Aviation, space, and environmental medicine最新文献

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.

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.

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.

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.

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.

Background: Spatial disorientation is a significant factor in a large percentage of military Class A aviation mishaps. While previous studies have analyzed accident statistics, they often suffer from methodological flaws, which lead to questionable conclusions.

Methods: The current study relied upon the Air Force Safety Automated System to document U.S. Air Force Class A mishap investigations during the past 21 yr. Human Factors Analysis and Classification System codes were used to determine mishaps involving pilot spatial disorientation. The data were combined with data from the Reliability and Maintainability Information System to determine the accident rate per flight hour.

Results: There were 72 spatial disorientation (SD) mishaps analyzed, resulting in loss of 101 lives and 65 aircraft since fiscal year (FY) 1993 for a total monetary cost of 2.32 billion. Class A mishaps involving spatial disorientation had a higher rate as a function of hours flown for helicopter and fighter/attack fixed wing aircraft than other aircraft. Additionally, mishap rates for F-16 fighter/attack aircraft were marginally larger than for other fighter/attack aircraft. Although SD mishaps at night had similar mishap rates to daytime SD mishaps when adjusted by flight hours, SD mishaps account for a larger percent of Class A mishaps during the night than during the day.

Discussion: SD mishaps were analyzed in terms of Class A mishaps per million flight hours. Results indicate that future SD research should be focused on fighter/attack and helicopter platforms. Updates to the Air Force safety center database are recommended.