K. Sophia Dyer

Be Prepared — The Boston Marathon and Mass-Casualty Events

The fact that there was not more loss of life in the Boston Marathon bombings is attributable in large part to the medical communitys prior efforts to build and sustain emergency-preparedness programs and to practice its response in exercises and drills.

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 cm2; 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/m2; 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.

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.

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.

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.

A Descriptive Analysis of Occupational Health Exposures in an Urban Emergency Medical Services System: 2007–2009

Abstract 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.

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.

A LABORATORYCOMPARISON OFEMERGENCYPERCUTANEOUS ANDSURGICALCRICOTHYROTOMY BYPREHOSPITALPERSONNEL

Objective. To compare the speeds and success rates of placement for percutaneous cricothyrotomy versus surgical or open cricothyrotomy. Methods. Twenty-two paramedics (mean 9.7 years of experience), with training in both methods, were timed using a pig trachea in a crossover model. An emergency physician performed timing and documentation of success; timing commenced after the equipment was ready and the membrane was identified. Paramedics were randomly assigned by a coin toss to start in either group. All were actively employed by a municipal third-service emergency medical services (EMS) agency. Paramedics who did not complete one of the methods correctly were excluded from speed analysis. Data were analyzed using descriptive statistics, a t-test of paired samples, and confidence intervals for matched samples. Results. Placement of a surgical cricothyrotomy was significantly faster (mean 28 seconds, range 10-78 seconds) than the percutaneous method (mean 123 seconds, range 58-257 seconds) (p < 0.001). Mean difference between the 20 matched percutaneous versus surgical pairs was 93.75 seconds (95% CI 72.3, 115.2). The surgical route had a 100% success rate at obtaining airway control, whereas the percutaneous method had a 90.9% success rate (p = 0.1). Conclusion. In an animal model, surgical cricothyrotomy appeared to be a preferable method for establishing a definitive airway over the percutaneous method. Further research is required to define the optimal approach in the prehospital setting for the invasive airway.

Use of Intranasal Naloxone by Basic Life Support Providers

Abstract 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 hospitals 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.