The Correlation between COVID-19 Hospitalizations and Emergency Medical Services Responses for Time-Sensitive Emergencies during the COVID-19 Pandemic.

OBJECTIVE: COVID-19 has had significant secondary effects on health care systems, including effects on emergency medical services (EMS) responses for time-sensitive emergencies. We evaluated the correlation between COVID-19 hospitalizations and EMS responses for time-sensitive emergencies in a large EMS system. METHODS: This was a retrospective study using data from the Los Angeles County EMS Agency. We abstracted data on EMS encounters for stroke, ST-elevation myocardial infarction (STEMI), out-of-hospital cardiac arrest (OHCA), and trauma from April 5, 2020 to March 6, 2021 and for the same time period in the preceding year. We also abstracted daily hospital admissions and censuses (total and intensive care unit [ICU]) for COVID-19 patients. We designated November 29, 2020 to February 27, 2021 as the period of surge. We calculated Spearman's correlations between the weekly averages of daily hospital admissions and census and EMS responses overall and for stroke, STEMI, OHCA, and trauma. RESULTS: During the study period, there were 70,616 patients admitted for confirmed COVID-19, including 12,467 (17.7%) patients admitted to the ICU. EMS responded to 899,794 calls, including 9,944 (1.1%) responses for stroke, 3,325 (0.4%) for STEMI, 11,207 (1.2%) for OHCA, and 114,846 (12.8%) for trauma. There was a significant correlation between total hospital COVID-19 positive patient admissions and EMS responses for all time-sensitive emergencies, including a positive correlation with stroke (0.41), STEMI (0.37), OHCA (0.78), and overall EMS responses (0.37); and a negative correlation with EMS responses for trauma (-0.48). ICU COVID-19 positive patient admissions also correlated with increases in EMS responses for stroke (0.39), STEMI (0.39), and OHCA (0.81); and decreased for trauma (-0.53). Similar though slightly weaker correlations were found when evaluating inpatient census. During the period of surge, the correlation with overall EMS responses increased substantially (0.88) and was very strong with OHCA (0.95). CONCLUSION: We found significant correlation between COVID-19 hospitalizations and the frequency of EMS responses for time-sensitive emergencies in this regional EMS system. EMS systems should consider the potential effects of this and future pandemics on EMS responses and prepare to meet non-pandemic resource needs during periods of surge, particularly for time-sensitive conditions.

Variation in Post-Cardiac Arrest Care Within a Regional EMS System.

Objective: Within Emergency Medical Systems (EMS) regional systems, there may be significant differences in the approach to patient care despite efforts to promote standardization. Identifying hospital-level factors that contribute to variations in care can provide opportunities to improve patient outcomes. The purpose of this analysis was to evaluate variation in post-cardiac arrest care within a large EMS system and explore the contribution of hospital-level factors. Methods: This was a retrospective analysis from a regional cardiac system serving over 10 million persons. Patients with out-of-hospital cardiac arrest (OHCA) with return of spontaneous circulation (ROSC) are transported to 36 cardiac arrest centers with 24/7 emergent coronary angiography (CAG) capabilities and targeted temperature management (TTM) policies based on regional guidelines. We included adult patients ≥18 years with non-traumatic OHCA from 2016-2018. Patients with a Do-Not-Resuscitate order and those who died in the emergency department (ED) were excluded. For the TTM analysis, we also excluded patients who were alert in the ED. The primary outcome was receiving CAG or TTM after cardiac arrest. The secondary outcome was neurologic recovery (dichotomized to define a "good" outcome as cerebral performance category (CPC) 1 or 2). We used generalized estimating equations including patient-level factors (age, sex, witnessed arrest, initial rhythm) and hospital-level factors (academic status, hospital size based on licensed beds, annual OHCA patient volume) to estimate the odds ratios associated with these variables. Results: There were 7831 patients with OHCA during the study period; 4694 were analyzed for CAG and 3903 for TTM. The median and range for treatment with CAG and TTM after OHCA was 23% (12-49%) and 58% (17-92%) respectively. Hospital size was associated with increased likelihood of CAG, adjusted odds ratio 1.71, 95% CI 1.05-2.86, p = 0.03. Academic status approached significance in its association with TTM, adjusted odds ratio 1.69, 95% CI 0.98-2.91, p = 0.06. Overall, 28% of patients survived with good neurologic outcome, ranging from 17 to 43% across hospitals. Conclusion: Within this regional cardiac system, there was significant variation in use of CAG and TTM after OHCA, which was not fully explained by patient-level factors. Hospital size was associated with increased CAG.

Prehospital Predictors of Atypical STEMI Symptoms.

