Most downloaded biology preprints, all time
in category emergency medicine
144 results found. For more information, click each entry to expand.
13,261 downloads medRxiv emergency medicine
Importance: Coronavirus disease 2019 (COVID-19) is a pandemic with no specific drugs and high mortality. The most urgent thing is to find effective treatments. Objective: To determine whether hydroxychloroquine application may be associated with a decreased risk of death in critically ill COVID-19 patients and what is potential mechanism. Design, Setting and Patients: This retrospective study included all 568 critically ill COVID-19 patients who were confirmed by pathogen laboratory tests despite antiviral treatment and had severe acute respiratory distress syndrome, PAO2/FIO2 <300 with need of mechanical ventilation in Tongji Hospital, Wuhan, between February 1 of 2020 to April 8 of 2020. All 568 patients received comparable basic treatments including antiviral drugs and antibiotics, and 48 of them additionally received oral hydroxychloroquine (HCQ) treatment (200 mg twice a day for 7-10 days). Primary endpoint is mortality of patients, and inflammatory cytokines levels were compared between hydroxychloroquine and non-hydroxychloroquine (NHCQ) treatments. MAIN OUTCOMES AND MEASURES: In-hospital death and hospital stay time (day) were obtained, level of inflammatory cytokine (IL-6) was measured and compared between HCQ and NHCQ treatments. RESULTS: The median age of 568 critically ill patients is 68 (57, 76) years old with 37.0% being female. Mortalities are 18.8% (9/48) in HCQ group and 45.8% (238/520) in NHCQ group (p<0.001). The time of hospital stay before patient death is 15 (10-21) days and 8 (4 - 14) days for the HCQ and NHCQ groups, respectively (p<0.05). The level of inflammatory cytokine IL-6 was significantly lowered from 22.2 (8.3-118.9) pg/mL at the beginning of the treatment to 5.2 (3.0-23.4) pg/ml (p<0.05) at the end of the treatment in the HCQ group but there is no change in the NHCQ group. CONCLUSIONS AND RELEVANCE: Hydroxychloroquine treatment is significantly associated with a decreased mortality in critically ill patients with COVID-19 through attenuation of inflammatory cytokine storm. Therefore, hydroxychloroquine should be prescribed for treatment of critically ill COVID-19 patients to save lives.
7,114 downloads medRxiv emergency medicine
With the recent COVID-19 pandemic, healthcare systems all over the world are struggling to manage the massive increase in emergency department (ED) visits. This has put an enormous demand on medical professionals. Increased wait times in the ED increases the risk of infection transmission. In this work we present an open-source, low cost, off-body system to assist in the automatic triage of patients in the ED based on widely available hardware. The system initially focuses on two symptoms of the infection - fever and cyanosis. The use of visible and far-infrared cameras allows for rapid assessment at a 1m distance, thus reducing the load on medical staff and lowering the risk of spreading the infection within hospitals. Its utility can be extended to a general clinical setting in non-emergency times as well to reduce wait time, channel the time and effort of healthcare professionals to more critical tasks and also prioritize severe cases. Our system consists of a Raspberry Pi 4, a Google Coral USB accelerator, a Raspberry Pi Camera v2 and a FLIR Lepton 3.5 Radiometry Long-Wave Infrared Camera with an associated IO module. Algorithms running in real-time detect the presence and body parts of individual(s) in view, and segments out the forehead and lip regions using PoseNet. The temperature of the forehead-eye area is estimated from the infrared camera image and cyanosis is assessed from the image of the lips in the visible spectrum. In our preliminary experiments, an accuracy of $97% was achieved for detecting fever and $77% for the detection of cyanosis, with a sensitivity of 91% and area under the receiver operating characteristic curve of 0.91. Heart rate and respiratory effort are also estimated from the visible camera. Although preliminary results are promising, we note that the entire system needs to be optimized before use and assessed for efficacy. The use of low-cost instrumentation will not produce temperature readings and identification of cyanosis that is acceptable in many situations. For this reason, we are releasing the full code stack and system design to allow others to rapidly iterate and improve the system. This may be of particular benefit in low-resource settings, and low-to-middle income countries in particular, which are just beginning to be affected by COVID-19.
