Outpatient Rule-Out Myocardial
Infarction in Observation Units
Louis G. Graff, IV, MD, FACP, FACEPAssociate Professor,
Clinical Medicine and Surgery
Director of Research, Emergency Medicine
University of Connecticut School of Medicine
Farmington, CT
Associate Director, Emergency Medicine
New Britain General Hospital
New Britain, CT
Quick Overview
Inpatient Rule-Out Myocardial Infarction Evaluation of Chest Pain Patients
Traditionally, most chest pain patients are evaluated for myocardial infarction (MI) in the hospital. The initial evaluation is in the emergency department (ED). This includes a history and physical examination by a physician, an initial electrocardiogram (ECG), and an evaluation of cardiac enzymes. These initial test results are judged unreliable since the majority of patients with MI do not have positive findings (ECG or cardiac enzymes) upon their initial presentation to the ED.(1,2) Thus, physicians hospitalize all symptomatic patients judged to be at risk for cardiac disease. This comprises 50% to 60% of chest pain patients who present to the ED. The patients are evaluated during their hospitalization with serial ECG and cardiac enzyme testing.This inpatient rule-out MI evaluation is a "lose, lose" approach to the evaluation of patients with chest pain. Quality of patient care can be poor. Many MI patients with atypical symptoms are not hospitalized; 4% to 13% of MI patients with chest pain are discharged with false reassurances that they are not having a MI. (3-7) Up to 25% of such patients die after being released from the ED. (3-5) This results in the number one malpractice problem in emergency medicine. (8,9)
Utilization of resources is also poor. In seeking to avoid misdiagnosing MI patients with atypical symptoms, the physician hospitalizes many noncardiac patients who may have some of the classic symptoms of MI. In fact, most patients admitted for MI rule out are found to have no serious cause of their symptoms. (10) These patients are in the hospital for 2 to 3 days with $4,000 to $5,000 in charges and $2,500 to $3,000 in true costs. (10,11)
Outpatient Rule-Out MI Evaluation of Chest Pain Patients
The outpatient rule-out MI evaluation of chest pain patients was developed to address these problems. (12 ) In many institutions that have adopted this model, ED chest pain patients judged to have a low probability of MI are transferred to an observation bed after initial evaluation. Here they are safely and effectively evaluated in ED-monitored observation beds for 6 to 12 hours with serial ECGs, serial cardiac enzymes and ECG monitoring, including continuous ST-segment monitoring.The outpatient rule-out MI evaluation is a "win, win" approach to the evaluation of patients with chest pain. Quality of patient care improves with observation. Serial stat testing of the MB isoenzyme of creatine kinase (CK-MB) identifies greater than 95% of MI patients during this period. (13,14) Nearly all other MI patients are identified by the physician from the clinical findings. The traditional approach to the evaluation of chest pain patients missed from 4% to 13% of patients with acute MI; (3,4,6,7) these patients were discharged with false reassurances. Studies on the value of testing chest pain patients during a period of observation have been released from the Medical College of Virginia Hospital in Richmond; the Brigham and Women's Hospital in Boston; the New Britain General Hospital in New Britain, Conn; and the Riverside Methodist Hospitals in Columbus, Ohio. They have shown MI miss rates ranging from 0% to 0.9%. Thus, the MI miss rate decreases from a range of 4% to 13% in the traditional approach to less than 1% in the observation approach (Figure 1).
Figure 1
Traditional Versus Observation Approach
Utilization of healthcare resources also improves with observation. The time required for evaluation is 6 to 12 hours rather than 3 to 31/2 days, (10,13) and the cost of patient care is $1,500 lower per patient. (11-15) Of those chest pain patients evaluated in the ED observation unit, 70% to 80% avoid hospital admission.
Evaluation for Unstable Angina
In addition to being evaluated for possible acute MI, patients with chest pain are evaluated for unstable angina in the outpatient observation setting. This is appropriate for patients judged to have a low (1% to 14%) probability of coronary artery disease. (16) The patient is then seen by a physician within 72 hours of release. The cost-effectiveness of diagnostic testing beyond a repeat ECG remains to be examined. Various testing strategies are presently being evaluated, eg, exercise stress testing, stress/thallium testing, sestamibi imaging, sestamibi stress imaging, and echo stress testing.(17,18)References
1. Hedges JR, Young GP, Henkel GF, et al. Serial ECG's are less accurate than serial CK-MB results for emergency department diagnosis of myocardial infarction. Ann Emerg Med. 1992;21:1445-1450.
2. Lee TH, Goldman L. Serum enzymes in the diagnosis of acute myocardial infarction. In: Sox HC Jr, ed. Common Diagnostic Tests: Use and Interpretation. 2nd ed. Philadelphia, Pa: American College of Physicians; 1990:35-66.
3. Tierney WM, Fitzgerald J, McHenry R, et al. Physicians' estimates of the probability of myocardial infarction in emergency room patients with chest pain. Med Decis Making. 1986;6:12-17.
4. Rouan GW, Hedges JR, Toltzis R, et al. A chest pain clinic to improve the follow-up of patients released from an urban university teaching hospital emergency department. Ann Emerg Med. 1987;16:1145-1150.
5. Ting HH, Lee TH, Soukup JR, et al. Impact of physician experience on triage of emergency room patients with acute chest pain at three teaching hospitals. Am J Med. 1991;91:401-408.
6. Lee TH, Rouan GW, Weisberg MC, et al. Clinical characteristics and natural history of patients with acute myocardial infarction sent home from the emergency room. J Am Coll Cardiol. 1987;60:219-224.
