Emergency Medical Services Arrival Research Articles

Survival After Intra-Arrest Transport vs On-Scene Cardiopulmonary Resuscitation in Children.

For pediatric out-of-hospital cardiac arrest (OHCA), emergency medical services (EMS) may elect to transport to the hospital during active cardiopulmonary resuscitation (CPR) (ie, intra-arrest transport) or to continue on-scene CPR for the entirety of the resuscitative effort. The comparative effectiveness of these strategies is unclear. To evaluate the association between intra-arrest transport compared with continued on-scene CPR and survival after pediatric OHCA, and to determine whether this association differs based on the timing of intra-arrest transport. This cohort study included pediatric patients aged younger than 18 years with EMS-treated OHCA between December 1, 2005 and June 30, 2015. Data were collected from the Resuscitation Outcomes Consortium Epidemiologic Registry, a prospective 10-site OHCA registry in the US and Canada. Data analysis was performed from May 2022 to February 2024. Intra-arrest transport, defined as an initiation of transport prior to the return of spontaneous circulation, and the interval between EMS arrival and intra-arrest transport. The primary outcome was survival to hospital discharge. Patients who underwent intra-arrest transport at any given minute after EMS arrival were compared with patients who were at risk of undergoing intra-arrest transport within the same minute using time-dependent propensity scores calculated from patient demographics, arrest characteristics, and EMS interventions. We examined subgroups based on age (<1 year vs ≥1 year). Of 2854 eligible pediatric patients (median [IQR] age, 1 [0-9] years); 1691 males [59.3%]) who experienced OHCA between December 2005 and June 2015, 1892 children (66.3%) were treated with intra-arrest transport and 962 children (33.7%) received continued on-scene CPR. The median (IQR) time between EMS arrival and intra-arrest transport was 15 (9-22) minutes. In the propensity score-matched cohort (3680 matched cases), there was no significant difference in survival to hospital discharge between the intra-arrest transport group and the continued on-scene CPR group (87 of 1840 patients [4.7%] vs 95 of 1840 patients [5.2%]; risk ratio [RR], 0.81 [95% CI, 0.59-1.10]). Survival to hospital discharge was not modified by the timing of intra-arrest transport (P value for the interaction between intra-arrest transport and time to matching = .10). Among patients aged younger than 1 year, intra-arrest transport was associated with lower survival to hospital discharge (RR, 0.52; 95% CI, 0.33-0.83) but there was no association for children aged 1 year or older (RR, 1.22; 95% CI, 0.77-1.93). In this cohort study of a North American OHCA registry, intra-arrest transport compared with continued on-scene CPR was not associated with survival to hospital discharge among children with OHCA. However, intra-arrest transport was associated with a lower likelihood of survival to hospital discharge among children aged younger than 1 year.

Infant out-of-hospital cardiac arrest during nights and weekends

BackgroundA growing body of evidence suggests outcomes for cardiac arrest in adults are worse during nights and weekends when compared with daytime and weekdays. Similar research has not yet been carried out in the infant setting. MethodsWe examined the National Emergency Medical Services Information System (NEMSIS), a database containing millions of emergency medical services (EMS) runs in the United States. Inclusion criteria were infant out-of-hospital cardiac arrests (patients <1 years old) taking place prior to EMS arrival between January 2021 and December 2022 where EMS documented whether return of spontaneous circulation (ROSC) was achieved. Cardiac arrests were classified as occurring during either the day (defined as 0800–1959) or the night (defined as 2000–0759) and weekends (Saturday/Sunday) or weekdays (Monday-Friday). Rates of ROSC achievement were compared. ResultsA total of 8549 infant cardiac arrests met inclusion criteria: 5074 (59.4%) took place during daytime compared with 3475 (40.6%) during nighttime, and 5989 (70.1%) arrests occurred on weekdays compared with 2560 (29.9%) on weekends. Rates of ROSC achievement were significantly lower on weekends versus weekdays (16.8% vs. 14.1%; p = 0.00097). A difference in ROSC rates when comparing daytime and nighttime was seen, but this difference was not statistically significant (16.4% vs. 15.3%; p = 0.08076). ConclusionROSC achievement rates for infant out-of-hospital cardiac arrest are significantly lower on weekends when compared with weekdays. Further study and quality improvement work is needed to better understand this.

Association of midazolam route of administration and need for recurrent dosing among children with seizures cared for by emergency medical services.

