Comparative anatomy of the porcine and human thoracic spines with reference to thoracoscopic surgical techniques

BACKGROUND

This study compared porcine and human thoracic spine anatomies for a better understanding of how structures encountered during thoracoscopy differ between training with a porcine model and actual surgery in humans.

METHODS

Parameters were measured including vertebral body height, width, and depth; disc height; rib spacing; spinal canal depth and width; and pedicle height and width.

RESULTS

Although most porcine vertebral structures were smaller, porcine pedicle height was significantly greater than that of humans because the porcine pedicle houses a unique transverse foramen. The longus colli and psoas attach, respectively, to T5 and T13 in swine and to T3 and T12 in humans. In swine, the azygos vein generally was absent. The intercostal veins drained into the hemiazygos vein.

CONCLUSIONS

Several thoracoscopically relevant anatomic differences between human and porcine spinal anatomies were identified. A thoracoscopic approach in a porcine model probably is best performed from the right side. The best general working area is between T6 and T10.

Factors associated with CPR certification within an elderly community

OBJECTIVE

To determine the frequency of CPR certification amongst residents living within a predominantly elderly community and examine the perceived barriers to learning basic CPR and factors associated with intent to become certified.

METHODS

A household survey was sent with a community newsletter to each home of a non-gated elderly community that requires one member of each household to be at least 55 years of age. The community consists of 2488 homes (approximately 4000 residents). Thirteen Yes/No questions were asked in a skip-pattern based upon the question: "Are you CPR certified?" Data analysis included univariate, bivariate, and logistic regression.

RESULTS

947 participants with a mean age of 69 completed and returned the survey. Forty-eight percent of the participants had received prior training in CPR. Eighty-four percent were not currently certified in CPR, and top reasons cited were: 'don't know why' (36%), 'lack of interest' (20%), 'concerned about health risks' (17%). Forty-six percent of those not certified desired certification. Increasing age was inversely associated with CPR certification status and the desire to be certified.

CONCLUSION

Almost half of the residents in this predominantly elderly community had received prior training in CPR, although most were not currently certified and cite significant specific and non-specific reasons and obstacles. Improved survival requires targeted interventions to achieve higher proportions of CPR-competent individuals in such high-risk communities.

Increasing paramedics' comfort and knowledge about children with special health care needs

This study evaluated a continuing education program for paramedics about children with special health care needs (CSHCN). Pretraining, posttraining, and follow-up surveys containing two scales (comfort with CSHCN management skills and comfort with Pediatric Advanced Life Support [PALS] skills) were administered. Objective measures of knowledge were obtained from pre- and posttraining tests. Differences in average scores were assessed using t-tests. Response rates for paramedics completing the program ranged from 94% for the posttraining survey, 81% for the initial comfort survey, 56% for the knowledge pretest, and 56% for the follow-up survey. PALS comfort scores were significantly higher than CSHCN comfort scores both before and after training, both P < .01. Posttraining surveys showed an increase in CSHCN comfort, P < .01. The follow-up surveys showed a significant decline in CSHCN comfort, P = .05. Scores on the tests showed a similar pattern, with a significant increase in knowledge from pre- to posttraining (P = .02) and a significant decrease in knowledge from posttraining to follow-up (P < .01). Comfort was significantly higher for standard pediatric skills than for specialized management skills. Completion of the self-study program was associated with an increase in comfort and knowledge, but there was some decay over time.

Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos

BACKGROUND

The use of automated external defibrillators by persons other than paramedics and emergency medical technicians is advocated by the American Heart Association and other organizations. However, there are few data on the outcomes when the devices are used by nonmedical personnel for out-of-hospital cardiac arrest.

METHODS

We studied a prospective series of cases of sudden cardiac arrest in casinos. Casino security officers were instructed in the use of automated external defibrillators. The locations where the defibrillators were stored in the casinos were chosen to make possible a target interval of three minutes or less from collapse to the first defibrillation. Our protocol called for a defibrillation first (if feasible), followed by manual cardiopulmonary resuscitation. The primary outcome was survival to discharge from the hospital.

RESULTS

Automated external defibrillators were used, 105 patients whose initial cardiac rhythm was ventricular fibrillation. Fifty-six of the patients 153 percent) survived to discharge from the hospital. Among the 90 patients whose collapse was witnessed (86 percent), the clinically relevant time intervals were a mean (+/-SD) of 3.5+/-2.9 minutes from collapse to attachment of the defibrillator, 4.4+/-2.9 minutes from collapse to the delivery of the first defibrillation shock, and 9.8+/-4.3 minutes from collapse to The arrival of the paramedics. The survival rate was 74 percent for those who received their first defibrillation no later than three minutes after a witnessed collapse and 49 percent for those who received their first defibrillation after more than three minutes.

CONCLUSIONS

Rapid defibrillation by nonmedical personnel using an automated external defibrillator can improve survival after out-of-hospital cardiac arrest due to ventricular fibrillation. Intervals of no more than three minutes from collapse to defibrillation are necessary to achieve the highest survival rates.

Use of emergency medical services by children with special health care needs

OBJECTIVE

This study describes emergency medical services (EMS) responses for children with special health care needs (CSHCN) in an urban area over a one-year period.

METHODS

A prospective surveillance system was established to identify EMS responses for children, 21 years of age or younger, with a congenital or acquired condition or a chronic physical or mental illness. Responses related to the special health care needs of the child were compared with unrelated responses.

RESULTS

During a one-year period, 924 responses were identified. Fewer than half of the responses were related to the child's special health care need. Younger children were significantly more likely to have a response related to their special needs than older children. Among related responses, seizure disorder was the most common diagnosis, while asthma was more common for unrelated responses. Almost 58% of the responses resulted in transport of the child to a hospital.

