Urban Emergency Medical Services Research Articles

Waveform Analysis–Guided Treatment Versus a Standard Shock-First Protocol for the Treatment of Out-of-Hospital Cardiac Arrest Presenting in Ventricular Fibrillation

Background— Ventricular fibrillation (VF) waveform properties have been shown to predict defibrillation success and outcomes among patients treated with immediate defibrillation. We postulated that a waveform analysis algorithm could be used to identify VF unlikely to respond to immediate defibrillation, allowing selective initial treatment with cardiopulmonary resuscitation in an effort to improve overall survival. Methods and Results— In a multicenter, double-blind, randomized study, out-of-hospital cardiac arrest patients in 2 urban emergency medical services systems were treated with automated external defibrillators using either a VF waveform analysis algorithm or the standard shock-first protocol. The VF waveform analysis used a predefined threshold value below which return of spontaneous circulation (ROSC) was unlikely with immediate defibrillation, allowing selective treatment with a 2-minute interval of cardiopulmonary resuscitation before initial defibrillation. The primary end point was survival to hospital discharge. Secondary end points included ROSC, sustained ROSC, and survival to hospital admission. Of 6738 patients enrolled, 987 patients with VF of primary cardiac origin were included in the primary analysis. No immediate or long-term survival benefit was noted for either treatment algorithm (ROSC, 42.5% versus 41.2%, P =0.70; sustained ROSC, 32.4% versus 33.4%, P =0.79; survival to admission, 34.1% versus 36.4%, P =0.46; survival to hospital discharge, 15.6% versus 17.2%, P =0.55, respectively). Conclusions— Use of a waveform analysis algorithm to guide the initial treatment of out-of-hospital cardiac arrest patients presenting in VF did not improve overall survival compared with a standard shock-first protocol. Further study is recommended to examine the role of waveform analysis for the guided management of VF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00535106.

Validation of the Los Angeles Pre-Hospital Stroke Screen (LAPSS) in a Chinese Urban Emergency Medical Service Population

Background and purposeEarly and accurate diagnosis of stroke by emergency medical service (EMS) paramedics is critical for reducing pre-hospital delays. The Los Angeles pre-hospital stroke screen (LAPSS) has been widely used as a validated screening tool for early identifying stroke patients by EMS paramedics. However, validation of LAPSS has never been performed in Chinese stroke population. This study is aimed to verify the LAPSS for early identifying stroke patients in a Chinese urban EMS.Methods76 paramedics of five urban first aid stations attached to Beijing 120 EMS were involved. The paramedics were trained by professionals to quickly screen patients based on LAPSS. Potential “target stroke” individuals who met the base LAPSS screen criteria were identified. Sensitivity and specificity analyses of the LAPSS were calculated.ResultsFrom June 10, 2009 to June 10, 2010, paramedics transported a total of 50,220 patients. 1550 patients who met the baseline screen criteria were identified as the potential “target stroke” population. 1130 patients had the completed LAPSS information datasheet and 997 patients were clinically diagnosed with stroke. The average time of completing the LAPSS was 4.3±3.0 minutes (median, 5 minutes). The sensitivity and specificity of the LAPSS in this study was 78.44% and 90.22%, respectively. After adjusting for age factor by excluding patients of >45 years old, the sensitivity was significantly increased to 82.95% with specificity unchanged.ConclusionThe paramedics of Beijing 120 EMS could efficiently use LAPSS as a screening tool for early identifying stroke patients. While the sensitivity of LAPSS in Chinese urban patient population was lower than those reported in previous LAPSS validation studies, the specificity was consistent with these studies. After excluded the item of “Age>45 years”, the sensitivity was improved.

Assessment of the Addition of Prehospital Continuous Positive Airway Pressure (CPAP) to an Urban Emergency Medical Services (EMS) System in Persons with Severe Respiratory Distress

