD, but has not been formally assessed in military aircrew. This retrospective cohort study is designed to compare the theoretical differences in downstream investigations and occupational outcomes in aircrew with suspected CAD comparing CTCA with existing CACS pathways.METHOD: A 2-yr retrospective cohort study of consecutive UK military patients who underwent a CTCA and CACS was undertaken. Patient demographics, CTCA and CACS results, and initial and final occupational restrictions were analyzed comparing current UK, Canadian, and U.S. pathways.RESULTS: There were 44 patients who underwent CACS and CTCA. The commonest indication for a CTCA was a positive exercise ECG. Increasing CACS, stenosis severity, and stenosis burden were associated with significantly greater likelihood of occupational restriction (P = < 0.01). Following CTCA, 26/44 (59%) patients were found to have evidence of CAD, with 13/44 (30%) having at least a single vessel stenosis ≥50%. All of these patients had subsequent occupational restrictions. Two patients with a calcium score ≤10 had at least 1 single vessel stenosis ≥50%.DISCUSSION: A CTCA pathway is potentially a better discriminator of CAD burden in aircrew when compared with CACS and may reduce downstream testing, allowing a more efficacious approach to CAD assessment in military aircrew.Parsons I, Pavitt C, Chamley R, d’Arcy J, Nicol E. CT coronary angiography vs. coronary artery calcium scoring for the occupational assessment of military aircrew. Aerosp Med Hum Perform. 2017; 88(2):76–81.

BACKGROUND: Despite improvements in medical technology, lung cancer metastasis remains a global health problem. The effects of microgravity on cell morphology, structure, functions, and their mechanisms have been widely studied; however, the biological effects of simulated microgravity on the interaction between cells and its eventual influence on the characteristics of cancer cells are yet to be discovered. We examined the effects of simulated microgravity on the metastatic ability of different lung cancer cells using a random positioning machine.METHODS: Human lung cancer cell lines of adenocarcinoma (A549) and squamous cell carcinoma (H1703) were cultured in a 3D clinostat system which was continuously rotated at 5 rpm for 36 h. The experimental and control group were cultured under identical conditions with the exception of clinorotation.RESULTS: Simulated microgravity had different effects on each lung cancer cell line. In A549 cells, the proliferation rate of the clinostat group (2.267 ± 0.010) after exposure to microgravity did not differ from that of the control group (2.271 ± 0.020). However, in H1703 cells, the proliferation rates of the clinostat group (0.534 ± 0.021) was lower than that of the control group (1.082 ± 0.021). The migratory ability of both A549 [remnant cell-free area: 33% (clinostat) vs. 78% (control)] and H1703 cells [40% (clinostat) vs. 68% (control)] were increased after exposure to microgravity. The results of the molecular changes in biomarkers after exposure to microgravity are preliminary.DISCUSSION: Simulated microgravity had different effects on the proliferation and migration of different lung cancer cell lines.Chung JH, Ahn CB, Son KH, Yi E, Son HS, Kim H-S, Lee SH. Simulated microgravity effects on nonsmall cell lung cancer cell proliferation and migration. Aerosp Med Hum Perform. 2017; 88(2):82–89.

BACKGROUND: The aim of the present study was to compare differences in electromyography (EMG) activation of the neck and shoulder muscles between groups of inexperienced and experienced pilots during controlled +G_z exposure in a centrifuge. METHODS: The subjects were volunteer cadets (inexperienced group) and lieutenants (experienced group) undergoing their first centrifuge training. The first group did not have any high performance aircraft (HPA) experience, while the latter one had a 1-yr experience of intense flying of HPA. During the centrifuge run, EMG activity was recorded from the left and right shoulder, neck flexor, and neck extensor muscles. RESULTS: The pilots without HPA experience had significantly higher muscle activity in the neck flexor and extensor muscles during the last 5 s of the recorded period at G levels exceeding +7.4. DISCUSSION: Muscle activity in the neck and shoulder muscles was gradually higher among the whole study group with increasing +G_z forces. Because pilots without any HPA experience had significantly higher muscle activity than their counterparts with experience of HPA, we suppose that the experience of high +G_z forces might lead to lower muscle activation in the same flight mission. Honkanen T, Oksa J, Mäntysaari MJ, Kyröläinen H, Avela J. Neck and Shoulder Muscle Activation Among Experienced and Inexperienced Pilots in +G_z Exposure. Aerosp Med Hum Perform. 2017; 88(2):90–95.