National guidelines in the United States recommend the intramuscular and intranasal routes for midazolam for the management of seizures in the prehospital setting. We evaluated the association of route of midazolam administration with the use of additional benzodiazepine doses for children with seizures cared for by emergency medical services (EMS). We conducted a retrospective cohort study from a US multiagency EMS dataset for the years 2018-2022, including children transported to the hospital with a clinician impression of seizures, convulsions, or status epilepticus, and who received an initial correct weight-based dose of midazolam (.2 mg/kg intramuscular, .1 mg/kg intravenous, .2 mg/kg intranasal). We evaluated the association of route of initial midazolam administration with provision of additional benzodiazepine dose in logistic regression models adjusted for age, vital signs, pulse oximetry, level of consciousness, and time spent with the patient. We included 2923 encounters with patients who received an appropriate weight-based dose of midazolam for seizures (46.3% intramuscular, 21.8% intranasal, 31.9% intravenous). The median time to the first dose of midazolam from EMS arrival was similar between children who received intramuscular (7.3 min, interquartile range [IQR] = 4.6-12.5) and intranasal midazolam (7.8 min, IQR = 4.5-13.4) and longer for intravenous midazolam (13.1 min, IQR = 8.2-19.4). At least one additional dose of midazolam was given to 21.4%. In multivariable models, intranasal midazolam was associated with higher odds (odds ratio [OR] = 1.39, 95% confidence interval [CI] = 1.10-1.76) and intravenous midazolam was associated with similar odds (OR = 1.00, 95% CI = .80-1.26) of requiring additional doses of benzodiazepines relative to intramuscular midazolam. Intranasal midazolam was associated with greater odds of repeated benzodiazepine dosing relative to initial intramuscular administration, but confounding factors could have affected this finding. Further study of the dosing and/or the prioritization of the intranasal route for pediatric seizures by EMS clinicians is warranted.

Чрезвычайные ситуации в мегаполисе: организация и результаты оказания экстренной медицинской помощи детям c термической травмой

Summary. The purpose of the study is to analyze the organization and results of providing medical care to children (affected, patients) who received thermal injury in emergency situations (ES) in the metropolis. Materials and methods of research. Research materials – data contained in the automated information and analytical system “Disaster Medicine of the City of Moscow” of the Moscow Territorial Scientific and Practical Center for Disaster Medicine of the Moscow Department of Health (CEMP). Statistical data processing was performed using the StatTech program (Stattech LLC, Russia). During the research, the computing and graphic capabilities of Microsoft Office programs were used. When carrying out the study, historical, statistical and analytical methods were used. Research results and their analysis. Of the 285 children with thermal burns received in emergencies, 124 (43.5%) were pronounced dead at the scene of the event before the arrival of emergency medical services (EMS) and specialized emergency response teams. Of the 161 patients who received emergency medical care, 133 (82.6%) were referred to hospital; 28 (17.4%) – for outpatient follow-up treatment. 24.2% of the total number of patients who received medical care were in extremely serious and serious condition, including 3.1% who required invasive respiratory support. It was noted that in the prehospital period, in 20% of cases, the severity of the condition of patients subsequently hospitalized in the hospital was assessed incorrectly.

Abstract TMP23: Mobile Stroke Unit to Mitigate Disparities in Stroke Treatment

Background: Studies have reported longer emergency department (ED) wait times and delayed stroke treatment for Black versus White patients. Minority patients also have severe stroke symptoms compared to White patients. We hypothesize that patients with acute stroke living in distressed communities will be treated faster in the Mobile Stroke Unit (MSU) than in the ED. Methods: This is a retrospective analysis of all patients who presented to Grady Memorial Hospital from January 1 2022-December 31, 2022, and received alteplase (tPA) either in the ED (by arrival of Emergency Medical Services) or the MSU. Patients evaluated in the MSU but received tPA in the ED were excluded from the study. Stroke treatment time metrics were compared for patients from the same zip codes between the two groups. Results: 169 patients treated with IV tPA in the ED or MSU were screened. 39 patients qualified for the study (11 MSU and 28 ED) with matching zip codes (8 zip codes were matched). 82% (32/39) were from at-risk or distressed communities. 87% (34/39) were Black, 44% male (17/39) and mean age was 63 years. The median alarm to CT time (minutes) was significantly shorter in MSU compared to ED (41 vs 79, p &lt;0.0001). The median alarm to thrombolysis time (minutes) was significantly shorter in the MSU compared to the ED (76 vs. 115, p &lt; 0.0001) (Figure 1). Conclusions: Patients from distressed communities get evaluated and treated faster in the MSU compared to ED. Our results suggest that having a MSU in distressed communities that include patients at high risk of stroke can help reduce disparities in stroke care by allowing for faster diagnosis and treatment. A larger sample size is required to compare functional outcomes.

Pediatric Out-of-Hospital Cardiac Arrest: The Role of the Telecommunicator in Recognition of Cardiac Arrest and Delivery of Bystander Cardiopulmonary Resuscitation.