6,883 downloads medRxiv emergency medicine
Introduction Hypoxia is the main cause of morbidity and mortality in COVID-19. During the COVID-19 pandemic some countries have reduced access to supplemental oxygen (e.g. oxygen rationing), whereas other nations have maintained and even improved access to supplemental oxygen. We examined whether such variation in the access to supplemental oxygen had any bearing on mortality in COVID-19. Methods Three independent investigators searched for, identified and extracted the nationally recommended target oxygen levels for the commencement of oxygen in COVID-19 pneumonia from the 29 worst affected countries. Mortality estimates were calculated from three independent sources. We then applied linear regression analysis to examine for potential association between national targets for the commencement of oxygen and case fatality rates. Results Of the 26 nations included, 15 had employed conservative oxygen strategies to manage COVID-19 pneumonia. Of them, Belgium, France, USA, Canada, China, Germany, Mexico, Spain, Sweden and the UK guidelines advised commencing oxygen when oxygen saturations (SpO2) fell to 91% or less. Target SpO2 ranged from 92% to 95% in the other 16 nations. Linear regression analysis demonstrated a strong inverse correlation between the national target for the commencement of oxygen and national case fatality rates (Spearmans Rho = -0.622, p < 0.001). Conclusion Our study highlights the disparity in oxygen provision for COVID-19 patients between the nations analysed, and indicates such disparity in access to supplemental oxygen may represent a modifiable factor associated with mortality during the pandemic.
5,101 downloads medRxiv emergency medicine
Background: A growing number of epidemiological cases are proving the possibility of airborne transmission of coronavirus disease 2019 (COVID-19). Ensuring adequate ventilation rate is essential to reduce the risk of infection in confined spaces. Methods: We obtained the quantum generation rate by a COVID-19 infector with a reproductive number based fitting approach, and then estimated the association between infected probability and ventilation rate with the Wells-Riley equation. Results: The estimated quantum generation rate of COVID-19 is 14-48 /h. To ensure infected probabolity less than 1%, ventilation rate lareger than common values (100-350 m3/h and 1200-4000 m3/h for 15 minutes and 3 hours exposure, respectively) is required. If both the infector and susceptibles wear masks, the ventilation rate ensuring less than 1% infected probability is reduced to 50-180 m3/h and 600-2000 m3/h correspondingly, which is easier to be achieved by normal ventilation mode applied in some typical scenarios, including offices, classrooms, buses and aircraft cabins. Interpretation: The risk of potential airborne transmission in confined spaces cannot be ignored. Strict preventive measures that have been widely adopted should be effective in reducing the risk of airborne transmitted infection.
3,473 downloads medRxiv emergency medicine
Objective: Emergency medical services (EMS) may serve as a key source of rapid data about the evolving health of COVID-19 affected populations. A study in Italy reported that EMS-documented out-of-hospital cardiac arrest rose by 58% during the peak-epidemic. EMS and hospital reports from several countries have suggested that silent hypoxemia-low oxygen saturation (SpO2) in the absence of dyspnea-is associated with COVID-19 outbreaks. It is unclear, however, how these phenomena can be generalized to low-and-middle-income countries (LMICs). Tijuana is a city on the Mexico-United States border that may serve as a bellwether for cities in other LMICs. Using EMS data, we assess changes in out-of-hospital mortality and the SpO2 of respiratory patients during the COVID-19 period. Methods: We calculated numbers of weekly out-of-hospital deaths and respiratory cases seen by EMS in Tijuana, and estimate the difference between peak-epidemic rates and forecasted 2014-2019 trends. Results were compared with official COVID-19 statistics, stratified by neighborhood socioeconomic status (SES), and examined for changing demographic or clinical features, including mean (SpO2). Results: An estimated 194.7 (95%CI: 135.5-253.9) excess out-of-hospital deaths events occurred during April 14th-May 11th, representing an increase of 145% (70%-338%) compared to forecasted trends. During the same window, only 8 COVID-19-positive, out-of-hospital deaths were reported in official statistics. This corresponded with a rise in respiratory cases of 274% (119%-1142%), and a drop in mean SpO2 to 77.7%, from 90.2% at baseline. Peak respiratory cases were concentrated in high-SES neighborhoods, while the highest out-of-hospital death rates were observed in low-SES areas. Conclusions: EMS systems may play an important sentinel role in monitoring excess out-of-hospital mortality and other trends during the COVID-19 crisis in LMICs. Using EMS data, we observed increases in out-of-hospital deaths in Tijuana that were nearly threefold greater magnitude than increases reported in Italy. Furthermore, these deaths may be missing from official records describing COVID-19 patients. We also found evidence of worsening hypoxemia among respiratory patients seen by EMS, suggesting a rise in silent hypoxemia, which should be met with increased detection and clinical management efforts. Finally, we observed that social disparities in out-of-hospital death that warrant monitoring and amelioration.