INTRODUCTION: Back pain has remained an issue of significance among aircraft crewmembers for decades, occurring in the majority of military helicopter pilots with potential deleterious effects on performance, safety, and operational readiness. This exploratory, correlational survey study was designed to evaluate the presence of patterns and relationships that may require further examination to understand causal factors.METHODS: The study population consisted of U.S. Army aviation crewmembers. Subjects (467) completed an anonymous survey, including questions regarding demographics, airframes, experience, pain history and severity, ergonomics, mitigation strategies, and duty limitations.RESULTS: Overall, 84.6% of participants reported back pain at some time during their flying career, with 77.8% reporting back pain in the last calendar year. Age was found to significantly correlate with earlier time to pain during flight, higher pain rating after flight, and occurrence of grounding. A stepwise linear regression model was used to explore the relationships between age, flight hours, and years of aviation experience, demonstrating age to be the significant variable accounting for the observed variance. Aircrew reported wear of combat-related survival equipment and poor lumbar support to be the most notable contributors.DISCUSSION: Back pain rates were consistent with previous studies. The relationship of age to back pain in this study may highlight unique pathophysiological pathways that should be further investigated within an occupational context to better understand the etiologic role. Enhanced seated lumbar support and combat-related survival equipment remain relatively low-cost/high-yield topics worthy of further investigation for exploiting efficient means to improve health, safety, and operational performance.Kelley AM, MacDonnell J, Grigley D, Campbell J, Gaydos SJ. Reported back pain in army aircrew in relation to airframe, gender, age, and experience. Aerosp Med Hum Perform. 2017; 88(2):96–103.

INTRODUCTION: NASA regularly performs ground-based offgas tests (OGTs), which allow prediction of accumulated volatile pollutant concentrations at first entry on orbit, on whole modules and vehicles scheduled to connect to the International Space Station (ISS). These data guide crew safety operations and allow for estimation of ISS air revitalization systems impact from additional pollutant load. Since volatiles released from vehicle, module, and payload materials can affect crew health and performance, prediction of first ingress air quality is important.METHODS: To assess whether toxicological risk is typically over or underpredicted, OGT and first ingress samples from 10 vehicles and modules were compared. Samples were analyzed by gas chromatography and gas chromatography-mass spectrometry. The rate of pollutant accumulation was extrapolated over time. Ratios of analytical values and Spacecraft Maximum Allowable Concentrations were used to predict total toxicity values (T-values) at first entry. Results were also compared by compound.RESULTS: Frequently overpredicted was 2-butanone (9/10), whereas propanal (6/10) and ethanol (8/10) were typically underpredicted, but T-values were not substantially affected. Ingress sample collection delay (estimated by octafluoropropane introduced from ISS atmosphere) and T-value prediction accuracy correlated well (R² = 0.9008), highlighting the importance of immediate air sample collection and accounting for ISS air dilution.DISCUSSION: Importantly, T-value predictions were conservative 70% of the time. Results also suggest that T-values can be normalized to octafluoropropane levels to adjust for ISS air dilution at first ingress. Finally, OGT and ingress sampling has allowed small leaks in vehicle fluid systems to be recognized and addressed.Romoser AA, Scully RR, Limero TF, De Vera V, Cheng PF, Hand JJ, James JT, Ryder VE. Predicting air quality at first ingress into vehicles visiting the International Space Station. Aerosp Med Hum Perform. 2017; 88(2):104–113.