CONCLUSIONS

Emergency medical services responses related to a child's special health care needs differ from unrelated responses. The most common special health care needs of children did not require treatment beyond the prehospital care provider's usual standard of care. These results are relevant for communities providing EMS services for CSHCN.

Development of an electronic emergency medical services patient care record

OBJECTIVE

The need for valid and reliable emergency medical services (EMS) data has long been recognized. EMS data are useful for monitoring resources and operations, documenting patient care and outcome, and evaluating injury prevention strategies. The goal of this project was to develop a computerized data set with the capability to generate a patient care record (PCR) to overcome some of the current EMS data limitations.

METHODS

The authors discuss developing an electronic PCR and analysis data set containing 233 variables. Data are collected for the following: incident, response, scene, patient, history, primary survey (including vital signs), physical examination, physiologic scores, diagnostics, plan (medications and procedures), assessment, and reevaluation. Software on a portable computer installed in an EMS response unit utilizes a graphical user interface for data collection by prehospital emergency care providers. A data set stores codes corresponding to user's selections. This data set supports data storage and analysis. The electronic PCR and data set can be useful to EMS agencies for collecting, storing, reporting, and analyzing information.

RESULTS

Variables are categorized into 12 main categories to categorize the variables and to drive data collection. The system provides the user with the ability to print out a record (using a portable printer installed in an ambulance) and analyze data stored in the data set.

CONCLUSION

This computerized approach overcomes many limitations inherent with using paper-based systems for research. Linked with emergency department, hospital discharge, and mortality data, EMS data can be used in systems analyses related to patient outcome.

Prehospital advanced life support for major trauma: critical need for clinical trials

A widely diverse body of information exists on the use of Advanced Life Support procedures by prehospital personnel. We compared and contrasted the literature that currently exists on this topic. We examined methodologies, results, and conclusions for each article. We also stress the need for critical clinical evaluations in this arena.

Development of new methods to assess the outcomes of emergency care

This article provides information supporting the need for new outcome measures in emergency care. It also addresses the use of these measures in emergency care, the impact of emergency care, identification of at-risk groups, new approaches to measuring patient satisfaction, quality of life, and cost-effectiveness, and the related unique implications for emergency medicine.

Development of new methods to assess the outcomes of emergency care

This article provides information supporting the need for new outcome measures in emergency care. It also addresses the use of outcome measures in emergency care, the impact of emergency care, identification of at-risk groups, new approaches to measuring patient satisfaction, quality of life and cost-effectiveness, and the unique related implications for emergency medicine.

Developing a foundation for the evaluation of expanded-scope EMS: a window of opportunity that cannot be ignored

EMS systems are about to undergo a major transformation. Not only will the scope of EMS change, but many experts believe that it will dramatically expand. Some see the "expanded scope" as entailing relatively limited changes, whereas others consider them to be more broad. Although no agreement is evident about the definition for expanded-scope EMS, it is hoped that all EMS professionals can agree that it must be implemented in a manner that can be carefully evaluated to determine its effects on patients and EMS systems. We present a framework for evaluating the effect of expanded-scope EMS in the various types of systems that currently exist. Special consideration must be given to the indirect effects that system changes may have on survival from out-of-hospital cardiac arrest. Numerous issues will affect our ability to properly assess expanded-scope EMS. The basic research models necessary to assess the impact of system change are lacking. Few EMS systems consistently produce significant volumes of good systems research ... that is, there are few "EMS laboratories." Cost-effectiveness and issues surrounding the "societal value" of EMS remain essentially unstudied. Reliable scoring methods, severity scales, and outcome measures are lacking: and, it is ethically and logistically difficult to justify withholding the "standard of care" in an effort to understand the impact of EMS interventions. Despite all of these barriers, it is time to pay the price of doing methodologically sound evaluations that ensure the most optimal societal impact by the EMS systems of the future.

Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model

BACKGROUND

The study objective was to develop a simple, generalizable predictive model for survival after out-of-hospital cardiac arrest due to ventricular fibrillation.

METHODS AND RESULTS

Logistic regression analysis of two retrospective series (n=205 and n=1667, respectively) of out-of-hospital cardiac arrests was performed on data sets from a Southwestern city (population, 415,000; area, 406 km2) and a Northwestern county (population, 1,038,000; area, 1399 km2). Both are served by similar two-tiered emergency response systems. All arrests were witnessed and occurred before the arrival of emergency responders, and the initial cardiac rhythm observed was ventricular fibrillation. The main outcome measure was survival to hospital discharge. Patient age, initiation of CPR by bystanders, interval from collapse to CPR, interval from collapse to defibrillation, bystander CPR/collapse-to-CPR interval interaction, and collapse-to-CPR/collapse-to-defibrillation interval interaction were significantly associated with survival. There was not a significant difference between observed survival rates at the two sites after control for significant predictors. A simplified predictive model retaining only collapse to CPR and collapse to defibrillation intervals performed comparably to the more complicated explanatory model.

CONCLUSIONS

The effectiveness of prehospital interventions for out-of-hospital cardiac arrest may be estimated from their influence on collapse to CPR and collapse to defibrillation intervals. A model derived from combined data from two geographically distinct populations did not identify site as a predictor of survival if clinically relevant predictor variables were controlled for. This model can be generalized to other US populations and used to project the local effectiveness of interventions to improve cardiac arrest survival.

Fatal trauma: the modal distribution of time to death is a function of patient demographics and regional resources

BACKGROUND

Unlike previous studies in an urban environment, this study examines traumatic death in a geographically diverse county in the southwestern United States.

METHODS

All deaths from blunt and penetrating trauma between November 15, 1991, and November 14, 1993, were included. As many as 150 variables were collected on each patient, including time of injury and time of death. Initial identification of cases was through manual review of death records. Information was supplemented by review of hospital records, case reports, and prehospital encounter forms.

