INTRODUCTION: Although hypobaric hypoxia training (HHT) is an essential component of aviation physiology training, it poses a risk of decompression sickness (DCS). DCS can sometimes be observed as a cluster of cases, which is referred to as epidemic DCS. In this report, we aim to evaluate an epidemic DCS episode that occurred following two consecutive HHT sessions.METHODS: A total of 16 trainees, all of whom were medical doctors, attended the aviation medicine training course in the aeromedical research and training center. They went through HHT in two sessions, each with eight trainees.RESULTS: Following two HHT sessions, five Type 1 DCS cases occurred among 18 personnel (16 trainees and 2 inside observers). DCS incidence rate was found to be 27.77%. They were successfully treated with hyperbaric oxygen therapy (HBOT).DISCUSSION: Since the DCS incidence rate was found to be higher than the average in such a short period of time, this cluster of cases was labeled as epidemic DCS. We carried out a thorough investigation into all possible causes by following some templates that were developed to conduct comprehensive investigations into epidemic DCS episodes. According to the psychological arguments discussed here, we placed a special emphasis on hysterical and psychosocial components, among other probable factors. In cases where the possibility of hysteria and placebo-nocebo responses exist, it is appropriate to conduct the training and treatment processes with these factors in mind. No matter what the triggering factor is and how the symptoms manifest, HBOT remains crucial in the treatment of DCS.Demir AE, Ata N. Hysteria as a trigger for epidemic decompression sickness following hypobaric hypoxia training. Aerosp Med Hum Perform. 2022; 93(10):712–716.

BACKGROUND: Teleoperation enables performing tasks in hazardous or inaccessible environments. The relationship between spatial ability and teleoperation performance has been extensively studied; however, relatively few studies have considered examples wherein the specific influence mechanism between the two is examined. This study aims to explore how individuals’ spatial ability affects teleoperation performance.METHODS: Forty subjects completed teleoperated expedition and escape tasks in a virtual unfamiliar environment according to the assigned requirements. After each expedition task, subjects’ mental model about the unfamiliar environment was evaluated. The escape task performance was measured in terms of path length, completion time, and the number of collisions. The impact of spatial ability on escape task performance wherein mental model as a mediator was examined. The Bootstrapping method was used to examine the hypothesis regarding the mediating role of mental model in the influence of spatial ability on teleoperation performance.RESULTS: Subjects with higher spatial ability exhibited significantly better mental models and had fewer collisions. In addition, subjects with better mental models had significantly shorter path lengths and spent marginally less time on escape. In general, the mental model appeared important for path length and completion time, but not collisions.CONCLUSIONS: The combined results of the two tasks preliminarily proved that spatial ability affected path length of the escape task through the mental model after the exploration task. The findings are expected to aid in astronaut selection and teleoperation training for space station missions.Pan D, Liu D, Tian Z, Zhang Y. Performance influence mechanism of individuals’ spatial ability in teleoperation. Aerosp Med Hum Perform. 2022; 93(10):717–724.

INTRODUCTION: Catheter ablation is a widely used and effective treatment option for many tachyarrhythmic disorders. This study analyzes all ablation cases in German military aircrew over a 17-yr period. Recurrence of different arrhythmias and ablation complications were analyzed with an aim of refining specific recommendations for aircrew employment.METHODS: All cases of catheter ablations in pilots and nonpilot aircrew examined at the German Air Force Centre of Aerospace Medicine from 2004 to 2020 were analyzed for sex, age, concomitant diseases, ablated arrhythmias, complications, recurrences, time elapsed from ablation to reablation, number of ablations, and aeromedical disposition, including restrictions in case of a return to flying duties.RESULTS: There were 36 aircrew who underwent catheter ablation; 7 were ablated for 2 or more different arrhythmias; 10 underwent more than one ablation. Ablated arrhythmias included atrioventricular (AV) nodal re-entrant tachycardias, accessory pathways, focal atrial tachycardias, typical and atypical atrial flutter, atrial fibrillation, and premature atrial and ventricular complexes. Recurrence rates differed between the arrhythmias and were lowest in AV re-entrant tachycardias. Complication rates were low.CONCLUSION: In this aircrew cohort, nearly all aircrew were able to return to flying duties following ablation, albeit some with restrictions. Restrictions depended on the underlying arrhythmia, the ablation procedure, and the symptoms prior to ablation. A basic understanding of different arrhythmias, ablation techniques, and long-term success rates is essential for the AME and for the responsible licensing authority. Close cooperation with an electrophysiologist is necessary prior to and after ablation to ensure optimal management of aircrew with arrythmias.Guettler N, Nicol E, Sammito S. Return to flying after catheter ablation of arrhythmic disorders in military aircrew. Aerosp Med Hum Perform. 2022; 93(10):725–733.

