Ocular complaints and diagnoses in spaceflight.

The NASA human system risk board (HSRB) has long focused on trauma and acute medical illness as a key contributor to high level in-flight medical risk. However, ocular issues, trauma, and complaints during spaceflight are poorly characterized. In a retrospective case series, the NASA data from the life sciences data archieve (LSDA) and the lifetime surveillance of astronaught health (LSAH) was queried for eye related complaints and conditions in spaceflight across international space station (ISS) missions and space shuttle (STS) missions. The ISS dataset included missions from the year 2000 to 2020, and the STS dataset included missions from 1981 to 2011. Data were reviewed and segmented into categories of ocular complaints. 135 STS missions and 63 ISS missions were included in this analysis. Ocular events were only noted across 83 STS missions (61.5%) and 41 ISS missions (65.1%). Overall, the most common ocular complaints were eye irritation (n = 80, 33.1%), ocular foreign body or foreign body sensation (n = 55, 22.7%), dry eye syndromes (n = 38, 15.7%), epiphora or excessive tearing (n = 19, 7.85%). Of all ocular complaints or diagnoses, 9 (3.72%) were considered higher severity (keratitis, corneal ulcer, chemical exposure, and corneal abrasion). However, seemingly none required evacuation from mission. Improved depiction of ocular symptoms and diagnoses, and a more standard classification system and process to describe ocular symptoms, diagnoses, and treatments in space is crucial to provide more effective and comprehensive treatments.

The value of a spaceflight clinical decision support system for earth-independent medical operations.

As NASA prepares for crewed lunar missions over the next several years, plans are also underway to journey farther into deep space. Deep space exploration will require a paradigm shift in astronaut medical support toward progressively earth-independent medical operations (EIMO). The Exploration Medical Capability (ExMC) element of NASA's Human Research Program (HRP) is investigating the feasibility and value of advanced capabilities to promote and enhance EIMO. Currently, astronauts rely on real-time communication with ground-based medical providers. However, as the distance from Earth increases, so do communication delays and disruptions. Moreover, resupply and evacuation will become increasingly complex, if not impossible, on deep space missions. In contrast to today's missions in low earth orbit (LEO), where most medical expertise and decision-making are ground-based, an exploration crew will need to autonomously detect, diagnose, treat, and prevent medical events. Due to the sheer amount of pre-mission training required to execute a human spaceflight mission, there is often little time to devote exclusively to medical training. One potential solution is to augment the long duration exploration crew's knowledge, skills, and abilities with a clinical decision support system (CDSS). An analysis of preliminary data indicates the potential benefits of a CDSS to mission outcomes when augmenting cognitive and procedural performance of an autonomous crew performing medical operations, and we provide an illustrative scenario of how such a CDSS might function.

A Qualitative Investigation of Space Exploration Medical Evacuation Risks.

INTRODUCTION: Exploration beyond low Earth orbit requires innovative solutions to support the crew medically, especially as the opportunity for timely evacuation to Earth diminishes. This includes assessing the risks and benefits that a complicated medical evacuation (MEDEVAC) poses to the injured crewmember, the crew, and the mission. This qualitative study identifies common MEDEVAC risk assessment principles used in spaceflight and other extreme environments to better inform future risk assessment tools and exploration mission concepts.METHODS: Semistructured interviews were conducted with subject matter experts in spaceflight and analog domains, including polar operations, undersea operations, combat medicine, and mountaineering. Transcripts were analyzed using the qualitative method of Thematic Analysis with the technique of consensus, co-occurrence, and comparison.RESULTS: Subject matter experts described 18 themes divided into two main categories: Primary Risk Considerations (e.g., crew, mission, resources, time) and Contributing Factors (e.g., psychological considerations, medical preparation, politics).DISCUSSION: Primary Risk Considerations can assess MEDEVAC risk across mission phases, with Contributing Factors acting as premission tools to adjust those risks. Inter- and intracategory connections identified medical support considerations, MEDEVAC support considerations, and philosophy as the most impactful Contributing Factors. Medical support considerations, psychological considerations, and political considerations were found to have unique aspects given the distances and societal impact of exploration vs. low Earth orbit spaceflight. The Contributing Factor theme of decision making was determined to be unique due to its impacts across both categories. These findings expand current considerations and are important inputs for exploration mission MEDEVAC Concepts of Operations.Almand A, Ko SY, Anderson A, Keller RJ, Zero M, Anderson AP, Laws JM, Lehnhardt K, Easter BD. A qualitative investigation of space exploration medical evacuation risks. Aerosp Med Hum Perform. 2023; 94(12):875-886.