BackgroundThe use of continuous positive airway pressure (CPAP)-assisted ventilation in the prehospital setting has not been well studied. ObjectivesThe purpose of this study was to measure the efficacy of adding prehospital CPAP to an urban emergency medical services (EMS) respiratory distress protocol for persons with respiratory distress. MethodsAn historical cohort analysis of consecutive EMS patients presenting during the years 2005–2010. Groups were matched for severity of respiratory distress. Physiologic variables were the primary outcomes obtained from first responders and upon triage in the Emergency Department. Additional outcomes included endotracheal intubation rate, hospital mortality, overall hospital length of stay (LOS), intensive care unit (ICU) admission, and ICU LOS. ResultsThere were a total of 410 consecutive patients with predetermined criteria for severe respiratory distress, 235 historical controls matched with 175 post-implementation patients, entered in the study. The average age was 67 years; 54% were men. There were significant median differences in heart and respiratory rates favoring the historical cohort (all p < 0.05). There were no significant differences in intubation rate, overall hospital LOS, ICU admission rate, ICU LOS, or hospital mortality (all p > 0.05). Patients who were continued on non-invasive ventilatory assistance had a significantly improved rate of intubation and ICU LOS (all p < 0.05). ConclusionThe addition of CPAP to an EMS prehospital respiratory distress protocol resulted in improved heart and respiratory rates. Though not statistically significant, decrease in overall and ICU LOS were observed. Patients with continued ventilatory assistance seemed to have improved rates of intubation and ICU LOS.

Effect of Time of Day on Prehospital Care and Outcomes After Out-of-Hospital Cardiac Arrest

More than 300 000 out-of-hospital cardiac arrests (OHCA) occur each year in the United States. The relationship between time of day and OHCA outcomes in the prehospital setting is unknown. Any such association may have important implications for emergency medical services resource allocation. We performed a retrospective review of cardiac arrest data from a large, urban emergency medical services system. Included were OHCA occurring in adults from January 2008 to February 2012. Excluded were traumatic arrests and cases in which resuscitation measures were not performed. Day was defined as 8 am to 7:59 pm; night, as 8 pm to 7:59 am. A relative risk regression model was used to evaluate the association between time of day and prehospital return of spontaneous circulation and 30-day survival, with adjustment for clinically relevant predictors of survival. Among the 4789 included cases, 1962 (41.0%) occurred at night. Mean age was 63.8 years (SD, 17.4 years); 54.5% were male. Patients with an OHCA occurring at night did not have significantly lower rates of prehospital return of spontaneous circulation compared with patients having daytime arrests (11.6% versus 12.8%; P=0.20). However, rates of 30-day survival were significantly lower at night (8.56% versus 10.9%; P=0.02). After adjustment for demographics, presenting rhythm, field termination, duration of call, dispatch-to-scene interval, automated external defibrillator application, bystander cardiopulmonary resuscitation, and location, 30-day survival remained significantly higher after daytime OHCA, with a relative risk of 1.10 (95% confidence interval, 1.02-1.18). Rates of 30-day survival were significantly higher for OHCA occurring during the day compared with at night, even after adjustment for patient, event, and prehospital care differences.

Assessing the Validity of the Cincinnati Prehospital Stroke Scale and the Medic Prehospital Assessment for Code Stroke in an Urban Emergency Medical Services Agency

Objectives. The primary objective of this study was to assess the effectiveness of two prehospital stroke screens in correctly classifying patients suspected of having a stroke. Secondarily, differences in the sensitivity and specificity of the two screening tools were assessed. Methods. We performed a retrospective assessment of the Cincinnati Prehospital Stroke Scale (CPSS) and the Medic Prehospital Assessment for Code Stroke (Med PACS) between March 1, 2011, and September 30, 2011, in a single emergency medical services (EMS) agency with seven local hospitals all classified as stroke-capable. We obtained data for this analysis from the EMS electronic patient care reports (ePCRs) and the Get With The Guidelines−Stroke (GWTG-S) registries maintained by the two local health care systems by matching on patient identifiers. The Med PACS was developed specifically for the EMS agency under study by a local team of neurologists, emergency physicians, and paramedics. All of the physical assessment elements of the CPSS were included within the Med PACS. Two additional physical assessment items, gaze and leg motor function, were included in the Med PACS. We classified patients as CPSS-positive or -negative and Med PACS-positive or -negative if any one of the physical assessment findings was present. We determined the presence of a hospital discharge diagnosis of stroke from GWTG-S. We calculated sensitivity and specificity with resultant 95% confidence intervals. Results. We enrolled 416 patients in this study, of whom 186 (44.7%) were diagnosed with a stroke. The Med PACS scale demonstrated a sensitivity of 0.742 (95% confidence interval [CI] 0.672–0.802), while the sensitivity for the CPSS was 0.790 (95% CI 0.723–0.845). The sensitivity of the CPSS was significantly higher than that of the Med PACS, with a difference of 0.048 (95% CI 0.009–0.088; p = 0.011). The specificities of these two scales were low, Med PACS 0.326 (95% CI 0.267–0.391) vs. CPSS 0.239 (95% CI 0.187–0.300), and the specificity of the Med PACS was significantly higher compared with the CPSS, with a difference in specificity of 0.086 (95% CI 0.042–0.131), p < 0.001. Conclusion. The two stroke scales under study demonstrated low sensitivity and specificity, with each scale performing marginally better in one of the two metrics assessed. Key words: emergency medical services; acute stroke; prehospital stroke screens; stroke scales; screening tools; CPSS; Med PACS