OBJECTIVE: The aim was to evaluate the well-being of professional pilots using a survey that included the World Health Organization (WHO)-5 Well-Being Index.METHODS: An electronic survey was sent to pilots between June 17–August 2, 2021. Pilots self-categorized as: airline transport pilot (ATP), commercial pilot, or both. Chi-squared and Fisher’s exact tests were used to evaluate differences between variables. Logistic regression was used to estimate the odds of impaired well-being.RESULTS: A total of 639 individuals returned the survey. The majority of respondents were ATPs and a majority identified as male. The average well-being score was 68.0 out of 100 possible, with 22% of respondents meeting the threshold definition of impaired well-being. The odds of having impaired well-being were not dependent on gender. In unadjusted analysis, the odds of impaired well-being were higher for those flying as commercial pilots as compared to airline transport pilots/both. Age was also strongly associated with impaired well-being, with younger pilots having greater odds of impaired well-being as compared to older pilots. Only a little over half of the surveyed pilots agreed or strongly agreed that pilot risk of occupational exposure to COVID-19 was appropriately controlled.CONCLUSION: This survey suggests an important connection between pilot age and impaired well-being scores during the COVID-19 pandemic. Future studies targeting the well-being of younger pilots will be of interest. Additionally, measures to reduce occupational risk of COVID-19 exposure may be helpful in view of the substantial fraction of pilots expressing concern regarding that risk.Stratton E, Haddon R, Murad MH, Petterson T, Nelson M, Cowl CT. COVID-19 pandemic effects on the well-being of professional pilots. Aerosp Med Hum Perform. 2022; 93(10):734–738.

BACKGROUND: Spacecraft maximum allowable concentrations (SMACs) provide guidance on allowable chemical exposures for nominal and emergency situations aboard spacecraft. SMACs are set to mitigate or preclude potential crew health effects and performance degradation. Hydrogen fluoride (HF) gas is highly irritating. Inhaled HF produces irritation primarily in the upper respiratory tract. HF is not routinely present in spacecraft atmospheres. However, it can be produced in spacecraft due to overheating or combustion events involving materials containing fluorinated organics.METHODS: Toxicological data relevant to SMAC development were collected from electronic databases using principles of systematic review, and from previous assessments and reviews of HF.RESULTS: The human inhalation data of Lund (short-term) and Largent (subchronic) showed that HF at approximately 3 ppm caused very mild respiratory irritation. NASA HF SMACs are based on these findings.DISCUSSION: The 1-h and 24-h SMACs are set at 3 ppm, a value consistent with NASA short-term SMAC criteria where crew may experience mild irritation. The 7-d, 30-d, 180-d, and 1000-d SMACs are set at 0.3 ppm to protect against any long-term crew health or performance effects that could be produced from HF exposures.Lam C-W, Ryder VE. Spacecraft maximum allowable concentrations for hydrogen fluoride. Aerosp Med Hum Perform. 2022; 93(10):746–748.

BACKGROUND:The challenges of climate change and increasing frequency of severe weather conditions has demanded innovative approaches to wildfire suppression. Australia’s wildfire management includes an expanding aviation program, providing both fixed and rotary wing aerial platforms for reconnaissance, incident management, and quick response aerial fire suppression. These operations have typically been limited to day visual flight rules operations, but recently trials have been undertaken extending the window of operations into the night, with the assistance of night vision systems. Already a demanding job, night aerial firefighting operations have the potential to place even greater physical and mental demands on crewmembers. This study was designed to investigate sleep, fatigue, and performance outcomes in Australian aerial firefighting crews.METHODS:A total of nine subjects undertook a 21-d protocol, completing a sleep and duty diary including ratings of fatigue and workload. Salivary cortisol was collected daily, with additional samples provided before and after each flight, and heart rate variability was monitored during flight. Actigraphy was also used to objectively measure sleep during the data collection period.RESULTS:Descriptive findings suggest that subjects generally obtained >7 h sleep prior to flights, but cortisol levels and self-reported fatigue increased postflight. Furthermore, the greatest reported workload was associated with the domains of ‘performance’ and ‘mental demand’ during flights.DISCUSSION:Future research is necessary to understand the impact of active wildfire response on sleep, stress, and workload on aerial firefighting crews.Sprajcer M, Roberts S, Aisbett B, Ferguson S, Demasi D, Shriane A, Thomas MJW. Sleep, workload, and stress in aerial firefighting crews. Aerosp Med Hum Perform. 2022; 93(10):749–754.

