Thromboelastography in acute immunologic reactions: a prospective pilot study.

Background: Biomarkers of fibrinolysis are elevated during acute immunologic reactions (allergic reactions and angioedema), although it is unclear whether fibrinolysis is associated with disease severity. Objectives: We investigated a possible association between maximum lysis (ML) measured by thromboelastography and the severity of acute immunologic reactions. Methods: We recruited patients with acute immunologic reactions at a high-volume emergency department. Clinical disease severity at presentation and at the end of the emergency department stay was assessed using a 5-grade scale, ranging from local symptoms to cardiac arrest. We determined ML on admission by thromboelastography (ROTEM's extrinsic [EXTEM], and aprotinin [APTEM] tests), expressed as ML%. Hyperfibrinolysis was defined as an ML of >15% in EXTEM, which was reversed by adding aprotinin (APTEM). We used exact logistic regression to investigate an association between ML% and disease severity (grades 1 and 2 [mild] vs 3-5 [severe]) and between hyperfibrinolysis and disease severity. Results: We included 31 patients (71% female; median age, 52 [IQR, 35-58] years; 10 [32%] with a severe reaction). ML% was higher in patients with severe symptoms (21 [IQR, 12-100] vs 10 [IQR, 4-17]). Logistic regression found a significant association between ML% and symptom severity (odds ratio, 1.07; 95% CI, 1.01-1.21; P = .003). Hyperfibrinolysis was detected in 6 patients and found to be associated with severe symptoms (odds ratio, 17.59; 95% CI, 1.52-991.09; P = .02). D-dimer, tryptase, and immunoglobulin E concentrations increased with the severity of immunologic reactions. Conclusion: ML, quantified by thromboelastography, is associated with the severity of acute immunologic reactions.

Social mass gathering events influence emergency medical services call volume.

Background: Prior literature suggests that mass gathering events pose challenges to an emergency medical services (EMS) system. We aimed to investigate whether events influence EMS call rates. Materials and methods: This study is a retrospective review of all primary response ambulance calls in Rhode Island (US) between January 1st, 2018 and August 31st, 2022. The number of EMS calls per day was taken from the state's EMS registry. Event data was collected using a Google (Google LLC, Mountain View, CA) search. We used separate Poisson regression models with the number of ambulance calls as the dependent and the social event categories sports, agricultural, music events, and public exhibitions as independent variables. All models controlled for the population at risk and the period of the COVID-19 pandemic. Results are presented as increases or decreases in calls per 100,000 inhabitants from the mean over the study period. Results: The mean number of daily EMS calls was 38 ± 4 per 100,000 inhabitants. EMS encountered significantly more missions on days with music events (+3, 95% CI [2; 3]) and public exhibitions (+2, 95% CI [1; 2]). In contrast, days with agricultural events were associated with fewer calls (-1, 95% CI [-1; 0]). We did not find any effect of sports events on call rates. Conclusion: Increased ambulance call volumes are observed on days with music events and public exhibitions. Days with agricultural events are associated with fewer EMS calls.

Drone-Facilitated Real-Time Video-Guided Feedback Helps to Improve the Quality of Lay Bystander Basic Life Support. A Randomized Controlled Simulation Trial.

OBJECTIVES: Telephone instructions are commonly used to improve cardiopulmonary resuscitation (CPR) by lay bystanders. This usually implies an audio but no visual connection between the provider and the emergency medical telecommunicator. We aimed to investigate whether video-guided feedback via a camera drone enhances the quality of CPR. METHODS: We conducted a randomized controlled simulation trial. Lay rescuers performed 8 min of CPR on an objective feedback manikin. Participants were randomized to receive telephone instructions with (intervention group) or without (control group) a drone providing a visual connection with the telecommunicator after a 2-min run-in phase. Performed work (total compression depth minus total lean depth) was the primary outcome. Secondary outcomes were the proportion of effective chest compressions, average compression depth, subjective physical strain measured every 2 min, and dexterity in the nine-hole peg test after the scenario. Outcomes were compared using the t- and Mann Whitney-U tests. A two-sided p-value of <0.05 was considered significant. RESULTS: We included 27 individuals (14 (52%) female, mean age 41 ± 14 years). Performed work was greater in the intervention than in the control group (41.3 ± 7.0 vs. 33.9 ± 10.9 m; absolute difference 7.5, 95% CI 1.4 to 14.8; p = 0.046), with higher average compression depth (49 ± 7 vs. 40 ± 13 mm; p = 0.041), and higher proportions of adequate chest compressions (43 (IQR 14-60) vs. 3 (0-29) %; p = 0.041). We did not find any significant differences regarding the remaining secondary outcomes. CONCLUSION: Video-guided feedback via drones might be a helpful tool to enhance the quality of telephone-assisted CPR in lay bystanders.

