Reversible adsorption (desorption) of aspirin from activated charcoal.

The potential desorption of aspirin from activated charcoal was investigated in eight patients in a randomized cross-over study. Despite prebinding of aspirin, systemic absorption did occur. Desorption from activated charcoal was characterized by a peak salicylate concentration that was 16% of control and a time to peak salicylate concentration that was delayed in the study group. Bioavailability of aspirin from activated charcoal described by area under the curve was 19% of control. Elimination half-lives were similar in both groups until 12 hours after ingestion, but after 12 hours the half-life of the study group was prolonged while salicylate concentrations were undetectable in the control group. Fifteen percent to 20% of aspirin prebound to charcoal may desorb leading to systemic absorption. Furthermore, release from activated charcoal is initially delayed then sustained through 30 hours.

Carboxyhemoglobin levels in patients with cocaine-related chest pain.

Carboxyhemoglobin (COHb) levels were measured in patients who came to an emergency department complaining of acute chest pain. For subjects not receiving prior oxygen therapy, those with cocaine-related chest pain (n = 10) had a higher mean COHb level than a comparison group (n = 28) with nonischemic chest pain (4.50 +/- 2.40 vs 2.73 +/- 0.66; p < 0.05). Four of the seven (57 percent) who smoked crack had COHb levels greater than 4.5 percent, while only one of six (17 percent) smokers of only tobacco had such a level. These findings suggest an additional mechanism, the formation of COHb, which could aggravate cocaine-induced cardiotoxicity.

Efficacy of topical anesthesia in children.

OBJECTIVES: To compare the efficacy of three formulations of a topical anesthetic solution composed of various concentrations of tetracaine hydrochloride, adrenaline (epinephrine), and cocaine hydrochloride (TAC), and to compare the cost of the topical anesthetic solutions with the cost of lidocaine infiltration. DESIGN: Randomized, double-blind clinical trial. SETTING: Urban pediatric emergency department. PARTICIPANTS: One hundred fifty-six children 3 to 18 years of age and older requiring topical anesthesia for suturing of lacerations. INTERVENTION: Children received 3 mL of one of the following study solutions: TAC 1 consisting of 0.5% tetracaine, 1:2000 dilution of adrenaline, 11.8% cocaine; TAC 2 that contained 1% tetracaine, 1:2000 dilution of adrenaline, 4% cocaine; or TAC 3 made up of 1% tetracaine and 4% cocaine, without adrenaline. MEASUREMENTS OR MAIN RESULTS: Patients were randomized to group 1 (n = 49), group 2 (n = 49), or group 3 (n = 58), and received TAC 1, TAC 2, or TAC 3, respectively. Patients in the three study groups were similar for age, gender, anatomic location and length of the laceration, and history of sutures or use of topical anesthesia. Based on the physician assessment of achievement of complete, partial, or no anesthesia, solutions containing 11.8% cocaine (TAC 1) and 4% cocaine with adrenaline (TAC 2) were more likely to produce complete anesthesia than the solution with 4% cocaine without adrenaline (TAC 3) (P < .001, chi 2). This difference was only noted when the laceration involved the face or scalp. A second dose of the TAC 3 solution was more often required to produce anesthesia when compared with the other two study drugs (P < .003, chi 2). The final cost to produce 3 mL of the study drugs, including the vials, was $16.39 for TAC 1, $8.67 for TAC 2, and $8.41 for TAC 3. CONCLUSIONS: The application of a TAC solution containing 4% cocaine is as effective as a TAC solution containing 11.8% cocaine. Use of the 4% solution decreases the cost of the agent. Adrenaline is a necessary ingredient in the anesthetic solution.

Pharmacokinetics of epsilon-aminocaproic acid during peritoneal dialysis.