Enabling Human Space Exploration Missions Through Progressively Earth Independent Medical Operations (EIMO).

Goal: Current Space Medicine operations depend on terrestrial support to manage medical events. As astronauts travel to destinations such as the Moon, Mars, and beyond, distance will substantially limit this support and require increasing medical autonomy from the crew. This paper defines Earth Independent Medical Operations (EIMO) and identifies key elements of a conceptual EIMO system. Methods: The NASA Human Research Program Exploration Medical Capability Element held a 2-day conference at Johnson Space Center in Houston, TX with NASA experts representing all aspects of Space Medicine. Results: EIMO will be a process enabling progressively resilient deep space exploration systems and crews to reduce risk and increase mission success. Terrestrial assets will continue to provide pre-mission screening, planning, health maintenance, and prevention, while onboard medical care will increasingly be the purview of the crew. Conclusions: This paper defines and describes the key components of EIMO.

A blinded, randomized controlled trial to evaluate ketamine/propofol versus ketamine alone for procedural sedation in children.

STUDY OBJECTIVE: The primary objective is to compare total sedation time when ketamine/propofol is used compared with ketamine alone for pediatric procedural sedation and analgesia. Secondary objectives include time to recovery, adverse events, efficacy, and satisfaction scores. METHODS: Children (aged 2 to 17 years) requiring procedural sedation and analgesia for management of an isolated orthopedic extremity injury were randomized to receive either ketamine/propofol or ketamine. Physicians, nurses, research assistants, and patients were blinded. Ketamine/propofol patients received an initial intravenous bolus dose of ketamine 0.5 mg/kg and propofol 0.5 mg/kg, followed by propofol 0.5 mg/kg and saline solution placebo every 2 minutes, titrated to deep sedation. Ketamine patients received an initial intravenous bolus dose of ketamine 1.0 mg/kg and Intralipid placebo, followed by ketamine 0.25 mg/kg and Intralipid placebo every 2 minutes, as required. RESULTS: One hundred thirty-six patients (67 ketamine/propofol, 69 ketamine) completed the trial. Median total sedation time was shorter (P=0.04) with ketamine/propofol (13 minutes) than with ketamine (16 minutes) alone (Δ -3 minutes; 95% confidence interval [CI] -5 to -2 minutes). Median recovery time was faster with ketamine/propofol (10 minutes) than with ketamine (12 minutes) alone (Δ -2 minutes; 95% CI -4 to -1 minute). There was less vomiting in the ketamine/propofol (2%) group compared with the ketamine (12%) group (Δ -10%; 95% CI -18% to -2%). All satisfaction scores were higher (P<0.05) with ketamine/propofol. CONCLUSION: When compared with ketamine alone for pediatric orthopedic reductions, the combination of ketamine and propofol produced slightly faster recoveries while also demonstrating less vomiting, higher satisfaction scores, and similar efficacy and airway complications.

Spaceflight validation of technology for point-of-care monitoring of peripheral blood WBC and differential in astronauts during space missions.