Telecommunicator CPR (T-CPR), whereby emergency dispatch facilitates cardiac arrest recognition and coaches CPR over the telephone, is an important strategy to increase early recognition and bystander CPR in adult out-of-hospital cardiac arrest (OHCA). Little is known about this treatment strategy in the pediatric population. We investigated the role of T-CPR and related performance among pediatric OHCA. This study was a retrospective cohort investigation of OHCA among individuals <18 years in King County, Washington, from April 1, 2013, to December 31, 2019. We reviewed the 911 audio recordings to determine if and how bystander CPR was delivered (unassisted or T-CPR), key time intervals in recognition of arrest, and key components of T-CPR delivery. Of the 185 eligible pediatric OHCAs, 23% (n=43) had bystander CPR initiated unassisted, 59% (n=109) required T-CPR, and 18% (n=33) did not receive CPR before emergency medical services arrival. Among all cases, cardiac arrest was recognized by the telecommunicator in 89% (n=165). Among those receiving T-CPR, the median (interquartile range) interval from start of call to OHCA recognition was 59 seconds (38-87) and first CPR intervention was 115 seconds (94-162). When stratified by age (≤8 versus >8), the older age group was less likely to receive CPR before emergency medical services arrival (88% versus 69%, P=0.002). For those receiving T-CPR, bystanders spent a median of 207 seconds (133-270) performing CPR. The median compression rate was 93 per minute (82-107) among those receiving T-CPR. T-CPR is an important strategy to increase early recognition and early CPR among pediatric OHCA.

Epidemiology of patients assessed for trauma by Swedish ambulance services: a retrospective registry study

BackgroundThere is a lack of knowledge regarding the epidemiology of severe trauma assessed by Swedish emergency medical services (EMS).AimTo investigate the prevalence of trauma in Sweden assessed by EMS from a national perspective and describe patient demography, aetiology, trauma type, prehospital triage and clinical outcomes.MethodsData from two national quality registries, the Swedish Ambulance Registry and the Swedish Trauma Registry (SweTrau) were collected from January 1 to December 31, 2019. Inclusion criteria were an Emergency Symptoms and Signs code equivalent to trauma in the Swedish Ambulance Registry and criteria fulfilled for SweTrau inclusion. Exclusion criteria were patients < 18 years old, those not transported to a hospital and those without a personal identification number.ResultsIn total, 53,120 patients with trauma were included (14% of primary EMS missions involving a personal identification number). Of those, 2,278 (4.3%) patients (median age: 45 years; 32% women) were reported in SweTrau to have severe or potentially severe trauma (penetrating: 7%, blunt: 93%). In terms of including all causes of trauma, the code for ‘trauma alert activation’ was most frequent (55%). The most frequent injury mechanism was an injury caused by a car (34%). Most (89%) cases were assigned Priority 1 (life-threatening condition) at the dispatch centre. 62% were regarded as potentially life threatening upon EMS arrival, whereas 29% were assessed as non-life-threatening. Overall, 25% of the patients had new injury severity scores > 15. 12% required invasive treatment, 11% were discharged with severe disability and the 30-day mortality rate was 3.6%.ConclusionIn this cross-sectional study, 14% of the primary EMS missions for one year were caused by trauma. However, only a small proportion of these cases are severe injuries, and the risk of severe disabilities and death appears to be limited. The most frequent aetiology of a severe trauma is injury caused by a car, and most severe traumas are blunt. Severe traumas are given the highest priority at the dispatch centre in the vast majority of cases, but nearly one-third of these cases are considered a low priority by the EMS nurse. The latter leaves room for improvement.

Enhancing global pediatric cardiac arrest outcomes through bystander cardiopulmonary resuscitation: A comprehensive systematic review

This systematic review investigates the impact of global bystander cardiopulmonary resuscitation (CPR) on outcomes in pediatric cardiac arrest cases. Through a meticulous examination of relevant worldwide studies retrieved from PubMed spanning 2018 to 2022, employing keywords such as “worldwide Bystander CPR (BCPR),” “worldwide out-of-hospital CPR,” and “pediatric CPR” with Boolean operators “OR” and “AND,” the study incorporates 10 selected articles out of the initially identified 13. Findings reveal that bystander-initiated CPR, predominantly chest-only CPR, is administered at rates ranging from 48% to 89% globally, with no significant gender-based disparity, but a lower likelihood observed among worldwide Black children. Return of spontaneous circulation (ROSC) is achieved in 20%–35% of cases and survival to hospital discharge in 5%–10% of instances. Factors associated with worldwide prehospital ROSC include epinephrine administration, bystander intervention before emergency medical services (EMS) arrival, older age, reduced time to EMS response, and worldwide automated external defibrillators. Notably, a shorter time to EMS arrival is the sole significant predictor of worldwide survival to hospital discharge. The study discerns no substantial distinction in achieving prehospital ROSC and favorable outcomes on a global scale. The conclusion underscores the varied worldwide outcomes in out-of-hospital cardiac arrest studies, attributing these variations to multifarious confounding factors. It identifies crucial predictors of prehospital ROSC and recommends targeted CPR training for underserved communities to enhance worldwide BCPR rates and ameliorate pediatric cardiac arrest outcomes.