Two patients requiring peritoneal dialysis were treated with epsilon-aminocaproic acid (EACA), an antifibrinolytic agent. Samples of serum and dialysate were assayed for EACA concentrations. Total body clearance, dialysis clearance, EACA half-life, and volume of distribution of EACA were calculated. Total body clearance of EACA was 26 ml/min, which is 25% of the drug clearance in patients with normal renal function. Our results suggest that patients undergoing peritoneal dialysis should receive 25% of the usual recommended dose of EACA. Dialysis clearance accounted for only 58% of total body clearance, suggesting an alternative route of elimination of EACA.

Research fundamentals VI: misconduct in biomedical research.

The goal of medical research is the acquisition and application of new knowledge for the benefit of individual patients and society as a whole. Achieving this goal requires excellence in scientific methodology, honesty in data collection and interpretation, and realistic assessment of the implications of the findings. Underlying all steps in the acquisition of new knowledge is the absolute need for application of the highest ethical standards for research. Occasionally, ethical principles of research are breached because of lack of understanding or the carelessness of researchers. However, researchers have the obligation to know and apply basic principles of research ethics in order to avoid, prevent, or recognize deviations from ethical scientific behavior. When intentional violations of the principles of ethical research occur, the impact to the scientific and lay community can be profound. Misconduct can be prevented if the ethical principles of research are understood and consistently applied. This paper describes the sources and detection of misconduct in the production of science in order to provide emergency researchers with the knowledge needed to prevent misconduct from occurring at all.

Implementing the Food and Drug Administration's final rule for waiver of informed consent in certain emergency research circumstances.

In 1996, the Food and Drug Administration released its Final Rule for Waiver of Informed Consent in Certain Emergency Research Circumstances (the Final Rule). The Department of Health and Human Services (DHHS) also released an update of its regulations related to waiver of informed consent in emergency research. These new regulations allow resuscitation research to proceed with a waiver of informed consent under very narrow and specific clinical research circumstances. Waiving informed consent for research participation has profound ethical and scientific implications. However, in unpredictable life-threatening clinical situations for which current therapy is unproven or unsatisfactory, patients usually are unable to consent on their own behalf to participate in clinical trials of potentially beneficial but experimental interventions. Because of the time-dependent nature of most resuscitation interventions, it is usually not feasible to identify and contact the legally authorized representative who can speak on behalf of the patient within the presumed therapeutic window of the intervention under investigation. For such clinical trials to proceed, a waiver of informed consent is usually necessary. Patients who are critically ill or injured and unable to provide meaningful prospective informed consent because of their current life-threatening condition are vulnerable and require additional protections beyond those for research subjects who can speak on their own behalf. The Final Rule and the DHHS-updated regulations incorporate a number of additional patient safeguards that must occur if a clinical trial is to proceed with waiver of informed consent. Specific means of adequately meeting these requirements are not described in the regulations. Although this was intentional on the part of the federal regulators so that individual protocols and research environments would direct the development of these patient safeguards, the lack of specific guidance has led to confusion on the appropriate implementation of the new regulations. This article reviews some of the key concepts of the Final Rule, with suggestions on their purpose and meaning. It also reviews the studies that have been approved to date to proceed with waiver of informed consent, and offers suggestions for the process of implementing the requirements of the Final Rule for research involving patients who are unable to give prospective informed consent.

Clinical characteristics as predictors of recurrent alcohol-related seizures.

OBJECTIVE: To determine whether clinical data available in the emergency department can accurately predict a subset of patients at low risk of developing recurrent seizures following one or more initial alcohol-related seizures in the out-of-hospital arena. METHODS: This was a retrospective secondary analysis of data obtained from the placebo arms of two prospective, randomized trials of drug treatments for the prevention of recurrent alcohol-related seizures. Subjects with and without one or more recurrent alcohol-related seizures during the study period were compared according to the following characteristics: 1) age, 2) gender, 3) daily ethanol consumption, 4) years of ethanol abuse, 5) previous alcohol-related seizure, 6) previous seizure of other etiology, 7) temperature, 8) heart rate, 9) systolic blood pressure, 10) diastolic blood pressure, 11) respiratory rate, and 12) ethanol level. Data were analyzed with t-tests and chi-square where appropriate. RESULTS: One hundred five placebo-treated patients were analyzed and 31 (30%) developed recurrent alcohol-related seizures. None of the listed characteristics were statistically different between the two groups except for the initial ethanol level. Subjects with an ethanol level higher than 100 mg/dL were less likely (0%) to develop recurrent seizures than patients with a level equal to or below 100 mg/dL (36%) (p < 0.01). CONCLUSIONS: An initial ethanol level higher than 100 mg/dL was significantly associated with a low risk for recurrent alcohol-related seizures during the observation period. No other low-risk clinical characteristics could be identified.