Effects of extracorporeal CO2 removal on gas exchange and ventilator settings: a systematic review and meta-analysis.

PURPOSE: A systematic review and meta-analysis to evaluate the impact of extracorporeal carbon dioxide removal (ECCO2R) on gas exchange and respiratory settings in critically ill adults with respiratory failure. METHODS: We conducted a comprehensive database search, including observational studies and randomized controlled trials (RCTs) from January 2000 to March 2022, targeting adult ICU patients undergoing ECCO2R. Primary outcomes were changes in gas exchange and ventilator settings 24 h after ECCO2R initiation, estimated as mean of differences, or proportions for adverse events (AEs); with subgroup analyses for disease indication and technology. Across RCTs, we assessed mortality, length of stay, ventilation days, and AEs as mean differences or odds ratios. RESULTS: A total of 49 studies encompassing 1672 patients were included. ECCO2R was associated with a significant decrease in PaCO2, plateau pressure, and tidal volume and an increase in pH across all patient groups, at an overall 19% adverse event rate. In ARDS and lung transplant patients, the PaO2/FiO2 ratio increased significantly while ventilator settings were variable. "Higher extraction" systems reduced PaCO2 and respiratory rate more efficiently. The three available RCTs did not demonstrate an effect on mortality, but a significantly longer ICU and hospital stay associated with ECCO2R. CONCLUSIONS: ECCO2R effectively reduces PaCO2 and acidosis allowing for less invasive ventilation. "Higher extraction" systems may be more efficient to achieve this goal. However, as RCTs have not shown a mortality benefit but increase AEs, ECCO2R's effects on clinical outcome remain unclear. Future studies should target patient groups that may benefit from ECCO2R. PROSPERO Registration No: CRD 42020154110 (on January 24, 2021).

Risk factors for pediatric intoxications in the prehospital setting. A geospatial survey.

Background: Socioeconomic factors and the COVID-19 pandemic influence children's physical and mental health. We aimed to investigate the association between a census tract's median household income [MHI in United States Dollars ($)] and pediatric intoxications in Rhode Island, the smallest state in the United States of America. Geographical hotspots, as well as interactions with the COVID-19 pandemic, should be identified. Methods: This study is a retrospective analysis of ambulance calls for pediatric (<18 years) intoxication in Rhode Island between March 1st, 2018, and February 28th, 2022. March 1st, 2020 was considered the beginning of the COVID-19 pandemic. Prehospital data were joined with information from the United States Census Bureau. The census tracts' case counts and MHI were examined using Poisson regression. Geographical clusters were identified with the Global Moran's I and local indicators of spatial association tests in ArcGIS Pro (Esri Corporation, Redlands, CA). Results: Inclusion criteria were met by 208 incidents (48% female, median age 16 (IQR 15 to 17) years). The regression model showed a 0.6% increase (IRR 1.006, 95% CI [1.002, 1.01], p = 0.003) in pediatric intoxications for every $ 1,000 increase in MHI. Interaction analysis showed that the effect of MHI was less pronounced during the pandemic (IRR 0.98, 95% CI [0.964, 0.997], p = 0.02). Thirty-four (14%) of the 244 census tracts contributed to geographical clusters, which changed after the onset of the pandemic. Conclusion: Higher median household income could be a risk factor for pediatric intoxications. Geographical hotspots changed with the pandemic.

