Characteristics and Experiences of Women Physicians and Professionals in NAEMSP.

Introduction: One of the six guiding principles of the EMS Agenda 2050 is to foster a socially equitable care delivery system. A specific recommendation within this principle is that "local EMS leadership, educators and clinicians [should] reflect the diversity of their communities." Research has shown that women comprise a minority of emergency medicine services (EMS) field clinicians. In academic settings, women are represented at lower rates among experienced EMS faculty than within Emergency Medicine clinicians or faculty at large. The reasons for these differences are also unknown. Little data exist describing the number or experience of female physicians and professionals in EMS.Purpose: Our objective was to describe the composition and experiences of EMS physicians, researchers and professionals who participate in the Women in EMS group of the National Association of EMS Physicians (NAEMSP).Methods: We performed a cross-sectional, mixed-methods descriptive study of women belonging to the Women in EMS Committee of NAEMSP. A survey was sent to the 143 members of this group using a list-serve, and the data was collected in Redcap.Results: Seventy-four people completed the survey. Respondents were 96% female, 82% Caucasian, 11% underrepresented minorities (URM), and 7% LGBTQI. Of the 88% that are physicians, 78% are board certified in Emergency Medicine, compared to 55% in EMS. Forty-eight percent reported they received some form of mentorship. Among these respondents, a minority reported female mentorship, which was usually from a remote rather than local mentor (41% vs. 15%). Eighty-three percent of respondents had experienced some form of discrimination or harassment in their career, but only 68% reported their workplace culture discourages such behavior. Thirty-three percent of respondents report receiving unequal recognition because of gender. Thematic evaluation of the qualitative responses showed that respondents felt there were fewer barriers to mentorship and professional advancement opportunities in local work versus national engagement.Conclusions: In a survey evaluating representation of female professionals in EMS, participants reported on their career representations, and experiences of gender-based inequity within their EMS career settings. Several opportunities exist to improve diversity, equity, and inclusion for women in EMS based on our findings.

Qualitative Assessment of a Medical Protocols Mobile Application at the Boston Marathon 2016.

OBJECTIVE: To examine the creation of a medical protocols mobile application for the Boston Marathon and its use by medical volunteers for the 2016 Boston Marathon. DESIGN: Anonymous questionnaire. SETTING: 2016 Boston Marathon. PARTICIPANTS: Two hundred ninety-four marathon medical volunteers. MAIN OUTCOME MEASURES: Responses regarding ease of use, acceptability, and usefulness of the International Institute of Race Medicine mobile application. RESULTS: In total, 88% of medical volunteers who participated in the study felt that the medical protocols mobile application was easy to use. Approximately 72% would use the app again, and 79% would recommend the app to others. However, only 15% of volunteers consistently used the app during the event, and 37% felt like it contributed to clinical decision-making. CONCLUSIONS: A medical protocols app was found to be useful and well accepted among medical volunteers who reported using the app, but only a minority of respondents used the app on marathon day or felt like it contributed to clinical care. Although new, mobile apps in race medicine should continue to be an area of development as providers increasingly integrate their use into clinical practice.

Pilot Paramedic Survey of Benefits, Risks, and Strategies for Pediatric Prehospital Telemedicine.

