Outcomes from out-of-hospital cardiac arrest in Detroit.

OBJECTIVE: To determine the out-of-hospital cardiac arrest survival rate, and prevalence of modifiable factors associated with survival, in Detroit, Michigan, over a 6-month period of time in 2002. METHODS: A retrospective review of all out-of-hospital cardiac arrests responded to by the Detroit Fire Department, Division of Emergency Medical Services. All elements of the EMS runsheet were transcribed to a database for analysis. Patient hospital records were reviewed to determine survival to hospital admission. All survivors to hospital admission were surveyed later in the Michigan Department of Vital Records death registry search. RESULTS: During this study timeframe, there were 538 confirmed out-of-hospital cardiac arrests within the City of Detroit, of which 67 were excluded for being dead on scene [51 (12.5%)] or having no available hospital records [16 (3.0%)]. Of the remaining 471 patients, 443 (94.1%) died before hospital admission. Only 44 (9.9%) of the 471 patients had a first recorded rhythm of ventricular fibrillation (VF), and 339 (76.5%) were asystolic. Of the 28 patients who survived to hospital admission, only 2 (7.1%) were noted to have a first rhythm of VF, and 15 (53.6%) were asystolic. Only one patient survived to hospital discharge. CONCLUSIONS: In this urban setting, out-of-hospital cardiac arrest is an almost uniformly fatal event.

Prognostic value of a normal or nonspecific initial electrocardiogram in acute myocardial infarction.

CONTEXT: Although previous studies have suggested that normal and nonspecific initial electrocardiograms (ECGs) are associated with a favorable prognosis for patients with acute myocardial infarction (AMI), their independent predictive value for mortality has not been examined. OBJECTIVE: To compare in-hospital mortality among patients with AMI who have normal or nonspecific initial ECGs with that of patients who have diagnostic ECGs. DESIGN, SETTING, AND PATIENTS: Multihospital observational study in which 391 208 patients with AMI met the study criteria between June 1994 and June 2000 and had ECGs that were normal (n = 30 759), nonspecific (n = 137 574), or diagnostic (n = 222 875; defined as ST-segment elevation or depression and/or left bundle-branch block). A logistic regression model was constructed using a propensity score for ECG findings and data on demographics, medical history, diagnostic procedures, and therapy to determine the independent prognostic value of a normal or nonspecific initial ECG. MAIN OUTCOME MEASURES: In-hospital mortality; composite outcome of in-hospital death and life-threatening adverse events. RESULTS: In-hospital mortality rates were 5.7%, 8.7%, and 11.5% while the rates of the composite of mortality and life-threatening adverse events were 19.2%, 27.5%, and 34.9% for the normal, nonspecific, and diagnostic ECG groups, respectively. After adjusting for other predictor variables, the odds of mortality for the normal ECG group was 0.59 (95% confidence interval [CI], 0.56-0.63; P<.001) and for the nonspecific group was 0.70 (95% CI, 0.68-0.72; P<.001), compared with the diagnostic ECG group. CONCLUSION: In this large cohort of patients with AMI, patients presenting with normal or nonspecific ECGs did have lower in-hospital mortality rates than those of patients with diagnostic ECGs, yet the absolute rates were still unexpectedly high.

The chest pain center in the emergency department.

Despite the improvement of medical treatment for acute coronary syndromes throughout the 20th century, the authors believe that many cases of life-threatening coronary events could be avoided through early detection of CAD and the use of preventive strategies. Establishing chest pain units that are linked to the ED is one excellent strategy to risk-stratify patients with symptoms who are at risk for sustaining an AMI or having lethal arrhythmias. There is a need for more research on chest pain units to determine the value for cost and to further optimize strategies for ACI detection and screening. In EDs with high volumes of chest pain patients, or high pressures to avoid hospital admissions, a planned, systematic, and rapid approach to the treatment of AMI and the diagnosis of chest pain is a rewarding necessity.

Impact of technetium-99m sestamibi imaging on the emergency department management and costs in the evaluation of low-risk chest pain.