Out-of-hospital cardiac arrest in residential aged care facilities is independently associated with lower survival in Perth, Australia

AimTo compare out-of-hospital cardiac arrest (OHCA) characteristics and outcomes between people aged ≥ 65 years who arrested in a residential aged care facility (RACF) versus a private residence in Perth, Australia. MethodsWe undertook a retrospective cohort study of OHCA cases attended by emergency medical services (EMS) in Perth, January 2018-December 2021. OHCA patient and event characteristics and survival outcomes were compared via univariate analysis. Multivariable logistic regression was used to investigate the relationship between residency type and (i) return of spontaneous circulation (ROSC) at emergency department (ED) and (ii) 30-day survival. ResultsA total of 435 OHCA occurred in RACFs versus 3,395 in private residences. RACF patients were significantly older (median age: 86 [IQR 79, 91] vs 78 [71, 85] years; p < 0.001), more commonly female (50.1% vs 36.8%; p < 0.001), bystander-witnessed arrests (34.9% vs 21.5%; p < 0.001), received bystander cardiopulmonary resuscitation (42.1% vs 28.6%; p < 0.001), had less shockable first monitored rhythms (4.0% vs 8.1%; p = 0.002) and more frequently had a “do not resuscitate” order identified (46.0% vs 13.6%; <0.001). Among those with EMS-attempted resuscitation or with defibrillation before EMS arrival, ROSC at ED and 30-day survival were significantly lower in the RACF group (6.2% vs 18.9%; p < 0.001 and 1.9% vs 7.7%; p < 0.001). The adjusted odds of ROSC at ED (aOR: 0.22 [95%CI: 0.10, 0.46]) and 30-day survival (aOR: 0.20 [95%CI 0.05, 0.92]) were significantly lower for RACF residents. ConclusionRACF residency was an independent predictor of lower survival from OHCA, highlighting the importance of end-of-life planning for RACF residents.

Prehospital identification of acute ischaemic stroke with large vessel occlusion: a retrospective study from western Norway

BackgroundIn 2019, the emergency medical services (EMS) covering the western Norway Regional Health Authority area implemented its version of the prehospital clinical criteria G-FAST (Gaze deviation, Facial palsy, Arm weakness,...

Bystander defibrillation increases 30-day survival even with short emergency medical service response time

Abstract Background Rates of bystander initiated defibrillation are increasing in many areas of the world (1-4), but the effect of defibrillation at different time points after recognition of out-of-hospital cardiac arrest (OHCA) remains largely unknown. Purpose To assess the effect on 30-day survival of bystander defibrillation at different intervals of emergency medical service (EMS) response time. Methods We included OHCAs from 2016 through 2020 from the Danish Cardiac Arrest Registry. Cases were included if they were ≥18 years of age, bystander witnessed, received bystander cardiopulmonary resuscitation (CPR), had EMS response time of 25 minutes or less and only the first OHCA for each subject was considered. We excluded cases witnessed by EMS or if they had missing values of OHCA-related variables. Crude survival proportions were calculated for each minute of EMS response time. Relative risks (RR) and corresponding 95 % confidence intervals (95 % CI) of the outcome (30-day survival) for eight different intervals of EMS response time were estimated using a causal inference framework utilizing Targeted Maximum Likelihood Estimation (TMLE) with ensemble Super Learning, adjusting for age, sex, place of arrest (public/private), initial cardiac rhythm (shockable/not shockable), and comorbidities (prior acute myocardial infarction, ischemic heart disease, heart failure, chronic obstructive pulmonary disease, stroke, cancer). Results We included 7,471 cases of bystander witnessed OHCA receiving CPR before EMS arrival. Of these, 14.7 % (1,098/7,471) received bystander defibrillation before arrival of EMS. Overall, 44.5 % (489/1,098) survived to 30 days when bystander defibrillation was performed versus 18.8 % (1,200/6,373) when no bystander defibrillation was performed. When examining the crude survival proportion for each minute of EMS response time, we found that 30-day survival was consistently higher in the group receiving bystander defibrillation for the first 20 minutes after which the survival was approximately the same for the two groups (Figure 1). When adjusting for confounders, we found statistically significantly increased relative risks of 30-day survival for patients receiving bystander defibrillation, compared to patients not bystander defibrillated, for all intervals of EMS response time, except for response times of 0-2 min., where the increase did not reach statistical significance (0-2 min: RR; 1.34 [95 % CI: 0.88-2.05], 2-4 min: RR; 1.37 [95 % CI: 1.10-1.70], 4-6 min: RR; 1.55 [95 % CI: 1.33-1.80], 6-8 min: RR; 2.23 [95 % CI: 1.86-2.67], 8-10 min: RR; 1.99 [95 % CI: 1.55-2.55], 10-12 min: RR; 1.89 [95 % CI: 1.34-2.68], 12-15 min: RR; 1.86 [95 CI: 1.22-2.84], &amp;gt;15 min: RR; 1.98 [95 % CI: 1.16-3.38]) (Figure 2). Conclusion For all intervals of EMS response time, bystander defibrillation increased 30-day survival of OHCA. The effect was significant for EMS response times as short as 2-4 minutes.