BACKGROUND: Using ultrasound imaging, vascular gas emboli (VGE) are observed after asymptomatic scuba dives and are considered a key element in the potential development of decompression sickness (DCS). Diving is also accompanied with vascular dysfunction, as measured by flow-mediated dilation (FMD). Previous studies showed significant intersubject variability to VGE for the same diving exposure and demonstrated that VGE can be reduced with even a single pre-dive intervention. Several preconditioning methods have been reported recently, seemingly acting either on VGE quantity or on endothelial inflammatory markers.METHODS: Nine male divers who consistently showed VGE postdive performed a standardized deep pool dive (33 m/108 ft, 20 min in 33°C water temperature) to investigate the effect of three different preconditioning interventions: heat exposure (a 30-min session of dry infrared sauna), whole-body vibration (a 30-min session on a vibration mattress), and dark chocolate ingestion (30 g of chocolate containing 86% cocoa). Dives were made one day per week and interventions were administered in a randomized order.RESULTS: These interventions were shown to selectively reduce VGE, FMD, or both compared to control dives. Vibration had an effect on VGE (39.54%, SEM 16.3%) but not on FMD postdive. Sauna had effects on both parameters (VGE: 26.64%, SEM 10.4%; FMD: 102.7%, SEM 2.1%), whereas chocolate only improved FMD (102.5%, SEM 1.7%).DISCUSSION: This experiment, which had the same subjects perform all control and preconditioning dives in wet but completely standardized diving conditions, demonstrates that endothelial dysfunction appears to not be solely related to VGE.Germonpré P, Balestra C. Preconditioning to reduce decompression stress in scuba divers. Aerosp Med Hum Perform. 2017; 88(2):114–120.

INTRODUCTION: High prevalence of neck pain among skydivers is related to parachute opening shock (POS) exposure, but few investigations of POS deceleration have been made. Existing data incorporate equipment movements, limiting its representability of skydiver deceleration. This study aims to describe POS decelerations and compare human- with equipment-attached data.METHODS: Wearing two triaxial accelerometers placed on the skydiver (neck-sensor) and equipment (rig-sensor), 20 participants made 2 skydives each. Due to technical issues, data from 35 skydives made by 19 participants were collected. Missing data were replaced using data substitution techniques. Acceleration axes were defined as posterior to anterior (+a_x), lateral right (+a_y), and caudal to cranial (+a_z). Deceleration magnitude [a_max (G)] and jerks (G · s⁻¹) during POS were analyzed.RESULTS: Two distinct phases related to skydiver positioning and acceleration direction were observed: 1) the x-phase (characterized by −a_x, rotating the skydiver); and 2) the z-phase (characterized by +a_z, skydiver vertically oriented). Compared to the rig-sensor, the neck-sensor yielded lower a_max (3.16 G vs. 6.96 G) and jerk (56.3 G · s⁻¹ vs. 149.0 G · s⁻¹) during the x-phase, and lower jerk (27.7 G · s⁻¹ vs. 54.5 G · s⁻¹) during the z-phase.DISCUSSION: The identified phases during POS should be considered in future neck pain preventive strategies. Accelerometer data differed, suggesting human-placed accelerometry to be more valid for measuring human acceleration.Gladh K, Lo Martire R, Äng BO, Lindholm P, Nilsson J, Westman A. Decelerations of parachute opening shock in skydivers. Aerosp Med Hum Perform. 2017; 88(2):121–127.

INTRODUCTION: Flights to high altitude can lead to exposure and unique pathology not seen in normal commercial aviation.METHODS: This paper assesses the potential for point-of-care ultrasound to aid in management and disposition of injured crewmembers from a high altitude incident. This was accomplished through a systematic literature review regarding current diagnostic and therapeutic uses of ultrasound for injuries expected in high altitude free fall and parachuting.RESULTS: While current research supports its utility in diagnostics, therapeutic procedures, and triage decisions, little research has been done regarding its utility in high altitude specific pathology, but its potential has been demonstrated.DISCUSSION: An algorithm was created for use in high altitude missions, in the event of an emergency descent and traumatic landing for an unconscious and hypotensive pilot, to rule out most life threatening causes. Each endpoint includes disposition, allowing concise decision-making.Galdamez LA, Clark JB, Antonsen EL. Point-of-care ultrasound utility and potential for high altitude crew recovery missions. Aerosp Med Hum Perform. 2017; 88(2):128–136.