3,362 downloads medRxiv emergency medicine
ABSTRACT Background: Widespread reports suggest the characteristics and disease course of coronavirus disease 2019 (COVID-19) and influenza differ, yet detailed comparisons of their clinical manifestations are lacking. Objective: Comparison of the epidemiology and clinical characteristics of COVID-19 patients with those of influenza patients in previous seasons at the same hospital Design: Admission rates, clinical measurements, and clinical outcomes from confirmed COVID-19 cases between March 1 and April 30, 2020 were compared with those from confirmed influenza cases in the previous five influenza seasons (8 months each) beginning September 1, 2014. Setting: Large tertiary care teaching hospital in Boston, Massachusetts Participants: Laboratory-confirmed COVID-19 and influenza inpatients Measurements: Patient demographics and medical history, mortality, incidence and duration of mechanical ventilation, incidences of vasopressor support and renal replacement therapy, hospital and intensive care admissions. Results: Data was abstracted from medical records of 1052 influenza patients and 583 COVID-19 patients. An average of 210 hospital admissions for influenza occurred per 8-month season compared to 583 COVID-19 admissions over two months. The median weekly number of COVID-19 patients requiring mechanical ventilation was 17 (IQR: 4, 34) compared to a weekly median of 1 (IQR: 0, 2) influenza patient (p=0.001). COVID-19 patients were significantly more likely to require mechanical ventilation (31% vs 8%), and had significantly higher mortality (20% vs. 3%; p<0.001 for all). Relatively more COVID-19 patients on mechanical ventilation lacked pre-existing conditions compared with mechanically ventilated influenza patients (25% vs 4%, p<0.001). Limitation: This is a single-center study which could limit generalization. Conclusion: COVID-19 resulted in more hospitalizations, higher morbidity, and higher mortality than influenza at the same hospital.
2,902 downloads medRxiv emergency medicine
BackgroundThe early identification of deterioration in suspected COVID-19 patients managed at home enables a more timely clinical intervention, which is likely to translate into improved outcomes. We undertook an analysis of COVID-19 patients conveyed by ambulance to hospital to investigate how oxygen saturation and measurements of other vital signs correlate to patient outcomes, to ascertain if clinical deterioration can be predicted with simple community physiological monitoring. MethodsA retrospective analysis of routinely collected clinical data relating to patients conveyed to hospital by ambulance was undertaken. We used descriptive statistics and predictive analytics to investigate how vital signs, measured at home by ambulance staff from the South Central Ambulance Service, correlate to patient outcomes. Information on patient comorbidities was obtained by linking the recorded vital sign measurements to the patients electronic health record at the Hampshire Hospitals NHS Foundation Trust. ROC analysis was performed using cross-validation to evaluate, in a retrospective fashion, the efficacy of different variables in predicting patient outcomes. ResultsWe identified 1,080 adults with a COVID-19 diagnosis who were conveyed by ambulance to either Basingstoke & North Hampshire Hospital or the Royal Hampshire County Hospital (Winchester) between March 1st and July 31st and whose diagnosis was clinically confirmed at hospital discharge. Vital signs measured by ambulance staff at first point of contact in the community correlated with patient short-term mortality or ICU admission. Oxygen saturations were the most predictive of mortality or ICU admission (AUROC 0.772 (95 % CI: 0.712-0.833)), followed by the NEWS2 score (AUROC 0.715 (95 % CI: 0.670-0.760), patient age (AUROC 0.690 (95 % CI: 0.642-0.737)), and respiration rate (AUROC 0.662 (95 % CI: 0.599-0.729)). Combining age with the NEWS2 score (AUROC 0.771 (95 % CI: 0.718-0.824)) or the measured oxygen saturation (AUROC 0.820 (95 % CI: 0.785-0.854)) increased the predictive ability but did not reach significance. ConclusionsInitial oxygen saturation measurements (on air) for confirmed COVID-19 patients conveyed by ambulance correlated with short-term (30-day) patient mortality or ICU admission, AUROC: 0.772 (95% CI: 0.712-0.833). We found that even small deflections in oxygen saturations of 1-2% below 96% confer an increased mortality risk in those with confirmed COVID at their initial community assessments.
