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American College of Emergency Physicians Information Paper: Chest Pain Units in Emergency Departments - A Report from the Short-Term Observation Services Section

Consensus Panel Members: Co-Chair, Louis Graff, MD, Co-Chair, Tony Joseph, MD, Robert Andelman, MD, Raymond Bahr, MD, David DeHart, MD, James Espinosa, MD, Brian Gibler, MD, Jim Hoekstra, MD, Lala Mathers-Dunbar, MD, Joseph P. Ornato, MD, Jack Page, MD, and Harry Severance, MD

From the American College of Emergency Physicians, Dallas, Texas. Manuscript received April 20, 1995; revised manuscript received and accepted July 31, 1995.

THE AMERICAN JOURNAL OF CARDIOLOGY® VOL. 76 NOVEMBER 15, 1995

Acute myocardial infarction (AMI) is the leading cause of death in the adult population in the United States. Recent advancements in the treatment of AMI have greatly reduced its mortality and morbidity. Yet these treatments are time dependent and necessitate rapid initiation. For good outcome, it is necessary for the patient to quickly recognize signs and symptoms of an AMI, for the physician to quickly diagnose the patient with an AMI, and quickly initiate the appropriate treatment, and it is desirable for the physician to identify patients with an AMI having atypical signs and symptoms of this disease process.

In the past, patient outcome has not been ideal for most patients being evaluated for chest pain. First, many patients wait too long after the onset of symptoms of acute myocardial infarction (AMI) before seeking medical care. The median delay from chest pain onset until the patient arrives in the emergency department (ED) is > 2 hours.1 The mean delay is significantly longer due to a small number of people who wait >= to 24 hours before accessing care. If a patient with an AMI is treated within 70 minutes, left ventricular damage can be minimized by aborting the infarct (mortality decreased to 1.6%).2 After delay, substantial myocardial necrosis can occur, minimizing the impact of medical interventions.

Second, after patients arrive in the ED, significant delays may occur before the physician makes the diagnosis of AMI and implements definitive care such as thrombolysis. Chest pain is one of the most common complaints of patients presenting to the ED, comprising 5% of ED visits.3 Yet, only 10% to 15% of patients with chest pain have an AMI.4-6 Most patients with chest pain do not have significant disease. Many factors contribute to the failure to provide prompt therapy: delays in obtaining an electrocardiogram, delays in decision-making on instituting thrombolytic drugs, and delays in preparing and obtaining medication, and asking for consultation in patients with clear evidence of AMI.7,8 Delays in the diagnosis of AMI may also be increased due to gender biases, staff perception of a patient's pain as noncardiac, or lack of rapidly available serum markers for AMI.9 Delays in administration of thrombolytics lead to larger infarct size, increased number of complications, and ultimately higher mortality.2

The third area of concern is physician failure to correctly diagnose AMI in patients with atypical signs and symptoms (4% to 13% of patients with AMI released from the ED with false reassurance that they do not have coronary artery disease as a cause of their symptoms).4-6 Many of these patients have complications from their AMI, with 11% to 25% dying.5,6 With these difficulties in diagnosing AMI, combined with complications from this serious disease process, it is not surprising that missed AMI is the most expensive cause of malpractice litigation against emergency physicians, constituting 20% of all dollars paid.10

Because of failure in traditionally approaching patients with chest pain, many EDs have begun chest pain units (CPUs) with designated resources of personnel, protocol, space, and equipment for the patient presenting with chest pain. A 1992 survey of American College of Emergency Physician's leadership (n = 319) showed that 9% of EDs had CPUs. Various names have been given to these programs: "Chest Pain ER," "Chest Pain Center," "Chest Pain Evaluation Unit," "Short-Stay ED Coronary Care Unit," "ED Monitored Observation Bed."11-15 These programs have developed approaches to improving the care of the patient with chest pain.