OBJECTIVE: A national survey found prehospital telemedicine had potential clinical applications but lacked provider opinion on its use for pediatric emergency care. We aimed to (1) estimate prehospital telemedicine use, (2) describe perceived benefits and risks of pediatric applications, and (3) identify preferred utilization strategies by paramedics. METHODS: We administered a 14-question survey to a convenience sample of 25 Massachusetts paramedics attending a regional course in 2018. Volunteer participants were offered a gift card. We compared respondents to a state database for sample representativeness. We present descriptive statistics and summarize qualitative responses. RESULTS: Twenty-five paramedics completed the survey (100% response); 23 (96%) were male, 21 (84%) 40 years or older, and 23 (92%) in urban practice. Respondents were older and more experienced than the average Massachusetts paramedic. Few had used prehospital telemedicine for patients younger than 12 years (8%; 95% confidence interval, 10-26%). Potential benefits included paramedic training (80%), real-time critical care support (68%), risk mitigation (68%), patient documentation (72%), decision support for hospital team activation (68%), and scene visualization (76%). Time delays from telemedicine equipment use (76%) and physician consultation (64%), broadband reliability (52%), and cost (56%) were potential risks. Respondents preferred video strategies for scene visualization, physician-assisted assessment and care. More respondents felt pediatric telemedicine applications would benefit rural/suburban settings than urban ones. CONCLUSIONS: Paramedics reported prehospital telemedicine is underutilized for children but identified potential benefits including provider telesupport, training, situational awareness, and documentation. Concerns included transportation delays, cost, and broadband availability. Video was preferred for limited pediatric exposure settings. These results inform which telemedicine applications and strategies paramedics favor for children.

Disparities in Emergency Department Visits Among Collocated Racial/Ethnic Medicare Enrollees.

STUDY OBJECTIVE: We estimate emergency department (ED) use differences across Medicare enrollees of different race/ethnicity who are residing in the same zip codes. METHODS: In this retrospective cohort study, we stratified all Medicare fee-for-service beneficiaries aged 66 years and older (2006 to 2012) by residence zip code and identified zip codes with racial/ethnic diversity, defined as containing at least 1 enrollee from each of 3 racial/ethnic groups: Hispanics, (non-Hispanic) blacks, and (non-Hispanic) whites. Our primary study population consisted of a stratified random sample of approximately equal number of each racial/ethnic group from each zip code with racial/ethnic diversity (N=1,563,631). We identified ED visits, comorbidities, primary-care-treatable status, and patient disposition. We characterized socioeconomic status by zip code poverty rate. The main outcome measure was the ratio of ED visit rate (number of visits/100 person-years) between each minority group and whites. RESULTS: Of 38,423 zip codes nationally, 41% met the racial/ethnic diversity criterion; these zip codes contained 85% of the Medicare fee-for-service beneficiaries. Among enrollees from zip codes with racial/ethnic diversity, the ED visit rate among whites was 45.4 (95% confidence interval 45.1 to 45.6), and the ED visit rate ratio was 1.34 (95% confidence interval 1.33 to 1.36) among blacks and 1.23 (95% confidence interval 1.22 to 1.24) among Hispanics. ED visit rate ratios for both minority groups were greater than 1.00 among all subgroups by age, comorbidity, zip code poverty rate, urban/rural area, and primary-care-treatable and disposition status. CONCLUSION: Among Medicare enrollees, blacks and Hispanics had higher ED use rates than whites overall and among subgroups by demographics and socioeconomic status.

Geographic Variation in Use of Ambulance Transport to the Emergency Department.

STUDY OBJECTIVE: Evidence on variability in emergency medical services use is limited. We obtain national evidence on geographic variation in the use of ambulance transport to the emergency department (ED) among Medicare enrollees and assess the role of health status, socioeconomic status, and provider availability. METHODS: We used 2010 Medicare claims data for a random sample of 999,999 enrollees aged 66 years and older, and identified ambulance transport and ED use. The main outcome measures were number of ambulance transports to the ED per 100 person-years (ambulance transport rate) and proportion (percentage) of ED visits by ambulance transport by hospital referral regions. RESULTS: The national ambulance transport rate was 22.2 and the overall proportion of ED visits by ambulance was 36.7%. Relative to hospital referral regions in the lowest rate quartile, those in the highest quartile had a 75% higher ambulance transport rate (incidence rate ratio [IRR] 1.75; 95% confidence interval [CI] 1.69 to 1.81) and a 15.5% higher proportion of ED visits by ambulance (IRR 1.155; 95% CI 1.146 to 1.164). Adjusting for health status, socioeconomic status, and provider availability reduced quartile 1 versus quartile 4 difference in ambulance transport rate by 43% (IRR 1.43; 95% CI 1.38 to 1.48) and proportion of ED visits by ambulance by 7% (IRR 1.145; 95% CI 1.135 to 1.155). Among the 3 covariate domains, health status was associated with the largest variability in ambulance transport rate (30.1%), followed by socioeconomic status (12.8%) and provider availability (2.9%). CONCLUSION: Geographic variability in ambulance use is large and associated with variation in patient health status and socioeconomic status.