2,787 downloads medRxiv emergency medicine
BackgroundSARS-CoV-2 has been a global pandemic, but the emergence of asymptomatic patients has caused difficulties in the prevention of the epidemic. Therefore, it is significant to understand the epidemiological characteristics of asymptomatic patients with SARS-CoV-2 infection. MethodsIn this single-center, retrospective and observational study, we collected data from 167 patients with SARS-CoV-2 infection treated in Chongqing Public Health Medical Center (Chongqing, China) from January to March 2020. The epidemiological characteristics and variable of these patients were collected and analyzed. Findings82.04% of the SARS-CoV-2 infected patients had a travel history in Wuhan or a history of contact with returnees from Wuhan, showing typical characteristics of imported cases, and the proportion of severe Covid-19 patients was 13.2%, of which 59% were imported from Wuhan. For the patients who was returnees from Wuhan, 18.1% was asymptomatic patients. In different infection periods, compared with the proportion after 1/31/2020, the proportion of asymptomatic patient among SARS-CoV-2 infected patient was higher(19% VS 1.5%). In different age groups, the proportion of asymptomatic patient was the highest(28.6%) in children group under 14, next in elder group over 70 (27.3%). Compared with mild and common Covid-19 patients, the mean latency of asymptomatic was longer (11.25 days VS 8.86 days), but the hospital length of stay was shorter (14.3 days VS 16.96 days). ConclusionThe SARS-CoV-2 prevention needs to focus on the screening of asymptomatic patients in the community with a history of contact with the imported population, especially for children and the elderly population.
2,551 downloads medRxiv emergency medicine
Cong Feng, Zhi Huang, Lili Wang, Xin Chen, Yongzhi Zhai, Feng Zhu, Hua Chen, Yingchan Wang, Xiangzheng Su, Sai Huang, Lin Tian, Weixiu Zhu, Wenzheng Sun, Liping Zhang, Qingru Han, Juan Zhang, Fei Pan, Li Chen, Zhihong Zhu, Hongju Xiao, Yu Liu, Gang Liu, Wei Chen, Tanshi Li
Currently, the prevention and control of COVID-19 outside Hubei province in China, and other countries has become more and more critically serious. We developed and validated a diagnosis aid model without CT images for early identification of suspected COVID-19 pneumonia (S-COVID-19-P) on admission in adult fever patients and made the validated model available via an online triage calculator. Patients admitted from Jan 14 to Feb 26, 2020 with the epidemiological history of exposure to COVID-19 were included [Model development (n = 132) and validation (n = 32)]. Candidate features included clinical symptoms, routine laboratory tests and other clinical information on admission. Features selection and model development were based on Lasso regression. The primary outcome is the development and validation of a diagnosis aid model for S-COVID-19-P early identification on admission. The development cohort contains 26 S-COVID-19-P and 7 confirmed COVID-19 pneumonia cases. The model performance in held-out testing set and validation cohort resulted in AUCs of 0.841 and 0.938, F-1 score of 0.571 and 0.667, recall of 1.000 and 1.000, specificity of 0.727 and 0.778, and the precision of 0.400 and 0.500. Based on this model, an optimized strategy for S-COVID-19-P early identification in fever clinics has also been designed. S-COVID-19-P could be identified early by a machine-learning model only used collected clinical information without CT images on admission in fever clinics with 100% recall score. The well performed and validated model has been deployed as an online triage tool, which is available at: https://intensivecare.shinyapps.io/COVID19/.
