Taibbi G, Cromwell RL, Zanello SB, Yarbough PO, Ploutz-Snyder RJ, Godley BF, Vizzeri G. Ocular outcomes evaluation in a 14-day head-down bed rest study. Aviat Space Environ Med 2014; 85:983–92.Introduction: We evaluated ocular outcomes in a 14-d head-down tilt (HDT) bed rest (BR) study designed to simulate the effects of microgravity on the human body. Methods: Healthy subjects were selected using NASA standard screening procedures. Standardized NASA BR conditions were implemented (e.g., strict sleep-wake cycle, standardized diet, 24-hour-a-day BR, continuous video monitoring). Subjects maintained a 6° HDT position for 14 consecutive days. Weekly ophthalmological examinations were performed in the sitting (pre/post-BR) and HDT (in-bed phase) positions. Equivalency tests with optimal-alpha techniques evaluated pre/post-BR differences in best-corrected visual acuity (BCVA), spherical equivalent, intraocular pressure (IOP), Spectral-domain OCT retinal nerve fiber layer thickness (RNFLT), optic disc and macular parameters. Results: 16 subjects (12 men and 4 women) were enrolled. Nearly all ocular outcomes were within our predefined clinically relevant thresholds following HDTBR, except near BCVA (pre/post-BR mean difference: -0.06 logMAR), spherical equivalent (-0.30 D), Tonopen XL IOP (+3.03 mmHg) and Spectralis OCT average (+1.14 μm), temporal-inferior (+1.58 μm) and nasal-inferior RNFLT (+3.48 μm). Modified Amsler grid, red dot test, confrontational visual field, and color vision were within normal limits throughout. No changes were detected on stereoscopic color fundus photography. Discussion: A few functional and structural changes were detected after 14-d HDTBR, notably an improved BCVA possibly due to learning effect and RNFL thickening without signs of optic disc edema. In general, 6° HDTBR determined a small nonprogressive IOP elevation, which returned to baseline levels post-BR. Further studies with different BR duration and/or tilt angle are warranted to investigate microgravity-induced ophthalmological changes.

Cialoni D, Pieri M, Balestra C, Marroni A. Flying after diving: in-flight echocardiography after a scuba diving week. Aviat Space Environ Med 2014; 85:993–8.Introduction: Flying after diving may increase decompression sickness risk (DCS), but strong evidence indicating minimum preflight surface intervals (PFSI) is missing. Methods: On return flights after a diving week on a live-aboard, 32 divers were examined by in-flight echocardiography with the following protocol: 1) outgoing flight, no previous dive; 2) during the diving week; 3) before the return flight after a 24-h PFSI; and 4) during the return flight. Results: All divers completed similar multiple repetitive dives during the diving week. All dives were equivalent as to inert gas load and gradient factor upon surfacing. No bubbles in the right heart were found in any diver during the outgoing flight or at the preflight control after a 24-h PFSI following the diving week. A significant increase in the number and grade of bubbles was observed during the return flight. However, bubbles were only observed in 6 of the 32 divers. These six divers were the same ones who developed bubbles after every dive. Conclusions: Having observed a 24-h preflight interval, the majority of divers did not develop bubbles during altitude exposure; however, it is intriguing to note that the same subjects who developed significant amounts of bubbles after every dive showed equally significant bubble grades during in-flight echocardiography notwithstanding a correct PFSI. This indicates a possible higher susceptibility to bubble formation in certain individuals, who may need longer PFSI before altitude exposure after scuba diving.

Chen X, Liu Y, Yu Q, Zheng L, Hong X, Yan F, Yu H. Dental caries status and oral health behavior among civilian pilots. Aviat Space Environ Med 2014; 85:999–1004.Objectives: This study was aimed at investigating the caries status of Chinese civilian pilots and the relationship between caries and oral health behaviors, including sugar intake, smoking, alcohol consumption, tooth brushing, and dental check-up attendance. Methods: This cross-sectional investigation enrolled pilots from Shenzhen Airline. A questionnaire was used to collect general information and oral health behaviors. The Decayed, Missing, and Filled Teeth (DMFT) Index, International Caries Detection and Assessment System (ICDAS) II, caries prevalence, and rate of missing teeth were recorded via oral examination. Rank correlation was used to reveal the correlation between caries and oral health behavior. Results: All of the pilots were men ages 21–58 yr (mean, 31.48 ± 7.20). In the caries group (CG), the frequency of tooth brushing and flossing was a little higher; more subjects had already given up smoking; more subjects had higher alcohol consumption; the sugar intake index (SII) was a little bit higher; and the last dental attendance time (LDAT) was shorter than that in the noncaries group (NCG). A total of 211 pilots (37.95%) had caries and 85 (15.29%) had missing teeth. The average DMFT was 2.19, while the mean ICDAS was 0.72. The frequency of sugary beverage consumption was negatively correlated with caries (r = −0.088), while a positive relationship was found between LDAT and caries (r = 0.094). Conclusions: Chinese civilian pilots have relatively good oral hygiene behavior and dental health. A relationship was found between sugary beverage consumption/LDAT and caries.