7. Puleo PR, Meyer D, Wathen C, et al. Use of a rapid assay of subforms of creatine kinase MB to diagnose or rule out acute myocardial infarction. N Engl J Med. 1994;331:561-566.
8. Rogers JT. Risk Management in Emergency Medicine. Dallas, Tex: Emergency Medicine Foundation-American College of Emergency Physicians; 1985:36.
9. Karcz A, Holbrook J, Burke MC, et al. Massachusetts emergency medicine closed malpractice claims 1980-1990. Ann Emerg Med. 1993;22:553-559.
10. Weingarten SR, Riedinger MS, Conner L, et al. Practice guidelines and reminders to reduce duration of hospital stay for patients with chest pain. Ann Intern Med. 1994;120:257-263.
11. Hoekstra JW, Gibler WB, Levy RC, et al. Emergency department diagnosis of acute myocardial infarction and ischemia: a cost analysis. Acad Emerg Med. 1994;1:103-110.
12. Graff LG, Joseph A, Andelman R, et al. American College of Emergency Physicians' information paper: chest pain units in emergency departments - a report from the Short-Term Observation Services Section. Am J Cardiol. 1995;76:1036-1039.
13. Gibler WB, Young GP, Hedges JR, et al. Early detection of acute myocardial infarction in patients presenting with chest pain and nondiagnostic ECGs: serial CK-MB. Ann Emerg Med. 1990;19:1359-1366.
14. Gibler WB, Young GP, Hedges JR, et al. Acute myocardial infarction and chest pain patients with nondiagnostic ECGs: serial CK-MB. Ann Emerg Med. 1992;21:504-512.
15. Gaspoz JM, Lee TH, Weinstein MC, et al. Cost-effectiveness of a new short-stay unit to "rule out" acute myocardial infarction in low-risk patients. J Am Coll Cardiol. 1994;24:1249-1259.
16. Braunwald E, Mark D, Johnson RH, et al. Unstable Angina Diagnosis and Management. Washington, DC: Agency for Health Care Policy and Research; 1994. US Dept of Health and Human Services publication AHCPR 94-0602. Clinical Practice Guideline No. 10.
17. Kerns JR, Shaub TF, Fontanarosa PB. Emergency cardiac stress testing in the evaluation of emergency department patients with atypical chest pain. Ann Emerg Med. 1993;22:794-798.
18. Varetto T, Cantalupi D, Altieri A, et al. Emergency room technetium 99m sestamibi imaging to rule out acute myocardial ischemic events in patients with nondiagnostic electrocardiograms. J Am Coll Cardiol. 1993;22:1804-1808.
Return to Index of Articles for Clinician;
Volume 14.4
- Faculty Listing 3
- Introduction: Community Message in Acute Myocardial Ischemia 4
- Concept of Community Chest Pain Centers in Emergency Departments 5
- Reawakening Awareness of the Importance of Prodromal Symptoms in the Shifting Paradigm to Early Heart Attack Care (EHAC) 7
- The Role of Emergency Medicine in the Future of American Medical Care: A Summary of the Josiah Macy, Jr, Foundation Conference 12
- From ACC/AHA Guidelines to Best Practice: Can "Acute MI Report Cards" Save Lives?Measuring Quality of Care for Patients With Cardiovascular Disease 16
- Improving Lay Responses to Cardiovascular Emergencies and the Potential of Shifting the Paradigm to Early Heart Attack Care 18
- National Survey of Chest Pain Centers Rationale and Potential Results 21
- Outpatient Rule-Out Myocardial Infarction in Observation Units 22
- Reducing Time to Thrombolytic Treatment 24
- Intervention Programs to Reduce Patient Delays in Acute Myocardial Infarction 29
- Public Education Using the Early Heart Attack Care Program Shawnee Mission Medical Center 31
- School Component: Early Heart Attack Care Program Development and Evaluation 33
- Educational Strategies to Prevent Prehospital Delay in Patients at High Risk for Acute Myocardial Infarction 36
- Precipitating Factors in Acute Cardiovascular Disease 41
- Use of Myocardial Perfusion Imaging in the Emergency Department for Risk Stratification 44
- The Evolution of Chest Pain Centers: The Impact of Technological Advances on the Evaluation of Patients With Possible Acute Ischemic Coronary Syndrome 47
- Critical Pathways for Triage and Treatment of Chest Pain Patients in the Emergency Department 53
- Chest Pain Centers: An Emerging Model for the Emergency Evaluation of Chest Pain and Treatment of Acute Myocardial Infarction 56
- The Key to Success in the Chest Pain Emergency Department: The Observational Role of theNurse 59
- Triage in Moderate Risk Patients With Chest Pain: The Emerging Role of Real-Time Continuous ECG Monitoring 61
- Diffusion of Innovations: The Introduction and Impact of the Chest Pain Emergency
- Department and its Comparison to the Coronary Care Unit Development 64
- Economics of Chest Pain Centers: What Really Matters? 68
Home | What's New | What is EHAC? | Abstracts & Articles
Reader's Digest | Contact Us | Search
Tips for Searching
www.ehac.org.
Site by AllSoldOut Internet Solutions
Visit the Clinical Information EHAC site at www.chestpaincenters.org.
Copyright © 1996-2001
by St. Agnes Healthcare. All Rights Reserved.
|
ABOUT
US FROM
DR. BAHR MORE
INFO SUBSCRIBE |