Lower serum cholesterol levels as a risk factor for critical illness polyneuropathy: a matched case-control study.

Critical illness polyneuropathy (CIP) is a frequent and underdiagnosed phenomenon among intensive care unit patients. The lipophilic nature of neuronal synapses may result in the association of low serum cholesterol levels with a higher rate of CIP development. We aimed to investigate this issue in critically ill patients. All cases diagnosed with CIP in our tertiary care hospital between 2013 and 2017 were 1:1 matched with controls without the condition by age, sex, and ICD diagnoses. The main risk factors examined were the differences in change between initial and minimum serum total cholesterol levels, and minimum serum total cholesterol levels between matched pairs. Other predictors were serum markers of acute inflammation. We included 67 cases and 67 controls (134 critically ill patients, 49% female, 46% medical). Serum total cholesterol levels decreased more profoundly in cases than controls (median: -74 (IQR -115 to -24) vs. -39 (IQR -82 to -4), median difference: -28, 95% CI [-51, -5]), mg/dl). Minimum serum total cholesterol levels were lower in the cases (median difference: -24, 95% CI [-39, -9], mg/dl). We found significant median differences across matched pairs in maximum serum C-reactive protein (8.9, 95% CI [4.6, 13.2], mg/dl), minimum albumin (-4.2, 95% CI [-6.7, -1.7], g/l), decrease in albumin (-3.9, 95% CI [-7.6, -0.2], g/l), and lowest cholinesterase levels (-0.72, 95% CI [-1.05, -0.39], U/l). Subsequently, more pronounced decreases in serum total cholesterol levels and lower minimum total cholesterol levels during critical care unit hospitalizations may be a risk factor for CIP.

Influence of high altitude after a prior ascent on physical exhaustion during cardiopulmonary resuscitation: a randomised crossover alpine field experiment.

BACKGROUND: Performing cardiopulmonary resuscitation (CPR) inevitably causes significant physical, as well as psychological stress for rescuers. Physical activity at high altitude, a hypobaric and hypoxic environment, similarly adds to the level of stress and causes multiple physiological changes. Continuous measurement of pulse rate serves as an objective measure of fatigue during CPR. We therefore aimed to investigate rescuers' heart rates as a measure of physical strain during CPR in a high-altitude alpine environment to provide a better understanding of the physiological changes under these very special conditions. METHODS: Twenty experienced mountaineers performed basic life support (BLS) on a manikin for 16 min, both at baseline altitude and at high altitude (3454 m) following a quick and exhausting ascent over 1200 m. Sequence of scenarios was randomised for analysis. Heart rate was continuously measured and compared between baseline and high altitude by absolute differences and robust confidence intervals. RESULTS: During CPR at baseline, the average heart rate increased from 87 bpm (SD 16 bpm) to 104 bpm [increase 17 bpm (95% CI 8.24-24.76)], compared to an increase from 119 bpm (SD 12 bpm) to 124 bpm [increase 5 bpm (95% CI - 1.59 to 12.19)] at high altitude [difference between two groups 32 bpm (95% CI 25-39)]. Differences between periods of chest compressions and ventilations were very similar at baseline [19 bpm (95%CI 16.98-20.27)] and at high altitude [20 bpm 95% CI 18.56-21.44)], despite starting from a much higher level at high altitude. The average heart rates of rescuers at high altitude at any point were higher than those at baseline at any other point. CONCLUSION: Performing BLS CPR causes exhaustion both at base level and at a high altitude. A further increase during CPR might imply a physiological reserve for adapting to additional physical exertion at high altitude. Phases of ventilation are much needed recovery-periods, but heart rates remain very high. Subjective measures of exhaustion, such as the BORG-scale, might lead to rescuers' overestimation of their own performance.

Serum neurofilament light chain as an early diagnostic biomarker for critical illness polyneuropathy.