Racial Differences in Receiving Morphine among Prehospital Patients with Blunt Trauma

BackgroundPain management is an important part of prehospital care, yet few studies have addressed the effects of age, sex, race, or pain severity on prehospital pain management. ObjectivesTo examine the association of sex, age, race, and pain severity with analgesia administration for blunt trauma in the prehospital setting. MethodsIn this retrospective cohort study, we used the automated registry of a large urban Emergency Medical Services agency to identify records of all patients transported for blunt trauma injuries between February 1 and November 1, 2009. We used bivariable and multivariable analyses with logistic regression models to determine the relationship between analgesia administration and patient sex, race, age, pain score on a pain scale, and time under prehospital care. ResultsWe identified 6398 blunt trauma cases. There were 516 patients (8%) who received analgesia overall; among patients for whom a pain scale was recorded, 25% received analgesia. By multivariable analysis, adjusting for race, sex, age, time with patient, and pain score, African-American and Hispanic patients were less likely than Caucasian patients to receive analgesia. Pain score and prehospital time were both significant predictors of analgesia administration, with higher pain score and longer prehospital time associated with increased administration of pain medication. Neither sex nor age was a significant predictor of analgesia administration in the regression analysis. ConclusionThis study suggests that Caucasians are more likely than African-Americans or Hispanics to receive prehospital analgesia for blunt trauma injuries. In addition, patients with whom paramedics spend more time and for whom a pain score is recorded are more likely to receive analgesia.

Exposure to Carbon Monoxide for Patients and Providers in an Urban Emergency Medical Service

Background. Carbon monoxide (CO) poisoning poses danger to both patients and emergency medical services (EMS) personnel, as its symptoms are nonspecific and EMS is currently not equipped to detect CO in ambient air. Objective. We aimed to assess the degree of non–fire-related CO exposure at the high-volume EMS system of a city with 2 million inhabitants. Methods. The EMS system was equipped with handheld CO detectors (Dräger Pac 3500), which were added to EMS standard backpacks and had to be carried to the patient at all times. During a period of one year, all alarms by those devices were recorded, sources of CO were confirmed by the fire department, and hospital follow-up was conducted for both patients and exposed EMS staff. Results. During the study period, there were 40 alarms, including two false alarms. Alarms occurred during the whole year, with a peak during the winter months. The median ambient CO concentration was 167 parts per million; gas heating systems were the main source of CO. One hundred ten patients and 108 EMS personnel were exposed. One hundred fifteen persons, including 22 EMS staff, had to be hospitalized, which represents one out of 1,000 total EMS patients. Conclusions. Carbon monoxide poisoning was found to be a significant matter for a high-volume EMS system. Handheld CO detectors helped in identifying those cases. Key words: carbon monoxide; emergency care, prehospital; equipment and supplies; poisoning

Clinical Events and Treatment in Prehospital Patients with ST-segment Elevation Myocardial Infarction

Background. Little is known about clinically important events and advanced care treatment that patients with ST-segment elevation myocardial infarction (STEMI) encounter in the prehospital setting. Objectives. We sought to determine the proportion of community patients with STEMI who experienced a clinically important event or received advanced care treatment prior to arrival at a designated percutaneous coronary intervention (PCI) laboratory or emergency department (ED). Methods. We reviewed 487 consecutive community patients with STEMI between May 2008 and June 2009. All patients were geographically within a single large “third-service” urban emergency medical services (EMS) system and were transported by paramedics with an advanced care scope of practice. We recorded predefined clinically important events and advanced care treatment that occurred in patients being transported directly to a PCI laboratory or ED (group 1) or interfacility transfer to a PCI laboratory (group 2). Results. One or more clinically important events occurred in 92 of 342 (26.9%) group 1 patients and nine of 145 (6.2%) group 2 patients. The most common were sinus bradycardia, hypotension, and cardiac arrest. Additionally, 33 of 342 (9.6%) group 1 and nine of 145 (6.2%) group 2 patients received one or more advanced care treatments. The most common were administration of morphine and administration of atropine. Eight group 1 patients and three group 2 patients received cardiopulmonary resuscitation (CPR) or defibrillation. Conclusions. Clinically important events and advanced care treatment are common in community STEMI patients undergoing prehospital transport or interfacility transfer to a PCI center. Several patients required CPR or defibrillation. Further research is needed to define the clinical experience of STEMI patients during the out-of-hospital phase and the scope of practice required of EMS providers to safely manage these patients. Key words: myocardial infarction; complications; emergency medical services; emergency treatment