RESULTS

A total of 710 traumatic deaths were analyzed. Approximately half of the victims, 52%, were pronounced dead at the scene. Of the 48% who were hospitalized, the most frequent mechanism of injury was a fall. Neurologic dysfunction was the most common cause of death. Two distinct peaks of time were found on analysis: 23% of patients died within the first 60 minutes, and 35% of patients died at 24 to 48 hours after injury.

CONCLUSIONS

Although there appears to continue to be a trimodal distribution of trauma deaths in urban environments, we found the distribution to be bimodal in an environment with a higher ratio of blunt to penetrating trauma.

Observational evaluation of compliance with traffic regulations among helmeted and nonhelmeted bicyclists

STUDY OBJECTIVE

To evaluate whether helmeted bicyclists are more compliant with traffic regulations than nonhelmeted bicyclists.

METHODS

This prospective observational study, using a convenience sample, was conducted during daylight hours at three separate intersections, marked with legal stop signs, near the campus of a major university. Data collected included helmet use, legal hand signal use to indicate a turn or stop, and whether the bicyclist came to a complete stop before proceeding through the intersection.

RESULTS

A total of 1,793 bicyclists were evaluated. Only 8.8% of the bicycle riders were wearing helmets. Helmeted bicyclists were 2.6 times more likely than nonhelmeted bicyclists to make legal stops (P < .000001; odds ratio [OR], 3.1; 95% confidence interval [CI], 2.1 to 4.6). They were also 7.1 times more likely to use hand signals (P < .000001; OR, 7.2; 95% CI, 2.8 to 18.2).

CONCLUSION

Helmeted bicycle riders showed a significantly greater compliance with two traffic laws than nonhelmeted bicyclists. They were 2.6 times more likely to stop at stop signs and 7.1 times more likely to use legal hand signals. This very strong association of helmet use with safer riding habits has implications for injury-control efforts aimed at preventing bicycle-related injuries.

Emergency medical service systems research: problems of the past, challenges of the future

Out-of-hospital emergency care was designed around the concept of a system of interrelated events that combine to offer a patient the best care possible outside the hospital. However, in contrast to the actual operations of emergency medical service (EMS) systems, research has not typically used systems-based models as the method for evaluation. In this discussion we outline the weaknesses of component-based research models in EMS evaluation and attempt to provide a "systems-analysis" framework that can be used for future research. Incorporation of this multidiscipline approach into EMS research is essential if there is to be any hope of finding answers to many of the important questions that remain in the arena of out-of-hospital health care.

Comparison of clinically significant infection rates among prehospital-versus in-hospital-initiated i.v. lines

STUDY OBJECTIVE

To compare the risk of infection for i.v. lines placed in the prehospital versus in the in-hospital setting in a midsized emergency medical service system.

DESIGN

A retrospective analysis was made of all i.v. line site infections among patients admitted to ward beds from a university hospital emergency department in 1992.

METHODS

The hospital's infection control team conducted daily ward rounds and a surveillance of all wound and blood cultures. Patients with signs and/or symptoms consistent with Centers for Disease Control and Prevention guidelines for skin and soft tissue infection were reported to the responsible medical team. Infections were documented based on consensus opinion between the infection control team and the physicians responsible for the care of the patient. IV lines placed in the prehospital phase of care were identified by electronic retrieval from the prehospital database.

RESULTS

Three thousand one hundred eighty-five patients who had a prehospital or an in-hospital i.v. line placed were admitted from the ED. Eight hundred fifty-nine i.v. lines were prehospital placed (27%), and 2,326 were in-hospital placed (73%). There was one infection in the prehospital group and four in the in-hospital group (infection rate: .0012 for prehospital patients and .0017 for in-hospital patients; P = .591 by Fisher's exact test).

CONCLUSION

Both cohorts had exceptionally low infection rates. No clinically or statistically significant increase in the risk of infection among prehospital- or in-hospital-initiated i.v. lines was identified.

A prospective investigation of the impact of alcohol consumption on helmet use, injury severity, medical resource utilization, and health care costs in bicycle-related trauma

STUDY OBJECTIVE

To examine if a relationship exists between bicycle-related injuries, consumption of alcohol, helmet use, and medical resource utilization.

DESIGN

A prospective cohort study with data from emergency department, operating room, and inpatient records.

SETTING

University-based trauma center in a medium-sized metropolitan area.

TYPE OF PARTICIPANTS

Adult victims (age > or = 18 years) of bicycle-related injury presenting to the emergency department. A total of 350 patients made up the study population.

RESULTS

Group 1 consisted of 29 patients (8.3%) with detectable blood alcohol levels at the time of the incident. Group 2 (321 patients) had a measured blood alcohol level of 0 or no clinical indication of alcohol consumption. Group 1 mean Injury Severity Score was 10.3, with six (20.7%) sustaining at least one severe anatomic injury. Group 2 had an Injury Severity Score of 3.3 (p < 0.0001), with only 4.4% (p = 0.0013) sustaining severe anatomic injury. Mean length of hospitalization for group 1 was 3.5 days, including a mean of 1.4 intensive care unit days. Mean hospitalization (0.5 days, p < 0.0001) and intensive care unit (0.1 days, p < 0.0001) were significantly lower in group 2. Mean combined hospital and physician charges were more than six times greater for group 1 ($7,206) than group 2 patients ($1170, p < 0.0001).

CONCLUSION

In patients presenting with bicycle-related injuries, prior consumption of alcohol is highly associated with greater injury severity, longer hospitalization, and higher health care costs. This information is useful in the development of injury prevention strategies to decrease incidence and severity of adult bicycle injuries.

A prospective in-field comparison of intravenous line placement by urban and nonurban emergency medical services personnel

STUDY HYPOTHESIS

Emergency medical services personnel are highly proficient at rapid i.v. line placement in the prehospital setting, with little difference between urban and nonurban areas in a geographically diverse state.