During long duration orbital space missions, astronauts experience immune system dysregulation, the persistent reactivation of latent herpesviruses, and some degree of clinical incidence. During planned NASA 'Artemis' deep space missions the stressors that cause this phenomenon will increase, while clinical care capability will likely be reduced. There is currently minimal clinical laboratory capability aboard the International Space Station (ISS). The ability to monitor the white blood cell count (WBC) and differential during spaceflight has been an unmet NASA medical requirement, primarily due to a lack of capable hardware. We performed ground and flight validation of a device designed to monitor WBC and differential within minutes from a fingerstick blood sample. This device is miniaturized, robust, and generally compatible with microgravity operations. Ground testing for spaceflight consisted of vibration tolerance, power/battery and interface requirements, electromagnetic interference (EMI), and basic evaluation of sample preparation and operations in the context of spaceflight constraints. The in-flight validation performed aboard the ISS by two astronauts included assessment of three levels of control solution (blood) samples as well as a real time analysis of a fingerstick blood sample by one of the crewmembers. Flight and ground testing of the same lot of control solutions yielded similar total WBC values. There was some select discrepancy between flight and ground data for the differential analysis. However, the data suggest that this issue is due to compromise of the control solutions as a result of storage length before flight operations, and not due to a microgravity-associated issue with instrument performance. This evaluation also yielded lessons learned regarding crewmember training for technique-sensitive small-volume biosample collection and handling in microgravity. The fingerstick analysis was successful and was the first real-time hematology assessment performed during spaceflight. This device may provide an in-mission monitoring capability for astronauts thereby assisting Flight Surgeons and the crew medical officer during both orbital and deep space missions.

Pearl-unjammed: the Seattle stone maneuver for ureteropelvic junction urolithiasis.

Renal colic encounters are common; in the United States alone, they represent greater than one million annual emergency department (ED) visits. Most of these stones are managed conservatively with a trial of passage. However, some lead to repeat colic episodes, secondary ED visits, increased anxiety, and increased cost. Of the 5%-10% of symptomatic stones that become lodged at the ureteropelvic junction and are larger than 5 mm, most require operative intervention. In the process of executing a NASA-funded study of ultrasonic repositioning of kidney stones, the subject was administered fluid to dilate the collecting system, placed in Trendelenburg bed positioning, and rolled to both sides. During this process a symptomatic, obstructing 9-mm ureteropelvic junction stone moved back into the kidney's lower pole/infundibulum and symptoms were immediately resolved. The patient remained asymptomatic for a period of 5 weeks at which point elective intervention was scheduled. This case demonstrates that ureteropelvic junction stones may be repositioned in a non-invasive manner, turning a stone that requires urgent intervention into one that can be managed electively.

Bridging the gap between military prolonged field care monitoring and exploration spaceflight: the compensatory reserve.

The concept of prolonged field care (PFC), or medical care applied beyond doctrinal planning timelines, is the top priority capability gap across the US Army. PFC is the idea that combat medics must be prepared to provide medical care to serious casualties in the field without the support of robust medical infrastructure or resources in the event of delayed medical evacuation. With limited resources, significant distances to travel before definitive care, and an inability to evacuate in a timely fashion, medical care during exploration spaceflight constitutes the ultimate example PFC. One of the main capability gaps for PFC in both military and spaceflight settings is the need for technologies for individualized monitoring of a patient's physiological status. A monitoring capability known as the compensatory reserve measurement (CRM) meets such a requirement. CRM is a small, portable, wearable technology that uses a machine learning and feature extraction-based algorithm to assess real-time changes in hundreds of specific features of arterial waveforms. Future development and advancement of CRM still faces engineering challenges to develop ruggedized wearable sensors that can measure waveforms for determining CRM from multiple sites on the body and account for less than optimal conditions (sweat, water, dirt, blood, movement, etc.). We show here the utility of a military wearable technology, CRM, which can be translated to space exploration.

Fracture Risk in Spaceflight and Potential Treatment Options.