2,496 downloads medRxiv emergency medicine
ObjectiveTo evaluate aerosol-spread in cardiopulmonary resuscitation (CPR) using different methods of airway management. Knowledge about Aerosol spread is vital during the SARS-CoV-2-Pandemic. MethodsTo evaluate feasibility we nebulized ultraviolet sensitive detergents into the artificial airway of a resuscitation dummy and performed CPR. The spread of the visualized aerosol was documented by a camera. In a second approach we applied nebulized detergents into human cadavers by an endotracheal tube and detected aerosol- spread during chest compressions the same way. We did recordings with undergoing compression- only-CPR, with a surgical mask and with an inserted laryngeal tube with and without a connected airway filter. ResultsMost aerosol-spread at the direction of the provider was visualized during compression-only-CPR. The use of a surgical mask deflected the spread. Inserting a laryngeal tube connected to an airway filter lead to a remarkable reduction of aerosol-spread. ConclusionThe early insertion of a laryngeal tube connected to an airway filter before starting chest compression may be good for two Things: the treatment of hypoxemia as the likeliest cause of cardiac arrest and for staff protection during CPR.
2,373 downloads medRxiv emergency medicine
We describe a minimum, rapidly scalable ventilator designed for COVID-19 patients with ARDS. Our design philosophy is not only to try to address potential ventilator shortages, but also to account for uncertainties in the supply chains of parts commonly used in traditional ventilators. To do so we employ a modular design approach and broadly explore taking advantage of parts from non-traditional supply chains. In our current prototype, we demonstrate volume control with assist control on a test lung and present a linear actuator-driven pinch valve-based implementation for both pressure control and volume control with decelerating inspiratory flow. We estimate the component cost of the system to be around $500. We publish our draft design documents and current implementation which is open and accessible in the hope that broadening the community globally will accelerate arriving at a solution and that peer review will improve the final design.
1,874 downloads medRxiv emergency medicine
Adrian Soto-Mota, Braulio A. Marfil Garza, Erick Martinez Rodriguez, Jose Omar Barreto Rodriguez, Alicia Estela Lopez Romo, Paolo Alberti Minutti, Juan Vicente Alejandre Loya, Felix Emmanuel Perez Talavera, Freddy Jose Avila-Cervera, Adriana Nohemi Velazquez Burciaga, Oscar Morado Aramburo, Luis Alberto Pina Olguin, Adrian Soto-Rodriguez, Andres Castaneda Prado, Patricio Santillan-Doherty, Juan O Galindo Galindo, Daniel Hernandez Gordillo, Juan Gutierrez Mejia
ABSTRACT - Importance: Many COVID-19 prognostic factors for disease severity have been identified and many scores have already been proposed to predict death and other outcomes. However, hospitals in developing countries often cannot measure some of the variables that have been reported as useful. - Objective: To assess the sensitivity, specificity, and predictive values of the novel LOW-HARM score (Lymphopenia, Oxygen saturation, White blood cells, Hypertension, Age, Renal injury, and Myocardial injury). - Design: Demographic and clinical data from patients with known clinical outcomes (death or discharge) was obtained. Patients were grouped according to their outcome. The LOW-HARM score was calculated for each patient and its distribution, potential cut-off values and demographic data were compared. - Setting: Twelve hospitals in ten different cities in Mexico. - Participants: Data from 438 patients was collected. A total of 400 (200 per group) was included in the analysis. - Exposure: All patients had an infection with SARS-CoV-2 confirmed by PCR. - Main Outcome: The sensitivity, specificity, and predictive values of different cut-offs of the LOW-HARM score to predict death. - Results: Mean scores at admission and their distributions were significantly lower in patients who were discharged compared to those who died during their hospitalization 10 (SD: 17) vs 70 (SD: 28). The overall AUC of the model was 95%. A cut-off > 65 points had a specificity of 98% and a positive predictive value of 96%. More than a third of the cases (36%) in the sample had a LOW-HARM score > 65 points. - Conclusions and relevance: The LOW-HARM score measured at admission is highly specific and useful for predicting mortality. It is easy to calculate and can be updated with individual clinical progression.
1,710 downloads medRxiv emergency medicine
Background and AimCoronaviruses disease 2019 (COVID-19), for the first time detected in Wuhan, China, rapidly speared around the world and be a Public Health Emergency of International Concern (PHEIC). The aim of the current survey is collecting laboratory findings, analysis them and reporting a specific pattern for help to COVID-19 diagnosis. MethodsTo collect laboratory characteristics, we searched "PubMed" electronic database with the following keywords: "COVID-19" "2019 novel coronavirus" "laboratory findings" "clinical characteristics". ResultsOnce the initial searches 493 studies were yielded. After removing duplicates studies 480 studies were remained. The 12 studies obtained from the literature, of which 58.3% (7) of studies were case-control (8-14), and 41.7% (5) remaining studies were designed as cross-sectional (1,15-18) ConclusionThe result of the current study showed that in the early stage of COVID-19 infection, maybe there are not significant laboratory findings, but with disease progression, the one or more than signs include increasing AST, ALT, LDH, CK, CRP, ESR, WBC, neutrophil, and decreasing Hemoglobin, lymphocyte count, eosinophil count can be seen. Elevating D-dimer and FDP are associated with ARDS development and can be used as prognostic factors.