DESIGN

Prospective evaluation by an in-field observer of timing, sequence, success rates, and patient characteristics for IV line placement by prehospital personnel for 1 year.

SETTING

Twenty advanced life support agencies from all four emergency medical service regions of Arizona.

PARTICIPANTS

Fifty-eight patients encountered by participating emergency medical service agencies who had at least one i.v. line placement attempt in the prehospital setting.

RESULTS

Urban agencies encountered 24 patients (41.4%), and nonurban agencies encountered 34 (58.6%). Fifty-seven of 58 patients (98.3%) had at least one successful i.v. line started before arrival at a hospital. All 24 urban patients and 33 of 34 nonurban patients (97.1%) had a successful i.v. line attempt (P = .586, power = .09). In the urban setting, 24 of 31 attempts (77.4%) were successful, and in the nonurban setting 35 of 52 attempts (67.3%) were successful (P = .464, power = .28). Mean i.v. line procedure intervals were 1.6 minutes in urban and 1.4 minutes in nonurban settings (P = .408, power = .7). Thirty of 31 i.v. line attempts (96.7%) were completed in less than 4 minutes in urban systems, and 49 of 52 IV line attempts (94.2%) were completed in less than 4 minutes in nonurban systems (P = .520, power = .13). Mean i.v. line procedure intervals were 1.3 minutes for successful attempts and 2.1 minutes for unsuccessful ones (P = .015). Mean i.v. line procedure intervals for on-scene attempts were 1.3 minutes compared with 2.0 minutes for attempts during transport (P = .005). On average, i.v. line attempts in trauma patients took only 1.0 minutes compared with 1.7 in medical patients (P = .017).

CONCLUSION

Personnel in the 20 advanced life support agencies studied were extremely adept (rate of 98.3%) at obtaining i.v. line access in the prehospital setting. The time required to complete i.v. line placement was very short, and little difference was noted between urban and nonurban providers. I.v. procedure intervals were shorter for successful attempts, on-scene attempts, and attempts in trauma patients compared with their counterparts.

Emergency vehicle intervals versus collapse-to-CPR and collapse-to-defibrillation intervals: monitoring emergency medical services system performance in sudden cardiac arrest

STUDY OBJECTIVE

To compare emergency vehicle response intervals with collapse-to-intervention intervals to determine which of these system data better correlated with survival after prehospital sudden cardiac arrest.

STUDY DESIGN

A 22-month case series, collected prospectively, of out-of-hospital cardiac arrests. Times of collapse, dispatch, scene arrival, CPR, and initial defibrillation were determined from dispatch records, recordings of arrest events, interviews with bystanders, and hospital records.

SETTING

Southwestern city (population, 400,000; area, 390 km2) with a two-tiered basic life support-advanced life support emergency medical services system. Emergency medical technician-firefighters without electrical defibrillation capability comprised the first response tier; firefighter-paramedics were the second tier.

PATIENTS

One hundred eighteen cases of witnessed, out-of-hospital cardiac arrest in adults with initial ventricular fibrillation.

MAIN OUTCOME MEASURES

Survival was defined as a patient who was discharged alive from the hospital.

RESULTS

Eighteen of 118 patients (15%) survived. Survivors did not differ significantly from nonsurvivors in age, sex, or basic life support or advanced life support response intervals. Survivors had significantly (P < .05) shorter intervals from collapse to CPR (1.7 versus 5.2 minutes) and to defibrillation (7.4 versus 9.5 minutes).

CONCLUSION

Collapse-to-intervention intervals, not emergency vehicle response intervals, should be used to characterize emergency medical services system performance in the treatment of sudden cardiac death.

Physician in-field observation of prehospital advanced life support personnel: a statewide evaluation

STUDY HYPOTHESIS

Direct physician observation of advanced life support (ALS) personnel is rare in a demographically diverse state.

STUDY POPULATION

Twenty ALS agencies from throughout Arizona.

METHODS

A board-certified emergency physician performed on-site interviews with the emergency medical services (EMS) supervisor of each agency to approximate the number of days per year that physicians observe ALS personnel in the field.

RESULTS

Only 11 agencies (55%) reported that physicians ever observed ALS personnel. Among all agencies, an estimated total of 84 observer-days occurred per year. The agencies staffed a total of 86 ALS units, resulting in an estimated 0.98 observer-days/unit/year (84/86). On the average, it took 3.4 ALS personnel to staff a given unit over time and the probability that an ALS provider would be on a unit on any given day was 0.29 (1/3.4). The probability of a given provider being observed during one year was approximately 0.29 (0.98 x 0.29). Thus, on the average, an ALS provider would be observed by a physician approximately once every 3.5 years (1/0.29). Among urban agencies, the "average" ALS provider would be observed once every 2.9 years. This compared to a likelihood of in-field observation of only once every 6.7 years for non-urban providers (p = .036).

CONCLUSIONS

The skills of ALS providers in Arizona are observed by a physician in the field very infrequently. Although an uncommon occurrence in urban agencies, observation of non-urban ALS personnel occurs even less frequently. In addition, nearly one-half of the agencies surveyed never had a physician-observer. Although a variety of skills evaluation methods exist, it remains unclear whether any method is as useful as direct observation. Future investigations are needed to evaluate whether in-field physician observation impacts skills, patient care, or outcome in EMS systems.

Prospective validation of a new model for evaluating emergency medical services systems by in-field observation of specific time intervals in prehospital care

STUDY OBJECTIVE

To develop and validate a new time interval model for evaluating operational and patient care issues in emergency medical service (EMS) systems. DESIGN/SETTING/TYPE OF PARTICIPANT: Prospective analysis of 300 EMS responses among 20 advanced life support agencies throughout an entire state by direct, in-field observation.