Introduction: Rapid prehospital identification of patients with ST-elevation myocardial infarction (STEMI) is a critical step to reduce time to treatment. Broad screening with field 12-lead ECGs can lead to a high rate of false positive STEMI activations due to low prevalence. One strategy to reduce false positive STEMI interpretations is to limit acquisition of 12-lead ECGs to patients who have symptoms strongly suggestive of STEMI, but this may delay care in patients who present atypically and lead to disparities in populations with more atypical presentations. We sought to assess patient factors associated with atypical STEMI presentation.Methods: We retrospectively analyzed consecutive adult patients for whom Los Angeles Fire Department paramedics obtained a field 12-lead ECG from July 2011 through June 2012. The regional STEMI receiving center registry was used to identify patients with STEMI. Patients were designated as having typical symptoms if paramedics documented provider impressions of chest pain/discomfort, cardiac arrest, or cardiac symptoms, otherwise they were designated as having atypical symptoms. We utilized logistic regression to determine patient factors (age, sex, race) associated with atypical STEMI presentation.Results: Of the 586 patients who had STEMI, 70% were male, 43% White, 16% Black, 20% Hispanic, 5% Asian and 16% were other or unspecified race. Twenty percent of STEMI patients (n = 117) had atypical symptoms. Women who had STEMI were older than men (74 years [IQR 62-83] vs. 60 years [IQR 53-70], p < 0.001). Univariate predictors of atypical symptoms were older age and female sex (p < 0.0001), while in multivariable analysis older age [odd ratio (OR) 1.05 per year, [95%CI 1.04-1.07, p < 0.0001] and black race (OR vs White 2.18, [95%CI 1.20-3.97], p = 0.011) were associated with atypical presentation.Conclusion: Limiting prehospital acquisition of 12-lead ECGs to patients with typical STEMI symptoms would result in one in five patients with STEMI having delayed recognition, disproportionally impacting patients of older age, women, and Black patients. Age, not sex, may be a better predictor of atypical STEMI presentation.

Safety and Effectiveness of Field Nitroglycerin in Patients with Suspected ST Elevation Myocardial Infarction.

Objective: While widely used in the treatment of cardiac conditions, only limited data characterize out-of-hospital nitroglycerin (NTG) use. We sought to determine the safety of out-of-hospital sublingual NTG administered for suspected ST-segment elevation myocardial infarction (STEMI) and its effect on the patient's pain score. Methods: We prospectively identified adult patients with suspected STEMI transported by paramedics to three percutaneous Coronary Intervention PCI-capable hospitals in a large urban-suburban emergency medical services (EMS) system. We compared patients who received field NTG to those who did not. The primary outcome was the change in systolic blood pressure (SBP) between initial EMS measurement and emergency department (ED) triage vital signs. Secondary outcomes included the frequency of hypotension (SBP < 100 mmHg) and bradycardia (HR < 60) on ED arrival, drop in SBP ≥ 30 mmHg, out-of-hospital cardiac arrest (OHCA), and the change in pain score compared to an a priori threshold of -1.39. Results: Among 940 EMS transports for suspected STEMI, we excluded 160 for initial SBP < 100 mmHg, leaving 780 subjects for the analysis. Median age was 67 with 61% male. NTG was administered to 340 (44%) patients. The median change in SBP was -10 mmHg (IQR -27, 2) and -3 mmHg (IQR -20, 9) in patients treated with and without NTG, respectively. The median difference in the decrease in SBP was 6 mmHg (95% CI 3, 9 mmHg). The frequencies of ED hypotension and bradycardia, the drop in SBP ≥ 30 mmHg, and the OHCA did not differ between groups. For patients with an initial pain score > 0, the average change in pain score for patients treated with NTG was -2.6 (95% CI -3.0, -2.2), while patients who did not receive NTG had a change in pain score of -1.4 (95% CI -1.8, -1.0). Conclusion: In this cohort, field NTG did not result in a clinically significant decrease in blood pressure when compared with patients who did not receive NTG. However, NTG did cause a clinically significant reduction in pain.

Therapeutic Hypothermia After Resuscitation From a Non-Shockable Rhythm Improves Outcomes in a Regionalized System of Cardiac Arrest Care.