This document was developed by the Short-Term Observation Services Section of the American College of Emergency Physicians to describe the components of these programs that are considered essential to a successful CPU program. This document was reviewed and approved for publication by the Board of Directors of the American College of Emergency Physicians. Six common components have been identified in CPUs:

  1. OUTREACH PROGRAM: an ED- or hospital-based community outreach program that educates the public to promptly seek medical care if they have symptoms of an AMI, such as chest pain, chest discomfort, shortness of breath, diaphoresis, syncope, and risk factors for coronary artery disease, particularly smoking.
  2. ATTACK PROGRAM: an ED attack program to minimize delays in institution of therapy for an AMI (thrombolytics, nitrates, heparin, aspirin, etc.).
  3. OBSERVATION PROGRAM: an ED or hospital observation program that monitors and evaluates low-risk patients to avoid the inadvertent release home of patients with AMI or unstable angina.
  4. UNIT DESIGN: an ED CPU that has a functional design for chest pain evaluation to accomplish optimal patient care. It includes appropriate cardiovascular monitoring equipment.
  5. UNIT STAFFING: additional ED physician and nursing staff sufficient to provide the additional services required for patients in the CPU.
  6. UNIT MANAGEMENT: CPU management structure based on continuous quality improvement program principles to ensure quality patient care and proper utilization of ED resources.

Outreach program - minimize patient delays in seeking medical care: For multiple reasons most patients delay many hours before seeking medical care.16 The median delay in seeking medical care is > 2 hours.1 Most of the benefit from aggressive medical intervention in the patient with an AMI is during the first hour or 2 of symptoms.2 With these long patient delays in seeking medical care, even prompt medical intervention (< 1/2-hour hospital delay in administering thrombolytics) is of limited effectiveness because most of the myocardial tissue has necrosed.17 If the patient delays seeking medical care until the myocardial tissue is nonviable, the physician can only treat the complications of AMI.

Thus, hospitals with specialized programs for chest pain patients (CPUs) offer hospital- or ED-based outreach programs. They seek to educate the public to seek medical help as soon as symptoms begin that could represent AMI including chest pain, chest discomfort, syncope and faintness.18 Outreach programs also educate the public to seek medical help as soon as prodromal symptoms begin that could represent angina. Most patients with AMI have had prodromal symptoms days to weeks before they have an AMI.19 If these patients seek medical care at the time of their prodromal symptoms, and the physician can identify that they are at risk of an AMI, then the AMI can be avoided. Multifaceted approaches, such as the Early Heart Attack Care program, utilize a broad range of techniques to educate and motivate the public to seek medical care before it is too late: videotapes, deputization programs and school programs.20

Outreach programs also seek to improve outcome by educating the public on the value of modifying risk factors for coronary artery disease. Smoking has a profound effect on the development of coronary artery disease. Cessation of smoking can significantly reduce a person's chance of developing AMI.2l Hypertension and hyperlipidemia are also treatable factors for development of atherosclerosis and coronary artery disease. Proper medical management of hypertension22 and hyperlipidemia23 reduces the person's risk of AMI. Exercise conditioning can also significantly reduce the risk of AMI.24 Model educational programs have been developed by the American Heart Association to educate the public on these issues. Public education to reduce risk factors to prevent AMI is the ultimate goal of our health care system, which can be facilitated by the emergency physician and the ED.

Attack program - minimize delays in the emergency department: CPUs include protocols to minimize delays in instituting definitive therapy to patients with chest pain. Up to 60% of patients with an AMI have a clinical presentation suggesting a high or moderate probability of myocardial infarction or unstable angina. The patient's initial history, physical finding, and electrocardiogram are consistent with AMI. The Myocardial Infarction Triage and Intervention trial has shown that prompt intervention in these patients can lower mortality to 1.6% by aborting the infarction.2 This window of opportunity starts to close 1 hour after the patient's symptoms begin. Many different strategies have been developed to prevent delays in instituting definitive therapy including the consensus strategy developed by the National Heart Attack Alert Program Coordinating Committee.9 Measures that decrease "mean time delay to thrombolysis" are appropriate whether in the prehospital setting (electrocardiogram performance by prehospital personnel), in the ED (centralization of thrombolytic equipment in a designated room or mobile cart), or in the hospital (protocols for decreasing delays in preparation and delivery of thrombolytic drugs to the bedside). The measure of success of a hospital program is not just compliance with certain clinical paths, but improvement in the efficiency and time of delivery of quality of patient care.

Observation program - minimize unintentional emergency department release: Many patients with AMI have an initial clinical presentation suggestive of low probability of AMI or unstable angina. The patient's history, physical examination, electrocardiogram, and initial serum cardiac markers do not suggest an AMI. Despite an atypical clinical presentation, the physician must avoid unintentional release of the patient with an initially unimpressive presentation of ischemic heart disease until observation/testing can provide a more definitive diagnosis.