Abstract 208: Innovative Web-Based e-Registry Enhances Survival After Out-of-Hospital Cardiac Arrest

Introduction: Patient and prehospital predictors of survival after OHCA include ventricular fibrillation, witnessed arrest, and receiving bystander cardiopulmonary resuscitation. Whether systems-based approaches on Emergency Medical Service (EMS) such as new registry or reform could improve survival have not been well studied. Hypothesis: An innovative web-based e-registry may enhance survival after OHCA. Methods: An urban EMS with 2.62 million residents in 272 squared km was studied. Traditionally the EMS operated an OHCA Registry by manual-traced paper archives that coordinated data collections across dispatch center, ambulance teams and receiving hospitals. After a 2-year redesign, a computerized Web e-Registry in 2010 was established. The ambulance team initiated an individual patient data block right after an OHCA event, and that data block was immediately pushed to the customized webpage of receiving hospital so that they could easily upload patient outcomes anytime online, and periodically update patient status to the Web system. Health Bureau tracked the compliance with data uploading among receiving hospitals. Fire Department staff reviewed and uploaded prehospital and defibrillator data to the Web. The outcomes of 2-hour sustained return of spontaneous circulation (2hr ROSC), survival to discharge, and favorable Cerebral Performance Category 1 and 2 at discharge (fCPC), and data-missing rate for 4 years before the e-Registry (n=7,499) were compared to those 1 year after (n=1,777). Results: After e-Registry, for arrest of shockable rhythm, fCPC increased by 9.5% (95% CI: 4.2-16.1%); for non-shockable arrest, 2hr ROSC (4.2%, 95% CI: 1.4-7.1%) and fCPC (0.7%, 95% CI: 0.2-1.4%) increased significantly. After adjusting for patient and EMS variables, e-Registry was associated with fCPC (adjusted odds ratio: 1.9, 95% CI: 1.1-3.6) for shockable arrest, 2hr ROSC (adjusted OR: 1.2, 95% CI: 1.1-1.4) and fCPC (adjusted OR: 2.3, 95% CI: 1.1-5.1) for non-shockable arrest. Outcomes data-missing rate was significantly reduced by 5.3% (95% CI: 2.8-7.9%). Conclusions: Compared to paper archives, systems-based intervention by launching web-based e-registry may enhance favorable CPC after OHCA and reduce outcomes data-missing rate.

The Prevalence of Methicillin-Resistant Staphylococcus Aureus among Out-of-Hospital Care Providers and Emergency Medical Technician Students

Objective. We compared the methicillin-resistant Staphylococcus aureus (MRSA) carrier rate among out-of-hospital care providers with greater than six months’ experience in emergency medical services (EMS) care with that of emergency medical technician (EMT) students with two months or less of observation time as part of their clinical training. Methods. We conducted a prospective study utilizing a convenience sample of out-of-hospital care providers and EMT students in an urban EMS system operating in the Midwest during October and November 2006. One hundred thirty-four out-of-hospital care providers and 152 EMT students were tested for MRSA susceptibility using the cefoxitin disk diffusion method. Results. Contrary to our hypothesis, we did not find a statistically significant difference in MRSA nasal colonization between out-of-hospital care providers (4.5%; 95% confidence interval [CI] 1.0, 8.0) and EMT students (5.3%; 95% CI 1.7, 8.8). A subgroup analysis showed that among out-of-hospital care providers, paramedics had a higher rate of nasal colonization than EMTs (5.6% vs. 2.2%). Conclusion. We found that out-of-hospital care providers and EMT students had higher nasal colonization rates than the reported rate for the U.S. population (0.084% at the time the study was conducted and 1.5% currently). It is imperative that both groups adhere to infection control practices.