OBJECTIVE: Therapeutic hypothermia (TH) improves neurologic outcome in patients resuscitated from ventricular fibrillation. The purpose of this study was to evaluate TH effects on neurologic outcome in patients resuscitated from a non-shockable out-of-hospital cardiac arrest rhythm. DESIGN AND SETTING: This is a retrospective cohort study of data reported to a registry in an emergency medical system in a large metropolitan region. Patients achieving field return of spontaneous circulation are transported to designated hospitals with TH protocols. PATIENTS: Patients with an initial non-shockable rhythm were identified. Patients were excluded if awake in the Emergency Department or if TH was withheld due to preexisting coma or death prior to initiation. The decision to initiate TH was determined by the treating physician. MEASUREMENTS: The primary outcome was survival with good neurologic outcome defined by a cerebral performance category of 1 or 2. MAIN RESULTS: Of the 2772 patients treated for cardiac arrest during the study period, there were 1713 patients resuscitated from cardiac arrest with an initial non-shockable rhythm and 1432 patients met inclusion criteria. The median age was 69 years [IQR 59-82]; 802 (56%) male. TH was induced in 596 (42%) patients. Survival with good neurologic outcome was 14% in the group receiving TH, compared with 5% in those not treated with TH (risk difference = 8%, 95% CI 5-12%). The adjusted OR for a CPC 1 or 2 with TH was 2.9 (95% CI 1.9-4.4). CONCLUSION: Analyzing the data collected from the registry of the standard practice in a large metropolitan region, TH is associated with improved neurologic outcome in patients resuscitated from initial non-shockable rhythms in a regionalized system for post-resuscitation care.

The Utility of Prehospital ECG Transmission in a Large EMS System.

BACKGROUND: Prehospital identification of STEMI and activation of the catheterization lab can improve door-to-balloon (D2B) times but may lead to decreased specificity and unnecessary resource utilization. The purpose of this study was to examine the effect of electrocardiogram (ECG) transmission on false-positive (FP) cath lab activations and time to reperfusion. METHODS: This is a retrospective cohort from a registry in a large metropolitan area with regionalized cardiac care and emergency medical services (EMS) with ECG transmission capabilities. Thirty-four designated STEMI receiving centers (SRC) contribute to this registry, from which patients with a prehospital ECG software interpretation of myocardial infarction (MI) indicated by ****Acute MI****, or manufacturer equivalent, were identified between April 2011 and September 2013. Frequency of FP field activations (defined as not resulting in emergent percutaneous coronary intervention [PCI] or referral for CABG during hospital admission) for patients with ECG transmission received by the SRC was compared to a reference group without successful ECG transmission. FP field activations were compared to the baseline frequency of FP ED activations. We hypothesized that successful transmission would reduce FP field activation to ED activation levels. Door-to-balloon and first medical contact-to-balloon (FMC2B) times were compared. The protocol for field cath lab activation varied by institution. RESULTS: There were 7,768 patients presenting with a prehospital ECG indicating MI. The ECG was received by the SRC for 2,156 patients (28%). Regardless of transmission, the cath lab was activated 77% of the time; this activation occurred from the field in 73% and 74% of the activations in the transmission and reference group, respectively. The overall proportion of FP activation was 57%. Among field activations, successful ECG transmission reduced the FP activation rate compared to without ECG transmission, 55% vs. 61% (RD = -6%, 95%CI -9, -3%). This led to an overall system reduction in FP activations of 5% (95%CI 2, 8%). ECG transmission had no effect on D2B and FMC2B time. CONCLUSION: Prehospital ECG transmission is associated with a small reduction in false-positive field activations for STEMI and had no effect on time to reperfusion in this cohort.

Effect of prehospital cardiac catheterization lab activation on door-to-balloon time, mortality, and false-positive activation.

BACKGROUND: Reperfusion of ST elevation myocardial infarction (STEMI) is most effective when performed early. Notification of the cardiac catheterization laboratory (cath lab) prior to hospital arrival based on paramedic-performed ECGs has been proposed as a strategy to decrease time to reperfusion and mortality. The purpose of this study was to compare the effects of cath lab activation prior to patient arrival versus activation after arrival at the emergency department (ED). METHODS: We performed a retrospective cohort study (n = 1933 cases) using Los Angeles County STEMI database from May 1, 2008 through August 31, 2009. The database includes patients arriving at a STEMI Receiving Center (SRC) by ambulance who were diagnosed with STEMI either before or after hospital arrival. We compared the cohort of patients with prehospital cath lab activation to those activated from the ED within 5 minutes of first ED ECG. Outcomes measured were mortality, door-to-balloon time, percent door-to-balloon time <90 min, and percentage of false-positive activations. RESULTS: Prehospital cath lab activations had mean door-to-balloon times 14 minutes shorter (95% CI 11-17), in-hospital mortality 1.5% higher (95% CI -1.0-5.2), and false-positive activation 7.8%, (95% CI 2.7-13.3) higher than ED activation. For prehospital activation, 93% (95% CI 91-94%) met a door-to-balloon target of 90 minutes versus 85% (95% CI 80-88%) for ED activations. CONCLUSION: Prehospital cath lab activation based on the prehospital ECG was associated with decreased door-to-balloon times but did not affect hospital mortality. False-positive activation was common and occurred more often with prehospital STEMI diagnosis.

Survival and neurologic outcome after out-of-hospital cardiac arrest: results one year after regionalization of post-cardiac arrest care in a large metropolitan area.

