Allergenic potency of various foods of mammalian origin in patients with α-Gal syndrome.

BACKGROUND: The α-Gal syndrome (AGS) is an emerging allergy to mammalian food caused by IgE-mediated reactions to the carbohydrate galactose-α-1,3-galactose (α-Gal). Mammalian food sources contain α-Gal, but the amount differs. The objective of this study was to investigate the allergenic potency of various foods of mammalian origin among AGS patients. METHODS: Twenty-six AGS patients were included. Food extracts from innards, lean meats, processed meat products, milk, and whey were analyzed. Immunoblot, ELISA, immunofluorescence, and basophil activation test were used to determine the α-Gal content, characterize IgE binding, and assess foods' allergenicity. RESULTS: The determined amount of α-Gal, IgE reactivity to food extracts, and food extract potencies to activate patients' basophils correlated well with each other. Pork and beef kidney showed the highest allergenicity. Beef liver and bacon showed allergenicity comparable to that of lean meats. Game meat seemed to have a higher allergenic potency than meats from farm-raised animals. The processed meat products liver pâté and black pudding, despite lower α-Gal content, demonstrated moderate allergenicity. Milk showed the lowest allergenicity. IgE reactivity to food extracts was highly similar for all patients and strongly dominated by the α-Gal epitope. CONCLUSIONS: The allergenic potency of mammalian meat depends on the origin of the meat, the different cuts, and type of processing, with innards posing the greatest risk to AGS patients. Even processed mammalian meat constitutes a risk. Dairy products show the lowest risk. This study highlights the importance of analyzing even more foods to improve the management of AGS.

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.

Short- and intermediate-term effects of a hospital-integrated walk-in clinic on emergency department-visits and case mix.

BACKGROUND AND IMPORTANCE: Emergency department (ED) admissions have been rising over the last decades, especially in countries without any effective gate-keeping functions. Integration of walk-in clinics into the hospital might reduce ED-visits. Over a longer period, however, the additional service of a walk-in clinic might attract even more patients, nullifying an initial decrease in patients for the ED. OBJECTIVES, DESIGN, SETTINGS AND PARTICIPANTS: This study aimed to determine short- and intermediate-term changes after the implementation of a hospital-integrated walk-in clinic. This is an observational study using routinely-collected health data. Study setting was the ED of a large tertiary care hospital in Austria, a country with universal health care and no regulations regarding level of care. OUTCOMES MEASURE AND ANALYSIS: ED-visits were compared between before (2015) and after (2017 and 2018) establishment of a hospital-integrated walk-in clinic. MAIN RESULTS: Total ED-visits decreased from 87,624 in 2015 to 67,479 in 2017, and 67,871 in 2018 (p < 0.001), mainly due to a decrease in non-urgent (ESI 4 & 5) cases (45,715 (54.1%) in 2015; 33,142 (51.3%) in 2017; 30,846 (47.5%) in 2018; short term OR non-urgent vs. urgent: 0.89 (95% CI 0.88-0.91); intermediate term OR urgent vs. non-urgent: 0.76 (95% CI 0.78-0.75)). A total of 2611 (13%) (2017) and 1714 (8.5%) (2018) patients were referred back to the ED. CONCLUSIONS: After the introduction of the walk-in clinic, ED-visits declined significantly. This remained stable over a two-year period. Reduction in ED-visits was mainly due to low-acuity patients not requiring admission to the hospital.

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.

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.

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.

Risk stratification in acute coronary syndrome: Evaluation of the GRACE and CRUSADE scores in the setting of a tertiary care centre.