A Prospective Observational Analysis of Ambulation After Motor Vehicle Collisions

Predicting injury patterns of patients based only on mechanism of injury is difficult and is well described in the literature. Characteristics of patients on-scene immediately following injury(ies) may lead to predicting injury patterns. Although reported frequently, the significance of victim ambulation after a motor vehicle crash is poorly understood. It was hypothesized that ambulation at the scene is not predictive of injury severity following a motor vehicle crash (MVC). A prospective, cohort study of 117 consecutive injured patients who were ambulatory after MVCs were enrolled. Paramedics in a large urban Emergency Medical Services (EMS) system were mandated to document "ambulatory" or "nonambulatory" for motor vehicle collisions in order to complete their prehospital electronic medical records. This assured accuracy and completeness in the data collection. All charts were abstracted for trauma-induced injury and imaging results. A total of 608 (10.9%) persons were ambulatory at the scene, of which 284 had an injury pattern documented in the prehospital or emergency department record. The average age was 35.9 (SD = 16.8) years, and 158 (55.6%) were male. A total of 707 injuries were identified in the 284 patients who had sustained injuries. Ambulation after motor vehicle collisions appears to be only infrequently associated with major injuries, although this population still may present with significant injuries. A larger, prospective study is warranted.

397 A Qualitative Analysis of the Effects of a Statewide Ban on Ambulance Diversion on an Urban Emergency Medical Services System

Study Objectives: To examine the attitudes of MD and RN ED leaders in a major metropolitan area towards ambulance diversion and the first statewide diversion ban implemented in Massachusetts on 1/1/2009. Perceptions of the effects of the ban on patients, providers, and key relationships (hospital staff, hospitals, emergency medical services), as well as hospital preparations for the ban were explored. We hypothesized that ED leadership key informants (KIs) would provide unique insight into the implementation and effects of the diversion ban and that perspectives on the ban could be affected by factors such as hospital size, prior experience with diversion or professional role.

Cardiac Arrest Survival Is Rare Without Prehospital Return of Spontaneous Circulation

Background. Emergency medical services (EMS) are crucial in the management of out-of-hospital cardiac arrest (OHCA). Despite accepted termination-of-resuscitation criteria, many patients are transported to the hospital without achieving field return of spontaneous circulation (ROSC). Objective. We examine field ROSC influence on OHCA survival to hospital discharge in two large urban EMS systems. Methods. A retrospective analysis of prospectively collected data was conducted. Data collection is a component of San Antonio Fire Department's comprehensive quality assurance/quality improvement program and Cincinnati Fire Department's participation in the Cardiac Arrest Registry to Enhance Survival (CARES) project. Attempted resuscitations of medical OHCA and cardiac OHCA for San Antonio and Cincinnati, respectively, from 2008 to 2010 were analyzed by city and in aggregate. Results. A total of 2,483 resuscitation attempts were evaluated. Age and gender distributions were similar between cities, but ethnic profiles differed. Cincinnati had 17% (p = 0.002) more patients with an initial shockable rhythm and was more likely to initiate transport before field ROSC. Overall survival to hospital discharge was 165 of 2,483 (6.6%). More than one-third (894 of 2,483, 36%) achieved field ROSC. Survival with field ROSC was 17.2% (154 of 894) and without field ROSC was 0.69% (11 of 1,589). Of the 11 survivors transported prior to field ROSC, nine received defibrillation by EMS. No asystolic patient survived to hospital discharge without field ROSC. Conclusion. Survival to hospital discharge after OHCA is rare without field ROSC. Resuscitation efforts should focus on achieving field ROSC. Transport should be reserved for patients with field ROSC or a shockable rhythm.

A NATIONWIDE SURVEY OF EMERGENCY MEDICAL SERVICES STANDARDS OF CARE FOR CARDIAC ARREST – VARIABILITY AMONGST AMERICA'S LARGEST URBAN SYSTEMS

Prehospital care for cardiac arrest (CA) impacts morbidity and mortality. Variability in emergency medical services (EMS) standards for CA management exists among large urban EMS systems related to each other and to the 2010 International Liaison Committee on Resuscitation/American Heart Association