RESULTS

Mean times (minutes) were response, 6.8; patient access, 1.0; initial assessment, 3.3; scene treatment, 4.4; patient removal, 5.5; transport, 11.7; delivery, 3.5; and recovery, 22.9. The largest component of the on-scene interval was patient removal. Scene treatment accounted for only 31.0% of the on-scene interval, whereas accessing and removing patients took nearly half of the on-scene interval (45.8%). Operational problems (eg, communications, equipment, uncooperative patient) increased patient removal (6.4 versus 4.5; P = .004), recovery (25.4 versus 20.2; P = .03), and out-of-service (43.0 versus 30.1; P = .007) intervals. Rural agencies had longer response (9.9 versus 6.4; P = .014), transport (21.9 versus 10.3; P < .0005), and recovery (29.8 versus 22.1; P = .049) interval than nonrural. The total on-scene interval was longer if an IV line was attempted at the scene (17.2 versus 12.2; P < .0001). This reflected an increase in scene treatment (9.2 versus 2.8; P < .0001), while patient access and patient removal remained unchanged. However, the time spent attempting IV lines at the scene accounted for only a small part of scene treatment (1.3 minutes; 14.1%) and an even smaller portion of the overall on-scene interval (7.6%). Most of the increase in scene treatment was accounted for by other activities than the IV line attempts.

CONCLUSION

A new model reported and studied prospectively is useful as an evaluative research tool for EMS systems and is broadly applicable to many settings in a demographically diverse state. This model can provide accurate information to system researchers, medical directors, and administrators for altering and improving EMS systems.

Reperfusion revisited

The field of thrombolytic treatment for a variety of clinical conditions has progressed extremely rapidly over the past decade. Unfortunately, answers to questions of the greatest interest to practicing physicians remain ambiguous. They include the following: For which problems should thrombolytic treatment be the treatment of choice? Which patients should receive thrombolytic treatment, and which should not? Which of the available thrombolytic agents is "best" for which problem in which patient? In this situation of clinical ambiguity, our experience with thrombolysis in AMI is instructive. The problems for which thrombolytic treatment are indicated have in common the attribute that they are "time-sensitive"; that is, optimal benefit is achieved with earlier initiation of treatment. We have learned that to minimize delay, emergency physicians must proactively agree with our colleagues in cardiology, family practice, internal medicine, pulmonary medicine, etc., on issues of patient selection, drug selection, and ancillary therapy. It is too late to argue such issues once the patient with a thrombotic or embolic disorder has arrived in the emergency department. By cooperating in advance, we can ensure our patients the maximum benefit from timely administration of this potent therapy while protecting them from avoidable complications and expense from its medically inappropriate use.

Meeting the goals of academia: characteristics of emergency medicine faculty academic work styles

STUDY OBJECTIVES

Emergency medicine faculty have 24-hour clinical responsibilities in addition to the academic requirements of research and administration/teaching. This study was undertaken to determine the existing and ideal work style of such faculty by professional rank, administrative title, and/or tenure versus clinical track.

DESIGN

Data analysis from department or residency directors of Accreditation Council for Graduate Medical Education-approved emergency medicine residency programs.

SETTING

ACGME-approved emergency medicine residency programs.

TYPE OF PARTICIPANTS

Emergency medicine faculty.

RESULTS

Ninety-three percent of programs submitted appropriate data. Programs averaged 11 full- and four part-time faculty. Mean time ranged from 15 to 30 hours per week with an average mean of 23 hours (48% of total work week) for clinical responsibilities, from ten to 32 hours per week with an average mean of 19 hours per week (38%) for administrative/teaching efforts, and from three to 14 hours per week with an average mean of seven hours per week (15%) for research. Total time averaged between 44 and 51 hours per week. Ideal work style emphasized less clinical time and a shorter work week. Responsibilities varied by rank, administrative position, and clinical versus tenure track.

CONCLUSION

Emergency medicine faculty accomplish the clinical, research, and teaching/administrative demands of academia by increasing the number of faculty, varying the faculty responsibilities by rank and title, and shortening the total work week. Research time is extremely limited.

Case and survival definitions in out-of-hospital cardiac arrest. Effect on survival rate calculation

OBJECTIVE

To determine the effect of different case and survival definitions of out-of-hospital cardiac arrest on survival rate calculations.

DESIGN

A 22-month case series of nontraumatic, out-of-hospital cardiac arrests.

SETTING

Southwestern city (population, 400,000; area, 390 km2) with a two-tiered emergency response system consisting of emergency medical technicians and paramedics.

PATIENTS

A consecutive sample of 372 patients found without palpable pulse of spontaneous respiration.

MAIN OUTCOME MEASURES

Survival rate after cardiac arrest was calculated using three case definitions of arrest and two definitions of survival.

RESULTS

Twenty percent of all patients survived to hospital admission and 6% survived to hospital discharge. Twenty-six percent of adults whose collapse was witnessed survived to hospital admission, and 10% survived to hospital discharge. Patients whose collapse was witnessed and who experienced initial ventricular fibrillation survived to hospital admission in 38% and to hospital discharge in 15% of cases.

CONCLUSIONS

The survival rate after out-of-hospital cardiac arrest varies widely depending on the case and survival definitions selected. To facilitate intersystem comparison and assessment of interventions designed to improve outcome, the Utstein Consensus Conference recommended that case and survival definitions should be adopted by all prehospital emergency systems.

The impact of injury severity and prehospital procedures on scene time in victims of major trauma

STUDY OBJECTIVE

To evaluate the relationship among injury severity, prehospital procedures, and time spent at the scene by paramedics for victims of major trauma.

DESIGN

Retrospective study of 98 consecutive patients with an Injury Severity Score of more than 15 who were brought to a trauma center by fire department paramedics.

SETTING

A medium-sized metropolitan emergency medical services (EMS) system and a Level I trauma center.