Use of Intranasal Naloxone by Basic Life Support Providers.

STUDY OBJECTIVES: Intranasal delivery of naloxone to reverse the effects of opioid overdose by Advanced Life Support (ALS) providers has been studied in several prehospital settings. In 2006, in response to the increase in opioid-related overdoses, a special waiver from the state allowed administration of intranasal naloxone by Basic Life Support (BLS) providers in our city. This study aimed to determine: 1) if patients who received a 2-mg dose of nasal naloxone administered by BLS required repeat dosing while in the emergency department (ED), and 2) the disposition of these patients. METHODS: This was a retrospective review of patients transported by an inner-city municipal ambulance service to one of three academic medical centers. We included patients aged 18 and older that were transported by ambulance between 1/1/2006 and 12/12/2012 and who received intranasal naloxone by BLS providers as per a state approved protocol. Site investigators matched EMS run data to patients from each hospital's EMR and performed a chart review to confirm that the patient was correctly identified and to record the outcomes of interest. Descriptive statistics were then generated. RESULTS: A total of 793 patients received nasal naloxone by BLS and were transported to three hospitals. ALS intervened and transported 116 (14.6%) patients, and 11 (1.4%) were intubated in the field. There were 724 (91.3%) patients successfully matched to an ED chart. Hospital A received 336 (46.4%) patients, Hospital B received 210 (29.0%) patients, and Hospital C received 178 (24.6%) patients. Mean age was 36.2 (SD 10.5) years and 522 (72.1%) were male; 702 (97.1%) were reported to have abused heroin while 21 (2.9%) used other opioids. Nasal naloxone had an effect per the prehospital record in 689 (95.2%) patients. An additional naloxone dose was given in the ED to 64 (8.8%) patients. ED dispositions were: 507 (70.0%) discharged, 105 (14.5%) admitted, and 112 (15.5%) other (e.g., left against medical advice, left without being seen, or transferred). CONCLUSIONS: Only a small percentage of patients receiving prehospital administration of nasal naloxone by BLS providers required additional doses of naloxone in the ED and the majority of patients were discharged.

Emergency medical services response to active shooter incidents: provider comfort level and attitudes before and after participation in a focused response training program.

INTRODUCTION: Emergency Medical Services (EMS) routinely stage in a secure area in response to active shooter incidents until the scene is declared safe by law enforcement. Due to the time-sensitive nature of injuries at these incidents, some EMS systems have adopted response tactics utilizing law enforcement protection to expedite life-saving medical care. OBJECTIVE: Describe EMS provider perceptions of preparedness, adequacy of training, and general attitudes toward active shooter incident response after completing a tactical awareness training program. METHODS: An unmatched, anonymous, closed-format survey utilizing a five-point Likert scale was distributed to participating EMS providers before and after a focused training session on joint EMS/police active shooter rescue team response. Descriptive statistics were used to compare survey results. Secondary analysis of responses based on prior military or tactical medicine training was performed using a chi-squared analysis. RESULTS: Two hundred fifty-six providers participated with 88% (225/256) pretraining and 88% (224/256) post-training surveys completed. Post-training, provider agreement that they felt adequately prepared to respond to an active shooter incident changed from 41% (92/225) to 89% (199/224), while agreement they felt adequately trained to provide medical care during an active shooter incident changed from 36% (82/225) to 87% (194/224). Post-training provider agreement that they should never enter a building with an active shooter changed from 73% (165/225) to 61% (137/224). Among the pretraining surveys, significantly more providers without prior military or tactical experience agreed they should never enter a building with an active shooter until the scene was declared safe (78% vs 50%, P = .002), while significantly more providers with prior experience felt both adequately trained to provide medical care in an active shooter environment (56% vs 31%, P = .007) and comfortable working jointly with law enforcement within a building if a shooter were still inside (76% vs 56%, P = .014). There was no difference in response to these questions in the post-training survey. CONCLUSIONS: Attitudes and perceptions regarding EMS active shooter incident response appear to change among providers after participation in a focused active shooter response training program. Further studies are needed to determine if these changes are significant and whether early EMS response during an active shooter incident improves patient outcomes.