BACKGROUND: Cardiac injury in trauma patients can be secondary to either blunt or penetrating trauma and is a significant cause of death. The commonest etiological factors for blunt cardiac injury include motor vehicle collisions, falls, and crush or blast injuries. The incidence of blunt cardiac injury following falls is reported to be between 5 and 50%.CASE REPORT: A combat pilot lost his life in an aircraft accident. Although he had ejected successfully just before the aircraft caught fire and his parachute had deployed fully, it was engulfed in the ball of fire rising up from the burning aircraft wreckage, causing the parachute to burn up. As a result, the pilot had a free fall from an estimated height of 70–80 ft (21–24 m). Autopsy revealed a ruptured right atrium and endocardial tears at the right atrioventricular junction. The left side of the heart and the coronary arteries were unscathed. The histopathological finding showed evidence that the cardiac injuries sustained were antemortem. The cause of death was ascertained to be due to cardiac rupture, leading to hemorrhagic shock.DISCUSSION: Cardiac rupture in this case appears to be a case of the ‘water hammer’ effect, the right atrium being the commonest site of blunt cardiac rupture. It is possible that the individual landed on his feet after his parachute got burnt in the ball of fire and the violent compression of the lower limb and abdominal veins, caused by the sudden hyperflexion of the lower limbs over the abdomen, caused the cardiac rupture in this case.CONCLUSION: The possibility of blunt cardiac trauma should always be kept in mind while dealing with survivors of ejection at low levels.Sharma MD, Gupta N, Rajkumar T, Sharma A. Cardiac rupture due to a fall from height: the ‘water hammer’ effect. Aerosp Med Hum Perform. 2022; 93(10):755–757.

INTRODUCTION: The flying status of commercial pilots with traumatic brain injury should not be based solely upon physical examination and imaging. Weaknesses exist in all neurocognitive assessment as the relationship of results to real-world performance, in this case piloting an airplane, can be best described as moderate. There is the possibility that a pilot’s ability to fly safely might be better evaluated by check rides with an instructor pilot in flight and in simulators. Research in this area is needed.Hastings J. The evaluation of traumatic brain injury: a call to action. Aerosp Med Hum Perform. 2022; 93(10):758–759.

BACKGROUND: With the increase in crewed commercial spaceflight and expeditions to the Moon and Mars, the risk of critical surgical problems and need for procedures increases. Appendicitis and appendectomy are the most common surgical pathology and procedure performed, respectively. The habitable volume of current spacecraft ranges from 4 m³ (Soyuz) to 425 m³ (International Space Station). We investigated the minimum volume required to perform an appendectomy and compared that to habitable spacecraft volumes.METHODS: The axes of a simulated operating room were marked and cameras placed to capture movements. An expert surgeon, chief surgical resident, junior surgical resident, and a nonsurgeon physician each performed a Focused Assessment with Sonography for Trauma and an appendectomy on a simulated patient. Dimensions and volume needed were collected and compared using unpaired t-tests.RESULTS: Mean volume (± SD) needed was 3.83 m³ ± 0.47 m³ for standing and 3.68 m³ ± 0.49 m³ for kneeling (P = 0.638). Minimal volume needed was 3.20 m³ for standing and 3.26 m³ for kneeling. Minimal theoretical volume was 2.99 m³ for standing and 2.87 m³ for kneeling.DISCUSSION: The unencumbered volume needed for an appendectomy is between 2.87 m³ and 4.3 m³. It may be technically feasible to perform an open appendectomy inside the smallest of currently operating spacecraft, at 4 m³ (Soyuz-MS). Space vessels operating without rapid evacuation to Earth will need to consider this volume for potential surgical emergencies. Additional investigation on microgravity and standardization of procedures for novices must be completed.Kamine TH, Siu M, Kramer K, Kelly E, Alouidor R, Fernandez G, Levin D. Spatial volume necessary to perform open appendectomy in a spacecraft. Aerosp Med Hum Perform. 2022; 93(10):760–763.