Space agency-specific standards for crew dose and risk assessment of ionising radiation exposures for the International Space Station.

The Partner Agencies of the International Space Station (ISS) maintain separate career exposure limits and shared Flight Rules that control the ionising radiation exposures that crewmembers can experience due to ambient environments throughout their space missions. In low Earth orbit as well as further out in space, energetic ions referred to as galactic cosmic radiation (GCR) easily penetrate spacecraft and spacecraft contents and consequently are always present at low dose rates. Protons and electrons that are trapped in the Earth's geomagnetic field are encountered intermittently, and a rare energetic solar particle event (SPE) may expose crew to (mostly) energetic protons. Space radiation protection goals are to optimize radiation exposures to maintain deleterious late effects at known and acceptable levels and to prevent any early effects that might compromise crew health and mission success. The conventional radiation protection metric effective dose provides a basic framework for limiting exposures associated with human spaceflight and can be communicated to all stakeholders. Additional metrics and uncertainty analyses are required to understand more completely and to convey nuanced information about potential impacts to an individual astronaut or to a space mission. Missions to remote destinations well beyond low Earth orbit (BLEO) are upcoming and bestow additional challenges that shape design and radiation protection needs. NASA has recently adopted a more permissive career exposure limit based upon effective dose and new restrictions on mission exposures imposed by nuclear technologies. This manuscript reviews the exposure limits that apply to the ISS crewmembers. This work was performed in collaboration with the advisory and guidance efforts of International Commission on Radiological Protection (ICRP) Task Group 115 and will be summarized in an upcoming ICRP Report.

Potential Value of Presepsin Guidance in Shortening Antibiotic Therapy in Septic Patients: a Multicenter, Prospective Cohort Trial.

INTRODUCTION: Long-term use of antibiotics for septic patients leads to bacterial resistance, increased mortality, and hospital stay. In this study, we investigated an emerging biomarker presepsin-guided strategy, which can be used to evaluate the shortening of antibiotic treatment in patients with sepsis without risking a worse outcome. METHODS: In this multicenter prospective cohort trial, patients were assigned to the presepsin or control groups. In the presepsin group, antibiotics were ceased based on predefined cut-off ranges of presepsin concentrations. The control group stopped antibiotics according to international guidelines. The primary endpoints were the number of days without antibiotics within 28 days and mortality at 28 and 90 days. Secondary endpoints were the percentage of patients with a recurrent infection, length of stay in ICU and hospital, hospitalization costs, days of first episode of antibiotic treatment, percentage of antibiotic administration and multidrug-resistant bacteria, and SOFA score. RESULTS: Overall, 656 out of an initial 708 patients were eligible and assigned to the presepsin group (n = 327) or the control group (n = 329). Patients in the presepsin group had significantly more days without antibiotics than those in the control group (14.54 days [SD 9.01] vs. 11.01 days [SD 7.73]; P < 0.001). Mortality in the presepsin group showed no difference to that in the control group at days 28 (17.7% vs. 18.2%; P = 0.868) and 90 (19.9% vs. 19.5%; P = 0.891). Patients in the presepsin group had a significantly shorter mean length of stay in the hospital and lower hospitalization costs than control subjects. There were no differences in the rate of recurrent infection and multidrug-resistant bacteria and the SOFA score tendency between the two groups. CONCLUSIONS: Presepsin guidance has potential to shorten the duration of antibiotic treatment in patients with sepsis without risking worse outcomes of death, recurrent infection, and aggravation of organ failure. TRIAL REGISTRATION: ChiCTR, ChiCTR1900024391. Registered 9 July 2019-Retrospectively registered, http://www.chictr.org.cn.

Monitoring and Dose Assessment for Children Following a Radiation Emergency-Part II: Calibration Factors for Thyroid Monitoring.

Past radiological and nuclear accidents have demonstrated that monitoring a large number of children following a radiological and nuclear emergency can be challenging, in accommodating their needs as well as adapting monitoring protocols and applying age-specific biokinetics to account for various ages and body sizes. This paper presents the derived calibration factors for thyroid monitoring of children of all ages recommended by the International Commission on Radiological Protection using four selected detectors at given times following a short-term (acute) intake of I by inhalation. These calibration factors were derived by Monte Carlo simulations using the models of various detectors and pediatric voxel phantoms. A collection of lookup tables is presented in this paper which may be directly used as a quick reference by emergency response personnel or technical experts performing thyroid monitoring and assessment without doing time-consuming calculations.