Psychological Assessment and Intervention at the Boston Marathon.

The Boston Marathon is a highly regarded event in the running world, not just for its prestige and challenging course, but also for its implementation of a psychology team to support runners. The 2013 Boston Marathon bombings underscored the essential role that mental health support plays at this event, prompting the development and expansion of its innovative care model. This review critically outlines, evaluates, and analyzes the approach and effectiveness of the psychological care model provided to runners on race day as part of the Boston Marathon medical team, including the standard of care, how it functions, and best practices for other marathons. The implications for this review contribute to the increasing trend of providing psychological care in marathon and other athletic settings, and to provide a framework for standardizing assessment and intervention procedures for both elite and novice runners.

The effect of an ambulance diversion ban on emergency department length of stay and ambulance turnaround time.

STUDY OBJECTIVE: Massachusetts became the first state in the nation to ban ambulance diversion in 2009. It was feared that the diversion ban would lead to increased emergency department (ED) crowding and ambulance turnaround time. We seek to characterize the effect of a statewide ambulance diversion ban on ED length of stay and ambulance turnaround time at Boston-area EDs. METHODS: We conducted a retrospective, pre-post observational analysis of 9 Boston-area hospital EDs before and after the ban. We used ED length of stay as a proxy for ED crowding. We compared hospitals individually and in aggregate to determine any changes in ED length of stay for admitted and discharged patients, ED volume, and turnaround time. RESULTS: No ED experienced an increase in ED length of stay for admitted or discharged patients or ambulance turnaround time despite an increase in volume for several EDs. There was an overall 3.6% increase in ED volume in our sample, a 10.4-minute decrease in length of stay for admitted patients, and a 2.2-minute decrease in turnaround time. When we compared high- and low-diverting EDs separately, neither saw an increase in length of stay, and both saw a decrease in turnaround time. CONCLUSION: After the first statewide ambulance diversion ban, there was no increase in ED length of stay or ambulance turnaround time at 9 Boston-area EDs. Several hospitals actually experienced improvements in these outcome measures. Our results suggest that the ban did not worsen ED crowding or ambulance availability at Boston-area hospitals.

The impact of heat waves on transport volumes in an urban emergency medical services system: a retrospective review.

INTRODUCTION: Heat waves pose a serious public health risk to particular patient populations, especially in urban areas. Emergency Medical Services (EMS) in many urban areas constitute the first line of regional preparation and response to major heat wave events; however, little is known on heat wave operational impact to the EMS system, such as call volume or demand. OBJECTIVE: To examine the effect of heat wave periods on overall urban EMS system call volume and transport volume as well as the nature of the call types. METHODS: Retrospective review of all emergency medical calls to an urban, two-tiered EMS system performed over a 5-year period from 2006-2010. Heat wave days (HWD) defined as two or more consecutive days of hot weather >32.2°C (90°F) were compared with similar non-heat wave days (nHWD) of the previous year to also include two calendar days prior to and after the heat wave. National Weather Service (NWS) temperature data, daily EMS call volume data, and call type codes were collected and underwent descriptive analysis. RESULTS: Thirty-one HWD were identified and compared with 93 nHWD. The mean maximum temperature for HWD was 34°C (93.2°F) compared with 25.3°C (77.6°F) for nHWD (P < .001). Average daily medical emergency calls (318.4 vs 296.3, P < .001) and actual patients transported per day (247.5 vs 198.3, P < .001) were significantly higher during HWD. There was no difference in daily medical emergency call volume or EMS transports between weekdays or weekend days. No significant differences on various call types were observed between HWD and nHWD except for "heat" related calls (7.7 vs 0.5, P < .001). CONCLUSION: Emergency Medical Services call volumes were significantly increased during heat waves, however there was minimal change in the types of calls received.