Work from the Multicenter Chest Pain Study Group has shown that 50% to 60% of patients who present to the ED with chest pain require an extended evaluation if virtually all of the patients with AMI are to be identified.25 All patients with atypical chest pain who are at risk of having an AMI cannot be evaluated in the hospital. It has been estimated to cost 1.5 million dollars per life saved to evaluate in the hospital a patient with a 5% probability of AMI.26 The ED observation bed is a more feasible site to evaluate the patient with chest pain having a low probability of AMI. The cost for observation in the ED is typically 20% to 50% the cost of in-hospital evaluation.11,12,27 Serial cardiac enzymes and continuous cardiac monitoring can identify the patient with an AMI who has an atypical clinical presentation. The work of the Emergency Medicine Cardiac Research Group has shown nearly all of these patients can be diagnosed in the ED observation bed in a short time period with the use of currently available diagnostic tests, such as serial rapid creatine kinase analysis and serial electrocardiograms with ST-segment trend monitoring.28

In addition to evaluating the patient with chest pain having a low probability of AMI (who under the traditional approach was discharged inadvertently from the ED), CPUs can be used to evaluate many such patients who have traditionally been admitted to the hospital. Fifty-five percent of patients with chest pain admitted to the hospital do not have cardiac disease.29 Most of these patients can be evaluated in CPUs at a savings of $2,000/patient compared with in-hospital admission.11,12,27 Nationwide, the savings to the health care system are substantial. One billion dollars per year are saved for every 10% of ED chest pain patients (500,000 patients) who are evaluated in CPUs rather than hospital intensive care units.

The patient with atypical signs and symptoms of cardiac disease who is experiencing unstable angina is also at risk of being released home with false reassurance that no serious disease exists. Up to 70% of patients with AMI have had prodromal symptoms before their infarction.19 Serial cardiac enzymes and electrocardiograms cannot diagnose unstable angina. Many patients, upon discharge from the CPU, are scheduled for a form of testing that is reliable for identifying ischemic heart disease. Many strategies are under investigation for fulfilling this role of identifying the patient who is at high risk of developing an AMI, such as thallium scans,30 echocardiograms,31 and sestamibi imaging.32

Chest pain evaluation unit: DESIGN: The CPU in the ED should be designed for the optimal delivery of diagnostic and therapeutic modalities to patients with chest discomfort. The unit should have appropriate diagnostic testing available to identify patients with an AMI and acute ischemic coronary disease, and should be equipped to resuscitate patients who become unstable.

Design of the CPU in the ED will vary between hospitals because many hospitals have different ED configurations. The area of the ED designated for the attack program should be designed to expedite administration of acute therapy to the patient with AMI. This may be a specifically designated area of the ED or a mobile cart with the appropriate equipment. The area of the ED designated for the observation program should be equipped to identify patients with ischemic coronary syndromes as well as AMI. This may be a designated unit or individual beds appropriately equipped and staffed. An ED with a small volume of patients with chest pain may provide services in usual ED beds, whereas an ED with a large volume of patients with chest pain may have a separate physical site, separate nursing services, and a separate nursing station.

Cardiovascular monitors are necessary for all patients evaluated in CPUs. The American College of Cardiology guidelines for cardiovascular monitoring call for adequate human surveillance 24 hours/day, with "the degree of human surveillance required being inversely proportional to the sophistication and reliability of cardiovascular equipment."33 The CPU typically contains patients with low to moderate probability of AMI. A single nurse for each patient is not required: constant human surveillance at the monitor is not necessary. Monitors with advanced features such as arrhythmia alarms, arrhythmia memory, and ST-segment trend monitoring are the rational choice for a CPU.

Several authoritative sources are available on the design of ED CPUs. The American Institute of Architects Guidelines on Health Care Facilities includes a section with specifications for ED observation units.34 This includes recommendations on the size and structure of the ED observation rooms. The American College of Emergency Physicians textbook on ED design has a chapter on the design of ED observation units35 and a chapter on the design of "Chest Pain EDs."36 Multiple model designs are reviewed and the relation between structure and function discussed. The American College of Emergency Physicians Observation Section has published information on the management of ED observation beds.37 These guidelines emphasize the need to design the treatment areas to be consistent with the type of service offered. Treatment areas for patients with symptoms requiring nonmonitored beds (abdominal pain, asthma) are designed differently from treatment areas for patients with symptoms requiring monitored beds (chest pain, syncope).

STAFFING: Traditional EDs provide services to patients over a 2- to 3-hour time period. The number of staff required to provide these services is proportional to the number of patients treated in the facility. EDs offering observation services, such as a CPU, provide services to selected patients over a 9- to 12-hour time period. Time studies have shown these observation patients require twice the amount of emergency physician services required by traditional ED patients.38 Observation patients require additional nursing services as well. Thus, EDs that provide CPU services need additional staffing.