Effects of Mild Hypothermia on Cardiac and Neurological Function in Piglets Under Pathological and Physiological Stress Conditions.

To investigate the different effects of mild hypothermia on pathological and physiological stress conditions in piglets, 30 pigs were randomized into four groups: cardiac arrest and mild hypothermia (CA-MH group), cardiac arrest and normothermia (CA-NH group), non-CA-MH (NCA-MH group), and a sham operation. The same hypothermia intervention was implemented in both CA-MH and NCA-MH groups. The CA-NH group did not undergo therapeutic hypothermia after resuscitation. The hemodynamic parameters were recorded. Cerebral metabolism variables and neurotransmitters in the extracellular fluid were collected through microdialysis tubes. The serum of venous blood was used to detect levels of inflammatory factors. The cerebral function was evaluated. At 24 and 72 hours after resuscitation, the cerebral performance category and neurological deficit score in the CA-NH group had higher values. Heart rate and cardiac output (CO) in the CA-MH group during cooling were lower than that of the CA-NH group, but CO was higher after rewarming. Glucose was higher during cooling, and extracellular lactate and lactate/pyruvate ratio in the CA-MH group were lower than that of the CA-NH group. Noradrenaline and 5-hydroxytryptamine in the CA-MH and NCA-MH groups were lower than that of the CA-NH group and sham group during cooling, respectively. Inflammatory factor levels, including interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, and tumor necrosis factor-α, in the CA-MH group were lower than that of the CA-NH group at cooling for 12 hours. These values in the NCA-MH group were higher than that of the sham group. Under a light and an electron microscope, the worse pathological results of heart and brain were observed in the two cardiac arrest groups. Mild hypothermia can provide limited organ protection in the specific pathological condition caused by ischemia-reperfusion, but it may produce a negative effect in a normal physiological state.

Effects of Mild Hypothermia on Cerebral Large and Small Microvessels Blood Flow in a Porcine Model of Cardiac Arrest.

BACKGROUND: The effect of mild hypothermia (MH) on microcirculation after resuscitation from cardiac arrest is controversial. The aim of this study was to determine whether MH improves or aggravates the disturbance of cerebral microcirculation. METHODS: Twenty domestic male pigs were randomized into the MH group (n = 8), non-hypothermia (NH) group (n = 8) or sham operation group (n = 4). In the MH group, the animals were initiated rapid intravascular cooling at 1 h after return of spontaneous circulation (ROSC) from 8 min ventricular fibrillation, and the core temperature was reduced to 33 °C for 12 h and then rewarmed to 37 °C. In the NH group, animals did not receive hypothermia treatment after ROSC. In the sham operation group, the same surgical procedure was performed, but without inducing ventricular fibrillation and hypothermia treatment. The cerebral microvascular flow index (MFI) of large microvessel (diameter > 20 µm) and small microvessel (diameter < 20 µm) was measured after ROSC. Cerebral oxygen extraction ratio, internal jugular venous-artery lactate difference, and CO2 difference were also calculated. RESULTS: Cerebral MFI dramatically reduced after ROSC, and MH further aggravated the decrease in MFI of small microvessel compared with NH (p < 0.05). Internal jugular venous-arterial lactate difference and CO2 difference, and oxygen extraction ratio were all significantly increased after ROSC. MH significantly decreased the values compared with NH (p < 0.05). CONCLUSIONS: MH decreases cerebral small microvessel blood flow and cerebral metabolism after ROSC compared with NH. However, the total effect is that cerebral oxygen supply-demand relationship is improved during hypothermia.

Monitoring and Dose Assessment for Children Following a Radiation Emergency Part I: Reference Values for In Vitro Bioassay.

Following a radiation emergency, children may be internally contaminated by the radionuclide(s) involved. Timely assessment of the contamination informs the need for medical treatment for those persons who had significant intakes and reassures those whose intakes are not a medical concern. In vitro bioassay reference values for children of all ICRP age groups are derived for 30 contamination scenario/radionuclide combinations involving 13 radionuclides. These bioassay values are derived from an intake that leads to a 70-y committed effective dose of 50 mSv or a 30-d RBE-weighted absorbed dose to the lungs of 0.2 Gy-Eq, depending on which criterion is more strict. These values are presented in a collection of lookup tables that can be used directly as references.