A descriptive analysis of occupational health exposures in an urban emergency medical services system: 2007-2009.

INTRODUCTION: Prehospital providers are exposed to various infectious disease hazards. Examining specific infectious exposures would be useful in describing their current trends as well as guidance with appropriate protective measures an emergency medical services (EMS) system should consider. OBJECTIVE: To describe the types of infectious occupational health exposures and associated outcomes reported at an urban EMS system. METHODS: A retrospective review of all reported exposures was performed for a three-year period from January 1, 2007, to December 31, 2009. Descriptive analysis was performed on data such as provider demographics, types of exposures reported, confirmation of exposure based on patient follow-up information, and outcomes. RESULTS: Three hundred ninety-seven exposure reports were filed with the designated infection control officer (ICO), resulting in an overall exposure rate of 1.2 per 1,000 EMS incidents. The most common exposure was to possible meningitis (n = 131, 32.9%), followed by tuberculosis (TB) (n = 68, 17.1%), viral respiratory infections (VRIs) such as influenza or H1N1 (n = 61, 15.4%), and body fluid splashes to skin or mucous membranes (n = 56, 14.1%). Body fluid splashes involving the eyes accounted for 41 cases (10.3%). Only six cases (1.5%) of needlestick injuries were reported. Three hundred thirty-two of all cases (83.6%) were considered true exposures to an infectious hazard, of which 177 (53.3%) were actually confirmed. Half of all exposures required only follow-up with the ICO (52.6%). One hundred twenty-seven cases (31.9%) required follow-up at a designated occupational health services or emergency department. Of these, only 23 cases (18.1%) required treatment. There was a significant trend of increasing incidence of VRI exposures from 2008 to 2009 (6.3% vs. 26.8%, p < 0.001), while a significant decrease in TB exposures was experienced during the same year (22.9% vs. 8.2%, p = 0.002). CONCLUSIONS: Trends in our data suggest increasing exposures to viral respiratory illnesses, whereas exposures to needlestick injuries were relatively infrequent. Efforts should continue to focus on proper respiratory protection to include eye protection in order to mitigate these exposure risks.

Exertional Heat Stroke at the Boston Marathon: Demographics and the Environment.

PURPOSE: This study aimed to assess associations between exertional heat stroke (EHS) and sex, age, prior performance, and environmental conditions, and report on resources needed for EHS cases at the Boston Marathon. METHODS: We analyzed participant characteristics, environmental data, and EHS medical encounters during the 2015-2019 Boston Marathon races. RESULTS: Among 136,161 starters, there was an incidence of 3.7 EHS cases per 10,000 starters (95% confidence interval, 2.8-4.9), representing 0.5% of all medical encounters. There were significant associations between sex and age (P < 0.0001), sex and start wave (P < 0.0001), and age group and start wave (P < 0.0001). Sex was not significantly associated with increased EHS incidence; however, age younger than 30 yr and assignment to the first two start waves were. All cases occurred at races with average wet bulb globe temperatures of 17°C-20°C. There was a linear correlation between EHS incidence and greater increases in wet bulb globe temperature from start to peak (R2 = 0.7688). A majority of cases (37; 72.5%) were race finishers; nonfinishers all presented after mile 18. Most were triaged 3-4 h after starting, and all were treated with ice water immersion. Treatment times were prolonged (mean (SD), 78.1 (47.5) min; range, 15-190 min); 29.4% (15 cases) developed posttreatment hypothermia, and 35.3% (18 cases) were given intravenous fluids. Most (31 cases; 64.6%) were discharged directly, although 16 cases (33.3%) required hospital transport. There were no fatalities. CONCLUSIONS: Younger and faster runners are at higher risk for EHS at the Boston Marathon. Greater increases in heat stress from start to peak during a marathon may exacerbate risk. EHS encounters comprise a small percentage of race-day medical encounters but require extensive resources and warrant risk mitigation efforts.