BACKGROUND: Post-resuscitation care of cardiac arrest patients at specialized centers may improve outcome after out-of-hospital cardiac arrest (OOHCA). This study describes experience with regionalized care of resuscitated patients. METHODS: Los Angeles (LA) County established regionalized cardiac care in 2006. Since 2010, protocols mandate transport of nontraumatic OOHCA patients with field return of spontaneous circulation (ROSC) to a STEMI Receiving Center (SRC) with a hypothermia protocol. All SRC report outcomes to a registry maintained by the LA County Emergency Medical Services (EMS) Agency. We report the first year's data. The primary outcome was survival with good neurologic outcome, defined by a Cerebral Performance Category (CPC) score of 1 or 2. RESULTS: The SRC treated 927 patients from April 2011 through March 2012 with median age 67; 38% were female. There were 342 patients (37%) who survived to hospital discharge. CPC scores were unknown in 47 patients. Of the 880 patients with known CPC scores, 197 (22%) survived to hospital discharge with a CPC score of 1 or 2. The initial rhythm was VF/VT in 311 (34%) patients, of whom 275 (88%) were witnessed. For patients with an initial shockable rhythm, 183 (59%) survived to hospital discharge and 120 (41%) had survival with good neurologic outcome. Excluding patients who were alert or died in the ED, 165 (71%) patients with shockable rhythms received therapeutic hypothermia (TH), of whom 67 (42%) had survival with good neurologic outcome. Overall, 387 patients (42%) received TH. In the TH group, the adjusted OR for CPC 1 or 2 was 2.0 (95%CI 1.2-3.5, p = 0.01), compared with no TH. In contrast, the proportion of survival with good neurologic outcome in the City of LA in 2001 for all witnessed arrests (irrespective of field ROSC) with a shockable rhythm was 6%. CONCLUSION: We found higher rates of neurologically intact survival from OOHCA in our system after regionalization of post-resuscitation care as compared to historical data.

A Novel Algorithm for Improving the Prehospital Diagnostic Accuracy of ST-Segment Elevation Myocardial Infarction.

INTRODUCTION: Early detection of ST-segment elevation myocardial infarction (STEMI) on the prehospital electrocardiogram (ECG) improves patient outcomes. Current software algorithms optimize sensitivity but have a high false-positive rate. The authors propose an algorithm to improve the specificity of STEMI diagnosis in the prehospital setting. METHODS: A dataset of prehospital ECGs with verified outcomes was used to validate an algorithm to identify true and false-positive software interpretations of STEMI. Four criteria implicated in prior research to differentiate STEMI true positives were applied: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. The test characteristics were calculated and regression analysis was used to examine the association between the number of criteria included and test characteristics. RESULTS: There were 44,611 cases available. Of these, 1,193 were identified as STEMI by the software interpretation. Applying all four criteria had the highest positive likelihood ratio of 353 (95% CI, 201-595) and specificity of 99.96% (95% CI, 99.93-99.98), but the lowest sensitivity (14%; 95% CI, 11-17) and worst negative likelihood ratio (0.86; 95% CI, 0.84-0.89). There was a strong correlation between increased positive likelihood ratio (r2 = 0.90) and specificity (r2 = 0.85) with increasing number of criteria. CONCLUSIONS: Prehospital ECGs with a high probability of true STEMI can be accurately identified using these four criteria: heart rate <130, QRS <100, verification of ST-segment elevation, and absence of artifact. Applying these criteria to prehospital ECGs with software interpretations of STEMI could decrease false-positive field activations, while also reducing the need to rely on transmission for physician over-read. This can have significant clinical and quality implications for Emergency Medical Services (EMS) systems.

Association of the COVID-19 Pandemic on Treatment Times for ST-Elevation Myocardial Infarction: Observations from the Los Angeles County Regional System.

Previous studies have documented longer treatment times and worse outcomes for patients with ST-elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI) during the COVID-19 pandemic. The objective of the present study was to evaluate the impact of the COVID-19 pandemic on treatment times and outcomes for patients with STEMI who underwent primary PCI within a regional system of care. This was a retrospective study using data from the Los Angeles County Emergency Medical Services Agency. Data on the emergency medical service activations were abstracted for patients with STEMI from March 19, 2020 to January 31, 2021, during the COVID-19 pandemic and for the same interval the previous year. All adult patients (≥18 years) with STEMI who underwent emergent coronary angiography were included. The primary end point was the first medical contact (FMC) to device time. The secondary end points included treatment time intervals, vascular complications, need for emergent coronary artery bypass surgery, length of hospital stay, and in-hospital mortality. During the study period, 3,017 patients underwent coronary angiography for STEMI, 1,893 patients pre-COVID-19 and 1,124 patients during COVID-19 (40% lower). A total of 2,334 patients (77%) underwent PCI. During the COVID-19 period, rates of PCI were significantly lower compared with the control period (75.1% vs 78.7%, p = 0.02). FMC to device time was shorter during the COVID-19 period compared with the control period (median 77.0 vs 81.0 minutes, p = 0.004). For patients with STEMI complicated by out-of-hospital cardiac arrest, FMC to device time was similar during the COVID-19 period compared with the control period (median 95.0 [33.0] vs 100.0 [40.0] minutes, p = 0.34). Vascular complications, the need for emergent bypass surgery, length of hospital stay, and in-hospital mortality were similar between the periods. In conclusion, in this large regional system of care, we found a relatively small but significant decrease in treatment times, yet overall, similar clinical outcomes for patients with STEMI who underwent primary PCI and were treated during the COVID-19 period compared with a control period. These findings suggest that mature cardiac systems of care were able to maintain efficient care despite the challenges of the COVID-19 pandemic.