Cocaine-associated chest pain: one-year follow-up.

OBJECTIVE: To determine the one-year mortality and incidence of myocardial infarction (MI) post-hospital discharge or ED release for patients with cocaine-associated chest pain. METHODS: A prospective, observational study of an inception cohort of consecutive patients who presented to one of four municipal hospital EDs with cocaine-associated chest pain. Patients were followed for one year from the end of the enrollment period. Main outcome parameters were the one-year actuarial survival and the frequency of nonfatal MI. RESULTS: Mortality data were available for all 203 patients at a mean of 408 days. Additional clinical information was available for 185 patients (91%). There were six deaths (one-year actuarial survival 98%; 95% CI, 95-100%); none from MI. Nonfatal MI occurred in two patients (1%; 95% CI, 0-2%). Continued cocaine use was common (60%; 95% CI, 52-68%) and was associated with recurrent chest pain (75% vs 31%, p < 0.0001). No MI or death was reported for patients who claimed to have ceased cocaine use. CONCLUSIONS: Patients who presented with cocaine-associated chest pain commonly continued to use cocaine after discharge. Urgent evaluation of coronary anatomy or cardiac stress tests may not be necessary for patients for whom MI is ruled out and who do not have recurrent potentially ischemic pain. The subsequent risk for MI and death in this group appears to be low. Intervention strategies should emphasize cessation of cocaine use.

The evaluation of cocaine-induced chest pain with acute myocardial perfusion imaging.

OBJECTIVE: To use myocardial perfusion imaging to determine the etiology of cocaine-induced chest pain in patients without ECG evidence of acute cardiac ischemia. METHODS: The authors conducted a prospective study of consecutive consenting patients aged 18-70 years with cocaine-induced chest pain who reported cocaine use within three days and presented with a chief complaint of chest pain occurring within three hours and lasting longer than 15 minutes with a normal or nondiagnostic ECG. Patients were excluded if they had a clear-cut noncardiac cause of chest pain, ECG evidence of acute cardiac ischemia, history of myocardial infarction, pregnancy, or lactation, required immediate hospitalization, or were unable to consent. Patients were injected with Tc-99m tetrofosmin and imaged. Perfusion scans were independently read by two nuclear radiologists. Clinicians blinded to scan results determined patient disposition. Patients with abnormal scans were asked to return for follow-up resting scans. RESULTS: Fourteen patients were enrolled. Twelve of the 14 patients had chest pain at the time of Tc-99m tetrofosmin injection. Ten of the 14 [(71%) 95% CI = 48% to 95%] scans were normal or within normal limits. Four of the 14 [(29%) 95% CI = 5% to 52%] were abnormal. Of the four patients with abnormal scans, two had follow-up scans that demonstrated an irreversible perfusion abnormality, and two who did not return for follow-up reported no subsequent hospitalizations for acute cardiac ischemia. CONCLUSION: Perfusion imaging did not demonstrate reversible ischemia in most patients (12/14, 86%) with cocaine-induced chest pain without ECG evidence of ischemia. These results suggest that cocaine-induced chest pain in most patients without ECG evidence of ischemia is not due to acute ischemia.

Prospective multicenter evaluation of cocaine-associated chest pain. Cocaine Associated Chest Pain (COCHPA) Study Group.