OBJECTIVES: To assess the impact of rest sestamibi scanning on emergency physicians' (EPs') diagnostic certainty and decision making (as assessed by the hypothetical disposition of patients) for 69 consenting stable patients with suspected acute cardiac ischemia and nondiagnostic electrocardiograms. The resultant impact on costs was examined as a secondary outcome. METHODS: Patients with suspected acute cardiac ischemia were injected with 25 mCi of sestamibi within two hours of active pain in one of three emergency department study sites. The probability of acute myocardial infarction (AMI) and unstable angina (UA), and hypothetical disposition decisions were recorded immediately before and after physicians were notified of scan results. Changes in disposition were classified as optimal or suboptimal. For the cost determinations, a cost-based decision support program was used. RESULTS: For the subgroup found to be free of acute cardiac events (ACEs) (n = 62), the EPs' post-sestamibi scan probabilities for AMI decreased by 11% and UA by 18% (p < 0.001 for both conditions). In seven patients with ACEs, the post-scan probabilities of AMI and UA increased, but neither was statistically significant. Scan results led to hypothetical disposition changes in 29 patients (42%), of which 27 (93%) were optimal (nine patients were reassigned to a lower level of care, two to a higher level, and 16 additional patients to "discharge-home" status). The strategy of scanning all patients who were low to moderate risk for acute cardiac ischemia would result in an increase of direct costs of care of $222 per patient evaluated, due to added cost of sestamibi scanning. CONCLUSIONS: Sestamibi scanning results appropriately affected the EPs' estimates of the probability of AMI and UA and improved disposition decisions. Scanning all low-risk patients would likely be associated with increased costs at this medical center.

Stress testing for risk stratification of patients with low to moderate probability of acute cardiac ischemia.

In summary, this article focused on the use of stress testing to risk-stratify patients at the conclusion of their emergency evaluation for ACI. As discussed, those patients in the probably not ACI category require additional risk stratification prior to discharge. It should be kept in mind that patients in this category are heterogeneous, containing subgroups at both higher and lower risk of ACI and cardiac events. The patients with lower pretest probability for ACI may only need exercise testing in the ED. Patients with higher pretest probability should undergo myocardial perfusion or echocardiographic stress testing to maximize diagnostic and prognostic information. Prognostic information is the key to provocative testing in the ED. Prognostic information is the component that will help emergency physicians identify the patients who may be discharged home safely without having to worry about a 6% annual cardiac death rate and a 10% overall death rate over the next 30 months. Stress testing provides this key prognostic data, and it can be obtained in short-stay chest pain observation units in a safe, timely, and cost-effective fashion.

Pretest probability assessment for selective rest sestamibi scans in stable chest pain patients.

The objective of this study was to determine whether pretest probability assessments permit more selective testing of chest pain patients with technetium-99m sestamibi scanning. Pretest probabilities of cardiac ischemia were measured both objectively (Acute Cardiac Ischemia Time-Insensitive Predictive Instrument [ACI-TIPI]) and subjectively (physician's estimate of the probability of unstable angina). Two groups were defined: patients whose postsestamibi scan led to a "downgrade" of the intensity of monitoring and those that resulted in no change in monitoring intensity. Sixty-five patients met study criteria; 25 had a disposition downgrade and 40 had no change. Pretest ACI-TIPI scores were similar in the two groups (29% +/- 18% versus 27% +/- 11%, mean +/- standard deviation; P = .95) as were the physician's assessment of unstable angina (39% +/- 22% versus 40% +/- 24%; P = .75). Objective or subjective pretest probabilities are not significantly different in patients who are likely to have their disposition altered by sestamibi scanning.

Predicting recovery from acute asthma in an emergency diagnostic and treatment unit.

OBJECTIVE: Optimal use of emergency diagnostic and treatment unit (EDTU) resources for treatment of acute asthma should be facilitated by the selection of patients with a high probability of discharge from the EDTU. The study goal was to identify characteristics of the patient or exacerbation that could be used to predict recovery of pulmonary function within 12 hours. METHODS: Comprehensive cohort design in an urban public hospital. The subjects were 269 patients with moderately severe asthma exacerbations. Data were collected for historical and presenting features and response to treatment over 12 hours. Two outcomes were examined: 1) discharge from the EDTU and 2) achieving 50% predicted peak expiratory flow rate (PEFR) within 12 hours. RESULTS: The two outcomes showed good concordance. The third-treatment PEFR was found to be predictive of both discharge and reaching 50% predicted PEFR within 12 hours. Since the objective measure of reaching 50% predicted PEFR is more readily defined and thus more generalizable, the authors focused on this outcome when describing prediction zones. Patients with 40% or higher PEFR after third treatment had an 89% probability of reaching 50% predicted in 12 hours, while those with a third-treatment PEFR lower than 32% predicted had only a 22% probability. CONCLUSIONS: A simple objective measure of pulmonary function early in treatment discriminated among those with high, low, and intermediate probabilities of achieving a specified level of PEFR within 12 hours. Awareness of this probability could assist clinicians attempting to predict discharge from the EDTU and facilitate decision making regarding utilization of EDTU resources.