Patterson CM, Woodcock T, Mollan IA, Nicol ED, McLoughlin DC. United Kingdom military aermedical evacuation in the post-9/11 era. Aviat Space Environ Med 2014; 85:1005–12.Background: Recent UK military operations in support of the fight against terrorism have resulted in UK military casualties. Movement of these casualties through the military medical chain requires a highly sophisticated aeromedical evacuation capability with worldwide reach. Recognition of the determinants of evacuation allows development to ensure optimal future configurations of military aeromedical evacuation services. Methods: The database recording aeromedical evacuations undertaken by the Royal Air Force was searched to provide demographic and clinical data for evacuations between 1 April 2003 and 31 March 2010. Diagnoses leading to evacuation were categorized according to International Classification of Diseases codes. Results: There were 21,477 medical evacuations undertaken. Analysis demonstrated 85.9% were for men and 86.5% were for military personnel, of whom 72.0% were in the army. The most common reasons for evacuation in military patients were musculoskeletal/connective tissue disorders (N = 9192; 50.0%), trauma (N = 1303; 7.1%), and mental health disorders (N = 1151; 6.3%). The most common reasons for evacuation in nonmilitary patients were musculoskeletal/connective tissue disorders (N = 734; 23.8%), genitourinary disorders (N = 325; 10.5%), and circulatory disorders (N = 255; 8.3%). Nontraumatic diagnoses were the determinants of evacuation in 92.9% of military and 95.1% of nonmilitary patients; 17.8% of trauma patients and 0.5% of nontrauma patients utilized high-dependency care. Discussion: The UK aeromedical evacuation system must have the capacity to evacuate large numbers of patients with nontraumatic diagnoses, but also the flexibility to accommodate smaller, more variable numbers of higher dependency trauma patients. The military medical chain must continually review the differing requirements of civilian patients transferred within their aeromedical system.

Davis SM, Davenport ED, Haynes JT, Alvarado RL. Regurgitant valvular disease prevalence and progression found on echocardiogram in military aviators. Aviat Space Environ Med 2014; 85:1013–8.Introduction: The prevalence, progression rates, and outcomes affecting aviator valvular heart disease have not been extensively studied. Methods: The U.S. Air Force (USAF) School of Aerospace Medicine’s Clinical Sciences Database was used to determine prevalence and progression rates for regurgitant valvular disease. A subset of the initial population was further evaluated for risk factors that increased the likelihood of progression. Descriptive statistical analysis, analysis of variance, and t-test calculations were completed. Results: There were 8475 unique aviators with some degree of valvular regurgitation for an overall prevalence of 3.0%. The mitral and aortic valves were most likely to have mild and moderate or greater regurgitation, respectively. Progression rates from mild to moderate were 8% in the aortic valve, 2% in the mitral valve, and less than 1% in the pulmonic and tricuspid valves. Progression rates from moderate to severe were over 20% for both the mitral and aortic valves. The only risk factors correlating to progression of valvular disease were lower levels of high-density lipoproteins in the mitral and aortic valves and triglycerides in the mitral valve. Discussion: In USAF aviators, progression rates for mild or greater aortic valve regurgitation and moderate or greater mitral valve regurgitation are significant and should be followed closely. Classic risk factors of age, tobacco use, elevated blood pressure, and hyperlipidemia have no association with increased risk of valvular progression or rate of progression. Study outcomes validate the current USAF policy for valvular heart disease in aviators.

