Aviation, space, and environmental medicine最新文献

Background: This study evaluated whether coronary artery calcium score (CACS) improved cardiovascular disease risk prediction when compared to the New Zealand Cardiovascular Risk Charts (NZ-CRC), and describes the potential utilization of CACS in cardiovascular disease (CVD) risk assessment of pilots.

Methods: A cross-sectional study was performed among asymptomatic patients who underwent coronary computed tomography angiography at Pacific Radiology Wellington, New Zealand, between August 2007 and July 2012 and had their CACS and CVD risk score calculated. Receiver-operating characteristics (ROC) analyses were used to measure the accuracy of the NZ-CRC and CACS. Reclassification analyses were performed to examine the net reclassification improvement (NRI) of CACS when compared to NZ-CRC.

Results: Over a 5-yr study period, 237 male asymptomatic patients with ages ranging from 30 to 69 yr with a mean (SD) of 53.24 (8.18) yr, were included. The area under the ROC curves (AUC) (95% CI) for CACS and NZ-CRC were 0.88 (0.83-0.93) and 0.66 (0.59-0.73), respectively. The NRI (95% CI) of the calcium scores was 0.39 (0.17-0.62). CACS should be assessed in pilots with 5-yr CVD risk scores of 5-10% and 10-15%.

Conclusion: CACS has a better accuracy than the NZ-CRC and reclassified a considerable proportion of asymptomatic patients into correct cardiovascular risk categories. An approach on how the CACS should be employed in the cardiovascular risk assessment of airline pilots is noted in this paper.

Introduction: Situation awareness (SA) is considered an essential prerequisite for safe flying. If the impact of visual scanning patterns on a pilot's situation awareness could be identified in flight operations, then eye-tracking tools could be integrated with flight simulators to improve training efficiency.

Method: Participating in this research were 18 qualified, mission-ready fighter pilots. The equipment included high-fidelity and fixed-base type flight simulators and mobile head-mounted eye-tracking devices to record a subject's eye movements and SA while performing air-to-surface tasks.

Results: There were significant differences in pilots' percentage of fixation in three operating phases: preparation (M = 46.09, SD = 14.79), aiming (M = 24.24, SD = 11.03), and release and break-away (M = 33.98, SD = 14.46). Also, there were significant differences in pilots' pupil sizes, which were largest in the aiming phase (M = 27,621, SD = 6390.8), followed by release and break-away (M = 27,173, SD = 5830.46), then preparation (M = 25,710, SD = 6078.79), which was the smallest. Furthermore, pilots with better SA performance showed lower perceived workload (M = 30.60, SD = 17.86), and pilots with poor SA performance showed higher perceived workload (M = 60.77, SD = 12.72). Pilots' percentage of fixation and average fixation duration among five different areas of interest showed significant differences as well.

Discussion: Eye-tracking devices can aid in capturing pilots' visual scan patterns and SA performance, unlike traditional flight simulators. Therefore, integrating eye-tracking devices into the simulator may be a useful method for promoting SA training in flight operations, and can provide in-depth understanding of the mechanism of visual scan patterns and information processing to improve training effectiveness in aviation.

Background: Setting Spacecraft Water Exposure Guidelines (SWEGs) for lead (Pb) in spacecraft drinking water has special challenges related to estimating the increase in blood lead levels (PbB) due to the release of lead to systemic circulation via microgravity-induced bone loss.

Methods: The effects on the PbB of lead in drinking water (PbW) and lead released from bones, and changes in lead exposure before, during, and after spaceflight, were evaluated using a physiologically based pharmacokinetic model that incorporated environmental lead exposure on Earth and in flight and included temporarily increased rates of osteoporosis during spaceflight.

Results: The model predicts that in 2030 (the earliest potential launch date for a long-duration mission), the average American astronaut would have a PbB of 1.7 microg x dl(-1) at launch and that, while in microgravity, PbB levels would decrease at PbW values less than about 9 microg L(-1) because of reduced exposure within the spacecraft to environmental lead. Astronauts with high concentrations of lead stored in bones could experience increases in PbB due to microgravity-accelerated release of lead from bones. While the resultant in-flight PbB would depend on their preflight bone lead levels, their PbB will not be significantly further elevated (< 1 microg x dl(-1)) by consuming water with a PbW of < or = 9 microg x dl(-1). Selection of a SWEG that would not result in an increase in blood lead is prudent given uncertainties about health effects at low exposures.