RESULTS

There were 66 male and 32 female patients with a mean age of 34 years. Thirty-two patients (32.6%) died. Blunt and penetrating trauma accounted for 68.4% and 31.6% of cases, respectively. Thirty-three patients (33.7%) had successful advanced airway procedures, and 81 (82.7%) had at least one IV line started in the field. Analysis of scene time, prehospital procedures, and injury severity parameters revealed that more procedures were performed in the field on the more severely injured cases; that despite this, there was a trend toward shorter scene time for more severely injured patients; and that there was a mean scene time of 8.1 minutes. This is the shortest scene time reported to date for prehospital trauma care in an EMS system.

CONCLUSION

Extremely short scene times can be attained without foregoing potentially life-saving advanced life support interventions in an urban EMS system with strong medical control. In such a system, the most severely injured victims may spend less time at the scene although more procedures are performed on them.

A prospective analysis of injury severity among helmeted and nonhelmeted bicyclists involved in collisions with motor vehicles

To evaluate the impact of helmet use on injury severity, patient information was prospectively obtained for all bicyclists involved in collisions with motor vehicles seen at a level-I trauma center from January 1986 to January 1989. Two hundred ninety-eight patients were evaluated; in 284 (95.3%, study group) cases there was documentation of helmet use or nonuse. One hundred sixteen patients (40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine patients (70.1%) had an ISS less than 15, while 85 (29.9%) were severely injured (ISS greater than 15). Only 5.2% of helmet users (6/116) had an ISS greater than 15 compared with 47.0% (79/168) of nonusers (p less than 0.0001). The mean ISS for helmet users was 3.8 compared with 18.0 for nonusers (p less than 0.0001). Mortality was higher for nonusers (10/168, 6.0%) than for helmet users (1/116, 0.9%; p less than 0.025). A striking finding was noted when the group of patients without major head injuries (246) was analyzed separately. Helmet users in this group still had a much lower mean ISS (3.6 vs. 12.9, p less than 0.001) and were much less likely to have an ISS greater than 15 (4.4% vs. 32.1%, p less than 0.0001) than were nonusers. In this group, 42 of 47 patients with an ISS greater than 15 (89.4%) were not wearing helmets. We conclude that helmet nonuse is strongly associated with severe injuries in this study population. This is true even when the patients without major head injuries are analyzed as a group; a finding to our knowledge not previously described.(ABSTRACT TRUNCATED AT 250 WORDS)

Update: drug therapy for acute myocardial infarction

Acute myocardial infarction is potentially a highly treatable disease. Immediate interventions are directed to decreasing tissue hypoxia with oxygen and improving bloodflow to ischemic myocardium using nitrates and thrombolytic agents. Cardiac workload should be reduced by eliminating endogenous catecholamine release with analgesia and sedation, and beta blockade in patients without CHF to decrease heart rate and myocardial oxygen demand. Treatment of the complications of AMI include dysrhythmia prophylaxis, monitoring and specific therapy. Treatment of pump failure includes using vasodilators, vasopressors and positive inotropic agents. Early recognition and timely initiation of appropriate therapy should be every physician's goal.

Transmission of 'toxic strep' syndrome from an infected child to a firefighter during CPR

Several cases of a toxic shocklike syndrome have been reported in the United States during the past five years in association with Streptococcus pyogenes infection. We report a case of a firefighter exposed during attempted CPR to the secretions of an S pyogenes-infected child. The firefighter developed an infection of the hand and subsequent febrile illness with hypotension, erythematous rash, renal failure, and hypocalcemia. Bacterial isolates of blood and cerebrospinal fluid from the deceased child were identical in type and exotoxin production with isolates grown from the hand wound of the firefighter. This is the first reported case of documented transmission of S pyogenes, causing a toxic shocklike syndrome in an emergency medical technician.

Cost-effectiveness analysis of paramedic emergency medical services in the treatment of prehospital cardiopulmonary arrest

STUDY OBJECTIVES

1) Identification of marginal costs associated with prehospital resuscitation of cardiopulmonary arrest; 2) Determination of cost effectiveness for such resuscitation; and 3) Comparison of cost effectiveness of paramedic care with selected other medical interventions.

DESIGN

Retrospective review of 190 cases of out-of-hospital cardiac arrest.

SETTING

City limits of a midsized southwestern city. The events studied took place outside of medical facilities.

TYPE OF PARTICIPANTS

Victims of out-of-hospital cardiac arrest for whom the EMS system was activated by a 911 telephone request for emergency medical assistance.

MEASUREMENTS AND MAIN RESULTS

The cost, including training, personnel, equipment, and response time maintenance, per year of life saved was found to be $8,886.00 for paramedic care. This result was compared with published cost-effectiveness figures for heart transplantation, liver transplantation, bone marrow transplantation, and chemotherapy for acute leukemia. Paramedic care was more cost effective, as measured by cost per year of life saved, than organ transplantation and chemotherapy for acute leukemia.

CONCLUSION

Out-of-hospital treatment by paramedics of cardiopulmonary arrest is more cost effective than heart, liver, bone marrow transplantation, or curative chemotherapy for acute leukemia.

Geriatric injury: an analysis of prehospital demographics, mechanisms, and patterns

STUDY OBJECTIVE

To evaluate emergency medical services (EMS) system use, injury mechanisms, and prehospital assessments among elderly victims of trauma.

DESIGN

We analyzed all prehospital data for injuries among patients 70 years old or older for whom 911 EMS dispatch was requested in a medium-sized metropolitan area during a 12-month period.