OBJECTIVE: Risk assessment plays a decisive role in the management of acute coronary syndrome (ACS). The GRACE and the CRUSADE scores are among the most frequently used risk assessment tools. We aimed to compare the performance of the GRACE and CRUSADE risk scores to predict in-hospital mortality and major bleeding in a contemporary ACS population at a high-volume academic hospital. METHODS: All patients treated for ACS from January 1, 2006 to December 31, 2015 at a tertiary care centre were prospectively enrolled. We calculated GRACE and CRUSADE risk scores. We compared the discrimination capacity of both scores for in-hospital mortality and major bleeding. RESULTS: In total 4087 patients (1151 [28.2%] female; age 62 ± 14 years) were included. Among these 2218 (54.3%) were diagnosed with ST-elevation myocardial infarction, 113 (2.8%) died in hospital and major bleeding occurred in 65 (1.6%). Discrimination capacity for in-hospital mortality of the GRACE score was superior to the CRUSADE score (receiver operator characteristic area under the curve (AUC) 0.91 (95% CI 0.89-0.93) vs 0.83 (95% CI 0.80-0.86); P < .01). Performance for major bleeding differed but was poor for both scores (AUC 0.71 [0.65-0.76] for GRACE vs 0.61 [0.55-0.68] for CRUSADE; P < .01). CONCLUSION: The GRACE score appears to be superior over CRUSADE to predict in-hospital mortality. Major bleeding is rare in the era of primary PCI and performance of both scores for this outcome was poor.

Impact of the COVID-19 Pandemic on Therapy and Outcome of Acute Exacerbations of Chronic Obstructive Lung Disease at the Emergency Department.

This study compared the treatment outcomes of acute exacerbation of COPD (AECOPD) at an academic tertiary care emergency department before and during the COVID-19 pandemic. Analyzing data from 976 patients, our study showed a significant surge in overall respiratory therapy interventions amidst the noticeable decline in the total number of AECOPD cases during the pandemic. The marked increase in the utilization of non-invasive ventilation (NIV) was particularly important, soaring from 12% to 18% during the pandemic. Interestingly, this heightened reliance on NIV stood in contrast to the stability observed in other therapeutic modalities, including oxygen insufflation alone, high-flow nasal cannulas, and invasive ventilation. This distinctive treatment pattern underscores the adaptability of healthcare providers in the face of novel challenges, with a discernible emphasis on the strategic utilization of NIV. The shift in patient acuity during the pandemic became evident as the data showed a cohort of individuals presenting with AECOPD who were more severely ill. This was reflected in the increased use of NIV and, notably, a statistically significant rise in one-year mortality rates-from 32% before the pandemic to 38% during the pandemic (p = 0.046). These findings underscore the intricate balance healthcare providers must strike in navigating the complexities of patient care during a public health crisis. A closer examination of the longitudinal trajectory revealed a subtle decrease in re-admission rates from 65% to 60%. The increased reliance on NIV, a key finding of this investigation, reflects a strategic response to the unique demands of the pandemic, potentially influenced by both medical considerations and non-medical factors, such as the prevalent "fear of aerosols" and the imperative to navigate transmission risks within the healthcare setting. These insights contribute to understanding the evolving dynamics of AECOPD management during public health crises.

Vaccine Based on Recombinant Fusion Protein Combining Hepatitis B Virus PreS with SARS-CoV-2 Wild-Type- and Omicron-Derived Receptor Binding Domain Strongly Induces Omicron-Neutralizing Antibodies in a Murine Model.

BACKGROUND: COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a recurrent endemic disease affecting the whole world. Since November 2021, Omicron and its subvariants have dominated in the spread of the disease. In order to prevent severe courses of disease, vaccines are needed to boost and maintain antibody levels capable of neutralizing Omicron. Recently, we produced and characterized a SARS-CoV-2 vaccine based on a recombinant fusion protein consisting of hepatitis B virus (HBV)-derived PreS and two SARS-CoV-2 wild-type RBDs. OBJECTIVES: To develop a PreS-RBD vaccine which induces high levels of Omicron-specific neutralizing antibodies. METHODS: We designed, produced, characterized and compared strain-specific (wild-type: W-PreS-W; Omicron: O-PreS-O), bivalent (mix of W-PreS-W and O-PreS-O) and chimeric (i.e., W-PreS-O) SARS-CoV-2 protein subunit vaccines. Immunogens were characterized in vitro using protein chemical methods, mass spectrometry, and circular dichroism in combination with thermal denaturation and immunological methods. In addition, BALB/c mice were immunized with aluminum-hydroxide-adsorbed proteins and aluminum hydroxide alone (i.e., placebo) to study the specific antibody and cytokine responses, safety and Omicron neutralization. RESULTS: Defined and pure immunogens could be produced in significant quantities as secreted and folded proteins in mammalian cells. The antibodies induced after vaccination with different doses of strain-specific, bivalent and chimeric PreS-RBD fusion proteins reacted with wild-type and Omicron RBD in a dose-dependent manner and resulted in a mixed Th1/Th2 immune response. Interestingly, the RBD-specific IgG levels induced with the different vaccines were comparable, but the W-PreS-O-induced virus neutralization titers against Omicron (median VNT50: 5000) were seven- and twofold higher than the W-PreS-W- and O-PreS-O-specific ones, respectively, and they were six-fold higher than those of the bivalent vaccine. CONCLUSION: Among the tested immunogens, the chimeric PreS-RBD subunit vaccine, W-PreS-O, induced the highest neutralizing antibody titers against Omicron. Thus, W-PreS-O seems to be a highly promising COVID-19 vaccine candidate for further preclinical and clinical evaluation.