OBJECTIVE: To describe a large cohort of patients who had chest pain following cocaine use, and to determine the incidence of and clinical characteristics predictive for myocardial infarction in this group of patients. METHODS: A prospective observational cohort study of consecutive patients with cocaine-associated chest pain was conducted in six municipal hospital emergency departments (EDs). Demographic variables, drug abuse patterns, medical histories, chest pain characteristics, ECG results, and laboratory data were recorded. Myocardial infarction was the primary endpoint. RESULTS: Fourteen of 246 patients (5.7%; 95% confidence interval [CI], 2.7-8.7%) had myocardial infarction, as diagnosed by elevated CK-MB isoenzyme levels. There were two deaths (0.8%). The patients had a median age of 33 years. The majority were male (71.5%), non-white (83.3%), cigarette smokers (83.3%) who used cocaine regularly. Chest pain began a median of 60 minutes after cocaine use and persisted for a median of 120 minutes. Chest pain was most frequently described as substernal (71.3%) and pressure-like (46.7%). Shortness of breath (59.3%) and diaphoresis (38.6%) were common. There was no clinical difference between patients who had myocardial infarctions and those who did not. Twelve patients had arrhythmias and four had congestive heart failure. All cases requiring intervention were evident upon presentation. An ECG revealing ischemia or infarction had a sensitivity of 35.7% for predicting a myocardial infarction. The specificity, positive predictive value, and negative predictive value of the ECGs were 89.9%, 17.9%, and 95.8%, respectively. CONCLUSIONS: Myocardial infarction in patients who have cocaine-associated chest pain is not uncommon. No clinical parameter available to the physician can adequately identify patients at very low risk for myocardial infarction. Therefore, all patients with cocaine-associated chest pain should be evaluated for myocardial infarction.

A public health approach to emergency medicine: preparing for the twenty-first century.

This paper focuses on the implications of an inadequate public health/preventive health care system for emergency medicine (EM), the role that EM providers can play in remedying critical health problems, and the benefits gained from a public health approach to EM. A broad definition of public health is adopted, suggesting shared goals of public health and EM. Critical problems posed for EM include alcohol, tobacco, and other drug abuse; injury; violence; sexually transmitted diseases and human immunodeficiency virus (HIV) infection occupational and environmental exposures; and the unmet health needs of minorities and women. A blueprint for future merging of public health issues with EM is presented that includes the application of public health principles to 1) clinical practice; 2) public education, community involvement, and public policy advocacy; 3) development of medical school and residency public health/prevention curricula and teaching methods; and 4) research opportunities and surveillance. Finally, recommendations are proposed that require restructuring the present health care system to provide resources, incentives, and organizational changes that promote an integration of public health and preventive services in the practice of EM.

Research ethics in emergency medicine.

A framework for the ethical conduct of research is constructed within this article. The historical developments and current state of ethical principles and regulations guiding ethical conduct of research are reviewed, while situations unique to emergency medicine research are highlighted. Also discussed are the related issues of scientific misconduct, conflict of interest, authorship guidelines, and publication ethics.

Participation of women in clinical trials of drug therapies: a context for the controversies.

Women's participation in clinical trials, particularly those involving drugs, has been said to be both overrepresented and underrepresented. How can this be? Studies of participation are compared and contrasted to elucidate some reasons for this contradiction. The history of women's participation in clinical trials is chronicled through policies and regulations filled with restrictions. Since 1993, however, the National Institutes of Health has mandated, and the Food and Drug Administration has emphasized, inclusion of women in clinical trials, only to be thwarted by other regulations excluding many women. Gender-specific analyses are required to detect gender differences in effects of pharmaceutical and nonpharmaceutical interventions, but they are seldom performed. The exclusion of women from clinical trials means that women's healthcare is compromised by lack of sex-specific information about dosing of drugs and unique uses of drugs. A database, although currently quite limited, tracks the participation of women in clinical trials funded by federal agencies, industries, and nonprofit groups. Federal regulations have recently changed. Additional changes in access to all phases of clinical trials and enhanced monitoring of clinical trials are recommended.