National Heart Attack Alert Program position paper: chest pain centers and programs for the evaluation of acute cardiac ischemia.

The National Heart Attack Alert Program (NHAAP), which is coordinated by the National Heart, Lung, and Blood Institute (NHLBI), promotes the early detection and optimal treatment of patients with acute myocardial infarction and other acute coronary ischemic syndromes. The NHAAP, having observed the development and growth of chest pain centers in emergency departments with special interest, created a task force to evaluate such centers and make recommendations pertaining to the management of patients with acute cardiac ischemia. This position paper offers recommendations to assist emergency physicians in EDs, including those with chest pain centers, in providing comprehensive care for patients with acute cardiac ischemia.

ECG scores for a triage of patients with acute myocardial infarction transported by the emergency medical system.

Prehospital triage of cardiac patients for bypass from community hospitals to cardiac centers may improve survival. This article determines if electrocardiogram (ECG)-based scoring triage methods (Aldrich MI scoring, QRS distortion, and the TIMI classification) and location of infarct (via 12 lead ECG) are associated with mortality before and after adjusting for age, sex, and race. It is a retrospective study of 291 AMI adult patients transported by ambulance to community hospitals or cardiac centers. Patients with an ED chief complaint of chest pain or dyspnea, presence of MI as defined by ECG findings of 0.1 mV of ST segment elevation in two leads or positive CPK-MB were eligible for the study. The primary outcome variable was 2-year mortality as determined with a metropolitan Detroit tri-county death index. Logistic regression was used to calculate the unadjusted and adjusted odds ratios (with 95% CIs) of the predictor variables with mortality. Of the initial population selected for the study (n = 291), 229 patients were eligible for the analysis. The mean age was 66 years (SD of 14.4) with 63.8% being male and 54% being white. The overall mortality point estimate was 21.3% (95% CI of 15.2 to 27.3%). Aldrich scores and QRS distortion (yes/no) were not associated with mortality. Patients classified as a "high risk" for AMI per TIMI status were almost 3 times more likely to die than those at "low risk" and reached borderline statistical significance (P = .06) after adjusting for the covariates. Having an anterior infarct, as opposed to an inferior infarct, was significantly associated with death before and after adjusting for the covariates (Unadjusted OR = 2.6, Adjusted OR = 2.8). Properly training emergency medical system professionals in this area may prove useful for identifying higher risk AMI patients in the prehospital setting.

A prediction model for prehospital triage of patients with suspected cardiac ischemia.

The American College of Cardiology recommends that patients with high risk acute myocardial infarction (AMI) be triaged to hospitals with percutaneous transluminal coronary angioplasty capability. However, there are no prehospital triage criteria to select candidates for bypassing community hospitals and being taken directly to "cardiac centers." This article assesses which independent variables predict death within 7 days in patients with suspected AMI transported by EMS. This is a retrospective study of 291 AMI patients transported by ambulance to 3 hospitals during 1996-1997. Included were patients who were (n = 244) > or =18 years of age, had a ED chief complaint of chest pain or dyspnea for whom we had mortality data. Mortality at 7 days, our primary outcome measure, was obtained by using a metropolitan Detroit tricounty death index records. Differences between the survivors and nonsurvivors were assessed using the Student's t-test and chi-square tests. Multiple triage criteria were assessed for optimal identification of high risk patients by constructing a logistic multivariate model. Among the study population, 15% died within 7 days (95% confidence interval (CI) 10.3-19.2), and this group represented 63.2% of all deaths over a 2 year surveillance period. Survivors, compared to nonsurvivors, were 14.1 years younger (P < or = .001) and more often men (P < or = 0.001). The dispatch time to ED arrival was less among survivors than nonsurvivors (42.8 vs. 50.6 min, P < or = .01). EMS vital signs differed by survivor status. Among survivors, HR was lower (-11.9 bpm; P < or = 0.01), RR was lower (-6.7 rpm; P < or = .001), SBP was higher (+14.5 mmHg; P < or = 0.05) and DBP was higher (+13.2 mm Hg; P < or = .01). A multivariate model identified the following as independent predictors of early mortality: female gender (OR = 2.3; P < or = .05), age > or =65 (OR = 5.9; P < or = .01), RR > or = 20 (OR = 4.6; P < or = .001), SBP < 120 (OR = 2.4; P < or = .05). The overall model was 86% sensitive and 53% specific with an area under the receiving operating characteristic curve of 0.8 (P < or = .001). A triage rule based on a multivariate model can identify the group at high risk of early cardiac death. This decision rule needs to be prospectively validated.