The First Meeting of the WHO Guideline Development Group for the Revision of the WHO 1999 Guidelines for Iodine Thyroid Blocking.

The meeting held in May 2014 in Würzburg, Germany, discussed the scope of the revision of the 1999 WHO guidelines for iodine thyroid blocking (ITB) by following the WHO handbook for guideline development. This article describes the process and methods of developing the revised, evidence-based WHO guidelines for ITB following nuclear and radiological accidents, the results of the kick-off meeting as well as further steps taken to complete the revision.

EURADOS intercomparison on emergency radiobioassay.

Nine laboratories participated in an intercomparison exercise organised by the European Radiation Dosimetry Group (EURADOS) for emergency radiobioassay involving four high-risk radionuclides ((239)Pu, (241)Am, (90)Sr and (226)Ra). Diverse methods of analysis were used by the participating laboratories for the in vitro determination of each of the four radionuclides in urine samples. Almost all the methods used are sensitive enough to meet the requirements for emergency radiobioassay derived for this project in reference to the Clinical Decision Guide introduced by the NCRP. Results from most of the methods meet the requirements of ISO 28218 on accuracy in terms of relative bias and relative precision. However, some technical gaps have been identified. For example, some laboratories do not have the ability to assay samples containing (226)Ra, and sample turnaround time would be expected to be much shorter than that reported by many laboratories, as timely results for internal contamination and early decisions on medical intervention are highly desired. Participating laboratories are expected to learn from each other on the methods used to improve the interoperability among these laboratories.

A new charging scheme in an emergency department observation unit under Beijing's basic medical insurance.

BACKGROUND: The new medical insurance policy (JRSYF(2010) No.255) was released by the Beijing Municipal Government and became effective on January 1, 2011. Medical expenses incurred during a stay in an emergency department (ED) observation unit can be reimbursed as a hospital admission. The aim of this study was to evaluate the impact of a new charging scheme during stays in ED observation unit under Beijing's Basic Medical Insurance. METHODS: Data for those patients who had stayed in ED observation unit in 2010 (before the implementation of a new charging scheme) and 2012 (after the implementation of this policy) were retrospectively analyzed in terms of length of stay, patients who were observed (PO), and median medical costs. RESULTS: After the implementation of a new charging scheme, compared with the year of 2010, in year of 2012, there were statistically significant longer lengths of stay at the observation unit (6 (4-9) vs. 5 (4-7) days; P < 0.001), more PO (2 257 vs. 1 783; P < 0.001), and more median medical costs (RMB 6 026 vs. 3 650 Yuan; P < 0.01). The proportion of elderly patients (≥ 60 years of age) in 2012 was larger than that in 2010 (70.22% vs. 63.71%; P < 0.01). It was performed on those patients who were admitted after the implementation of a new charging scheme. Compared with patients who were not admitted had stayed in ED observation units, the patients who were admitted had stayed in ED observation units that had a higher proportion for >15 days (36.22% vs. 5.61%; P < 0.01); they had higher median medical costs RMB (9 186 vs. 5 668 Yuan; P < 0.001) and they were more elderly (≥ 60 years of age) (86.10% vs. 66.39%; P < 0.01). CONCLUSIONS: The new charging scheme under Beijing's Basic Medical Insurance allows patients to get access to inpatient admission more easily. It lowers patients' financial burden in ED observation unit. Since more people stay at ED observation unit, it increases ED payments by the insurance system. However, it slows the turnover rate of ED observation unit and causes overcrowding in ED. Hence, the advantages and disadvantages of the new policy are obvious.

Evaluation of community-acquired sepsis by PIRO system in the emergency department.