Special considerations in hazardous materials burns.

Those practicing Emergency Medicine are frequently faced with a patient presenting with a chemical burn. Most dermal chemical burns are minor and do not require specialized treatment. Occasionally, however, the clinician may be in the position of responding to a chemical burn in which standard therapy of irrigation and good wound care may not be sufficient or, at worst, contraindicated. Several burn conditions will be reviewed, some of those requiring only specific decontamination techniques, as in hot tar, others posing special hazards to clinicians, as in elemental metals, and finally, examples are given of hazardous materials requiring attention to systemic effects, as in hydrofluoric acid.

Self-reported provider safety in an urban emergency medical system.

INTRODUCTION: Emergency Medical Service (EMS) personnel often respond to dangerous scenes and encounter hostile individuals without police support. No recent data describes the frequency of physical or verbal assaults or which providers have increased fear for their safety. This information may help to guide interventions to improve safety. Our objective was to describe self-reported abuse and perceptions of safety and to determine if there are differences between gender, shift, and years of experience in a busy two-tiered, third service urban EMS system. METHODS: This was a secondary analysis of an anonymous, cross-sectional work safety survey of EMS providers. This survey included demographics, years of experience, history of verbal and physical assault, safety behavior following an assault and perceptions of safety. Descriptive statistics were generated. RESULTS: Eighty-nine percent (196/221) of EMS providers completed the survey. Most were male (72%) and between the ages of 25 and 50 years (66%). The majority of providers had worked in this service for more than five years (54%), and many for more than ten years (37%). Verbal assaults were reported by 88% (172/196, 95% CI [82.4%-91.6%]). Although 80% (156/196, 95% CI [73.4%-84.6%]) reported physical assaults, only 40% (62/156, 95% CI [32.4%-47.6%]) sought medical care and 49% (76/156, 95% CI [41%-56.6%]) reported the assault to police. The proportion of those who sought medical care and reported the assault to the police was not the same across years of experience (p<0.0001). Fear for personal safety was reported by 68% (134/196, 95% CI [61.6%-74.5%]). There was no statistical difference in assault by gender; however, females feared more for their safety compared to men (38/50, 76% v 96/142, 68%, p=0.02). The proportion of those who have ever been physically assaulted was not the same across shift worked (p=0.01). CONCLUSION: The majority of EMS providers surveyed reported an assault and certain groups had a higher rate of assault. Most assaults were not reported to the police and medical care was infrequently sought following an event. The majority of providers reported feeling fear for their personal safety. Further research into enhancing safety mechanisms is needed.

Myocardial adaptations to recreational marathon training among middle-aged men.

BACKGROUND: Myocardial adaptations to exercise have been well documented among competitive athletes. To what degree cardiac remodeling occurs among recreational exercisers is unknown. We sought to evaluate the effect of recreational marathon training on myocardial structure and function comprehensively. METHODS AND RESULTS: Male runners (n=45; age, 48±7 years; 64% with ≥1 cardiovascular risk factor) participated in a structured marathon-training program. Echocardiography, cardiopulmonary exercise testing, and laboratory evaluation were performed pre and post training to quantify changes in myocardial structure and function, cardiorespiratory fitness, and traditional cardiac risk parameters. Completion of an 18-week running program (25±9 miles/wk) led to increased cardiorespiratory fitness (peak oxygen consumption, 44.6±5.2 versus 46.3±5.4 mL/kg per minute; P<0.001). In this setting, there was a significant structural cardiac remodeling characterized by dilation of the left ventricle (end-diastolic volume, 156±26 versus 172±28 mL, P<0.001), right ventricle (end-diastolic area=27.0±4.8 versus 28.6±4.3 cm(2); P=0.02), and left atrium (end-diastolic volume, 65±19 versus 72±19; P=0.02). Functional adaptations included increases in both early (E'=12.4±2.5 versus 13.2±2.0 cm/s; P=0.007) and late (A'=11.5±1.9 versus 12.2±2.1 cm/s; P=0.02) left ventricular diastolic velocities. Myocardial remodeling was accompanied by beneficial changes in cardiovascular risk factors, including body mass index (27.0±2.7 versus 26.7±2.6 kg/m(2); P<0.001), total cholesterol (199±33 versus 192±29 mg/dL; P=0.01), low-density lipoprotein (120±29 versus 114±26 mg/dL; P=0.01), and triglycerides (100±52 versus 85±36 mg/dL; P=0.02). CONCLUSIONS: Among middle-aged men, recreational marathon training is associated with biventricular dilation, enhanced left ventricular diastolic function, and favorable changes in nonmyocardial determinants of cardiovascular risk. Recreational marathon training may, therefore, serve as an effective strategy for decreasing incident cardiovascular disease.