RESULTS

A total of 1,154 cases occurred (women, 65.1%), which represented 30.3% of all 911 dispatches involving elderly patients. Injury mechanisms were fall (60.7%), motor vehicle accident (MVA; 21.5%), fight (2.4%), accidental poisoning (2.3%), and choking (2.1%). Persons in their 90s had a lower frequency of MVAs (3.4%) than did younger patients (23.0%) (P less than .005). The most frequent injuries determined by prehospital assessment were head or face (25.1%), upper extremity (17.2%), hip (14.5%), lower extremity (13.8%), back (9.8%), and chest or abdomen (5.0%). The frequency of serious neurologic injuries was less for falls or MVAs than for other mechanisms (P less than .005). Suspected hip (P less than .001) and pelvic (P less than .005) injuries occurred more frequently during falls than during other mechanisms of injury, whereas back injuries occurred most frequently in MVAs (P less than .001). Seventy-one fall victims (10.1%) had suspected medical causes of their fall. Twelve patients (1.0%) were in cardiac arrest.

CONCLUSION

We report injury patterns and mechanisms among elderly victims of trauma presenting to an EMS system. A knowledge of these patterns will be useful to emergency physicians and EMS administrators.

Prehospital cardiac arrest: the impact of witnessed collapse and bystander CPR in a metropolitan EMS system with short response times

OBJECTIVE

Numerous studies have shown initiation of bystander CPR to significantly improve survival from prehospital cardiac arrest. However, in emergency medical services (EMS) systems with very short response times, bystander CPR has not been shown to impact outcome. The purpose of this study was to determine the effect of bystander CPR on survival from out-of-hospital cardiac arrest in such a system.

DESIGN

Prehospital, hospital, and death certificate data from a medium-sized metropolitan area were retrospectively analyzed for adult, nontraumatic cardiac arrest during a 16-month period.

RESULTS

A total of 298 patients met study criteria. One hundred ninety-five arrests (65.4%) were witnessed, and 103 (34.6%) were unwitnessed. Twenty-five witnessed victims (12.8%) were discharged alive, whereas no unwitnessed victims survived (P less than .001). Patients suffering a witnessed episode of ventricular fibrillation/tachycardia (VF/VT) were more likely to survive (21.9%) than were other patients (2.0%, P less than .0001). Among witnessed patients, initiation of bystander CPR was associated with a significant improvement in survival (20.0%) compared with the no-bystander CPR group (9.2%, P less than .05). Bystander CPR was also associated with improved outcome when witnessed patients with successful prehospital resuscitation were evaluated as a group; 18 had bystander CPR, of whom 13 (72.2%) survived compared with only 12 of 38 patients with no bystander CPR (31.6%, P less than .01).

CONCLUSION

Our data revealed improved survival rates when bystander CPR was initiated on victims of witnessed cardiac arrest in an EMS system with short response times.

Prehospital data entry compliance by paramedics after institution of a comprehensive EMS data collection tool

OBJECTIVE

To determine the completeness of data entry by paramedics after an extensive modification of the prehospital first-care form in an urban emergency medical services (EMS) system.

DESIGN

Comprehensive medical information was added to the EMS data collection tool used by a metropolitan fire department. We evaluated the frequency of failure to enter data pertaining to medical assessment and/or treatment of victims of cardiac arrest after implementation of the system.

RESULTS

Failure to enter data in the first month was compared with two subsequent two-month blocks. A high rate of noncompliance existed in the first month (all medical data were missing in 24.6%). However, the subsequent two months revealed a marked decline in noncompliance (4.4%, P less than .001). This decline was maintained after a three-month interim (5.0%, P less than .001).

CONCLUSION

Data entry noncompliance can be a significant problem after implementation of a new prehospital data collection system. However, compliance can be markedly improved over a relatively short period. Because EMS system evaluation is based on data collected in the field. EMS researchers and administrators must be aware of the data entry compliance rate in their system when attempting to make conclusions from such information.

Computer modeling of emergency medical system performance

Emergency medical services (EMS) system managers face difficult problems when determining the need for system expansion and unit deployment. Information relevant to the decision is often limited and frequently not in a usable format. This lack of usable information often results in decisions that create less-than-optimal EMS systems. A constant search for greater efficiency prompted the development of a computer simulation model to analyze the current EMS system operated by the Tucson Fire Department and to provide statistical information on the effects of potential vehicle base locations on system performance. The simulation model generates data that reflect a variety of parameters necessary in base location analysis. Included in the performance statistics for each unit and for the entire system are indicators of unit use rates, minimum and maximum response times, and proportion of calls reached within the critical response time of eight minutes or less. The model has been carefully validated and used in unit redeployment and unit activation in Tucson, Arizona.

Critical care air transportation of the severely injured: does long distance transport adversely affect survival?

Civilian aeromedical transportation systems, both fixed and rotary wing, have proliferated since the middle 1970s. However, outcome data substantiating the benefit of these services have been slow in coming. From February 22, 1982, through March 5, 1984, Airlift Northwest transported 118 trauma patients (aged 15 years and older) an average distance of 340 miles (range, 100 to 800 miles) with fixed-wing aircraft. The in-hospital mortality for this group was 19% compared with 18% for a comparable group of trauma patients who were ground-transported from within the city limits of Seattle, Washington. The two groups did not differ significantly in age, Injury Severity Score, or Glasgow Coma Score. These results suggest that some part of the clinical benefit of a regional trauma center may be extended up to 800 miles with no increase in transport-related mortality.

Evaluation of EMS management training offered during emergency medicine residency training

Physician involvement in the provision of both direct and indirect medical control to emergency medical providers is critical to the effective operation of an emergency medical services (EMS) system. We conducted a survey of all accredited emergency medicine residency programs in the United States to determine the content of EMS instruction provided to these physicians-in-training. The majority of programs provide an introduction to direct medical control, to EMS organizational structure, and the opportunity to participate in EMS-related research. Less than 65%, however, provide formal instruction in EMS risk management or quality assurance or the opportunity to observe policy-making bodies related to EMS. The importance placed on EMS during residency training is variable. EMS is the domain of emergency medicine, and adequate training of residents for these responsibilities is imperative.