Conclusion: A SWEG of 9 microg x L(-1) would protect astronauts on long-duration spaceflights by ensuring that PbB values will not exceed prelaunch levels.

Long-duration exposure to the space environment causes physical adaptations that are deleterious to optimal functioning on Earth. Post-mission rehabilitation traditionally concentrates on regaining general muscle strength, neuromuscular control, and lumbo-pelvic stability. A particular problem is muscle imbalance caused by the hypertrophy of the flexor and atrophy of the extensor and local lumbo-pelvic muscles, increasing the risk of post-mission injury. A method currently used in European human spaceflight to aid post-mission recovery involves a motor control approach, focusing initially on teaching voluntary contraction of specific lumbo-pelvic muscles and optimizing spinal position, progressing to functional retraining in weight bearing positions. An alternative approach would be to use a Functional Readaptive Exercise Device to appropriately recruit this musculature, thus complementing current rehabilitation programs. Advances in post-mission recovery of this nature may both improve astronaut healthcare and aid terrestrial healthcare through more effective treatment of low back pain and accelerated post bed rest rehabilitation.

Introduction: We examined responses of volunteers with known medical disease to G forces in a centrifuge to evaluate how potential commercial spaceflight participants (SFPs) might tolerate the forces of spaceflight despite significant medical history.

Methods: Volunteers were recruited based upon suitability for each of five disease categories (hypertension, cardiovascular disease, diabetes, lung disease, back or neck problems) or a control group. Subjects underwent seven centrifuge runs over 2 d. Day 1 consisted of two +G(z) runs (peak = +3.5 G(z), Run 2) and two +G(x), runs (peak = +6.0 G(x), Run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +G(x) and +G(z), peak = +6.0 G(x)/+4.0 G(z)). Data collected included blood pressure, electrocardiogram, pulse oximetry, neurovestibular exams, and post-run questionnaires regarding motion sickness, disorientation, grayout, and other symptoms.

Results: A total of 335 subjects registered for participation, of which 86 (63 men, 23 women, age 20-78 yr) participated in centrifuge trials. The most common causes for disqualification were weight and severe and uncontrolled medical or psychiatric disease. Five subjects voluntarily withdrew from the second day of testing: three for anxiety reasons, one for back strain, and one for time constraints. Maximum hemodynamic values recorded included HR of 192 bpm, systolic BP of 217 mmHg, and diastolic BP of 144 mmHg. Common subjective complaints included grayout (69%), nausea (20%), and chest discomfort (6%). Despite their medical history, no subject experienced significant adverse physiological responses to centrifuge profiles.

Discussion: These results suggest that most individuals with well-controlled medical conditions can withstand acceleration forces of launch and re-entry profiles of current commercial spaceflight vehicles.

Background: Experiencing an acute coronary event in a remote or community hospital can be fatal, particularly if the event is complicated by cardiogenic shock. Many remote and community hospitals do not have adequate resources to support such a compromised patient. Extrapolating from the domestic hub-and-spoke model, presently used between academic tertiary care facilities and community hospitals, we outline the implementation of such an ad hoc arrangement between Panama (spoke) and South Florida (hub).

Case report: We transported a team of cardiovascular experts from Florida to Panama, in tandem air ambulances (to limit mandatory crew rest time), to implant a left ventricular assist device (LVAD) in a patient in cardiogenic shock refractory to mechanical/pharmacological support. The low profile LVAD inserted percutaneously by the American team stabilized the patient (a U.S. citizen on assignment in Panama), enabling his air ambulance transport back to South Florida.

Discussion: In this first-of-a-kind report, we outline the challenges and logistics involved in the planning, resuscitation, and aeromedical transport of a patient who was discharged from the hub hospital in Florida after just 30 d.