Abstract 391: Association Between Defibrillation to Epinephrine Interval and Short-Term Outcomes in Out-of-Hospital Cardiac Arrest Patients With Shockable Rhythm

Background: The optimal timing of epinephrine administration after defibrillation in out-of-hospital cardiac arrest (OHCA) patients with shockable rhythm is unknown. Aim: We evaluated the association between defibrillation to epinephrine interval and short-term outcomes. Methods: Between 2011 and 2020, we enrolled 1,259,960 OHCA patients from a nationwide prospective population-based registry in Japan. After applying exclusion criteria, 20,905 patients with shockable rhythm as the first documented rhythm at emergency medical services (EMS) arrival who received epinephrine after defibrillation were eligible for the study. Clinical outcomes included prehospital return of spontaneous circulation (ROSC), survival, and favorable neurological outcome at 30 days. To examine whether each variable predicted a good short-term outcome, multivariable logistic regression models were constructed using age, gender, year, district, origin of cardiac arrest, witnessed arrest, bystander-initiated cardiopulmonary resuscitation, call to EMS arrival interval, EMS arrival to defibrillation interval, and defibrillation to epinephrine interval. Results: At 30 days, 1,618 patients (8%) had a favorable neurological outcome. The defibrillation to epinephrine interval in these patients was significantly shorter than the interval in patients with an unfavorable neurological outcome [8 (5-12) vs 11 (7-16) min; P&lt;0.001]. The proportion of patients who achieved prehospital ROSC, survived, or had a favorable neurological outcome at 30 days decreased as time to epinephrine after defibrillation increased (P&lt;0.001 for trend). Multivariable analysis showed that shorter defibrillation to epinephrine interval independently predicted good outcomes ( Table ). Conclusion: A shorter defibrillation to epinephrine interval is significantly associated with good short-term outcomes in OHCA patients with shockable rhythm.

Abstract 126: Does a Difference in Bystander Cardiopulmonary Resuscitation Initiation and Continuation Exist Due to Patient Sex After Accounting for the Bystander-Patient Relationship?

Introduction/Background: Differences in bystander cardiopulmonary resuscitation (B-CPR) provision based on the patient’s sex have been reported extensively, with equivocal results. Research question: Do differences in B-CPR according to the patient’s sex exist after adjusting for the bystander-patient relationship? Aim: To explore sex differences in B-CPR initiation and continuation for out-of-hospital cardiac arrest (OHCA) patients while accounting for the bystander-patient relationship. Methods: We analysed consecutive paramedic-confirmed OHCA emergency calls, from 1 January to 30 April 2021, in Western Australia. Calls included were non-traumatic, non- emergency medical service (EMS)-witnessed OHCA, where the bystander was with the patient and CPR was not already in progress. Calls were reviewed in full, and patient and bystander characteristics were coded. Bystander relationship was categorised as either related to the patient or unrelated. We performed a logistic regression of B-CPR initiation by sex, adjusting for patient age (&lt;65 and ≥65) and location (private and public), and bystander-patient relationship. Results: Of the 295 calls included, 203 (69%) of the patients were male, and 164 (56%) were over 65 years of age. Two thirds of the bystanders (65%) were related to the patient. The majority of OHCAs were in private locations (84%). Bystander CPR was initiated in 205 (69%) calls, 69% (139 out of 201) in male patients and 70% (66 out of 94) in female patients (p=0.85). There was no difference in CPR initiation between male and female patients, unadjusted (odds ratio, OR=0.95, 95% confidence interval, 95% CI = 0.56-1.62), or when adjusted for bystander-patient relationship, location, and patient age (OR=0.92, 95% CI=0.53-1.59). Of those who started CPR (205), 175 (85%) bystanders continued performing CPR till EMS arrived. Male OHCA patients were less likely to have CPR continue to EMS arrival than female OHCA patients (OR=0.46, 95% CI=0.16-1.29). Conclusion: There was no effect of patient sex on bystander CPR, both before and after accounting for bystander-patient relationship. Bystanders were more likely to continue performing CPR on female OHCA patients.