Elevated prehospital point-of-care glucose is associated with worse neurologic outcome after out-of-hospital cardiac arrest.

OBJECTIVES: Hyperglycemia is associated with poor outcomes in critically-ill patients. This has implications for prognostication of patients with out-of-hospital cardiac arrest (OHCA) and for post-resuscitation care. We assessed the association of hyperglycemia, on field point-of-care (POC) testing, with survival and neurologic outcome in patients with return of spontaneous circulation (ROSC) after OHCA. METHODS: This was a retrospective analysis of data in a regional cardiac care system from April 2011 through December 2017 of adult patients with OHCA and ROSC who had a field POC glucose. Patients were excluded if they were hypoglycemic (glucose <60 mg/dl) or received empiric dextrose. We compared hyperglycemic (glucose >250 mg/dL) with euglycemic (glucose 60-250 mg/dL) patients. Primary outcome was survival to hospital discharge (SHD). Secondary outcome was survival with good neurologic outcome (cerebral performance category 1 or 2 at discharge). We determined the adjusted odds ratios (AORs) for SHD and survival with good neurologic outcome. RESULTS: Of 9008 patients with OHCA and ROSC, 6995 patients were included; 1941 (28%) were hyperglycemic and 5054 (72%) were euglycemic. Hyperglycemic patients were more likely to be female, of non-White race, and have an initial non-shockable rhythm compared to euglycemic patients (p < 0.0001 for all). Hyperglycemic patients were less likely to have SHD compared to euglycemic survivors, 24.4% vs 32.9%, risk difference (RD) -8.5% (95 %CI -10.8%, -6.2%), p < 0.0001. Hyperglycemic survivors were also less likely to have good neurologic outcome compared to euglycemic survivors, 57.0% vs 64.6%, RD -7.6% (95 %CI -12.9%, -2.4%), p = 0.004. The AOR for SHD was 0.72 (95 %CI 0.62, 0.85), p < 0.0001 and for good neurologic outcome, 0.70 (95 %CI 0.57, 0.86), p = 0.0005. CONCLUSION: In patients with OHCA, hyperglycemia on field POC glucose was associated with lower survival and worse neurologic outcome.

Establishing a multicenter, preclinical consortium in resuscitation: A pilot experimental trial evaluating epinephrine in cardiac arrest.

BACKGROUND: Large animal studies are an important step in the translation pathway, but single laboratory experiments do not replicate the variability in patient populations. Our objective was to demonstrate the feasibility of performing a multicenter, preclinical, randomized, double-blinded, placebo-controlled cardiac arrest trial. We evaluated the effect of epinephrine on coronary perfusion pressure (CPP) as previous single laboratory studies have reported mixed results. METHODS: Forty-five swine from 5 different laboratories (Ann Arbor, MI; Baltimore, MD; Los Angeles, CA; Pittsburgh, PA; Toronto, ON) using a standard treatment protocol. Ventricular fibrillation was induced and left untreated for 6 min before starting continuous cardiopulmonary resuscitation (CPR). After 2 min of CPR, 9 animals from each lab were randomized to 1 of 3 interventions given over 12 minutes: (1) Continuous IV epinephrine infusion (0.00375 mg/kg/min) with placebo IV normal saline (NS) boluses every 4 min, (2) Continuous placebo IV NS infusion with IV epinephrine boluses (0.015 mg/kg) every 4 min or (3) Placebo IV NS for both infusion and boluses. The primary outcome was mean CPP during the 12 mins of drug therapy. RESULTS: There were no significant differences in mean CPP between the three groups: 14.4 ± 6.8 mmHg (epinephrine Infusion), 16.9 ± 5.9 mmHg (epinephrine bolus), and 14.4 ± 5.5 mmHg (placebo) (p = NS). Sensitivity analysis demonstrated inter-laboratory variability in the magnitude of the treatment effect (p = 0.004). CONCLUSION: This study demonstrated the feasibility of performing a multicenter, preclinical, randomized, double-blinded cardiac arrest trials. Standard dose epinephrine by bolus or continuous infusion did not increase coronary perfusion pressure during CPR when compared to placebo.