INTRODUCTION: Understanding the effects of microgravity on bone is essential, since humans are now considering long-distance spaceflight missions. It is well known that bone mineral density (BMD) decreases during long-duration spaceflight. While the risk of fracture in a microgravity environment is believed to be low, the potential risk for fracture increases upon re-entering a gravity environment. The objective of this study was to determine skeletal regions of high-risk for fracture after long-duration spaceflight and identify management protocols for those fractures.METHODS: A literature search was conducted on current fracture risk predictive models and suggestions for treatment.RESULTS: Exercise with the Advanced Resistance Exercise Device (ARED), T2 treadmill, and cycle ergometer with vibration isolation and stabilization (CEVIS) on the International Space Station (ISS) is part of a fundamental long-duration spaceflight strategy to mitigate BMD loss. Additionally, studies have shown that bisphosphonates have an additive effect for preventing bone loss. However, if a fracture were to occur, treatments that improve bone healing in space (in addition to standard management modalities such as splinting) include the use of low-intensity pulsed ultrasound, electromagnetic field therapy, and intermittent subcutaneous injections of parathyroid hormone. In the event of a complicated fracture, surgical intervention with a universal external fixation device could be a viable option for management.CONCLUSION: In conclusion, the best strategy for mitigating musculoskeletal injuries for deep-space missions will be a combination of BMD loss reduction coupled with improvements in management protocols for potential fractures.Swaffield TP, Neviaser AS, Lehnhardt K. Fracture risk in spaceflight and potential treatment options. Aerosp Med Hum Perform. 2018; 89(12):1060-1067.

Simulation Training for In-Flight Medical Emergencies Improves Provider Knowledge and Confidence.

INTRODUCTION: In-flight medical emergencies require healthcare providers to operate in confined spaces with limited resources and delayed access to definitive care. These emergencies are common, with an estimated frequency of 1 per 100 to 1000 flights. Despite this, training for medical response in these environments is limited. We hypothesize that integrating such education into a pre-existing medical student elective course would improve knowledge and ability to respond appropriately to in-flight medical emergencies.METHODS: The available literature surrounding in-flight medical emergencies was reviewed. Syncope, respiratory distress, allergic reaction, and cardiac arrest were identified as common and potentially life-threatening complaints. Simulation cases were designed for each of these complaints and a simulation room was modified to mimic an airplane cabin. These simulation cases and accompanying relevant didactic lectures were incorporated into an existing wilderness and extreme environmental medicine course, with multiple-choice tests completed by the students at the beginning and end of the 2-wk course.RESULTS: Participating in this study were 18 students. The pretest average was 76%, which improved to 87% on the posttest. Qualitative feedback regarding this type of training was overwhelmingly positive.DISCUSSION: Simulation-based training for in-flight medical emergencies can significantly improve medical students' knowledge. This training was very well received by the students. Opportunities for training to manage in-flight medical emergencies remain limited; incorporating such training into existing curricula could provide a means by which to improve provider knowledge. Such a curriculum could be adapted for use by flight crews and other populations.Padaki A, Redha W, Clark T, Nichols T, Jacoby L, Slivka R, Ranniger C, Lehnhardt K. Simulation training for in-flight medical emergencies improves provider knowledge and confidence. Aerosp Med Hum Perform. 2018; 89(12):1076-1079.

Is obesity a predictor of mortality, morbidity and readmission after cardiac surgery?

INTRODUCTION: Obesity has been described as a risk factor for the development of coronary artery disease, but it has not been determined whether obesity is associated with adverse outcomes after cardiac surgery. Therefore, we analyzed a large cohort of patients who had undergone cardiac surgery to determine whether obesity is a predictor of mortality, morbidity or early readmission to hospital. METHODS: At the London Health Sciences Centre, an academic tertiary care centre, we prospectively entered data from the cardiac surgical database from July 1999 to April 2002. We collected data on 1310 consecutive, unselected patients who underwent cardiac surgery during that time. We assessed the degree of obesity using the body mass index (BMI), and we prospectively documented the occurrence of 10 major complications after surgery. They included stroke, reoperation for bleeding, life-threatening cardiac arrest or arrhythmia, new renal failure requiring dialysis, septicemia, mediastinitis, sternal dehiscence, respiratory failure, postoperative myocardial infarction and low cardiac output necessitating intra-aortic balloon pump use. Univariable and multivariable analyses were conducted to determine the factors associated with and predictive of postoperative death and major complications. RESULTS: An increased BMI did not increase the risk of early postoperative death. Furthermore, increased BMI was not a predictor of a patient experiencing any of the major complications, except sternal dehiscence. An increased BMI was associated with a higher likelihood of readmission to hospital within 30 days of discharge. CONCLUSION: Obesity was not associated with adverse outcomes after cardiac operations, aside from the increased risks of sternal dehiscence and early hospital readmission.