Cobbett EA, Blickensderfer EL, Lanicci J. Evaluating an education/training module to foster knowledge of cockpit weather technology. Aviat Space Environ Med 2014; 85:1019–25.Background: Previous research has indicated that general aviation (GA) pilots may use the sophisticated meteorological information available to them via a variety of Next-Generation Weather Radar (NEXRAD) based weather products in a manner that actually decreases flight safety. Methods: The current study examined an education/training method designed to enable GA pilots to use NEXRAD-based products effectively in convective weather situations. The training method was lecture combined with paper-based scenario exercises. Results: A multivariate analysis of variance revealed that subjects in the training condition performed significantly better than did subjects in the control condition on several knowledge and attitude measures. Subjects in the training condition improved from a mean score of 66% to 80% on the radar-knowledge test and from 62% to 75% on the scenario-knowledge test. Discussion: Although additional research is needed, these results demonstrated that pilots can benefit from a well-designed education/training program involving specific areas of aviation weather-related knowledge.

Parr JC, Miller ME, Schubert Kabban CM, Pellettiere JA, Perry CE. Development of an updated tensile neck injury criterion. Aviat Space Environ Med 2014; 85:1026–32.Background: Ejection neck safety remains a concern in military aviation with the growing use of helmet mounted displays (HMDs) worn for entire mission durations. The original USAF tensile neck injury criterion proposed by Carter et al. (4) is updated and an injury protection limit for tensile loading is presented to evaluate escape system and HMD safety. Methods: An existent tensile neck injury criterion was updated through the addition of newer post mortem human subject (PMHS) tensile loading and injury data and the application of Survival Analysis to account for censoring in this data. The updated risk function was constructed with a combined human subject (N = 208) and PMHS (N = 22) data set. Results: An updated AIS 3+ tensile neck injury criterion is proposed based upon human and PMHS data. This limit is significantly more conservative than the criterion proposed by Carter in 2000, yielding a 5% risk of AIS 3+ injury at a force of 1136 N as compared to a corresponding force of 1559 N. Discussion: The inclusion of recent PMHS data into the original tensile neck injury criterion results in an injury protection limit that is significantly more conservative, as recent PMHS data is substantially less censored than the PMHS data included in the earlier criterion. The updated tensile risk function developed in this work is consistent with the tensile risk function published by the Federal Aviation Administration used as the basis for their neck injury criterion for side facing aircraft seats.

Strangman GE, Sipes W, Beven G. Human cognitive performance in spaceflight and analogue environments. Aviat Space Environ Med 2014; 85:1033–48.Maintaining intact cognitive performance is a high priority for space exploration. This review seeks to summarize the cumulative results of existing studies of cognitive performance in spaceflight and analogue environments. We focused on long-duration (>21 d) studies for which no review has previously been conducted. There were 11 published studies identified for long-duration spaceflight (N = 42 subjects) as well as 21 shorter spaceflight studies (N = 70 subjects). Overall, spaceflight cognitive studies ranged from 6-438 d in duration. Some 55 spaceflight analogue studies were also identified, ranging from 6 to 520 d. The diverse nature of experimental procedures and protocols precluded formal meta-analysis. In general, the available evidence fails to strongly support or refute the existence of specific cognitive deficits in low Earth orbit during long-duration spaceflight, which may be due in large part to small numbers of subjects. The studies consistently suggest that novel environments (spaceflight or other) induce variable alterations in cognitive performance across individuals, consistent with known astronaut experiences. This highlights the need to better quantify the magnitude and scope of this interindividual variability, and understand its underlying factors, when predicting in-flight cognitive functioning for extended periods.

Gempp E, De Maistre S, Louge P. Serum albumin as a biomarker of capillary leak in scuba divers with neurological decompression sickness. Aviat Space Environ Med 2014; 85:1049–52.Background: Prior reports have shown that decompression sickness (DCS) in scuba divers is accompanied by vascular endothelium damage attributed to gas emboli formation, resulting in capillary leak with hemoconcentration. The significance of serum albumin as a biomarker of vascular permeability in this condition has been insufficiently investigated. We studied whether there was a relationship between low serum albumin values on admission and the occurrence of neurological DCS. Methods: Demographic, diving, and laboratory data of 52 randomly selected DCS divers were compared with those of 52 asymptomatic divers referred for inadequate decompression. The diagnostic performance of serum albumin in predicting neurological DCS was assessed. Results: Both groups did not differ from the variables examined. Serum albumin was significantly lower in injured divers than in controls (38.7 ± 3 g · L⁻¹ vs. 41 ± 2.9 g · L⁻¹). At a cut-off value of 35.2 g · L⁻¹, we found a specificity of 98% (95% CI 90–100) and a sensitivity of 16% (95% CI 7–28) for the prediction of neurological DCS development. Conclusion: Our findings suggest that hypoalbuminemia at initial presentation, albeit rare, accurately predicts the occurrence of neurological DCS in scuba divers. The prognostic value of this biomarker and the potential beneficial role of albumin infusion in more severe cases remain to be investigated.