MANAGEMENT: EDs with CPUs have a vigorous quality management and utilization program. The structure and function of the chest pain program are continuously reviewed. Problems are identified and addressed that relate to adding observation services to the ED mix of services. A continuous quality improvement process is used to identify problems in patient care, analyze the patient care system, and devise changes in the patient care system to address the problems.39,40 The American College of Emergency Physicians has published guidelines on the management of ED observation beds.37 These guidelines recommend the use of indicants for measuring outcomes and proper utilization of resources. The measurement of success of the program is improvement in the outcome indicators of service (e.g., mean delay time until administration of thrombolytics, percent of AMIs not diagnosed by the emergency physician, and hospital mortality in patients with acute AMIs).

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  2. Weaver WD, Cerquerin M, Halstrom AT, Litwin PE, Martin JS, Kudenchuk PJ, Eisenberg M. Prehospital initiation versus hospital initiation of thrombolysis: the Myocardial Infarction Triage and Intervention trial (MITI). JAMA 1993;270:1211-1216.
  3. Cochrane DG, Allegra JR, Graff LG, Epidemiology of observation services. In: Graff L, ed. Observation Medicine. Boston, MA: Andover Medical Publishers, 1993:37-45.
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  6. Goldman L, Cook EF, Brand DA, Lee TH, Rouan GW, Weisberg L, Acampora D, Stasiulewicz C, Walshon J, Terranova G, Gottlieb L, Kobernick M, Goldstein-Wayne B, Copen D, Daley K, Brandt AA, Jones D, Mellors J, Jakubowski R. A computer protocol to predict myocardial infarction in emergency department patients with chest pain. N Engl J Med 1988;318:797-803.
  7. Ornato JP. Role of the emergency department in decreasing the time to thrombolytic therapy in acute myocardial infarction. Clin Cardiol 1990;13:V48-V52.
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  12. Gaspoz JM, Lee TH, Cook EF, Weisberg MC, Goldman L. Outcome of patients who were admitted to a new short-stay unit to "rule out" myocardial infarction. Am J Cardiol 1991;68:145-149.
  13. Bahr RD. Chest pain ER - an idea whose time has come. J Cardiovasc Manage 1991; Sept/Oct:5-11.
  14. Gibler WB. Chest pain evaluation in the emergency department: beyond triage. Am J Emerg Med 1994:12:121-122.
  15. Gaspoz J, Lee TH, Weinstein MC, Cook EF, Goldman P, Komaroff AL, Goldman L. Cost-effectiveness of a new short-stay unit to "rule out" acute myocardial infarction in low risk patients. J Am Coll Cardiol l994;24:l249-1259.
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  17. Tiefenbrunn AJ, Sobel BE. Timing of coronary recanalization: paradigms, paradoxes, and pertinence. Circulation 1992;85:2311-2315.
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IMPLICATIONS FOR COST-EFFECTIVENESS

In the past, physicians faced a dilemma when evaluating patients with chest pain. The traditional approach provides poor utilization of health care resources: 50% to 60% of emergency department chest pain patients are admitted to the hospital after an initial evaluation. Most are found to be free of cardiac disease during the hospitalization. The average length of stay for these patients is 3 days, and the average hospital costs are $5,000 to $6,000. Fewer chest pain patients should he admitted to the hospital. The traditional approach also provides poor quality patient care: 5% of myocardial infarction patients have atypical clinical symptoms, and the physician thus does not identify their condition during the initial emergency department evaluation. More chest pain patients need a "rule-out" evaluation, which, until the introduction of chest pain units, could only be obtained during hospitalization.

Chest pain units allow the physician to be more selective in the choice of which chest pain patients should be admitted to the hospital. Low to moderate probability of myocardial infarction can he ruled out in the observation unit rather than in the hospital. Costs are thus lowered for patient care. Chest pain units also allow the physician to be more aggressive; an increasing percentage of emergency department chest pain patients are evaluated with serial electrocardiograms and cardiac enzymes. Low probability of myocardial infarction can also be ruled out in the observation unit, rather than discharging the patient home after an initial evaluation. Thus, quality of patient care is improved. Chest pain units are the answer to the dilemma of evaluating patients with chest pain, and are a win-win situation for both the patient and the physician.

Louis Graff, MD

Copyright © 1995-1998. The American Journal of Cardiology, November 15, 1995.

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New Britain General Hospital
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