BACKGROUND: Critical illness polyneuropathy (CIP) commonly occurs in critical care unit (CCU) patients, but timely diagnosis can be challenging. Therefore, new biomarkers, such as serum neurofilament light chain (sNfL), could help to improve early identification of patients with this condition. METHODS: CIP was diagnosed or excluded with neurological assessment and nerve conduction measurement in a prospective study of CCU patients. sNfL and secondary predictors for neuropathy (neuron-specific enolase (NSE), S100, folic acid, and vitamin B12) were measured at admission. Cases and controls were compared regarding the predictors. RESULTS: Nineteen patients met the inclusion criteria. CIP was considered definitely or most likely present in seven (37%, cases) and definitely or most likely absent in 12 individuals (63%, controls). At admission, sNfL levels were significantly higher in the cases than in the controls: 405 (IQR 77 to 835) vs. 27 (IQR 12 to 90) pg/mL; difference of medians 375, 95% confidence interval [14, 736], pg/mL; P=0.04. We found no significant differences regarding the secondary predictors at baseline. Cases had longer durations of CCU stay (median 19 (IQR 11 to 44) vs. 8 (IQR five to ten) and increased mortality (57% vs. 33% deceased) compared to controls. CONCLUSIONS: Levels of serum neurofilament light chain are higher in patients who develop CIP soon after CCU admission and might be helpful in identifying those individuals early.

Socioeconomic Risk Factors for Pediatric Out-of-hospital Cardiac Arrest: A Statewide Analysis.

INTRODUCTION: Economic hardship is a major threat to children's health, implying that pediatric out-of-hospital cardiac arrest (pOHCA) might be promoted by lower incomes and child poverty. To target resources, it is helpful to identify geographical hotspots. Rhode Island is the smallest state by area in the United States of America. It has one million inhabitants and is comparable to many larger cities worldwide. We aimed to investigate the possible associations of pOHCA with economic factors and the coronavirus 2019 (COVID-19) pandemic. Our goal was to identify high-risk areas and evaluate whether the COVID-19 pandemic had an influence on delays in prehospital care. METHODS: We analyzed all pOHCA cases (patients <18 years of age) in Rhode Island between March 1, 2018-February 28, 2022. We performed Poisson regression with pOHCA as dependent and economic risk factors (median household income [MHI] and child poverty rate from the US Census Bureau) as well as the COVID-19 pandemic as independent variables. Hotspots were identified using local indicators of spatial association (LISA) statistics. We used linear regression to assess the association of emergency nedical services-related times with economic risk factors and COVID-19. RESULTS: A total of 51 cases met our inclusion criteria. Lower MHIs (incidence-rate ratio [IRR]) 0.99 per $1,000 MHI; P=0.01) and higher child poverty rates (IRR 1.02 per percent; P=0.02) were significantly associated with higher numbers of ambulance calls due to pOHCA. The pandemic did not have a significant influence (IRR 1.1; P=0.7). LISA identified 12 census tracts as hotspots (P<0.01). The pandemic was not associated with delays in prehospital care. CONCLUSION: Lower median household income and higher child poverty rate are associated with higher numbers of pediatric out-of-hospital cardiac arrest.

Arterial stiffness in acute coronary syndrome as a potential triage tool: a prospective observational study.