Does early postresuscitation stress hyperglycemia affect 72-hour neurologic outcome? Preliminary observations in the Swine model.

BACKGROUND: Hyperglycemia is common in the early period following resuscitation from cardiac arrest and has been shown to be a predictor of neurologic outcome in retrospective studies. OBJECTIVE: To evaluate neurologic outcome and early postarrest hyperglycemia in a swine cardiac arrest model. METHODS: Electrically induced ventricular fibrillation cardiac arrest was induced in 22 anesthetized and instrumented swine. After 7 minutes, cardiopulmonary resuscitation (CPR) and Advanced Cardiac Life Support were initiated. Twenty-one animals were resuscitated and plasma glucose concentration was measured at intervals for 60 minutes after resuscitation. The animals were observed for 72 hours and the neurologic score was determined at 24-hour intervals. RESULTS: Ten animals had a peak plasma glucose value ≥ 226 mg/dL during the initial 60 minutes after resuscitation. The neurologic scores at 72 hours in these animals (mean score = 0, mean overall cerebral performance category = 1) were the same as those in the animals with a peak plasma glucose value <226 mg/dL. The end-tidal carbon dioxide (CO(2)) values measured during CPR, times to restoration of spontaneous circulation, and epinephrine doses were not significantly different between the animals with a peak glucose concentration ≥ 226 mg/dL and those with lower values. The sample size afforded a power of 95% to detect a 50-point difference from the lowest score (0 points) of the porcine neurologic outcome scale. CONCLUSION: In this standard porcine model of witnessed out-of-hospital cardiac arrest, early postresuscitation stress hyperglycemia did not appear to affect neurologic outcome. During the prehospital phase of treatment and transport, treatment of hyperglycemia by emergency medical services providers may not be warranted.

Advanced rescuer- versus citizen-witnessed cardiac arrest: Is there a difference in outcome?

BACKGROUND: Substantial financial and human resources are invested in training and maintaining advanced life support (ALS) skills of paramedics who are deployed to the field in response to out-of-hospital cardiac arrest. It would be expected that patients who experience cardiac arrest in the presence of a trained health care practitioner, such as a paramedic, have better outcomes. OBJECTIVE: To compare the rates of return of spontaneous circulation (ROSC), survival to hospital admission (SHA), and survival to hospital discharge (SHD) between paramedic-witnessed out-of-hospital cardiac arrest vs. citizen-witnessed out-of-hospital cardiac arrest. METHODS: In this retrospective cohort study, the records of all out-of-hospital nontraumatic cardiac arrest patients presenting to a municipal teaching hospital from November 1, 1994, through June 30, 2008, were reviewed. The age, gender, race, rhythm on paramedic arrival, presence of bystander cardiopulmonary resuscitation (CPR), whether it was a witnessed arrest and, if witnessed, whether it was a paramedic-witnessed arrest, site of the arrest, and the rate of SHD were noted. A univariate odds ratio was computed to describe the association between paramedic-witnessed out-of-hospital cardiac arrest vs.citizen-witnessed out-of-hospital cardiac arrest and SHD. A multivariable logistic regression analysis was also performed, controlling for age, gender, arrest rhythm, bystander CPR, and site of arrest. RESULTS: Of the total cohort of 1,294 out-of-hospital cardiac arrests, 750 (52.6%) were either paramedic-witnessed (154/750 = 20.5%) or citizen-witnessed (596/750 = 79.5%). Among the witnessed cardiac arrests, overall the SHD was 53 of 750 (7.1%). On univariate analysis, the ROSC, SHA, or SHD rates were not statistically significantly different between paramedic- and citizen-witnessed arrests. Even after multivariable adjustment, the ROSC, SHA, and SHD rates were not significantly different between paramedic- and citizen-witnessed arrests. CONCLUSIONS: Among our study population of out-of-hospital cardiac arrest victims, paramedic-witnessed arrests did not appear to have improved survival rates when compared with citizen-witnessed arrests.

Mastering Electrocardiogram Interpretation Skills Through a Perceptual and Adaptive Learning Module.