Implementation of a computerized management information system in an urban fire department

An important aspect in the effective management of an emergency medical services system is the ability to monitor system performance. To provide this information on a timely basis, a comprehensive data collection system is required. We describe the design, implementation, use, and effect of a comprehensive, computerized data retrieval system within an urban fire department. Building on a data collection system already in place, it was possible to minimize the cost and accelerate the training process. A comparison is included between the different type of systems available for use with prehospital providers. Use of prehospital data collection systems results in more in-depth understanding of system operations and the status of prehospital medical care provided to the community.

Thermal stability of prehospital medications

To evaluate the effect of prolonged environmental extremes on common prehospital medications, four identical sets of 23 drugs were placed in a simulated environment for up to four weeks. Subsequently, the samples were analyzed by gas chromatography-mass spectrometry for evidence of degradation byproducts. Twenty-one of the 23 samples showed no breakdown products; however, isoproterenol demonstrated 11% loss of parent compound after four weeks of environmental exposure. Epinephrine manifested a change in its ionized state after exposure to heat; the physiologic effect of this change was not determined. Our results suggest that rural and suburban emergency medical services providers, whose medications may not be replaced until they are used in patient care, must monitor their drug boxes' duration of exposure to uncontrolled conditions.

A new model for providing prehospital medical care in large stadiums

To determine proper priorities for the provision of health care in large stadiums, we studied the medical incident patterns occurring in a major college facility and combined this with previously reported information from four other large stadiums. Medical incidents were an uncommon occurrence (1.20 to 5.23 per 10,000 people) with true medical emergencies being even more unusual (0.09 to 0.31 per 10,000 people). Cardiac arrest was rare (0.01 to 0.04 events per 10,000 people). However, the rates of successful resuscitation in three studies were 85% or higher. The previous studies were descriptive in nature and failed to provide specific recommendations for medical aid system configuration or response times. A model is proposed to provide rapid response of advanced life support care to victims of cardiac arrest. We believe that the use of this model in large stadiums throughout the United States could save as many as 100 lives during each football season.

Air transport following surgical stabilization: an extension of regionalized trauma care

A 30-month retrospective review was performed of all trauma patients initially evaluated and operatively stabilized at Level III hospitals, with subsequent specialized air transport within 48 hours of injury to the regional Level I trauma center in Seattle. Nineteen patients were identified, with a mean ISS of 44 (range, 20-66). Mean transport time and distance were 2.4 hours and 456 miles, respectively. The estimated average ground transport time for the same patients was 23.8 hours. No deaths occurred during transport, and the overall survival rate was 58%. Transport charges averaged $4,162, which was 14% of the complete hospitalization cost. We conclude that: 1) patient survival after air transport was no different than that predicted for trauma victims with immediate access to a trauma center; 2) postoperative hemodynamic instability predicted a poor outcome; 3) the higher cost of air relative to ground transport is outweighed by significant time savings in these critically injured patients; and 4) air transport following operative stabilization represents an extension of regionalized trauma care to the isolated areas of Washington and Alaska.

Pulmonary embolism

Pulmonary embolism remains a challenging problem in diagnosis and management for the emergency physician. Although its clinical presentation is protean and often ambiguous, risk stratification can be accomplished based on the predictive power of a limited number of physical and historical characteristics. Ventilation-perfusion lung scanning occupies a central position in the work-up of suspected PE; however, evidence exists that it may be misused by many physicians. A low probability V-Q scan does not exclude the diagnosis of PE. Patients with other than normal- or high-probability patterns of pulmonary ventilation and perfusion on lung scanning require further investigation. Noninvasive venous studies are useful when indicative of proximal deep venous thrombosis, but are normal in many patients with acute PE. Heparin remains the standard of treatment for most patients with PE. Vena cava filters effectively reduce the incidence of recurrent PE in patients with contraindications to anticoagulation. Thrombolytic therapy offers potential advantages in the treatment of patients with shock due to their PE. Case reports of PE treated with tissue-type plasminogen activator, a new thrombus-specific fibrinolytic agent, are encouraging but preliminary.

Pulmonary embolism

The incidence and mortality of acute pulmonary embolism (PE) remain ill defined, particularly in the setting of the emergency department. However, high-risk groups can be identified based on medical conditions known to predispose patients to venous thrombosis. Recent research into the physiologic regulation of coagulation and thrombolysis reveals that recurrent venous thrombosis and PE may be caused by heritable deficiencies and abnormalities of plasma proteins. To decide among options for evaluation and treatment of patients suspected of PE, physicians combine clinical assessment with patterns observed on radionuclide ventilation-perfusion (V/Q) scans. However, the prevalence of PE among patients with "low probability" V/Q scans suggests that current physician behavior may be imprudent. Heparin anticoagulation continues to be standard therapy for acute PE, but newer clot-specific thrombolytic drugs may offer superior benefits with acceptable complication rates in carefully selected patients.

Occupational exposure to hepatitis B in paramedics

To determine their occupational risk for hepatitis B infection, 59 Seattle paramedics were tested for hepatitis B serum markers. Evidence of antibody to hepatitis B surface antigen (anti-HBs) or antibody to hepatitis B core antigen (anti-HBc) was found in 25%, a rate five times that of a similar Seattle population. Seropositivity did not correlate with age, race, clinical history, or length of service. Of the 15 paramedics with seropositivity to hepatitis B virus six initially had low titers of either anti-HBs or anti-HBc. Four of the six demonstrated persistent low-grade seropositivity on retesting. Paramedics are at increased risk of hepatitis B infection. The high frequency of low-titer anti-HBs suggests that frequent low-level exposure to hepatitis B virus occurs in this population; hepatitis B vaccine should be strongly considered for paramedics.