Ide WW. Central serous chorioretinopathy following hypobaric chamber exposure. Aviat Space Environ Med 2014; 85:1053–5.Background: Hypobaric hypoxic exposures are associated with a number of risks, most notably decompression sickness and various ophthalmologic disorders, including high altitude retinopathy. Central serous chorioretinopathy (CSCR) is an idiopathic condition that typically affects young males and is associated with several comorbidities and medications; however, an association with hypoxia or high altitude has not been identified. We present a case of CSCR in an aviator following a simulated flight in a hypobaric chamber. Case Report: A 30-yr-old male U.S. Navy pilot presented with complaints of painless unilateral scotoma, micropsia, and blurred vision 1 h after completing a training exercise in a hypobaric chamber. A dilated fundoscopic examination, macular optical coherence tomography, and intravenous fluorescein angiography confirmed a diagnosis of CSCR. The patient was restricted from flying duty and observed for a period of 1 mo, after which point his symptoms spontaneously resolved and flight status was restored. Discussion: Complaints of visual symptoms immediately following hypobaric exposure should primarily trigger suspicion of decompression sickness; however, once ruled out, patients should be referred to an eye specialist for detailed ocular examination. This case suggests a possible link between CSCR and hypobaric hypoxia as a topic of further investigation.

Xu X-R, Wang B-R, Zhang Y, Jin Z-G. Radiotherapeutic treatment of a fighter pilot with nasopharyngeal carcinoma. Aviat Space Environ Med 2014; 85:1056–60.Background: Radiotherapy is the standard and most effective treatment for nasopharyngeal carcinoma (NPC) in its early stages. However, its application in fighter pilots returning to flying duties with NPC has not been previously reported, presumably due to post-radiotherapeutic complications. Case report: A 36-yr-old male fighter pilot had a painless mass in the left neck for 5 mo. Pathological diagnosis demonstrated nonkeratinizing squamous cell carcinoma in the left nasopharynx which had metastasized to lymph nodes in the left side of the neck. He was diagnosed and staged with NPC (T₁N₂M₀) before treatment with radiotherapy and adjuvant chemotherapy. The patient suffered from catarrhal otitis media and xerostomia after 3 mo of radiotherapy, but these symptoms resolved. After a total of 8 mo of radiotherapy, he was in remission with no evidence of tumor recurrence or metastasis. He had normal Eustachian tube, hearing, and vestibular function before and after hypobaric chamber testing and passed all flight-related physical examinations. Consequently, he was granted a medical waiver and returned to flying status in two-seat fighter aircraft, flying for 53 h in a 12-mo period. After passing all flight-related tests again, he was then allowed to fly in single-seat aircraft. At the time of submission of this article, he has flown for 147 h and remained on flying status for 26 mo. He will be monitored annually for long-term effects of radiotherapy and/or disease recurrence. Conclusions: Fighter pilots with NPC may be safely considered for medical waiver with appropriate monitoring after successful treatment.

Keeton KE, Richard EE, Davis JR. Solution Mechanism Guide: implementing innovation within a research & development organization. Aviat Space Environ Med 2014; 85:1061–2.In order to create a culture more open to novel problem-solving mechanisms, NASA’s Human Health and Performance Directorate (HH&P) created a strategic knowledge management tool that educates employees about innovative problem-solving techniques, the Solution Mechanism Guide (SMG). The SMG is a web-based, interactive guide that leverages existing and innovative problem-solving methods and presents this information as a unique user experience so that the employee is empowered to make the best decision about which problem-solving tool best meets their needs. By integrating new and innovative methods with existing problem solving tools, the SMG seamlessly introduces open innovation and collaboration concepts within HH&P to more effectively address human health and performance risks. This commentary reviews the path of creating a more open and innovative culture within HH&P and the process and development steps that were taken to develop the SMG.

Ikede A. You’re the flight surgeon: obstructive sleep apnea. Aviat Space Environ Med 2014; 85:1063–4.

Kipp RC. You’re the flight surgeon: splenosis. Aviat Space Environ Med 2014; 85:1064–5.