Aviation, space, and environmental medicine最新文献

Introduction: Historically, space has been the venue of the healthy individual. With the advent of commercial spaceflight, we face the novel prospect of routinely exposing spaceflight participants (SPFs) with multiple comorbidities to the space environment. Preflight screening procedures must be developed to identify those individuals at increased risk during flight. We examined the responses of volunteers to centrifuge accelerations mimicking commercial suborbital spaceflight profiles to evaluate how potential SFPs might tolerate such forces. We evaluated our screening process for medical approval of subjects for centrifuge participation for applicability to commercial spaceflight operations.

Methods: All registered subjects completed a medical questionnaire, physical examination, and electrocardiogram. Subjects with identified concerns including cardiopulmonary disease, hypertension, and diabetes were required to provide documentation of their conditions.

Results: There were 335 subjects who registered for the study, 124 who completed all prescreening, and 86 subjects who participated in centrifuge trials. Due to prior medical history, five subjects were disqualified, most commonly for psychiatric reasons or uncontrolled medical conditions. Of the subjects approved, four individuals experienced abnormal physiological responses to centrifuge profiles, including one back strain and three with anxiety reactions.

Discussion: The screening methods used were judged to be sufficient to identify individuals physically capable of tolerating simulated suborbital flight. Improved methods will be needed to identify susceptibility to anxiety reactions. While severe or uncontrolled disease was excluded, many subjects successfully participated in centrifuge trials despite medical histories of disease that are disqualifying under historical spaceflight screening regimes. Such screening techniques are applicable for use in future commercial spaceflight operations.

Introduction: Bio-mathematical models are increasingly used for predicting fatigue in airline operations, and have been proposed as a possible component of fatigue risk management systems (FRMS). There is a need to continue to evaluate fatigue models against data collected from crews conducting commercial flight operations.

Methods: A comparison was made between several in-flight studies of pilot fatigue, conducted over a 10-yr period on a variety of operations, and the predictions of a widely used bio-mathematical model, the System for Aircrew Fatigue Evaluation (SAFE). The in-flight studies collected a variety of subjective ratings as well as reaction time on a performance task.

Results: Overall correlation between observed and predicted fatigue was stronger for subjective fatigue than reaction time. More detailed analysis on selected studies shows discrepancies between predicted and observed fatigue, which may be explained by a variety of confounders. Closer analysis of the duty time, time of day, and schedule length show discrepancies of up to 15% between observed and predicted fatigue.

Discussion: This study provides comparison between the predictions of one bio-mathematical model, SAFE, and observed fatigue measures across a number of operations. Possible causes of discrepancies are discussed. There is potential for more comparison studies of this type with the various available models.

Background: There is a widely held belief that strenuous exercise should be avoided on arrival at high altitude (HA) and during acclimatization. Data from chamber studies are contradictory and the studies are usually of short duration, therefore differing from the "real world."

Methods: We studied 48 trekkers during a 10-d ascent to 16,827 ft (5129 m) in the Cordillera Real area of Bolivia. Borg Rating of Perceived Exertion (RPE) scores were recorded for the hardest perceived exertion during the day after ascents to 12,576, 14,600, and 16,827 ft (3833, 4450, and 5129 m). Heart rate, Spo2, and Lake Louise Score (LLS) were recorded simultaneously. Statistical testing was performed using SPSS 21 software. A P-value of ≤ 0.05 was deemed significant.

Results: Acute mountain sickness (AMS) rates were higher after trekking days with higher levels of perceived exertion. The LLS was higher in those with a Borg RPE score ≥ 15 both following exercise (mean LLS 2.6 vs. 1.7) and at rest the following day (mean LLS 2.7 vs. 1.7). Heart rate was higher in those with high Borg RPE scores (80 vs. 87) and oxygen saturations lower at rest (86 vs. 83) the following morning.

Discussion: This data lends weight to the advice of moderate exertion during a trek to HA and suggests that reducing perceived exertion may reduce AMS.

Background: Hot air ballooning incidents are relatively rare; however, when they do occur they are likely to result in a fatality or serious injury. Human error is commonly attributed as the cause of hot air ballooning incidents; however, error in itself is not an explanation for safety failures. This research aims to identify and establish the relative importance of factors contributing toward hot air ballooning incidents.

Methods: Twenty-two Australian Ballooning Federation (ABF) incident reports were thematically coded using a bottom-up approach to identify causal factors. Subsequently, 69 balloonists (mean 19.51 yr experience) participated in a survey to identify additional causal factors and rate (out of 7) the perceived frequency and potential impact to ballooning operations of each of the previously identified causal factors. Perceived associated risk was calculated by multiplying mean perceived frequency and impact ratings.

Results: Incident report coding identified 54 causal factors within 9 higher level areas: Attributes, Crew Resource Management, Equipment, Errors, Instructors, Organizational, Physical Environment, Regulatory Body, and Violations. Overall, 'weather', 'inexperience,' and 'poor/inappropriate decisions' were rated as having greatest perceived associated risk.

Discussion: Although errors were nominated as a prominent cause of hot air ballooning incidents, physical environment and personal attributes are also particularly important for safe hot air ballooning operations. In identifying a range of causal factors, the areas of weakness surrounding ballooning operations have been defined; it is hoped that targeted safety and training strategies can now be put into place to remove these contributing factors and reduce the chance of pilot error.