Abstract 410: Differences in Survivability of Out-of-Hospital Cardiac Arrest in Rural versus Urban Minnesota

Background: Out-of-Hospital Cardiac Arrest (OHCA) survival has improved in North America due to improved awareness, training, and bystander CPR. An important factor complicating OHCA survival is location on initial arrest, due to distance and access to emergency medical services (EMS). Aims: We sought to examine characteristics of OHCA encounters in Minnesota and determine underlying factors for differences in OHCA survival in rural versus urban areas. Methods: We examined data from the Cardiac Arrest Registry to Enhance Survival (CARES) registry between 2013-2021 in Minnesota. The analyses included encounters from 31 EMS services across the state. The Office of Management and Budget (OMB) county rural-urban classification schema was used to designate categories of rural (non-metropolitan counties of less than 50,000 population) versus urban (metropolitan counties with populations of 50,000 or more). Results: We identified 21,257 patient encounters, of which 3,524 (16.6%) of encounters were designated as rural and 17,733 (83.4%) as urban. In our cohort, patients were predominately male. Rural arrest patients tended to be older (mean age, 64.5 vs 60.6 years, p&lt;0.01) and had a higher prevalence of heart disease (32.2% vs 26.9%, p&lt;0.01). Rural arrests were more likely to be witnessed (57.1% vs 51.6%, p&lt;0.01), receive bystander CPR (42.3% vs 35.2%, p&lt;0.01), and have AED use prior to EMS arrival (55.7% vs 53.5%, p&lt;0.01). The average time for EMS arrival at scene of arrest was longer among rural encounters (12.9 vs 10.6 minutes; p&lt;0.01). Overall, survival-to-discharge was significantly lower among rural versus urban communities (9.3% vs 13.1%, p&lt;0.01). Conclusion: In this analysis of the CARES dataset in Minnesota, there were significant differences in survival characteristics between rural vs urban OHCA patients. These findings warrant greater investment in rural EMS agencies and modifiable resuscitation practices to improve survival among rural communities.

Abstract 338: Temporal Characteristics of a Smartphone Alert System for CPR in a Mid-Sized Metropolitan Area

Introduction: Smartphone alert systems (SAS) mobilize trained volunteers to initiate CPR prior to Emergency Medical Services (EMS) arrival. Among the potential factors affecting the probability of a successful response is time; time of day, day of the week, and season each present plausible barriers to response. We sought to examine the temporal characteristics of an SAS in order to better understand this relationship between time and system performance. Methods: Operational records were obtained from the PulsePoint deployment in Allegheny County, Pennsylvania, USA for the period June 2016 to May 2023. PulsePoint sends alerts including nearby AED locations to volunteer responders within a 400m radius of public cardiac arrest events. Case data included alert time and number of responders and AEDs within range of the event. We associated each PulsePoint event with an 8-hour Timeframe (TF) {1 (00:00-07:59), 2 (08:00-15:59), and 3 (16:00-23:59)}, a day of the week, and a season. For each, we calculated the median number of associated responders and AEDs, and the total number of events. We then compared each across each time variable with a Mann-Whitney U-test or Kruskal-Wallis test. Results: There were a total of 2354 events in the capture period. Alerts were least common on Sundays (12.4%) and most common on Tuesday (15.6%). Alerts most frequently occurred in TF2 (45.6% vs TF1: 18.3, TF3: 36.1) and were similar between seasons. Weekday alerts had a higher median number of responders than weekend alerts {3 (1-5) vs 2 (1-4), p=0.004}. Responder count was lower for TF1 than TF2 and TF3 {2 (1-4) vs 3(1-5) vs 3(1-5), p &lt; 0.001}. Count of proximal AEDs did not vary by any of the temporal characteristics. Conclusion: Both event frequency and number of notified responders were associated with day of the week and time of day. Either feature is more complicated than meets the eye, and may include associations with diurnal population movement cycles, overall patterns in emergency services utilization, and responder device configuration preferences. All could be influential in optimizing such SAS deployments.

Abstract 429: The Association Between Naloxone Administration and Outcomes for Out-of-Hospital Cardiac Arrest Due to Suspected Overdose