BACKGROUND: Diagnosis and percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) are time-sensitive. Triage and algorithms identify patients at high-risk. However, additional prediction tools are warranted for prioritized care based on predicted coronary pathologies and PCI complexity. Pulse-wave velocity (PWV) is a non-invasive measurement related to cardiovascular morbidity, and their exact value in ACS evaluation is unclear. METHODS: In patients undergoing coronary angiography (CA) and - if warranted - PCI for ACS evaluation at a tertiary university hospital in Vienna, Austria, brachial-ankle (ba)PWV and carotid-femoral (cf)PWV were prospectively measured from January 2020 to January 2021. RESULTS: PWV was measured in 58 patients (60.3% male; 65 [61-69] years). Risk prediction scores (GRACE, CRUSADE, TIMI), cardiac enzymes, and fraction of patients with a three-vessel disease were significantly higher in the pathological PWV ranges. Adjusted for age and comorbidities, baPWV independently predicted the LAD being relevantly stenotic (crude OR=1.416 [1.143-1.755], P=0.001; adjusted OR=1.340 [1.039-1.727], P=0.024; cut-off 15.5 m/s in CART-analysis), being the culprit lesion (crude OR=1.320 [1.094-1.594], P=0.004; adjusted OR=1.311 [1.037-1.657], P=0.024; cut-off 15.5 m/s), and being totally occluded (crude OR=1.422 [1.113-1.818], P=0.005; adjusted OR=1.677 [1.189-2.366], P=0.003; cut-off 19.6 m/s). Moreover, CA or PCI complexity were associated with higher PWV. CONCLUSIONS: Pathological PWV as a surrogate for arterial stiffness, polyvascular disease and a larger atherosclerotic burden was associated with GRACE, CRUSADE, and TIMI scores, and PCI duration and complexity. BaPWV independently predicted relevant LAD pathologies, and is suggested as a potential novel triage and prioritization tool for suspected NSTE-ACS in emergency departments.

Increases in Ambulance Call Volume Are an Early Warning Sign of Major COVID-19 Surges in Children.

Background: Infectious diseases, including COVID-19, have a severe impact on child health globally. We investigated whether emergency medical service (EMS) calls are a bellwether for future COVID-19 caseloads. We elaborated on geographical hotspots and socioeconomic risk factors. Methods: All EMS calls for suspected infectious disease in the pediatric population (under 18 years of age) in Rhode Island between 1 March 2018 and 28 February 2022 were included in this quasi-experimental ecological study. The first of March 2020 was the beginning of the COVID-19 pandemic. We used the 2020 census tract and the most recent COVID-19 data. We investigated associations between pediatric EMS calls and positive COVID-19 tests with time series analysis and identified geographical clusters using local indicators of spatial association. Economic risk factors were examined using Poisson regression. Results: We included 980 pediatric ambulance calls. Calls during the omicron wave were significantly associated with increases in positive COVID-19 tests one week later (p < 0.001). Lower median household income (IRR 0.99, 95% CI [0.99, 0.99]; p < 0.001) and a higher child poverty rate (IRR 1.02, 95% CI [1.02, 1.02]; p < 0.001) were associated with increased EMS calls. Neighborhood hotspots changed over time. Conclusion: Ambulance calls might be a predictor for major surges of COVID-19 in children.

Factors influencing door-to-triage- and triage-to-patient administration-time.

BACKGROUND: Overcrowding decreases quality of care. Triage and patient administration are possible bottlenecks. We aimed to identify factors influencing door-to-triage- and triage-to-patient administration-time in a prospective observational study at a tertiary care center with 70,000 patients per year. METHODS: Measurement of aforementioned times at convenience-sampled time intervals on 16 days. Linear regression modelling with times as dependent variable, and demographic, medical and structural factors as covariables, testing for interactions with risk factor "weekend". RESULTS: We included 360 patients (183 female (51%)). Median door-to-triage-time was 6 (IQR 3-11) minutes, triage-to-patient administration-time was 5 (IQR 3-8) minutes. Overall door-to-triage-time was significantly shorter during weekends compared to weekdays (absolute difference 3 (IQR 1-7) minutes; 5 (IQR 3-8) vs. 8 (IQR 4-15) minutes, p < 0.01). Other influencing factors were closing hours of non-emergency department healthcare facilities (3.5 min more), number of ESI 2 patients seen during the interval (3 min more for each patient per hour), and ambulance activity (2 min more for each patient per hour brought by ambulance). CONCLUSIONS: Day of time and week as well as frequency of patients with urgent conditions and those brought by ambulance significantly increased door-to-triage times. This should be kept in mind when organizing ED workflow.

The use of personal protection equipment does not negatively affect paramedics' attention and dexterity: a prospective triple-cross over randomized controlled non-inferiority trial.