Although accurate interpretation of the standard 12-lead electrocardiogram (ECG) is fundamental to diagnosing heart disease, several prior studies report low accuracy rates among medical students, residents, and practicing physicians. The objective of this study was to determine if an online ECG Perceptual and Adaptive Learning Module (ECG PALM) is an efficient instrument to teach ECG interpretation. The ECG PALM consists of 415 unique ECG tracings with associated pretest, posttest, and delayed tests, each using 30 additional ECGs to gauge the effectiveness and durability of training. Between 2013 and 2015, a total of 113 third-year and 156 fourth-year medical students and 34 first-year, 41 second-year, and 37 third-year emergency medicine residents completed the PALM and associated tests. We measured two mastery criteria: accuracy, the percentage of correct interpretations, and fluency, the percentage of images interpreted accurately within 15 seconds. The ECG PALM produced statistically significant improvements (0.0001 < p < 0.0045) in student and resident performance for both accuracy (effect size = 0.9 to 3.2) and fluency (effect size = 2.5 to 3.1) following training ranging from 46 ± 24 minutes (R3s) to 88 ± 32 minutes (third-year medical students). Medical students and residents performed significantly better on a test the year following training (delayed test) than those without prior ECG PALM training (pretest). The fluency of R3 residents in classifying the 15 diagnostic categories was less than 60% for nine of the 15 diagnoses and greater than 80% for only one. Following PALM training, fluency was higher than 80% for seven of the 15 categories and less than 60% for only two categories. Accuracy in recognizing ST-elevation myocardial infarctions (STEMIs) was high both before and after PALM training for R3s, but fluency was only 64% for anterior STEMIs on the pretest, increasing to 93% following PALM training. These observations suggest that the ECG PALM is an effective and durable supplemental tool for developing mastery in interpreting common ECG abnormalities.

Emergency Medical Services Responses to Out-of-Hospital Cardiac Arrest and Suspected ST-Segment-Elevation Myocardial Infarction During the COVID-19 Pandemic in Los Angeles County.

Background Public health emergencies may significantly impact emergency medical services responses to cardiovascular emergencies. We compared emergency medical services responses to out-of-hospital cardiac arrest (OHCA) and ST-segment‒elevation myocardial infarction (STEMI) during the 2020 COVID-19 pandemic to 2018 to 2019 and evaluated the impact of California's March 19, 2020 stay-at-home order. Methods and Results We conducted a population-based cross-sectional study using Los Angeles County emergency medical services registry data for adult patients with paramedic provider impression (PI) of OHCA or STEMI from February through May in 2018 to 2020. After March 19, 2020, weekly counts for PI-OHCA were higher (173 versus 135; incidence rate ratios, 1.28; 95% CI, 1.19‒1.37; P<0.001) while PI-STEMI were lower (57 versus 65; incidence rate ratios, 0.87; 95% CI, 0.78‒0.97; P=0.02) compared with 2018 and 2019. After adjusting for seasonal variation in PI-OHCA and decreased PI-STEMI, the increase in PI-OHCA observed after March 19, 2020 remained significant (P=0.02). The proportion of PI-OHCA who received defibrillation (16% versus 23%; risk difference [RD], -6.91%; 95% CI, -9.55% to -4.26%; P<0.001) and had return of spontaneous circulation (17% versus 29%; RD, -11.98%; 95% CI, -14.76% to -9.18%; P<0.001) were lower after March 19 in 2020 compared with 2018 and 2019. There was also a significant increase in dead on arrival emergency medical services responses in 2020 compared with 2018 and 2019, starting around the time of the stay-at-home order (P<0.001). Conclusions Paramedics in Los Angeles County, CA responded to increased PI-OHCA and decreased PI-STEMI following the stay-at-home order. The increased PI-OHCA was not fully explained by the reduction in PI-STEMI. Field defibrillation and return of spontaneous circulation were lower. It is critical that public health messaging stress that emergency care should not be delayed.

Infliximab attenuates early myocardial dysfunction after resuscitation in a swine cardiac arrest model.

OBJECTIVE: Left ventricular dysfunction after successful cardiopulmonary resuscitation contributes to early death after resuscitation. Proinflammatory cytokines are known to decrease myocardial function, and tumor necrosis factor-alpha has been shown to increase after successful resuscitation. We hypothesized that blocking the effects of tumor necrosis factor-alpha with infliximab would prevent or minimize postresuscitation cardiac dysfunction. DESIGN: Randomized, placebo-controlled comparative study. SETTING: Large animal research laboratory. SUBJECTS: Twenty-eight anesthetized and instrumented domestic male swine (Yorkshire and Yorkshire/Hampshire mix; weight, 35-45 kg). INTERVENTIONS: Infusion of infliximab (5 mg/kg) or normal saline after resuscitation from ventricular fibrillation cardiac arrest. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables, indices of left ventricular function, and tumor necrosis factor-alpha were measured before and after 8 mins of cardiac arrest during the early postresuscitation period (3 hrs). Within 5 mins of restoration of spontaneous circulation, 14 animals received infliximab, 5 mg/kg, infused over 30 mins. Fourteen animals received an infusion of normal saline. Inotropes and vasopressors were not administered to either group after resuscitation. Tumor necrosis factor-alpha increased after restoration of circulation and remained elevated throughout the observation period. Differences between groups were not significant. Interleukin-1beta concentration did not change significantly during the observation period in either study group. Mean arterial pressure and stroke work were significantly greater in the infliximab group within 30 mins of resuscitation, and these differences were sustained throughout the 3-hr postresuscitation period. The effect of tumor necrosis factor-alpha blockade was evident only in animals with a significant increase (doubling) in plasma tumor necrosis factor-alpha at 30 mins after arrest. CONCLUSION: Tumor necrosis factor-alpha plays a role in cardiac dysfunction after arrest and infliximab may attenuate or prevent postresuscitation myocardial dysfunction when administered immediately after resuscitation.