1,516 downloads medRxiv emergency medicine
Abstract Background The coronavirus disease 2019 (COVID-19) pandemic presents significant safety challenges to healthcare professionals. In some jurisdictions, over 10% of confirmed cases of COVID-19 have been found among healthcare workers. Aerosol-generating medical procedures (AGMPs) may increase the risk of nosocomial transmission, exacerbated by present global shortages of personal protective equipment (PPE). Improved methods for mitigating risk during AGMPs are therefore urgently needed. Methods The Aerosol Containment Enclosure (ACE) was constructed from acrylic with silicone gaskets for arm port seals and completed with a thin plastic sheet. Hospital wall suction generated negative pressure within the ACE. To evaluate protective capability, differential pressures were recorded under static conditions and during simulated AGMPs. Smoke flow patterns, fluorescence aerosolization, and sodium saccharin aerosolization tests were also conducted. Results Negative pressures of up to -47.7 mmH2O were obtained using the enclosure with two wall suction units (combined outflow of 70 L min-1), with inflow of O2 of 15 L min-1. Negative pressures between -10 and -35 mmH2O were maintained during simulated AGMPs, including oxygen delivery by mask, airway suctioning, bag-mask manual ventilation and endotracheal intubation of a potential COVID-19 patient. The ACE effectively contained smoke, fluorescein aerosol, and sodium saccharin aerosol within the enclosure during use. Conclusions The ACE is capable of maintaining negative pressure during simulated AGMPs. In all cases, containment was improved relative to an identical enclosure with non-occluded ports at ambient pressure. During the current COVID-19 pandemic, the use of such a device may assist in reducing nosocomial infections among healthcare providers.
1,456 downloads medRxiv emergency medicine
BackgroundThe COVID-19 pandemic is a global challenge that is not just limited to the physical consequences but also a significant degree of a mental health crisis. Self-harm (SH) and suicide are its extreme effects. The aim of this study was to provide an overview of the impact of the COVID-19 pandemic on the occurrence and clinical profile of suicide and SH in our ED. MethodsThis is a cross-sectional observational study conducted in the ED of a tertiary care center. Records of all fatal and nonfatal SH patients presenting to the ED during the lockdown period (March 24-June 23, 2020; Period1), matching periods in the previous year (March 24-June 23,2019; Period 2) and 3 months period prior (December 24 2019-March 23, 2020; Period 3) was included by searching the electronic medical record (EMR) system. The prevalence and the clinical profile of the patients were compared between these three periods. ResultsA total of 125 (periods 1=55, 2=38, and 3=32) suicide and SH cases were analyzed. The cases of suicide/SH had increased by 44% and 71.9% during the lockdown period in comparison to the period 2 and 3. Organophosphate poisoning was the most common mode. Females were predominant in all three periods with a mean age of 32 (95%CI: 29.3-34.7). There was a significant delay in arrival of the patients in period 1 (p-value=0.045) with increased hospital admission (p-value =0.009) and in-hospital mortality (18.2% vs 2.6 % and 3.1%) (p-value=.001). ConclusionWe found an increase in patients presenting with suicide and SH in our ED during the pandemic which is likely to reflect an increased prevalence of mental illness in the community. We hope that the result will prime all mental health care stakeholders to initiate mental health screening and intervention for the vulnerable population during this period of crisis.