BACKGROUND: Sinusoidal lower body negative pressure (SLBNP) has been used to investigate the cardiovascular response to slow periodic changes in blood shifts, but measurements of slow fluctuations take a long time if measured for each period of SLBNP separately. Our study aimed to investigate whether the cardiovascular responses to superimposed SLBNP (S-SLBNP), which is expected to reduce the measurement time, are different from responses measured individually.METHODS: S-SLBNP was configured by superimposing two conventional SLBNPs (C-SLBNP) at 180-s and 30-s periods in the pressure range from 0 to −25 mmHg. As the S-SLBNP has double the static load of C-SLBNP, we also used offset SLBNP (O-SLBNP), which has the same static load level as S-SLBNP. Heart rate (HR), thoracic impedance (Z₀), and mean arterial pressure (MAP) were measured from 11 male subjects. The transfer functions of gains from MAP to HR (Gain-HR/MAP) and from Z₀ to HR (Gain-HR/Z₀) were calculated as indexes of arterial baroreflex and cardiopulmonary baroreflex regulation of HR, respectively.RESULTS: The Gain-HR/MAP in the 180-s period (2.11 ± 0.17 bpm/mmHg; mean ± SEM) was larger than that of the 30-s period (1.04 ± 0.09 bpm/mmHg); however, there was no significant difference between the SLBNP conditions. The Gain-HR/Z₀ in C-SLBNP (9.37 ± 1.47 bpm/ohm) was smaller than that of the other conditions [18.46 ± 2.45 bpm/ohm (O-SLBNP); 16.09 ± 2.29 bpm/ohm (S-SLBNP)].DISCUSSION: Using S-SLBNP could reduce the measurement time needed to examine the arterial baroreflex. However, the cardiopulmonary baroreflex was modified by the static load of SLBNP.Ishibashi K, Oyama F, Yoshida H, Iwanaga K. Additive effects of sinusoidal lower body negative pressure on cardiovascular responses. Aerosp Med Hum Perform. 2017; 88(2):137–141.

BACKGROUND: Currently it is not unusual for general aviation pilots in the United States to continue to fly beyond the age of 70, even into their 80s and 90s. Pilots have regular examinations according to protocols which do not specify special or additional requirements for pilots over 70 yr of age. Additionally, the third class medical reforms passed by the U.S. Senate on 15 July 2016 could potentially result in even less stringent medical certification requirements for general aviation pilots.METHODS: Accident rates, medical parameters, autopsy findings, and toxicological findings from the U.S. National Transportation Safety Board (NTSB) general aviation (GA) accident database were analyzed to assess potential risk factors with accident outcomes.RESULTS: During 2003–2012, there were 114 (113 men, 1 woman) general aviation fatal accidents involving pilots ages 70 to 92 yr. A combination of 3 or more drugs were found in 13 (13%) of deceased pilots. The most frequent drugs were first generation antihistamines and antidepressants represented the next highest proportion of possible performance-affecting medications.CONCLUSION: This study indicates that there are critical medical factors that may contribute to fatal accidents among elderly pilots. Polypharmacy use should be taken into consideration, especially during periodic health examinations and fatal aviation investigations involving elderly pilots.Vuorio A, Asmayawati S, Budowle B, Griffiths R, Strandberg T, Kuoppala J, Sajantila A. General aviation pilots over 70 years old. Aerosp Med Hum Perform. 2017; 88(2):142–145.

BACKGROUND: The aim of this study was to quantify causes of medical disqualification (groundings) of Norwegian commercial pilots for the period 2006–2010, and to compare our findings with former Norwegian studies on the subject to reveal possible changes in the disease spectrum over the last decades. We compared our data with previous studies for the periods 1982–1997 and 1997–2001, respectively.METHODS: The material was collected from the aeromedical section's archive. Files on all grounded pilots have been reviewed and classified by age group and diagnosis and grounding rates have been calculated.RESULTS: From the study population comprising 12,552 pilot-years for the years 2006–2010 inclusive, 85 pilots were permanently grounded, i.e., an average grounding rate of 6.8 per 1000 pilot-years.DISCUSSION: Compared with previous data there is a significant decrease in the disqualification rate due to cardiovascular conditions, while the disqualification rates due to ear, nose, and throat conditions and neurological conditions have both increased significantly.Høva JK, Thorheim L, Wagstaff AS. Medical reasons for loss of license in Norwegian professional pilots. Aerosp Med Hum Perform. 2017; 88(2):146–149.

Kahl CG. You’re the flight surgeon: immunoglobulin A nephropathy. Aerosp Med Hum Perform. 2017; 88(2):150–153.