Cost comparison of searching the Iowa Drug Information Service index manually and by computer.

A cost comparison of searching the Iowa Drug Information Service index manually and by computer is presented. Identical searches were performed on a computer system and by hand. The searches were timed and the results compared. Costs of start-up, maintenance, and operation were calculated for the manual and computer systems. Both systems yielded a similar number of relevant references. Start-up and maintenance costs were found more expensive for the computer system, but operational costs were less expensive (p less than 0.05). Operational costs varied according to the number of uses per year. Operational costs were found to increase faster for the manual system than the computer system. At 980 uses per year, the overall cost of the computer system was less than the manual system. A dedicated microcomputer system to search the Iowa Drug Information Service index was found less costly than, and as effective as, the common manual system.

Lorazepam for the prevention of recurrent seizures related to alcohol.

BACKGROUND AND METHODS: Alcohol abuse is one of the most common causes of seizures in adults. In a randomized, double-blind study, we compared lorazepam with placebo for the prevention of recurrent seizures related to alcohol. Over a 21-month period, we studied consecutive patients with chronic alcohol abuse who were at least 21 years of age and who presented to the emergency departments of two hospitals in Boston after a witnessed, generalized seizure. The patients were randomly assigned to receive either 2 mg of lorazepam in 2 ml of normal saline or 4 ml of normal saline intravenously and then observed for six hours. The primary end point was the occurrence of a second seizure during the observation period. RESULTS: Of the 229 patients who were initially evaluated, 186 met the entry criteria. In the lorazepam group, 3 of 100 patients (3 percent) had a second seizure, as compared with 21 of 86 patients (24 percent) in the placebo group (odds ratio for seizure with the use of placebo, 10.4; 95 percent confidence interval, 3.6 to 30.2; P<0.001). Forty-two percent of the placebo group were admitted to the hospital, as compared with 29 percent of the lorazepam group (odds ratio for admission, 2.1; 95 percent confidence interval, 1.1 to 4.0; P=0.02). Seven patients in the placebo group and one in the lorazepam group were transported to an emergency department in Boston with a second seizure within 48 hours after hospital discharge. CONCLUSIONS: Treatment with intravenous lorazepam is associated with a significant reduction in the risk of recurrent seizures related to alcohol.

Acute cardiac ischemia in patients with cocaine-associated complaints: results of a multicenter trial.

STUDY OBJECTIVE: To describe the characteristics of a large group of patients who presented to emergency departments with cocaine-associated symptoms consistent with acute cardiac ischemia (ACI) and to determine the incidence of confirmed ACI including acute myocardial infarction (AMI) in this population. METHODS: We performed a substudy on all patients in a multicenter prospective clinical trial (the Acute Cardiac Ischemia-Time Insensitive Predictive Instrument [ACI-TIPI] Clinical Trial) that enrolled ED patients with chest pain or other symptoms consistent with ACI including subjects with identified cocaine use. Demographic and clinical features, including initial and follow-up clinical data, ECGs, and tests to determine serum creatine kinase isoenzyme MB subunit concentrations, were analyzed. Diagnoses of AMI followed the World Health Organization criteria for AMI and of angina pectoris, the Canadian Cardiovascular Society Classification. RESULTS: Of the 10,689 patients enrolled in the trial, 293 (2.7%) had cocaine-associated complaints. Among the 10 participating hospitals, the incidence of patients with cocaine-associated symptoms varied from 0.3% to 8.4%. Only 6 patients (2.0%, 95% confidence interval [CI] 0.76% to 4.4%) had a diagnosis of ACI; 4 (1.4%, 95% CI 0.37% to 3.5%) had unstable angina, and 2 (0.7%, 95% CI 0.08% to 2.4%) had AMI. Although patients with cocaine-induced complaints were as likely to be admitted to the coronary care unit compared with all study patients without cocaine use (14% versus 18%, P =.14, difference not significant), these patients were much less likely to have confirmed unstable angina (1.4% versus 9.3%, P <.001) or AMI (0. 7% versus 8.6%, P <.001). Compared with patients younger than 45 years, patients with cocaine usage were more likely to be admitted to the ICU (14% versus 8.0%, P =.0018) but less likely to have confirmed AMI (0.7% versus 2.8%, P =.033). CONCLUSION: Patients presenting to EDs with cocaine-associated chest pain or related symptoms infrequently had ACI, and even less so, AMI. This suggests the need for selectivity in the hospitalization of patients with such cocaine-associated symptoms.