BACKGROUND: The COVID-19 pandemic led to widespread use of personal protection equipment (PPE), including filtering face piece (FFP) masks, throughout the world. PPE. Previous studies indicate that PPE impairs neurocognitive performance in healthcare workers. Concerns for personnel safety have led to special recommendations regarding basic life support (BLS) in patients with a potential SARS-CoV-2 infection, including the use of PPE. Established instruments are available to assess attention and dexterity in BLS settings, respectively. We aimed to evaluate the influence of PPE with different types of FFP masks on these two neuropsychological components of EMS personnel during BLS. METHODS: This was a randomized controlled non-inferiority triple-crossover study. Teams of paramedics completed three 12-min long BLS scenarios on a manikin after having climbed three flights of stairs with equipment, each in three experimental conditions: (a) without pandemic PPE, (b) with PPE including a FFP2 mask with an expiration valve and (c) with PPE including an FFP2 mask without an expiration valve. The teams and intervention sequences were randomized. We measured the shift in concentration performance using the d2 test and dexterity using the nine-hole peg test (NHPT). We compared results between the three conditions. For the primary outcome, the non-inferiority margin was set at 20 points. RESULTS: Forty-eight paramedics participated. Concentration performance was significantly better after each scenario, with no differences noted between groups: d2 shift control versus with valve - 8.3 (95% CI - 19.4 to 2.7) points; control versus without valve - 8.5 (- 19.7 to 2.7) points; with valve versus without valve 0.1 (- 11.1 to 11.3) points. Similar results were found for the NHPT: + 0.3 (- 0.7 to 1.4), - 0.4 (- 1.4 to 0.7), 0.7 (- 0.4 to 1.8) s respectively. CONCLUSION: Attention increases when performing BLS. Attention and dexterity are not inferior when wearing PPE, including FFP2 masks. PPE should be used on a low-threshold basis.

Impact of more conservative European Society of Cardiology guidelines on the management of patients with acute chest pain.

OBJECTIVE: Early diagnosis or rule-out of acute coronary syndrome (ACS) is a key competence of emergency medicine. Changes in the NSTE-ACS guidelines of the European Society of Cardiology (ESC) in 2015 and 2020 both warranted a henceforth more conservative approach regarding high-sensitivity troponin t (hsTnt) testing. We aimed to assess the impact of more conservative guidelines on the frequency of early rule-out and prolonged observation with repeated hsTnt testing at a high-volume tertiary care emergency department. PATIENTS AND METHODS: We conducted a pre- and post-changeover analysis 3 months before and 3 months after transition from less (hsTnt cut-off 30 ng/L, 3-hour rule-out) to more conservative (hsTnt cut-off 14 ng/L, 1-hour rule-out) guidelines in 2015, comparing proportions of patients requiring repeated testing. RESULTS: We included 5442 cases of symptoms suspicious of acute cardiac origin (3451 before, 1991 after, 2370 (44%) female, age 55 (SD 19) years). The proportion of patients fulfilling early-rule out criteria decreased from 68% (2348 patients) before to 60% (1195 patients) with the 2015 guidelines (P < .01). Those requiring repeated testing significantly (P < .01) increased from 22% (743 patients) to 25% (494 patients). Positive results in repeated testing significantly (P = .02) decreased from 43% (320 patients) to 37% (181 patients). Invasive diagnostics were performed in 91 patients (2.6%) before and in 75 patients (3.8%) after (P = .02) the guideline revision. CONCLUSION: The implementation of the more conservative 2015 ESC guidelines led to a minor rise in prolonged observations because of an increase in negative repeated testing and to an increase in invasive procedures.

The use of personal protection equipment does not impair the quality of cardiopulmonary resuscitation: A prospective triple-cross over randomised controlled non-inferiority trial.

