Preliminary Evidence-Based Method of Medical Kit Design for Wilderness Expeditions Modeled by a High-Altitude Expedition to Mount Kilimanjaro.

BACKGROUND: Wilderness expeditions require extensive planning and the correct medical supplies to ensure clinical care is possible in the event of illness or injury. There are gaps in the literature regarding evidence-based methods for medical kit design. OBJECTIVES: This report describes a preliminary method for predicting medical events to determine medical supply requirements for a wilderness expedition. The performance of this method was evaluated using data from the 2017 Equal Playing Field (EPF) expedition to Mount Kilimanjaro. METHODS: Eight reports documenting medical events during wilderness expeditions were reviewed. Incidence data were consolidated into a new dataset, and a subset of data from adventure race expeditions (ARS) was created. The cumulative incidence of medical events was then predicted for the 9-day EPF expedition. The medical supply list was determined based on indication. The effectiveness of the full dataset and ARS to predict the cumulative incidence of medical events by category during the EPF expedition was evaluated using regression analysis. RESULTS: The ARS predicted a higher incidence rate of medical events than the full dataset did but underestimated the EPF expedition incidence rate. The full dataset was a weak predictor of the cumulative incidence of medical events by category during the EPF expedition, while the ARS was a strong predictor. The finalized medical kit overestimated all nonreusable supplies. CONCLUSIONS: The medical kit created using this method managed all medical events in the field. This report demonstrates the potential utility of using a tailored, evidence-based approach to design a medical kit for wilderness expeditions.

Designing efficient emergency departments: Discrete event simulation of internal-waiting areas and split flow sorting.

OBJECTIVE: Evaluate nine different models, the interaction of three flow models (ESI, intake attending physician, and no split flow) and three physical design typologies (zero, one, and two internal-waiting areas), on Emergency Department (ED) flow and patient-centered metrics. METHODS: Discrete Event Simulation (DES) was used to systematically manipulate flow and physical design. Three base models were developed and validated using ED and patient specific data. Subsequently, systematic manipulations of flow and internal-waiting areas were performed on other models. Five outcomes of interest were tracked - length of stay (LOS), bed utilization rate, door to provider time, left without being seen rate, and number of movements per patient. Models were compared for statistical significance and effect size using ANOVA, and linear and non-linear regression. RESULTS: The shortest LOS (mean 175.2 min) and highest bed utilization rate (5.02 patients/bed/day) were obtained with flow split by an intake attending physician with two internal-waiting areas. These represented improvements of 54 min and 1.48 patients/bed/day over the control model. Two-way ANOVA demonstrated that both physical design and flow type were statistically significant predictors of all outcomes of interest (p < .0001). Depending on flow type, adding one additional internal-waiting area resulted in decreased LOS (range 10.6-21.8 min), increased bed utilization (range 0.23-0.40 patients/bed/day), decreased D2P (range 1.3-4.8 min), and decreased LWBS (0.66%-2.0%). CONCLUSION: Based on a DES model with empirical data from a single institution, combining flow split by an intake attending physician and multiple internal-waiting areas resulted in improved ED operational and patient-centered metrics.

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 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.

The use of mechanical ventilation in the ED.

OBJECTIVES: Although EDs are responsible for the initial care of critically ill patients and the amount of critical care provided in the ED is increasing, there are few data examining mechanical ventilation (MV) in the ED. In addition, characteristics of ED-based ventilation may affect planning for ventilator shortages during pandemic influenza or bioterrorist events. The study examined the epidemiology of MV in US EDs, including demographic, clinical, and hospital characteristics; indications for MV; ED length of stay (LOS); and in-hospital mortality. METHODS: This study was a retrospective review of the 1993 to 2007 National Hospital Ambulatory Medical Care Survey ED data sets. Ventilated patients were compared with ED patients admitted to the intensive care unit (ICU) and to all other ED visits. RESULTS: There were 3.6 million ED MV visits (95% confidence interval [CI], 3.2-4.0 million) over the study period. Sex, age, race, and payment source were similar for mechanically ventilated and ICU patients (P > .05 for all). Approximately 12.5% of ventilated patients underwent cardiopulmonary resuscitation compared with 1.7% of ICU admissions and 0.2% of all other ED visits (P < .0001). Accordingly, in-hospital mortality was significantly higher for ventilated patients (24%; 95% CI, 13.1%-34.9%) than both comparison groups (9.3% and 2.5%, respectively). Median LOS for ventilated patients was 197 minutes (interquartile range, 112-313 minutes) compared with 224 minutes for ICU admissions and 140 minutes for all other ED visits. CONCLUSIONS: Patients undergoing ED MV have particularly high in-hospital mortality rates, but their ED LOS is sufficient for implementation of evidence-based ventilator interventions.

The influence of perceived stress on the human microbiome.

OBJECTIVE: Microbial dysbiosis, a shift from commensal to pathogenic microbiota, is often associated with mental health and the gut-brain axis, where dysbiosis in the gut may be linked to dysfunction in the brain. Many studies focus on dysbiosis induced by clinical events or traumatic incidents; however, many professions in austere or demanding environments may encounter continuously compounded stressors. This study seeks to explore the relationship between microbial populations and stress, both perceived and biochemical. RESULTS: Eight individuals enrolled in the study to provide a longitudinal assessment of the impact of stress on gut health, with four individuals providing enough samples for analysis. Eleven core microbial genera were identified, although the relative abundance of these genera and other members of the microbial population shifted over time. Although our results indicate a potential relationship between perceived stress and microbial composition of the gut, no association with biochemical stress was observed. Increases in perceived stress seem to elucidate a change in potentially beneficial Bacteroides, with a loss in Firmicutes phyla. This shift occurred in multiple individuals, whereas using cortisol as a stress biomarker showed contradictory responses. These preliminary data provide a potential mechanism for gut monitoring, while identifying targets for downstream modulation.

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.

The stability of metabolic syndrome in children and adolescents.

CONTEXT: Some studies suggest the presence of metabolic syndrome before adulthood may identify those at high risk for later cardiovascular morbidity, but there are few data examining the reliability of pediatric metabolic syndrome. OBJECTIVE: To examine the short- and long-term stability of pediatric metabolic syndrome. DESIGN: Metabolic syndrome was defined as having at least three of the following: waist circumference, blood pressure, and fasting serum triglycerides in the 90th or higher percentile for age/sex; high-density lipoprotein-cholesterol 10th or lower percentile for age/sex; and fasting serum glucose of at least 100 mg/dl. Short-term metabolic syndrome stability (repeated measurements within 60 d) was assessed in obese youth ages 6-17 yr. Long-term metabolic syndrome stability (repeated measurements more than 1.5 yr apart) was studied in 146 obese and nonobese children age 6-12 yr at baseline. PATIENTS AND SETTING: Convenience samples of obese and nonobese youth ages 6-17 yr participating in research studies were collected at a clinical research hospital. RESULTS: Short-term metabolic syndrome stability (repeat measurements performed 19.7 +/- 13.1 d apart) was assessed in 220 children. The diagnosis of metabolic syndrome was unstable in 31.6% of cases. At their short-term follow-up visit, incidence of metabolic syndrome among participants who did not have metabolic syndrome at baseline was 24%. In the long term (repeat measurements performed 5.6 +/- 1.9 yr apart), the diagnosis of metabolic syndrome was unstable in 45.5% of cases. CONCLUSIONS: Cutoff-point-based definitions for pediatric metabolic syndrome have substantial instability in the short and long term. The value of making a cutoff-point-based diagnosis of metabolic syndrome during childhood or adolescence remains in question.