Resting sestamibi imaging for the prognosis of low-risk chest pain.

OBJECTIVE: To assess the prognostic value of resting Tc-99m sestamibi scanning for adverse cardiac events (ACEs) in ED chest pain patients with a low probability of acute cardiac ischemia (ACI). METHODS: Sixty-nine consenting, hemodynamically stable patients with chest pain and a nondiagnostic electrocardiogram received an injection of 25 mCi of sestamibi during or within two hours of active pain. Scans were interpreted locally by a nuclear cardiologist or radiologist. Interrater reliability was assessed. ACEs of myocardial infarction (MI), death, or revascularization were assessed during the index hospitalization and over a one-year follow-up period. RESULTS: For ACEs, rest scanning with sestamibi had a sensitivity of 71% (95% CI = 0.33 to 0.97), a specificity of 92% (95% CI = 0.82 to 0.97), and an accuracy of 90% (95% CI = 0.87 to 0.99). The positive predictive value was 50% (95% CI = 0.19 to 0.82) and the negative predictive value was 97% (95% CI = 0.87 to 0.98). Sestamibi scanning was highly discriminating, with 62% of patients with positive scans but only 3% with negative scans having ACEs (p<0.001, log rank test). CONCLUSION: In patients with low-risk chest pain, sestamibi scanning has good specificity and moderate sensitivity for ACEs over a 12-month period.

Patient satisfaction with an emergency department asthma observation unit.

OBJECTIVE: To compare levels of patient satisfaction between the diagnostic and treatment protocols in an ED-based asthma observation unit (AOU) and those with standard inpatient hospitalization. METHODS: This was a prospective, randomized, controlled trial with a sample of 163 patients presenting to the ED with acute asthma exacerbations over a 30-month period. Eligible patients were those who could not resolve their symptoms after three hours of standard ED therapy. Patients were then randomly assigned to an ED-based AOU (experimental group) or to customary inpatient care (control group). Patient satisfaction and problems with care processes were assessed by standardized instrumentation at discharge in both groups. RESULTS: The AOU patients scored higher than those randomized to the inpatient hospitalization protocol on four summary ratings of patient satisfaction measures: received service wanted, recommendation of the service to others, satisfaction with the service, and overall satisfaction. The AOU patients reported fewer total number of problems with care received, and fewer specific problems with communication, emotional support, physical comfort, and special needs, than did the inpatient group. However, the AOU patients reported more problems regarding their knowledge of financial costs and liabilities for their service than did the inpatients. CONCLUSION: Patients were more satisfied and had fewer problems with rapid diagnosis and treatment in the AOU than they did with routine inpatient hospitalization. Since AOUs represent a new ambulatory service modality, patients would benefit from greater awareness of the costs and coverage for AOUs as compared with hospital inpatient care. These findings have important implications for the future short- and long-term success and feasibility of ED-based AOUs.

Evaluation and risk stratification of patients with chest pain in the emergency department. Predictors of life-threatening events.

While assessing chest pain in the emergency department, physicians must first estimate the probability of acute ischemic states in the patient. This first estimate is based on the patient's history, physical examination, and electrocardiogram. Patients who meet the threshold for acute cardiac ischemia are further evaluated to confirm or exclude this diagnosis, while other life-threatening factors are excluded.

A national survey of emergency department chest pain centers in the United States.