Impact of the first COVID-19 lockdown in Austria on laboratory and mental parameters in diabetic patients: a retrospective analysis highlighting the importance of regular medical consultations in a patient cohort.

BACKGROUND: Due to the COVID-19 pandemic, the first lockdown was implemented in Austria for almost 7 weeks. In contrast to many other countries, medical consultations were permitted, either by telemedicine or at doctors' offices. Nevertheless, restrictions related to this lockdown could possibly cause an increased risk of deterioration in health, especially in diabetes. This study aimed to assess the impact of Austria's first lockdown on laboratory and mental parameters in a type-2 diabetes mellitus cohort. METHODS: Overall 347 mainly elderly patients with type-2 diabetes (56% male; aged 63.7±10.1 years) were included in this retrospective practitioner-based analysis. Laboratory as well as mental parameters were compared from before and after the lockdown. RESULTS: The lockdown showed no significant effect on HbA1c levels. On the other hand, total cholesterol (P<0.001) and LDL cholesterol (P<0.001) levels improved significantly, whereas body weight (P<0.01) and mental well-being based on the EQ-5D-3L questionnaire (P<0.01) increased significantly in terms of worsening. CONCLUSIONS: Lack of movement and staying at home resulted in a significant weight gain and worsening of mental well-being in type-2 diabetes during the first lockdown in Austria. Thanks to regular medical consultations, laboratory parameters remained stable or even improved. Thus, routine health check-ups in mainly elderly type 2 diabetic patients are essential to minimize the deterioration of health conditions during lockdowns.

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.

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.

From Allergen Molecules to Molecular Immunotherapy of Nut Allergy: A Hard Nut to Crack.

Peanuts and tree nuts are two of the most common elicitors of immunoglobulin E (IgE)-mediated food allergy. Nut allergy is frequently associated with systemic reactions and can lead to potentially life-threatening respiratory and circulatory symptoms. Furthermore, nut allergy usually persists throughout life. Whether sensitized patients exhibit severe and life-threatening reactions (e.g., anaphylaxis), mild and/or local reactions (e.g., pollen-food allergy syndrome) or no relevant symptoms depends much on IgE recognition of digestion-resistant class I food allergens, IgE cross-reactivity of class II food allergens with respiratory allergens and clinically not relevant plant-derived carbohydrate epitopes, respectively. Accordingly, molecular allergy diagnosis based on the measurement of allergen-specific IgE levels to allergen molecules provides important information in addition to provocation testing in the diagnosis of food allergy. Molecular allergy diagnosis helps identifying the genuinely sensitizing nuts, it determines IgE sensitization to class I and II food allergen molecules and hence provides a basis for personalized forms of treatment such as precise prescription of diet and allergen-specific immunotherapy (AIT). Currently available forms of nut-specific AIT are based only on allergen extracts, have been mainly developed for peanut but not for other nuts and, unlike AIT for respiratory allergies which utilize often subcutaneous administration, are given preferentially by the oral route. Here we review prevalence of allergy to peanut and tree nuts in different populations of the world, summarize knowledge regarding the involved nut allergen molecules and current AIT approaches for nut allergy. We argue that nut-specific AIT may benefit from molecular subcutaneous AIT (SCIT) approaches but identify also possible hurdles for such an approach and explain why molecular SCIT may be a hard nut to crack.

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.

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.