More Science for the New Subspecialty

More Science for the New Subspecialty

Utilization of Prehospital Dispatch Protocols to Identify Low-Acuity Patients

Objectives. To describe the experience of a U.S. emergency medical services (EMS) agency utilizing a dispatch algorithm to identify low-acuity patients and determine whether secondary telephone triage by a nurse was associated with subsequent hospital admission among those patients. Methods. This was a retrospective study of all patients meeting the low-acuity Omega classification by the Medical Priority Dispatch System (MPDS) in a large urban EMS system, conducted in two phases. Patients were excluded from the study if a refusal for transport was obtained, the call was received from a third-party caller, the MPDS system was not used, the patient was being referred from a skilled nursing facility, school, or university nursing office or physician's office, or if the call was referred to the Carolina Poison Center. Patients were enrolled over two phases using two different versions of the MPDS protocol, and in phase 2 patients were offered the option of speaking with an advice-line nurse. The outcome of interest was emergency department disposition, classified as hospital admission or discharge home. Admission to an intensive care unit (ICU) bed was also collected as a subcategory of hospital admission. Results. Of the 1,862 patients in phase 1, 69.3% were discharged home from the emergency department, whereas in phase 2, 73.0% of the 1,078 patients were discharged home. Individuals were most frequently admitted to the hospital across both phases if they had a dispatch determinant of pregnancy, psychiatric/behavioral, fall, sick person. Hospital admission was also associated with receiving an EMS or emergency department procedure. There were 530 patients in phase 2 who underwent secondary triage by an advice-line nurse. Among this cohort of patients, 134 (25.3%) required subsequent hospital admission, with a further three (2.2%) requiring an ICU admission. Conclusions. This study identified a method for classifying patients during the dispatch period as low-acuity while attempting to ensure that those individuals received the medical care that they needed. Key words: emergency medical services; emergency medical dispatch; triage.

Cardiac Movement Identified on Prehospital Echocardiography Predicts Outcome in Cardiac Arrest Patients

Introduction. The prognostic value of emergency echocardiography (EE) in the management of cardiac arrest patients has previously been studied in an in-hospital setting. These studies mainly included patients who underwent cardiopulmonary resuscitation (CPR) by emergency medicine technicians at the scene and who arrived at the emergency department (ED) still in a state of cardiac arrest. In most European countries, cardiac arrest patients are normally treated by physician-staffed emergency medical services (EMS) teams on scene. Transportation to the ED while undergoing CPR is uncommon. Objective. To evaluate the ability of EE to predict outcome in cardiac arrest patients when it is performed by ultrasound-inexperienced emergency physicians on scene. Methods. We performed a prospective, observational study of nonconsecutive, nontrauma, adult cardiac arrest patients who were treated by physician-staffed urban EMS teams on scene. Participating emergency physicians (EPs) received a two-hour course in EE during CPR. After initial procedures were accomplished, EE was performed during a rhythm and pulse check. A single subxiphoid, four-chamber view was required for study enrollment. We defined sonographic evidence of cardiac kinetic activity as any detected motion of the myocardium, ranging from visible ventricular fibrillation to coordinated ventricular contractions. The CPR had to be continued for at least 15 minutes after the initial echocardiography. No clinical decisions were made based on the results of EE. Results. Forty-two patients were enrolled in the study. The heart could be visualized successfully in all patients. Five (11.9%) patients survived to hospital admission. Of the 32 patients who had cardiac standstill on initial EE, only one (3.1%) survived to hospital admission, whereas four out of 10 (40%) patients with cardiac movement on initial EE survived to hospital admission (p = 0.008). Neither asystole on initial electrocardiogram nor peak capnography value, age, bystander CPR, or downtime was a significant predictor of survival. Only cardiac movement was associated with survival, and cardiac standstill at any time during CPR resulted in a positive predictive value of 97.1% for death at the scene. Conclusion. Our results support the idea of focused echocardiography as an additional criterion in the evaluation of outcome in CPR patients and demonstrate its feasibility in the prehospital setting.