Background: Opioid overdose is increasingly implicated in the development of out-of-hospital cardiac arrest (OHCA) and is a leading cause of death for adults 25 to 64 years old. Aim: Evaluate the association between naloxone use and outcomes after OHCA due to suspected overdose. Methods: This study was a secondary analysis of data collected in the Portland Cardiac Arrest Epidemiologic Registry, a database containing details of Emergency Medical Services (EMS)-treated cases of cardiac arrest around Portland, OR. Eligible patients had non-traumatic OHCA due to presumed overdose with naloxone (exposed) or without naloxone administration (control). We excluded patients with return of spontaneous circulation (ROSC) before the first dose of naloxone. The primary outcome was ROSC at emergency department (ED) arrival. Secondary outcomes included survival to admission; survival to hospital discharge; and cerebral perfusion category score ≤2 at discharge (functional survival). We performed multivariable logistic regressions adjusting for age, sex, arrest location, witness status, bystander interventions, initial EMS rhythm, time from 911 call to EMS arrival, and year of arrest. We separately assessed the subgroup with non-shockable initial rhythms. Results: Of 3,942 OHCA from 2018-2021, EMS documented an overdose etiology in 249. Of these, 236 (94.8%) had all variables and 18 were excluded for achieving ROSC prior to naloxone, resulting in 218 cases for analysis (171 receiving naloxone). Patients receiving naloxone had no difference in adjusted odds (aOR [95% CI]) of ROSC at ED arrival (1.43 [0.64-3.20]), survival to admission (1.87 [0.85-4.10]), survival to discharge (1.99 [0.39-10.30]) and functional survival (1.99 [0.34-11.55]). The subgroup with non-shockable rhythms showed higher odds of survival to admission (2.55 [1.09-5.92]) but not ROSC at ED arrival (1.60 [0.68-3.75]), survival to discharge (8.43 [0.84-84.20]), or good neurologic outcomes (7.26 [0.75-70.42]). Conclusions: For OHCA due to suspected overdose, those with initial non-shockable rhythms who received naloxone had higher adjusted odds of survival to admission than those who did not. Larger studies are necessary to evaluate the impact of naloxone on OHCA outcomes.

Abstract 267: Neighborhood Socioeconomic Status Influences Rates of Pre-EMS Cardiac Arrest Resuscitation

Introduction: Out-of-hospital cardiac arrest is a leading cause of both morbidity and mortality in the United States and globally. After cardiac arrest onset, emergency medical services (EMS) might not arrive before irreversible injury takes place. Thus, pre-EMS resuscitation - including CPR and automated external defibrillator (AED) use - is associated with improvements in outcomes. We sought to determine if rates of pre-EMS CPR and pre-EMS AED use vary across neighborhood socioeconomic status using a database of EMS activations throughout the United States. Methods: The National Emergency Medical Services Information System (NEMSIS) is a large and nationally-representative database of EMS activations populated from more than ten-thousand EMS agencies throughout the US. We examined cardiac arrests in adult patients (18+ years of age) between January 2017 and December 2019 where EMS providers documented the ZIP code of the arrest, whether CPR prior to EMS arrival was provided, and whether an AED was applied prior to EMS arrival. The ZIP code of the arrest was used to group arrests based on socioeconomic status data from the US Census Bureau. Rates of pre-EMS CPR and pre-EMS AED use were then compared, and ZIP codes with under 5% of residents below the poverty line served as benchmarks. Results: 366,280 cardiac arrests met inclusion criteria. Both Pre-EMS CPR and pre-EMS AED use were highest in ZIP Codes where less than 5% of the population is below the poverty line (p&lt; .00001). Furthermore, a consistent decrease in rates of pre-EMS interventions was seen as the percent of individuals below the poverty line increased (Figure 1). Conclusion: We found a strong relationship between neighborhood socioeconomic status and pre-EMS cardiac arrest interventions. One explanation may be access to CPR training. Further studies should continue to interrogate cardiac arrest disparities that have already been reported and seek to identify new unreported disparities as well.

Improving EMS response times for out-of-hospital cardiac arrest in urban areas using drone-like vertical take-off and landing air ambulances: An international, simulation-based cohort study

BackgroundAdvances in vertical take-off and landing (VTOL) technologies may enable drone-like crewed air ambulances to rapidly respond to out-of-hospital cardiac arrest (OHCA) in urban areas. We estimated the impact of incorporating VTOL air ambulances on OHCA response intervals in two large urban centres in France and Canada. MethodsWe included adult OHCAs occurring between Jan. 2017–Dec. 2018 within Greater Paris in France and Metro Vancouver in Canada. Both regions utilize tiered OHCA response with basic (BLS)- and advanced life support (ALS)-capable units. We simulated incorporating 1–2 ALS-capable VTOL air ambulances dedicated to OHCA response in each study region, and computed time intervals from call reception by emergency medical services (EMS) to arrival of the: (1) first ALS unit (“call-to-ALS arrival interval”); and (2) first EMS unit (“call-to-first EMS arrival interval”). ResultsThere were 6,217 OHCAs included during the study period (3,760 in Greater Paris and 2,457 in Metro Vancouver). Historical median call-to-ALS arrival intervals were 21 min [IQR 16–29] in Greater Paris and 12 min [IQR 9–17] in Metro Vancouver, while median call-to-first EMS arrival intervals were 11 min [IQR 8–14] and 7 min [IQR 5–8] respectively. Incorporating 1–2 VTOL air ambulances improved median call-to-ALS arrival intervals to 7–9 min and call-to-first EMS arrival intervals to 6–8 min in both study regions (all P < 0.001). ConclusionVTOL air ambulances dedicated to OHCA response may improve EMS response intervals, with substantial improvements in ALS response metrics.