Neurologically intact survival in a porcine model of cardiac arrest: manual cardiopulmonary resuscitation vs. LifeBelt cardiopulmonary resuscitation.

OBJECTIVE: To compare the LifeBelt (Deca-Medica, Inc., Columbus, OH), a novel cardiopulmonary resuscitation (CPR) device, with manual CPR on the outcome of neurologically intact survival in a porcine model of cardiac arrest. METHODS: Twenty-two adolescent swine were randomized by permuted block design to resuscitation using LifeBelt (n = 12) or manual CPR (n = 10). The animals were instrumented with right atrial and aortic pressure catheters while they were under general anesthesia with isoflurane and nitrous oxide. Ventricular fibrillation (VF) was induced with a bipolar pacing catheter placed in the right ventricle. After 7 minutes of untreated VF, chest compressions with either LifeBelt or manual CPR were initiated along with standard Advanced Cardiac Life Support. Survivors were assigned a neurologic score using the neurologic deficit score and the cerebral performance category (CPC) score at 24, 48, and 72 hours following resuscitation by a veterinarian blinded to treatment allocation. RESULTS: There were no significant differences in prearrest hemodynamic parameters or in important resuscitation variables between the groups. One of 12 of the LifeBelt animals failed to achieve return of spontaneous circulation (0.08, 95% confidence interval [CI] 0.002-0.38). The remaining 11 had a neurologic deficit score of 0 and a CPC score of 1, indicating normal neurologic function. All of the manual CPR animals survived. One of 10 manual CPR survivors (0.10, 95% CI 0.003-0.45) had a neurologic deficit score of 260 and a CPC score of 3, indicating moderate disability, while the remaining animals had a neurologic deficit score of 0 and a CPC score of 1. CONCLUSIONS: In this porcine model of cardiac arrest, we did not detect significant differences in neurologically intact survival between LifeBelt CPR and manual CPR.

Amiodarone for the emergency care of children.

Amiodarone is a class 3 antiarrhythmic agent used for a broad range of arrhythmias including adenosine-resistant supraventricular tachycardia, junctional ectopic tachycardia, and ventricular tachycardia. Compared with adults, there are few data on its use in children with arrhythmias resistant to conventional therapy. National and international guidelines for cardiopulmonary resuscitation and emergency cardiovascular care recommend its use for a variety of arrhythmias based on case reports, cohort studies, and extrapolation from adult data. This article will review the historical development, chemical properties, metabolism, indications and contraindications, and adverse effects of amiodarone in infants and children. After completing this CME activity, the reader should be able to utilize amiodarone in the pediatric population for arrhythmias and identify complications associated with its use.

Implementation of Targeted Temperature Management After Out-of-Hospital Cardiac Arrest: Observations From the Los Angeles County Regional System.

Background Despite the benefits of targeted temperature management (TTM) for out-of-hospital cardiac arrest), implementation within the United States remains low. The objective of this study was to evaluate the prevalence and factors associated with TTM use in a large, urban-suburban regional system of care. Methods and Results This was a retrospective analysis from the Los Angeles County regional cardiac system of care serving a population of >10 million residents. All adult patients aged ≥18 years with non-traumatic out-of-hospital cardiac arrest transported to a cardiac arrest center from April 2011 to August 2017 were included. Patients awake and alert in the emergency department and patients who died in the emergency department before consideration for TTM were excluded. The primary outcome measure was prevalence of TTM use. The secondary analysis were annual trends in TTM use over the study period and factors associated with TTM use. The study population included 8072 patients; 4154 patients (51.5%) received TTM and 3767 patients (46.7%) did not receive TTM. Median age was 67 years, 4780 patients (59.2%) were men, 4645 patients (57.5%) were non-White, and the most common arrest location was personal residence in 4841 patients (60.0%). In the adjusted analysis, younger age, male sex, an initial shockable rhythm, witnessed arrest, and receiving coronary angiography were associated with receiving TTM. Conclusions Within this regional system of care, use of TTM was higher than previously reported in the literature at just over 50%. Use of integrated systems of care may be a novel method to increase TTM use within the United States.