Critical Pathways for Triage and Treatment Of Chest Pain Patients in the Emergency Department
Joseph P. Ornato, MD, FACCProfessor of Internal Medicine (Cardiology)
Director of Research
Department of Emergency Medicine
Virginia Commonwealth University/Medical College of Virginia
Richmond, VA
Quick Overview
Introduction
Aggressive intervention, including thrombolytic therapy and mechanical revascularization, has been demonstrated to reduce mortality and minimize left ventricular damage consistently when initiated early after the onset of symptoms of acute myocardial infarction (AMI). (1-6) The need for urgent diagnosis and intervention has prompted many institutions to explore alternative methods for rapid screening of patients who present to the emergency department (ED) with chest pain.The purpose of this paper is to: (1) describe a process for the multidisciplinary development of a comprehensive strategy for triage and evaluation of patients who present to the ED with chest pain; (2) describe a specific strategy that has evolved at the Medical College of Virginia that incorporates several different technologies, including standard 12-lead electrocardiography (ECG), echocardiography, continuous ST-segment monitoring, myocardial markers of necrosis, and technetium Tc-99m sestamibi; and (3) present preliminary results on our first 18 months of experience using this strategy.
Clinical Pathways "Track" Approach
The Medical College of Virginia is a 1,080-bed tertiary care academic medical center. Its 96-bed ED complex is divided into five contiguous subspecialty treatment units (acute medicine/cardiac, acute surgery/trauma, pediatrics, obstetrics/gynecology, and episodic primary care). Together, the five units treat more than 108,000 emergency patients per year.We have recently implemented a sophisticated Cardiac Emergency Department approach to the triage and treatment of patients with suspected cardiac ischemia. (7) The strategy has three basic goals: (1) to rule out AMI; (2) to rule out unstable angina; and (3) to screen for the presence of clinically significant coronary artery disease (CAD) in patients who are believed to be at risk.
All patients with chest pain are brought directly into the treatment unit; an ECG is begun immediately by nurses or specially trained technicians. The senior physician in charge of the unit is shown the ECG, takes a brief history, examines the patient, and makes an immediate triage decision, assigning the patient to one of five levels or tracks (see Figure 1).
Figure 1
Chest Pain Critical Pathways in the ED
Patients with obvious AMI or unstable angina are treated promptly in the ED and transferred to the coronary care unit (CCU) or cardiac catheterization laboratory for further care. Less obvious cases are "fast-tracked" in the CCU with continuous ST-segment monitoring and accelerated creatine kinase-MB and myoglobin determinations, followed by a technetium Tc-99m sestamibi rest and exercise study or cardiac catheterization. Atypical low-risk cases have technetium Tc-99m sestamibi injected within minutes after arrival in the ED. A gated single photon emission computed tomography (SPECT) rest scan is performed directly from the ED. If it demonstrates evidence of cardiac ischemia or impaired left ventricular function, the patient is admitted to the CCU on a fast-track rule-out AMI protocol. If both studies are negative, the patient is sent home and returns the next day for an exercise gated SPECT technetium Tc-99m sestamibi study.
Quick Overview
Preliminary Experience With This Strategy
To determine the ability of radionuclide imaging to detect significant CAD in "low-risk" ED patients with chest pain, we compared the results of resting technetium Tc-99m sestamibi SPECT myocardial perfusion imaging (MIBI) done in the ED with coronary angiography. ED physicians assigned all chest pain patients to one of five triage levels based on the clinical probability of acute cardiac ischemia. They initially judged 433 patients to be at relatively low risk of acute cardiac ischemia (level 4) because they had chest pain of less than 30 minutes' duration and nondiagnostic ECGs. A resting MIBI was performed for all of these patients. The study population consisted of 49 of the 433 patients (45% M, 55% F, median age 57 years, age range 31 to 86) for whom the CCU attending cardiologist ordered coronary angiography, either because the resting MIBI was abnormal (n=34) or because there was other clinical suspicion of acute cardiac ischemia (n=15).There was a significant correlation (n=49; P< .0003) between the MIBI results and angiographic findings of significant CAD (>75% narrowing in at least one major epicardial vessel). MIBI results correlated best with the coronary angiographic findings when the radioisotope was injected during pain (n=21; P< .0004); however, results also correlated when the radioisotope was not injected during pain (n=28, P< .01). These findings suggest that MIBI is of value for detecting significant CAD in "low-risk" ED chest pain patients.
To determine whether our systematic protocol for triaging ED patients with chest pain is cost-effective, we compared median hospital length of stay (LOS) in days and median hospital charges per patient in thousands of dollars in a sample of CCU patients admitted for evaluation of chest pain before (1992; n=67) and after (1994; n=31) institution of our comprehensive triage protocol. In the absence of ECG evidence of AMI or unstable angina, patients were injected with technetium Tc-99m sestamibi in the ED and a gated SPECT rest perfusion scan was performed. Scan results were used to stratify patients for CCU admission. We analyzed the impact of the protocol on a sample of patients admitted to the CCU who had a final diagnosis of AMI (ICD 410), unstable angina (ICD 411), and noncardiac chest pain (ICD 786.5) from before and after institution of the protocol. Distribution of patients in each category (percentage of CCU admissions for chest pain, LOS, and charges) is shown in Table 1.
Hospital charges for AMI increased despite a 37% decrease in length of stay, reflecting inflationary changes from 1992 to 1994 (the protocol was not designed to alter AMI patient care in any way). For groups impacted by the protocol (unstable angina and noncardiac chest pain), there has been a dramatic decrease in length of stay and a modest decrease in hospital charges (6% and 31%, respectively). The number of ED chest pain patients admitted to the hospital has decreased by more than 20% since protocol institution. With the protocol, more unstable angina patients and fewer noncardiac patients are now admitted to the CCU.
Conclusion
Our experience thus far appears to support the value of a systematic approach to the triage and treatment of chest pain patients in the ED. The strategy appears to identify patients with acute coronary syndromes and/or underlying CAD who might have been overlooked with a more traditional approach. At our institution, the chest pain critical pathways appear to be highly cost-effective, primarily by reducing the number of unnecessary hospital admissions and dramatically reducing the length of hospital stay for many patients.References
1. Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto Miocardico (GISSI). Effectiveness of intravenous thrombolytic treatment in acute myocardial infarction. Lancet. 1986;1:397-402.
2. ISIS (Second International Study of Infarct Survival) Collaborative Group. Randomized trial of intravenous streptokinase, oral aspirin, both or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. Lancet. 1988;2:349-360.
3. Wilcox RG, Olsson CG, Skene AM, et al. (for the ASSET Study Group). Trial of tissue plasminogen activator for mortality reduction in acute myocardial infarction. Lancet. 1988;2:525-530.
4. AIMS Trial Study Group. Effect of intravenous APSAC on mortality after acute myocardial infarction: preliminary report of a placebo-controlled clinical trial. Lancet. 1988;1:545-549.
5. AIMS Trial Study Group. Long-term effects of intravenous anistreptase in acute myocardial infarction: final report of the AIMS study. Lancet. 1990;335:427-431.
6. The GUSTO Investigators. An international randomized trial comparing four thrombolytic strategies for acute myocardial infarction. N Engl J Med. 1993;329:673-682.
7. Tatum JL, Ornato JP, Jesse RL, et al. A diagnostic strategy using Tc-99m sestamibi for evaluation of patients with chest pain in the emergency department. Circulation. 1994;90:I367. Abstract.
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
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