1,451 downloads medRxiv emergency medicine
Background This study examined whether the presence and severity of Type 1 Respiratory Failure (T1RF), as measured by the ratio of pulse oximetry to estimated fraction of inspired oxygen (SpO2/eFiO2 ratio), is a predictor of in-hospital mortality in patients presenting to the ED with suspected COVID19 infection. Methods We undertook a prospective observational cohort study of patients admitted to hospital with suspected COVID-19 in a single ED in England. We used univariate and multiple logistic regression to examine whether the presence and severity of T1RF in the ED was independently associated with in-hospital mortality. Results 180 patients with suspected COVID19 infection met the inclusion criteria for this study, of which 39 (22%) died. Severity of T1RF was associated with increased mortality with odds ratios (OR) and 95% confidence intervals of 1.58 (0.49 to 5.14), 3.60 (1.23 to 10.6) and 18.5 (5.65 to 60.8) for mild, moderate and severe T1RF, respectively. After adjusting for age, gender, pre-existing cardiovascular disease, neutrophil-lymphocyte ration (NLR) and estimated glomerular filtration rate (eGFR), the association remained, with ORs of 0.63 (0.13 to 3.03), 3.95 (0.94 to 16.6) and 45.8 (7.25 to 290). The results were consistent across a number of sensitivity analyses. Conclusions Severity of T1RF in the ED is an important prognostic factor of mortality in patients admitted with suspected COVID19 infection. Current prediction models frequently do not include this factor and should be applied with caution. Further large scale research on predictors of mortality in COVID19 infection should include SpO2/eFiO2 ratios or a similar measure of respiratory dysfunction.
1,376 downloads medRxiv emergency medicine
Objectives: To identify the diagnostic accuracy of common imaging modalities, chest X-ray (CXR) and computed tomography (CT) for diagnosis of COVID-19 in the general emergency population in the UK and to find the association between imaging features and outcomes in these patients. Design: Retrospective analysis of electronic patient records Setting: Tertiary academic health science centre and designated centre for high consequence infectious diseases in London, UK. Participants: 1,198 patients who attended the emergency department with paired RT-PCR swabs for SARS-CoV 2 and CXR between 16th March and 16th April 2020 Main outcome measures: Sensitivity and specificity of CXR and CT for diagnosis of COVID-19 using the British Society of Thoracic Imaging reporting templates. Reference standard was any reverse transcriptase polymerase chain reaction (RT-PCR) positive naso-oropharyngeal swab within 30 days of attendance. Odds ratios of CXR in association with vital signs, laboratory values and 30-day outcomes were calculated. Results: Sensitivity and specificity of CXR for COVID-19 diagnosis were 0.56 (95% CI 0.51-0.60) and 0.60 (95% CI 0.54-0.65), respectively. For CT scans these were 0.85 (95% CI 0.79-0.90) and 0.50 (95% CI 0.41-0.60), respectively. This gave a statistically significant mean increase in sensitivity with CT compared with CXR, of 29% (95% CI 19%-38%, p<0.0001). Specificity was not significantly different between the two modalities. Chest X-ray findings were not statistically significantly or clinical meaningfully associated with vital signs, laboratory parameters or 30-day outcomes. Conclusions: Computed tomography has substantially improved diagnostic performance over CXR in COVID-19. CT should be strongly considered in the initial assessment for suspected COVID-19. This gives potential for increased sensitivity and considerably faster turnaround time, where capacity allows and balanced against excess radiation exposure risk.
1,294 downloads medRxiv emergency medicine
For the past 50 years, positive pressure ventilation has been a cornerstone of treatment for respiratory failure. Consensus surrounding the epidemiology of respiratory failure has permitted a relatively good fit between the supply of ventilators and the demand. However, the current COVID-19 pandemic has increased demand for mechanical ventilators well beyond supply. Respiratory failure complicates most critically ill patients with COVID-19 and is characterized by highly heterogeneous pulmonary parenchymal involvement, profound hypoxemia and pulmonary vascular injury. The profound increase in the incidence of respiratory failure has exposed critical shortages in the supply of mechanical ventilators, and those with the necessary skills to treat. While most traditional ventilators rely on an internal compressor and mixer to moderate and control the gas mixture delivered to a patient, the current emergency climate has catalyzed alternative designs that might enable greater flexibility in terms of supply chain, manufacturing, storage and maintenance. Design considerations of these 'emergency response' ventilators have generally fallen into two categories: those that rely on mechanical compression of a known volume of gas and those powered by an internal compressor to deliver time cycled pressure- or volume-limited gas to the patient. The present work introduces a low-cost, ventilator designed and built in accordance with the Emergence Use guidance provided by the US Food and Drug Administration (FDA) wherein an external gas supply feeds into the ventilator and time limited flow interruption guarantees tidal volume. The goal of this device is to