AIM: Prior studies suggest that the use of personal protective equipment might impair the quality of critical care. We investigated the influence of personal protective equipment on out-of-hospital cardiopulmonary resuscitation. METHODS: Randomised controlled non-inferiority triple-crossover study. Forty-eight emergency medical service providers, randomized into teams of two, performed 12 min of basic life support (BLS) on a manikin after climbing 3 flights of stairs. Three scenarios were completed in a randomised order: Without personal protective equipment, with personal protective equipment including a filtering face piece (FFP) 2 mask with valve, and with personal protective equipment including an FFP2 mask without valve. The primary outcome was mean depth of chest compressions with a pre-defined non-inferiority margin of 3.5 mm. Secondary outcomes included other measurements of CPR quality, providers' subjective exhaustion levels, and providers' vital signs, including end-tidal CO2. RESULTS: Differences regarding the primary outcome were well below the pre-defined non-inferiority margins for both control vs. personal protective equipment without valve (absolute difference 1 mm, 95% CI [-1, 2]) and control vs. personal protective equipment with valve (absolute difference 1 mm, [-0.2, 2]). This was also true for secondary outcomes regarding quality of chest compressions and providers' vital signs including etCO2. Subjective physical strain after BLS was higher in the personal protective equipment groups (Borg 4 (SD 3) without valve, 4 (SD 2) with valve) than in the control group (Borg 3 (SD 2)). CONCLUSION: PPE including masks with and without expiration valve is safe for use without concerns regarding the impairment of CPR quality.

Extreme weather conditions as a gender-specific risk factor for acute myocardial infarction.

BACKGROUND: Acute coronary syndrome is a disease with high prevalence and high mortality. Exposure to heat or cold increases the risks of myocardial infarction significantly. Gender-specific effects of this have not yet been examined. Our goal was to determine whether extreme weather conditions, which become more and more frequent, are gender-specific risk factors for myocardial infarction, in order to help provide faster diagnosis and revascularization therapy for patients. METHODS: We analysed the incidence of ST-elevation myocardial infarction (STEMI) in a large urban area over a 65-months period in a cohort study. A day was the unit of analysis. Incidence rate ratios (IRR) with Poisson regression models were calculated. All patients with STEMI on Saturdays and Sundays were included. Gender, high or low perceived temperatures (PT), a function of temperature, wind speed and humidity, and meteorological cold and heat warnings by the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) were considered as risk factors. RESULTS: During the 562 days of the study period, a total of 1109 patients with STEMI (803; 72% men, mean age 61;14 years) were included. The gender difference between men and women was much more pronounced on cold (0 °C) days (85% of patients male; 1.8 per day) than on hot (20 °C) days (71% male; 1.4 per day) or days without extreme temperatures (72% male; 1.4 per day). We found significant interaction between gender and cold days (IRR of the interaction term 2.3 (95% CI 1.2-4.6), p = 0.02). No gender-specific effect was observed on warm days (IRR for interaction 0.9 (95% CI 0.6-1.3), p = 0.3). CONCLUSION: Low perceived temperature pronouncedly increases the already elevated risk for STEMI in males. Whether this effect is based on gender alone, or on one of the cardiovascular risk factors which are more common in men, is up to further study.

Generalisability of randomised trials evaluating perioperative ß-blocker therapy in noncardiac surgery.

BACKGROUND: The limited applicability of evidence from RCTs in real-word practice is considered a potential bottleneck for evidence-based practice but rarely systematically assessed. Using our failure to recruit patients into a perioperative beta-blocker trial, we set out to analyse the restrictiveness and generalisability of trial eligibility criteria in a real-world cohort. METHODS: We prospectively included adult patients (≥18 yr) scheduled for elective noncardiac surgery at an academic tertiary care facility who were screened for inclusion in a planned perioperative beta-blocker RCT, which was terminated owing to recruitment failure. The primary outcome was the proportion of screened patients who matched the eligibility criteria of 36 published RCTs included in a large Cochrane meta-analysis on perioperative beta-blocker therapy. The pragmatic/explanatory level of each RCT was assessed using the PRagmatic-Explanatory Continuum Indicator Summary 2 (PRECIS-2) score, which ranges from 9 points (indicating a very explanatory study) to 45 points (indicating a very pragmatic study). RESULTS: A total of 2241 patients (54% female, n=1215; 52 [standard deviation, 20] yr) were included for the assessment of trial eligibility between October 2015 and January 2016. Only a small proportion of patients matched the inclusion and exclusion criteria for each of the 36 RCTs, ranging from 53% to 0%. The average proportion of patients who did match the eligibility criteria of all 36 RCTs was 6.5% (n=145; 95% confidence interval, 6.3-6.6). A higher PRECIS-2 score was associated with a higher proportion of matching patients (P<0.001). CONCLUSIONS: Trial eligibility criteria in perioperative beta-blocker therapy trials are overly restrictive and not generalisable to a real-world surgical population. CLINICAL TRIAL REGISTRATION: EudraCT#: 2015-002366-23.

