Decision Rule Improves Cardiac Triage
Abstract & Commentary
Synopsis: The clinical decision rule tested in this study reduced unnecessary hospital admissions in patients with suspected acute cardiac ischemia without affecting safety.
Source: Reilly BM, et al. JAMA. 2002;288:342-350.
Among patients admitted from the emergency department (ED) with possible acute cardiac ischemia, as few as 25% are diagnosed with unstable angina or acute myocardial infarction (MI) and less than 5% experience a life-threatening complication. Concurrently, 2% to 5% of at-risk patients are improperly diagnosed in the ED and not triaged to cardiac care units.
To test ability to improve triage decisions, Reilly and associates compared outcomes in consecutive patients admitted from the ED with suspected acute cardiac ischemia during 2 periods: prior to using a clinical decision rule (pre-intervention group: n = 207) and after implementation (intervention group: n = 1008). The study took place in a 700-bed urban teaching hospital (Cook County) with an ED staffed by full-time emergency medicine attending physicians and residents. Patients were enrolled if they had an admitting diagnosis of acute MI, "rule-out MI," unstable angina, acute cardiac ischemia, or coronary artery disease if cardiac enzyme tests were ordered. Patients were followed after discharge from the ED if they presented with complaints of chest pain, epigastric pain, or dyspnea, and a 12-lead ECG was performed to evaluate possible acute cardiac ischemia.
The prediction rule stratified patients into 4 risk groups (high, moderate, low, and very low) according to ECG findings and the presence or absence of 3 "urgent factors:" systolic blood pressure < 100 mm Hg, rales heard above both lung bases, and known unstable ischemic heart disease. Safety was defined as the proportion of all patients who experienced major cardiac complications within 72 hours who were triaged to a coronary care unit or telemetry unit after ED evaluation. Efficiency was defined as the proportion of all patients who did not experience major cardiac complications who were triaged to a ED observation unit or an unmonitored unit.
Of the 973 intervention-group patients who did not experience major complications, 350 were sent to an observation unit or unmonitored ward. Thus, efficiency during the intervention was 36% (350/973), significantly higher than in the pre-intervention period (21% [42/198]; P < 0.001). Of 35 intervention-group patients who experienced major cardiac complications, 33 were triaged to a coronary care unit (n = 18), or telemetry unit (n = 15). Thus, safety in the intervention group (94% [33/35]) was not significantly different from pre-intervention (89% [8/9]; P = 0.57). Subgroup analysis indicated higher efficiency when physicians used the decision rule (P < 0.01). Improved efficiency was explained solely by different triage decisions for very low-risk patients. Attending physicians evaluated the decision prediction rule favorably (68%), and 84% believed it improved patient care.
Comment by Leslie A. Hoffman, PhD, RN
The major finding of this study was that use of the clinical decision rule reduced unnecessary admissions to inpatient-monitored beds without increasing complications among patients who were triaged to short-stay or unmonitored units. This change was achieved primarily by improving the identification of very low risk patients, and not admitting these patients to telemetry units.
In 1996, Goldman and colleagues1 published a prediction rule for major cardiac complications within 72 hours after evaluation in the ED in patients who present with suspected acute cardiac ischemia. The rule was derived and validated in more than 15,000 ED patients; however, its effect on patient outcomes was never measured prior to this study. Prior to implementing the present study, the research team created a 1-page summary (available on request) that incorporated the risk-stratification algorithm and guidelines for its use. The study’s primary outcome measures—safety and efficiency—link the decisions made using the prediction rule with a critical outcome of the decision—occurrence of a life-threatening complication within 72 hours.
The prediction rule used by the team was concise and appeared to reliably guide practice in this setting. It included prompts for physicians to provide the clinical data necessary to apply the rule accurately and included space for an explanation if the decision made differed from recommendations. Physicians used the decision rule in 832 (83%) of the 1008 intervention-group patients and evaluated it favorably. To secure this high level of approval, the team preceded use of the prediction rule by baseline data collection and 3-months of pilot testing and simulated effect analysis, a process described as essential groundwork to ensure physician support.
The study used several strategies to eliminate bias. Research assistants, blinded to the risk stratification process, enrolled all eligible patients, identified the triage site, and interviewed patients to obtain contact information for post-hospital follow-up. Patients who could not be contacted by phone were visited at their residences. If patients were lost to follow-up, death records were searched for 12 months. Follow-up was complete in 994 (98.6%) of cases. No deaths were documented in the remaining 14 patients. Two physicians blinded to the risk stratification process, reviewed records to determine possible complications and, if there was disagreement, a third physician helped to resolve the disagreement. Sample size was chosen based on a power analysis that indicated a sample of 1000 patients provided > 80% power to detect a 10% difference.
There is no precise risk threshold that can uniformly dictate which patients should be admitted from the ED to a specific hospital unit. Pending future research, the clinical prediction rule tested in this study appears to provide a reliable evidence-based foundation for decision-making in this challenging area.
Dr. Hoffman is Professor Medical-Surgical Nursing Chair, Department of Acute/Tertiary Care University of Pittsburgh School of Nursing.
Reference
1. Goldman L, et al. N Engl J Med. 1996;334:1498-1504.
Synopsis: The clinical decision rule tested in this study reduced unnecessary hospital admissions in patients with suspected acute cardiac ischemia without affecting safety.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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