Emergency Medical Services Response Time and Mortality in an Urban Setting

Background. A common tenet in emergency medical services (EMS) is that faster response equates to better patient outcome, translated by some EMS operations into a goal of a response time of 8 minutes or less for advanced life support (ALS) units responding to life-threatening events. Objective. To explore whether an 8-minute EMS response time was associated with mortality. Methods. This was a one-year retrospective cohort study of adults with a life-threatening event as assessed at the time of the 9-1-1 call (Medical Priority Dispatch System Echo- or Delta-level event). The study setting was an urban all-ALS EMS system serving a population of approximately 1 million. Response time was defined as 9-1-1 call receipt to ALS unit arrival on scene, and outcome was defined as all-cause mortality at hospital discharge. Potential covariates included patient acuity, age, gender, and combined scene and transport interval time. Stratified analysis and logistic regression were used to assess the response time–mortality association. Results. There were 7,760 unit responses that met the inclusion criteria; 1,865 (24%) were ≥8 minutes. The average patient age was 56.7 years (standard deviation = 21.5). For patients with a response time ≥8 minutes, 7.1% died, compared with 6.4% for patients with a response time ≤7 minutes 59 seconds (risk difference 0.7%; 95% confidence interval [CI]: –0.5%, 2.0%). The adjusted odds ratio of mortality for ≥8 minutes was 1.19 (95% CI: 0.97, 1.47). An exploratory analysis suggested there may be a small beneficial effect of response ≤7 minutes 59 seconds for those who survived to become an inpatient (adjusted odds ratio = 1.30; 95% CI: 1.00, 1.69). Conclusions. These results call into question the clinical effectiveness of a dichotomous 8-minute ALS response time on decreasing mortality for the majority of adult patients identified as having a life-threatening event at the time of the 9-1-1 call. However, this study does not suggest that rapid EMS response is undesirable or unimportant for certain patients. This analysis highlights the need for further research on who may benefit from rapid EMS response, whether these individuals can be identified at the time of the 9-1-1 call, and what the optimum response time is.

EMS Providers’ Perceptions of Safety Climate and Adherence to Safe Work Practices

Background. Occupational injuries are an important source of morbidity for emergency medical services (EMS) providers. Previous work has shown that employee perceptions of an organization's commitment to safety (i.e., safety climate) correlate with adherence to safe practices. Objective. To assess the association between perceived safety climate and compliance with safety procedures in an urban EMS system with >100,000 calls/year. Methods. EMS providers were issued a self-administered survey that included questions on demographics, years of experience, perceived safety climate, and adherence to safety procedures. Safety climate was assessed with a 20-item validated instrument. Adherence to safety procedures was assessed with a nine-item list of safety behaviors. Strict adherence to safety procedures was defined as endorsing “agree” or “strongly agree” on 80% of items. The effect of safety climate on compliance with safe practices was estimated using multiple logistic regression. Results. One hundred ninety-six of 221 providers (89%) completed surveys; 74% were male; the median age was 36–40 years; and the median amount of experience was 8 years. One hundred twenty-seven of 196 respondents (65%) reported strict adherence to safe work practice. Factor analysis confirmed the original six-factor grouping of questions; frequent safety-related feedback/training was significantly associated with safe practices (odds ratio [OR] = 2.14, 95% confidence interval [CI] = 1.01–4.51). Conclusion. EMS workers perceiving a high degree of perceived safety climate was associated with twofold greater odds of self-reported level of strict adherence to safe work practices. Frequent safety-related feedback/training was the one dimension of safety climate that had the strongest association with adherence to safe workplace behaviors.

Low–Fractional Oxygen Concentration Continuous Positive Airway Pressure is Effective in the Prehospital Setting

Objective. The objective of this study was to determine the effects of low–fractional concentration of inspired oxygen (FiO2) continuous positive airway pressure (CPAP) in prehospital noninvasive ventilation (NIV). With increasing concerns about the detrimental effects of hyperoxia, we sought to determine whether CPAP using a low FiO2 (28%–30%) was effective in the prehospital setting. Methods. The study was a six-month prospective, nonblinded observational study conducted in a large, busy urban emergency medical services (EMS) system (Las Vegas, NV). Results. A total of 340 patients participated in the study. Most patients presented with symptoms consistent with a diagnosis of congestive heart failure/acute pulmonary edema (47.4%), followed by chronic obstructive pulmonary disease (COPD) (40.9%), asthma (22.7%), and pneumonia (15.9%). Improvements were seen in respiratory rate (p = 0.00) and oxygen saturation (p = 0.00). The overall CPAP discontinuation rate was 16.5%. The most common reason for CPAP discontinuation was anxiety/claustrophobia. The total number of patients requiring prehospital intubation was 5.6%. Subjective paramedic assessment of patient status at hospital delivery found that 71.5% of patients’ conditions were improved, 15.1% remained unchanged, and 13.4% were worse. Conclusions. CPAP using a low FiO2 (28%–30%) was highly effective in the treatment of commonly encountered prehospital respiratory emergencies.