Considering clonal hematopoiesis of indeterminate potential in space radiation risk analysis for hematologic cancers and cardiovascular disease.

BACKGROUND: Expanding human presence in space through long-duration exploration missions and commercial space operations warrants improvements in approaches for quantifying crew space radiation health risks. Currently, risk assessment models for radiogenic cancer and cardiovascular disease consider age, sex, and tobacco use, but do not incorporate other modifiable (e.g., body weight, physical activity, diet, environment) and non-modifiable individual risk factors (e.g., genetics, medical history, race/ethnicity, family history) that may greatly influence crew health both in-mission and long-term. For example, clonal hematopoiesis of indeterminate potential (CHIP) is a relatively common age-related condition that is an emerging risk factor for a variety of diseases including cardiovascular disease and cancer. CHIP carrier status may therefore exacerbate health risks associated with space radiation exposure. METHODS: In the present study, published CHIP hazard ratios were used to modify background hazard rates for coronary heart disease, stroke, and hematologic cancers in the National Aeronautics and Space Administration space radiation risk assessment model. The risk of radiation exposure-induced death for these endpoints was projected for a future Mars exploration mission scenario. RESULTS: Here we show appreciable increases in the lifetime risk of exposure-induced death for hematologic malignancies, coronary heart disease, and stroke, which are observed as a function of age after radiation exposure for male and female crew members that are directly attributable to the elevated health risks for CHIP carriers. CONCLUSIONS: We discuss the importance of evaluating individual risk factors such as CHIP as part of a comprehensive space radiation risk assessment strategy aimed at effective risk communication and disease surveillance for astronauts embarking on future exploration missions.

Space radiation exposure is a major hazard of spaceflight that may increase cancer and cardiovascular disease risks for future astronauts exploring the moon and Mars. There is a need for accurate risk assessment that considers individual risk factors to support informed consent and medical management of these risks. Clonal hematopoiesis of indeterminate potential (CHIP) is a condition that occurs when copies of variant cells accumulate in the blood of otherwise healthy individuals. CHIP is an emerging risk factor linked with blood cancers and cardiovascular disease. We evaluated how CHIP can alter space radiation health risks in astronauts for a Mars exploration mission scenario. We find large increases in lifetime risk of space radiation exposure-induced death for hematologic malignancies and cardiovascular disease in CHIP carriers. These results suggest that increased screening may help facilitate better management of radiation risks.

Maximizing Patient Coverage Through Optimal Allocation of Residents and Scribes to Shifts in an Emergency Department.

Residents and scribes in an Emergency Department (ED) work closely with an attending physician. Residents care for patients under the supervision of the attending physician, whereas scribes assist physicians with documentation contemporaneously with the patient encounter. Optimal allocation of these roles to shifts is crucial to improve patient care, physician productivity, and to increase learning opportunities for residents. Since resident and scribe availability varies on a monthly basis, the allocation of these roles into different shifts within a pre-designed ED physician shift template must be dynamically adjusted. Using historical patient flow timestamp data as well as information about the patient-coverage capacity of an ED care team, a data-driven model was developed for optimally determining which shifts must be staffed by residents and scribes to maximize patient coverage and to calculate the relative importance of a shift. This relative importance metric aids decision-making in adjusting the allocation of residents and scribes to various shifts as their availability fluctuates. Since the model uses historical timestamp data, which all EDs are mandated to collect, the approach is generalizable to all EDs.

Retrospective Evaluation of Clinical Symptoms Due to Mild Hypobaric Hypoxia Exposure in Microgravity.

INTRODUCTION: A habitat atmosphere of 34% oxygen (O2) and 66% nitrogen (N2) at 8.2 psia (56.5 kPa) is proposed to minimize the risk of decompression sickness during extravehicular activity. The resulting inspired O2 partial pressure (PIo2) of 128 mmHg is similar to that experienced during portions of 41 Space Shuttle missions that used a "staged" denitrogenation (prebreathe) protocol with an atmosphere of 26.5% O2 and 73.5% N2 at 10.2 psia (70.3 kPa). We evaluated symptoms possibly linked to mild hypoxia in astronauts breathing a PIo2 of 127 mmHg. METHODS: Environmental data were used to determine time in the shuttle at 10.2 psia and time at 14.7 psia (101.3 kPa). A total of 14 possible hypoxia symptoms were compared with symptoms collected during normoxic shuttle operations at 14.7 psia using logistic regression. RESULTS: There were 134.1 d (788.8 person days) under the 10.2 psia staged condition with a mean of 3.17 ± 2.2 SD d/mission. There were 258.81 d at 14.7 psia (2192.95 person days). An average of 4.31 potentially hypoxia-related symptoms per mission day was documented under the staged condition compared with 4.08 per mission day during the normoxic condition. Logistic regression showed no symptoms were significantly associated with just the 10.2 psia condition. DISCUSSION: Chronic exposure to a PIo2 of 127 mmHg is well-tolerated by healthy humans on Earth. A similar short-duration exposure on the shuttle resulted in no increased reporting of possible hypoxia-related symptoms. However, chronic mild hypoxia interactions with physiological changes due to microgravity adaptations remain unclear.Wessel JH III, Schaefer CM, Thompson MS, Norcross JR, Bekdash OS. Retrospective evaluation of clinical symptoms due to mild hypobaric hypoxia exposure in microgravity. Aerosp Med Hum Perform. 2018; 89(9):792-797.

A Descriptive Analysis of Occupational Fatalities Due to Felonious Assault Among U.S. Law Enforcement Officers During Tactical Incidents, 1996-2014.

INTRODUCTION: Little is known about occupational fatalities among tactical officers. A greater understanding of such injuries is needed to improve officer safety. The purpose of this study was to provide a descriptive analysis of line-of-duty deaths secondary to felonious assault during tactical incidents. METHODS: Retrospective analysis was performed of open-source de-identified Federal Bureau of Investigation Uniform Crime Reporting Law Enforcement Officers Killed and Assaulted (LEOKA) data inclusive of the years 1996-2014. Officers were included if the fatal injury occurred during operations by a Special Weapons and Tactics (SWAT) team, fugitive task force, narcotics task force, or if the LEOKA narrative described the event as a tactical situation. RESULTS: Of 1,012 officer deaths during the study period, 57 (5.6%) involved tactical officers. On average (± standard deviation), victim officers were 37.3 ± 7.8 years of age at the time of death, with 11.7 ± 6.6 years of law enforcement experience. High-risk warrant service accounted for 63.2% of fatalities. A single officer was killed in 91.2% of incidents; 49.1% of cases involved injuries to other officers. The majority of officers (59.6%) killed were the first officer(s) to enter the scene. The most commonly identified cause of death was head trauma (n = 28). Chest trauma accounted for 14 deaths; 10 (71.4%) sustained an entry wound via the ballistic vest armhole. Where recorded, 52.0% of officers died within the first hour of injury. The provision or nature of buddy care, tactical emergency medical services (EMS) care, or conventional EMS care was rarely noted. CONCLUSION: Tactical officer deaths most commonly occur during high-risk warrant service, and most often involve the first officer(s) to enter a scene, suggesting an opportunity for improved operational tactics. The frequency of fatal axillary penetration suggests the opportunity for ballistic protection redesign. Information is lacking regarding on-scene care, limiting the ability to determine optimal medical procedures for downed officers during tactical operations. Nearly 50% of victim officers survived more than 1 hour from time of injury, suggesting opportunities to intervene and potentially affect outcomes.