Clinical pharmacy education in new England: a report of the Whispering Pines Conference.

Clinical pharmacy practice as it relates to the future of the pharmacy profession has been examined at Hilton Head in 1985 and at regional conferences throughout the U.S. between 1986 and 1988. However, clinical pharmacy education and its role in the future of the profession had not been the focus of this type of "futuristic" conference. In 1988, the clinical pharmacy faculties from the four colleges of pharmacy in New England met to discuss the "Directions for Clinical Pharmacy Education in New England." Through a series of workshops, and stimulated by challenges from keynote speakers, the participants focused on the current status of clinical pharmacy education in New England, the barriers to change, and the strategies required to accomplish these changes. Consensus on prioritization of changes and their strategies was reached, and those that could be implemented in the near future were identified. Since the conference, changes have occurred and the professional networking that began at the conference has continued. This paper is a summary of the proceedings of this conference.

The lack of efficacy of phenytoin in the prevention of recurrent alcohol-related seizures.

STUDY OBJECTIVE: To determine the effectiveness of IV phenytoin in the prevention of recurrent alcohol-related seizures during a six-hour observation period. DESIGN: Prospective, randomized, double-blind trial comparing IV phenytoin with normal saline placebo, conducted from January 1990 through December 1991. SETTING: Emergency department of an inner-city, university-affiliated, teaching hospital. PARTICIPANTS: One hundred forty-seven consecutive adults more than 25 years of age who presented with a witnessed generalized seizure in the setting of chronic alcohol abuse. INTERVENTIONS: Eligible subjects received 15 mg/kg of phenytoin or normal saline at an equivalent volume over 20 minutes by IV pump. Patients were observed for six hours in the ED after drug administration. Those experiencing a second seizure were admitted to the hospital. RESULTS: One hundred patients completed the study. Recurrent alcohol-related seizures occurred in ten of 49 patients (20.4%) in the phenytoin group and in 12 of 51 patients (23.5%) in the placebo group. chi 2 analysis revealed no statistically significant difference between the two groups (chi 2 = 0.142; P = .706). The 95% confidence interval for the difference was -0.13 to + 0.19. The relative risk of recurrence between groups was 0.868 with a 95% confidence interval of 0.412 to 1.826. CONCLUSION: No significant benefit of phenytoin administration in the prevention of recurrent alcohol-related seizures during a six-hour observation period was demonstrated.

Nitroglycerin in the treatment of cocaine associated chest pain--clinical safety and efficacy.