Although chest pain centers are promoted as improving emergency cardiac care, no data exist on their structure and processes. This national study determines the 1995 prevalence rate for emergency department (ED)-based chest pain centers in the United States and compares organizational differences of EDs with and without such centers. A mail survey was directed to 476 EDs randomly selected from the American Hospital Association's database of metropolitan hospitals (n = 2,309); the response rate was 63%. The prevalence of chest pain centers was 22.5% (95% confidence interval 18% to 27%), which yielded a projection of 520 centers in the United States in 1995. EDs with centers had higher overall patient volumes, greater use of high-technology testing, lower treatment times for thrombolytic therapy, and more advertising (all p <0.05). Hospitals with centers had greater market competition and more beds per annual admissions, cardiac catheterization, and open heart surgery capability (all p <0.05). Logistic regression identified open heart surgery, high-admission volumes, and nonprofit status as independent predictors of hospitals having chest pain centers. Thus, chest pain centers have a moderate prevalence, offer more services and marketing efforts than standard EDs, and tend to be hosted by large nonprofit hospitals.

Emergency Department Observation Unit versus hospital inpatient care for a chronic asthmatic population: a randomized trial of health status outcome and cost.

OBJECTIVES: This study was designed to determine if an accelerated treatment protocol administered to acute asthmatics presenting to a Hospital Emergency Department Observation Unit (EDOU) can offset the need for inpatient admissions and reduce total cost per episode of care without sacrificing patient quality of life. METHODS: The authors used a prospective randomized controlled trial comparing postintervention patient quality of life for EDOU care versus standard inpatient care as measured by the standardized Medical Outcomes Study (MOS) SF-36 instrument. Other measures reported include: clinical status as measured by peak flow rates, total cost per treatment arm using microcosting techniques, and relapse-free survival 8 weeks after treatment. Eligible patients (n = 113) were assigned randomly to an EDOU or inpatient care from a consecutive sample of 250 acute asthmatic patients presenting to an urban hospital emergency department who could not resolve their acute asthma exacerbation after 3 hours of emergency department therapy. RESULTS: Patients assigned to the EDOU had lower mean costs of treatment (EDOU = $1,202 versus Hospital Inpatient = $2,247) and higher quality of life outcomes after intervention in five of eight domains measured by the MOS SF-36: Physical Functioning, Role Functioning-Emotional, Social Functioning, Mental Health, and Vitality. No differences were found in clinical outcomes as measured by peak flow rates or postintervention relapse-free survival. Univariate comparative findings were re-examined and confirmed through multivariable analysis when baseline SF-36 scores and postintervention peak expiratory flow rates clinical status were used as covariates. CONCLUSIONS: The study showed that the EDOU was a lower cost and more effective treatment alternative for a refractory asthmatic population presenting to the Emergency Department. Several baseline MOS SF-36 domains proved useful in predicting or validating posttreatment clinical status, relapse, and total costs of care. Outcome SF-36 domain scores were also useful in identifying patients with the most favorable clinical, cost, and relapse rate outcomes at the study endpoint.

Funding strategies for emergency medicine research.

The importance of adequate funding for sustaining research efforts cannot be overemphasized. This article addresses funding strategies for emergency physicians, including the necessity of establishing a research track record, developing a well-written grant proposal, and anticipating the grant review process. Funding sources are reviewed with an emphasis on federal institute support and private foundations (including the Emergency Medicine Foundation) in the United States. Sources of current grant support information available from the Internet are provided. Recommendations for enhancing research funding in emergency medicine (EM) are made, including enhancement of formal research training, promotion of EM research and investigators, federal study section membership, and collaboration with established investigators.

Prediction of relapse within eight weeks after an acute asthma exacerbation in adults.

Associations between historical, presenting, and treatment-related characteristics and relapse within 8 weeks after a moderate to severe asthma exacerbation were studied in a cohort of 284 adult asthmatics. Data were collected prospectively, and a multivariate model was developed and internally validated. Within 10 days, only 8% had relapsed, increasing to 45% by 8 weeks. Three variables that could be identified at the time of discharge were independently associated with relapse. These included: having made three or more visits to an emergency department in the prior 6 months (hazard ratio (HR) = 2.3, 95% CI = 1.6-3.4); difficulty performing work or activities as a result of physical health in the 4 weeks prior (HR = 2.7, 95% CI = 1.6-4.3); discontinuing hospital-based treatment for the exacerbation within 24 hours without having achieved a peak expiratory flow rate of at least 50% of predicted (HR = 2.6, 95% CI = 1.6-4.1). These risk factors may help to identify patients with poorly controlled asthma in need of more intensive and comprehensive management.