Early identification of patients with chest pain at very low risk of acute myocardial infarction using clinical information and ECG only.

BACKGROUND: A considerable proportion of patients with angina-like symptoms in an emergency department have very low pretest probability for acute myocardial infarction (AMI). Numerous algorithms exist for the exclusion of AMI, usually including laboratory tests. We aimed to investigate whether patients with very low risk can safely be identified by ECG and clinical information without biomarker testing, contributing to saving time and costs. METHODS: Prospective diagnostic test accuracy study. We included all consecutive patients presenting with angina at the department of emergency medicine of a tertiary care hospital during a 1-year period. Using clinical information without biomarker testing and ECG, the "Mini-GRACE score," based on the well-established GRACE-score without using laboratory parameters was calculated. In a cohort design we compared the index test Mini-GRACE to AMI as reference standard in the final diagnosis using standard measures of diagnostic test accuracy. RESULTS: We included 2755 patients (44% female, age 44 ± 17 years). AMI was diagnosed in 103 (4%) patients, among those 44% with STEMI. Overall 2562 patients (93%) had a negative "Mini-GRACE," four (0.2%) of these patients had myocardial infarction, and this results in a sensitivity of 96.1% (95% CI 90.4%-98.9%), specificity 96.5% (95.7%-97.1%), positive predictive value 51.3% (46.3%-56.3%) and negative predictive value 99.8% (99.6%-99.9%). Model performance according to C statistic (0.90) and Brier score (0.0045) was excellent. In rule-out patients 30-day mortality was 0.3% and 1-year mortality was 0.8%. CONCLUSIONS: Patients with very low risk of AMI can be identified with high certainty using clinical information without biomarker testing and ECG. Cardiac biomarkers might be avoided in such cases, potentially leading to a significant cost reduction.

Influence of physical strain at high altitude on the quality of cardiopulmonary resuscitation.

BACKGROUND: High quality cardiopulmonary resuscitation is a key factor in survival with good overall quality of life after out-of-hospital cardiac arrest. Current evidence is predominantly based on studies conducted at low altitude, and do not take into account the special circumstances of alpine rescue missions. We therefore aimed to investigate the influence of physical strain at high altitude on the quality of cardiopulmonary resuscitation. METHODS: Alpine field study. Twenty experienced mountaineers of the Austrian Mountain Rescue Service trained in Basic Life Support (BLS) performed BLS on a manikin in groups of two for 16 min. The scenario was executed at baseline altitude and immediately after a quick ascent over an altitude difference of 1200 m at 3454 m above sea level. The sequence of scenarios was randomised for a cross over analysis. Quality of CPR and exhaustion of participants (vital signs, Borg-Scale, Nine hole peg test) were measured and compared between high altitude and baseline using random-effects linear regression models. RESULTS: The primary outcome of chest compression depth significantly decreased at high altitude compared to baseline by 1 cm (95% CI 0.5 to 1.3 cm, p < 0.01). There was a significant reduction in the proportion of chest compressions in the target depth (at least 5 cm pressure depth) by 55% (95% CI 29 to 82%, p < 0.01) and in the duration of the release phase by 75 ms (95% CI 48 to 101 ms, p < 0.01). No significant difference was found regarding hands-off times, compression frequency or exhaustion. CONCLUSION: Physical strain during a realistic alpine rescue mission scenario at high altitude led to a significant reduction in quality of resuscitation. Resuscitation guidelines developed at sea level are not directly applicable in the mountain terrain.