allow a patient to be treated by a single ventilator platform, capable of supporting the various treatment paradigms during a potential COVID-19 related hospitalization. This is a unique aspect of this design as it attempts to become a one-device-one-visit solution to the problem. The device is designed as a single use ventilator that is sufficiently robust to treat a patient being mechanically ventilated. The overall design philosophy and its applicability in this new crisis-laden world view is first described, followed by both bench top and animal testing results used to confirm the precision, capability, safety and reliability of this low cost and novel approach to mechanical ventilation during the COVID-19 pandemic. The ventilator is shown to perform in a range of critical requirements listed in the FDA emergency regulations and can safely and effectively ventilate a porcine subject. As of August 2020, only 13 emergency ventilators have been authorized by the FDA, and this work represents the first to publish animal data using the ventilator. This proof-of-concept provides support for this cost-effective, readily mass-produced ventilator that can be used to support patients when the demand for ventilators outstrips supply in hospital settings worldwide. More details for this project can be found at https://ventilator.stanford.edu/
1,262 downloads medRxiv emergency medicine
Lung ultrasound (LUS) has an established evidence base and has proven useful in previous viral epidemics. An understanding of the utility of LUS in COVID-19 is crucial to determine its most suitable role based on local circumstances. A scoping review was thus undertaken to explore the utility of LUS in COVID-19 and guide future research. 33 studies were identified which represent a rapidly expanding evidence base for LUS in COVID-19. The quality of the included studies was relatively low. However LUS appears to be a highly sensitive and fairly specific test for COVID-19 in all ages and in pregnancy and is almost certainly more sensitive than CXR. The precise diagnostic accuracy of LUS may be influenced by various factors including disease severity, pre-existing lung disease, scanning protocol, operator experience, disease prevalence and the reference standard. High quality research is needed in various fields including: diagnostic accuracy in undifferentiated patients; triage and prognostication; monitoring progression and guiding interventions; persistence of residual LUS findings; inter-observer agreement; and the role of contrast-enhanced LUS.
1,207 downloads medRxiv emergency medicine
BackgroundThe use of the 12-lead ECG is common in UK paramedic practice but its value depends upon accurate placement of the ECG-electrodes. Several studies have shown widespread variation in the placement of chest electrodes by other health professionals but no studies have addressed the accuracy of paramedics. The main objective of this study was to ascertain the accuracy of the chest lead placements by registered paramedics. MethodsRegistered paramedics who attended the Emergency Services Show in Birmingham in September 2018 were invited to participate in this observational study. Participants were asked to place the chest electrodes on a male model in accordance with their current practice. Correct positioning was determined against the Society for Cardiological Science & Technologys Clinical Guidelines for recording a standard 12-lead electrocardiogram (2017) with a tolerance of 19mm being deemed acceptable based upon previous studies. Results52 eligible participants completed the study. Measurement of electrode placement in the craniocaudal and mediolateral planes showed a high level of inaccuracy with 3/52 (5.8%) participants able to accurately place all chest leads. In leads V1 - V3, the majority of incorrect placements were related to vertical displacement with most participants able to identify the correct horizontal position. In V4, the tendency was to place the lead too low and to the left of the pre-determined position whilst V5 tended to be below the expected positioning but in the correct horizontal alignment. There was a less defined pattern of error in V6 although vertical displacement was more likely than horizontal displacement. ConclusionsOur study identified a high level of variation in the placement of chest ECG electrodes which could alter the morphology of the ECG. From a patient safety perspective, we would advocate that paramedics leave the chest electrodes in situ to allow hospital staff to assess the accuracy of the placements. Key messagesWhat is already known on this subject O_LIThe recording of a prehospital ECG has become increasingly common in sophisticated Emergency Medical Services across the world C_LIO_LIThe accuracy of precordial ECG electrode placement has been studied with other health professionals and has highlighted varying degrees of accuracy. C_LIO_LIInaccurate electrode placement can lead to aberrant ECG readings and application of unnecessary treatment or the withholding of indicated treatment C_LI What this study adds O_LIIn this observational cohort study, we found significant variation in the placement of the precordial ECG electrodes by UK registered paramedics C_LIO_LIWe recommend that paramedics leave the prehospital ECG electrodes in situ to allow hospital staff to assess the accuracy of the placements. C_LI
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