The predisposition, infection/insult, response, and organ dysfunction (PIRO) staging system for septic patients allows grouping of heterogeneous patients into homogeneous subgroups. The purposes of this single-center, prospective, observational cohort study were to create a PIRO system for patients with community-acquired sepsis (CAS) presenting to the emergency department (ED) and assess its prognostic and stratification capabilities. Septic patients were enrolled and allocated to derivation (n = 831) or validation (n = 860) cohorts according to their enrollment dates. The derivation cohort was used to identify independent predictors of mortality and create a PIRO system by binary logistic regression analysis, and the prognostic performance of PIRO was investigated in the validation cohort by receiver operator characteristic (ROC) curve. Ten independent predictors of 28-day mortality were identified. The PIRO system combined the components of predisposition (age, chronic obstructive pulmonary disease, hypoalbuminemia), infection (central nervous system infection), response (temperature, procalcitonin), and organ dysfunction (brain natriuretic peptide, troponin I, mean arterial pressure, Glasgow coma scale score). The area under the ROC of PIRO was 0.833 for the derivation cohort and 0.813 for the validation cohort. There was a stepwise increase in 28-day mortality with increasing PIRO score and the differences between the low- (PIRO 0-10), intermediate- (11-20), and high- (>20) risk groups were very significant in both cohorts (p < 0.01). The present study demonstrates that this PIRO system is valuable for prognosis and risk stratification in patients with CAS in the ED.

International workshop on emergency radiobioassay: considerations, gaps and recommendations.

An international workshop on emergency radiobioassay was held in Ottawa, Canada, 1-3 September 2010. Sixty-five scientists and public health officials from five countries attended the workshop and gave 36 presentations. During the workshop, many considerations were raised, gaps identified, and recommendations given for emergency radiobioassay for both preparedness and response in case of a radiological or nuclear incident. In short, some bioassay methods and protocols need to be developed, validated, and exercised; national and international radiobioassay laboratory networks should be established; and communications and collaborations among public health officials, monitoring experts, and medical staff are encouraged. All these activities are required to make us better prepared for an RN emergency.

[A comparison of severity of illness scoring system for emergency department patients with systemic inflammatory response syndrome].

OBJECTIVE: To evaluate the predictive ability of 3 scoring systems, i.e. acute physiology and chronic health evaluation II (APACHE II) score, simplified acute physiology score II (SAPS II) and mortality in emergency department sepsis (MEDS) score in patients presenting systemic inflammatory response syndrome (SIRS) in emergency department. METHODS: Six hundred and twenty-one adult patients with SIRS admitted from December 2006 to September 2007 in the emergency department of Beijing Chaoyang Hospital were eligible for the study. The first 24-hour admission data necessary for the calculation of APACHE II score, SAPS II score, MEDS score and basic demographic statistics were collected and the outcomes in 28 days were recorded. Logistic regression analysis was used to determine the independent predictors for 28-day mortality. Discrimination of each scoring system was assessed with the areas under the receiver operating characteristics (ROC) curve (AUC). RESULTS: A total of 222 patients died in 28 days in a total of 621 patients. The age and mean levels of 3 scoring systems were predominantly higher in nonsurvivors than survivors (73 years vs. 70 years for age, P<0.05; 18 vs. 14 for APACHE II score, P<0.01; 36 vs. 24 for SAPS II score, P<0.01; 14 vs. 7 for MEDS score, P<0.01). The independent predictors of 28-day mortality were APACHE II score, SAPS II score and MEDS score. The AUCs were 0.715, 0.774 and 0.965 for APACHE II score, SAPS II score and MEDS score, respectively. There was significant difference between MEDS score and APACHE II score in AUC (Z=35.435, P<0.01). CONCLUSION: In emergency department patients with SIRS, the MEDS score possesses more predictive ability than APACHE II score.

Estimating the benefits of pollution reduction on agricultural yields: Taiwan's air pollution emission fees program.

Taiwan's implementation of the 1997 Air Pollution Emissions Fees Program will conceivably lead to long-term reductions in pollution emissions. The purpose of this paper is to estimate the benefits to Taiwan from the expected reduction in crop losses as a direct result of such a decrease in air pollution. We employ a demand-supply framework for rice production to estimate the change in social welfare resulting from changes in the concentration of certain pollutants in the atmosphere. Our empirical results show that, in the year 1997, social welfare increments resulting from the decline in sulfur dioxide concentrations in the atmosphere ranged between US dollars 946200 and US dollars 2435800. Meanwhile, during the same period, the increase in social welfare due to the decline in the ozone concentration in the atmosphere ranged between US dollars 838100 and US dollars 1927000. The average benefit from the reduction in both sulfur dioxide and ozone concentrations is calculated to be between US dollars 2.67 and US dollars 6.86 per acre (for sulfur dioxide), and from US dollars 2.36 to US dollars 5.43 per acre (for ozone).