A composite model of survival from out-of-hospital cardiac arrest using the Cardiac Arrest Registry to Enhance Survival (CARES).

OBJECTIVE: Using CARES data, to develop a composite multivariate logistic regression model of survival for projecting survival rates for out-of-hospital arrests of presumed cardiac etiology (OHCA). METHODS: This is an analysis of 25,975 OHCA cases (from October 1, 2005 to December 31, 2011) occurring before EMS/first responder arrival and involving attempted resuscitation by responders from 125 EMS agencies. RESULTS: The survival-at-hospital discharge rate was 9% for all cases, 16% for bystander-witnessed cases, 4% for unwitnessed cases, and 32% for bystander-witnessed pVT/VF cases. The model was estimated separately for each set of cases above. Generally, our first equation showed that joint presence of a presenting rhythm of pVT/VF and return of spontaneous circulation in the pre-hospital setting (PREHOSPROSC) is a substantial direct predictor of patient survival (e.g., 55% of such cases survived). Bystander AED use, and, for witnessed cases, bystander CPR and response time are significant but less sizable direct predictors of survival. Our second equation shows that these variables make an additional, indirect contribution to survival by affecting the probability of joint presence of pVT/VF and PREHOSPROSC. The model yields survival rate projections for various improvement scenarios; for example, if all cases had involved bystander AED use (vs. 4% currently), the survival rate would have increased to 14%. Approximately one-half of projected increases come from indirect effects that would have been missed by the conventional single-equation approach. CONCLUSION: The composite model describes major connections among predictors of survival, and yields specific projections for consideration when allocating scarce resources to impact OHCA survival.

A model of survival from out-of-hospital cardiac arrest using the Boston EMS arrest registry.

OBJECTIVES: To characterize the survival rate for out-of-hospital arrests of cardiac aetiology and predictor variables associated with survival in Boston, MA, and to develop a composite multivariate logistic regression model for projecting survival rates. METHODS: This is a retrospective analysis of all arrests of presumed cardiac aetiology (from January 1, 2004 to December 31, 2007) where resuscitation was attempted (n=1156) by 911 emergency responders. RESULTS: The survival-at-hospital discharge rate was 11% (vs. 1-10% often reported). The coefficients and odds ratios in the first equation of the model show that joint presence of presenting rhythm of ventricular fibrillation/tachycardia (VF/VT) and return of spontaneous circulation in the pre-hospital setting (ROSC) is a substantial direct predictor of survival (e.g., 54% of such cases survive). Response time, public location, witnessed, and age are significant but less sizable direct predictors of survival. A second equation shows that these four variables make an additional indirect contribution to survival by affecting the probability of joint presence of VF/VT and ROSC; bystander CPR also makes such an indirect contribution but no significant direct one as shown in the first equation. The projected survival rate if cases had always experienced bystander CPR and rapid response time of less than four minutes is 21%. CONCLUSIONS: The unique model describes the major contribution of VF/VT and ROSC, and key relationships among predictors of survival. These connections may have otherwise gone underreported using standard approaches and should be considered when allocating scarce resources to impact cardiac arrest survival.