Acute SARS-CoV-2 Infection and Incidence and Outcomes of Out-of-Hospital Cardiac Arrest

Little is known about how COVID-19 affects the incidence or outcomes of out-of-hospital cardiac arrest (OHCA), and it is possible that more generalized factors beyond SARS-CoV-2 infection are primarily responsible for changes in OHCA incidence and outcome. To assess whether COVID-19 is associated with OHCA incidence and outcomes. This retrospective cohort study was conducted in Seattle and King County, Washington. Participants included persons aged 18 years or older with nontraumatic OHCA attended by emergency medical services (EMS) between January 1, 2018, and December 31, 2021. Data analysis was performed from November 2022 to March 2023. Prepandemic (2018-2019) and pandemic (2020-2021) periods and SARS-CoV-2 infection. The primary outcomes were OHCA incidence and patient outcomes (ie, survival to hospital discharge). Mediation analysis was used to determine the percentage change in OHCA incidence and outcomes between prepandemic and pandemic periods that was attributable to acute SARS-CoV-2 infection vs conventional Utstein elements related to OHCA circumstances (ie, witness status and OHCA location) and resuscitation care (ie, bystander cardiopulmonary resuscitation, early defibrillation, and EMS response intervals). There were a total of 13 081 patients with OHCA (7102 dead upon EMS arrival and 5979 EMS treated). Among EMS-treated patients, the median (IQR) age was 64.0 (51.0-75.0) years, 3864 (64.6%) were male, and 1027 (17.2%) survived to hospital discharge. The total number of patients with OHCA increased by 19.0% (from 5963 in the prepandemic period to 7118 in the pandemic period), corresponding to an incidence increase from 168.8 to 195.3 events per 100 000 person-years. Of EMS-treated patients with OHCA during the pandemic period, 194 (6.2%) were acutely infected with SARS-CoV-2 compared with 7 of 191 EMS-attended but untreated patients with OHCA (3.7%). In time-series correlation analysis, there was a positive correlation between community SARS-CoV-2 incidence and overall OHCA incidence (r = 0.27; P = .01), as well as OHCA incidence with acute SARS-CoV-2 infection (r = 0.43; P < .001). The survival rate during the pandemic period was lower than that in the prepandemic period (483 patients [15.4%] vs 544 patients [19.2%]). During the pandemic, those with OHCA and acute SARS-CoV-2 infection had lower likelihood of survival compared with those without acute infection (12 patients [6.2%] vs 471 patients [16.0%]). SARS-CoV-2 infection itself accounted for 18.5% of the pandemic survival decline, whereas Utstein elements mediated 68.2% of the survival decline. In this cohort study of COVID-19 and OHCA, a substantial proportion of the higher OHCA incidence and lower survival during the pandemic was not directly due to SARS-CoV-2 infection but indirect factors that challenged OHCA prevention and treatment.

Racial, Ethnic, and Socioeconomic Disparities in Prehospital Encounters for Children with Asthma

Objective Asthma represents one of the most common medical conditions among children encountered by emergency medical services (EMS). While care disparities for children with asthma have been observed in other healthcare settings, limited data exist characterizing disparities in prehospital care. We sought to characterize differences in prehospital treatment and transport of children with suspected asthma exacerbations by race and ethnicity, within the context of community socioeconomic status. Methods We conducted a multi-agency retrospective study of EMS encounters in 2019 for children (2–17 years) with asthma and wheezing using a national prehospital database. Our primary outcomes included EMS transport and prehospital bronchodilator or systemic corticosteroid administration. Scene socioeconomic status was evaluated using the social vulnerability index. We used generalized estimating equations to estimate adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) for prehospital bronchodilator use or steroid use by race and ethnicity, adjusting for age, presence of abnormal vital signs, community size, bronchodilator use prior to EMS arrival, and transport disposition. Results We analyzed 5,266 EMS encounters (median age 8 years). Approximately half (53%) were Black non-Hispanic and 34% were White non-Hispanic. Overall, 77% were transported by EMS. In an adjusted model, Black non-Hispanic children were 25% less likely to be transported compared to White non-Hispanic children (aOR: 0.75, 95%CI: 0.58–0.96). EMS administered at least one bronchodilator to 81% of Black non-Hispanic patients, 73% of Hispanic patients, and 68% of White, non-Hispanic patients. Relative to White non-Hispanic children, EMS bronchodilator administration was greater for Black non-Hispanic children, (aOR: 1.55, 95%CI: 1.25–1.93), after controlling for scene socioeconomic status and potential confounding variables. Systemic corticosteroids were administered in 3% of all encounters. Odds of prehospital systemic corticosteroid administration did not differ significantly by race and ethnicity. Conclusion Black non-Hispanic children comprised a larger proportion of EMS encounters for asthma and were more likely to receive a bronchodilator in adjusted analyses accounting for community socioeconomic status. However, these children were less likely to be transported by EMS. These findings may reflect disease severity not manifested by abnormal vital signs, management, and other social factors that warrant further investigation.