The optimal medical regimen for the treatment of cocaine associated myocardial ischemia has not been defined. While animal and human data demonstrate the risks of beta-adrenergic blockade, studies in the cardiac catheterization laboratory suggest a beneficial role of nitroglycerin. We performed a prospective multicenter observational study to evaluate the clinical safety and efficacy of nitroglycerin in the treatment of cocaine associated chest pain at six municipal hospital centers. Of 246 patients presenting with cocaine associated chest pain, 83 patients were treated with nitroglycerin at the discretion of the treating physician. Relief of chest pain and/or adverse hemodynamic outcome were the primary endpoints. Baseline comparisons of patients treated with nitroglycerin to those not treated with nitroglycerin found that the treated patients were at higher risk of ischemic heart disease. They were older (36 years vs 32 years, p = 0.0008), more likely to have an ischemic electrocardiogram (27% vs 4%, p < 0.0001), to be admitted (94% vs 40%, p < 0.0001), and to have a discharge diagnosis of ischemic heart disease (41% vs 9%, p < 0.0001). Nitroglycerin was beneficial in 41 patients (49%; 95% CI, 38-60%): 37 patients (45%) had relief or reduction in the severity of chest pain and 4 patients (5%) had other beneficial effects. Only one patient had an adverse outcome (transient hypotension in the setting of a right ventricular infarct). Nitroglycerin is safe and possibly effective in the treatment of cocaine associated chest pain.

Use of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) to assist with triage of patients with chest pain or other symptoms suggestive of acute cardiac ischemia. A multicenter, controlled clinical trial.

BACKGROUND: Approximately 6 million U.S. patients present to emergency departments annually with symptoms suggesting acute cardiac ischemia. Triage decisions for these patients are important but remain difficult. OBJECTIVE: To test whether computerized prediction of the probability of acute ischemia, used with electrocardiography, improves the accuracy of triage decisions. DESIGN: Controlled clinical trial. SETTING: 10 hospital emergency departments in the midwestern, southeastern, and northeastern United States. PATIENTS: 10689 patients with chest pain or other symptoms suggestive of acute cardiac ischemia. INTERVENTION: The probability of acute ischemia predicted by the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI), either automatically printed or not printed on patients' electrocardiograms. MEASUREMENTS: Emergency department triage to a coronary care unit (CCU), telemetry unit, ward, or home. Other measurements were the bed capacity of the CCU relative to that of the telemetry unit; training or supervision status of the triaging physician; and patient diagnoses and outcomes based on clinical, electrocardiographic, and creatine kinase data. RESULTS: For patients without cardiac ischemia, in hospitals with high-capacity CCUs and relatively low-capacity cardiac telemetry units, use of ACI-TIPI was associated with a reduction in CCU admissions from 15% to 12%, a change of -16% (95% CI, -30% to 0%), and an increase in emergency department discharges to home from 49% to 52%, a change of 6% (CI, 0% to 14%; overall P=0.09). Across all hospitals, for patients evaluated by unsupervised residents, use of ACI-TIPI was associated with a reduction in CCU admissions from 14% to 10%, a change of -32% (CI, -55% to 3%); a reduction in telemetry unit admissions from 39% to 31%, a change of -20% (CI, -34% to -2%); and an increase in discharges to home from 45% to 56%, a change of 25% (CI, 8% to 45%; overall P=0.008). Among patients with stable angina, in hospitals with high-capacity CCUs, use of ACI-TIPI was associated with a reduction in CCU admissions from 26% to 13%, a change of -50% (CI, -70% to -17%), and an increase in discharges to home from 20% to 22%, a change of 10% (CI, -29% to 71%; overall P=0.02). At hospitals with high-capacity telemetry units, use of ACI-TIPI was associated with a reduction in telemetry unit admissions from 68% to 59%, a change of -14% (CI, -27% to 1%), and an increase in emergency department discharges to home from 10% to 21%, a change of 100% (CI, 22% to 230%; overall P=0.02). Among patients with acute myocardial infarction or unstable angina, use of ACI-TIPI did not change appropriate admission (96%) to the CCU or telemetry unit at hospitals with high-capacity CCUs or telemetry units. CONCLUSIONS: Use of ACI-TIPI was associated with reduced hospitalization among emergency department patients without acute cardiac ischemia. This result varied as expected according to the CCU and cardiac telemetry unit capacities and physician supervision at individual hospitals. Appropriate admission for unstable angina or acute infarction was not affected. If ACI-TIPI is used widely in the United States, its potential incremental impact may be more than 200000 fewer unnecessary hospitalizations and more than 100000 fewer unnecessary CCU admissions.