Care of patients with a low probability of acute myocardial infarction. Cost effectiveness of alternatives to coronary-care-unit admission

2-D echocardiography prediction of adverse events in ED patients with chest pain

The objective of this study was to establish the efficacy of two-dimensional (2-D) echocardiography (echo) in predicting adverse cardiac events in patients presenting to the ED with possible acute coronary syndrome (ACS). Patients 25 years of age or older having symptoms consistent with ACS and a non-diagnostic electrocardiogram (ECG) were evaluated with 0-, 3-, 6-, and 9-hour creatine kinase -MB (CK-MB) assays and continuous 12-lead ECG ST-segment monitoring. Patients with normal serial CK-MB assays and no ECG changes after 9 hours had a resting 2-D transthoracic echo performed. A positive 2-D echo was defined as segmental or global wall motion abnormalities. Patients were followed up after 6 months to identify adverse events resulting from ACS. Of the 1112 patients receiving an echo, 18 had positive studies. None had adverse events on follow-up. Of the 1094 patients with a negative 2-D echo, 15 had adverse events (2 acute myocardial infarctions, 2 coronary artery bypass graftings, and 11 percutaneous transluminal coronary angioplasties). Resting 2-D echo did not predict cardiac adverse events in patients with possible ACS and non-diagnostic serial 12-lead ECG and normal serial CK-MB at the end of a 9-hour evaluation.

Is telemetry monitoring necessary in low-risk suspected acute chest pain syndromes?

BACKGROUND

Non-ICU telemetry monitoring has proven to be a valuable resource for patients suspected of having an acute myocardial infarction. While a significant number of patients are admitted to these units, the actual incidence of events or interventions is low.

OBJECTIVE

To identify a subset of patients in whom telemetry monitoring does not alter management.

DESIGN

Prospective observational study.

SETTING

Large tertiary care facility.

PATIENTS

A total of 414 patients consecutively admitted from the emergency department for suspected acute coronary syndromes were studied. Patients were excluded if they presented with ST-segment elevations, were revascularized on hospital admission, were admitted to a surgical service, were transferred from another floor or unit, or remained in the emergency department for the course of the stay.

OUTCOMES

Events were defined as development of myocardial infarction, episodes of chest pain, new or rapid atrial arrhythmias, ventricular arrhythmias, any form of AV nodal block, and asystole. Intervention or change in management was any increase, decrease, or change in medication, cardioversion, electrophysiology study, or transfer to the ICU.

RESULTS

Patients who had atypical chest pain and normal ECG findings were significantly less likely to have both intervention and events (4 interventions vs 23 interventions [p < 0.0001], 12 events vs 45 events [p < 0.0001]), compared to those with typical chest pain and abnormal ECG findings. When normal laboratory values were added, only four telemetry events were observed.

CONCLUSION

Patients with atypical chest pain and normal ECG findings represent a subset of patients with low risk for life-threatening arrhythmia. Use of telemetry monitoring in this subset of patients should be reevaluated.

The development and role of predictive instruments in acute coronary events: improving diagnosis and management

The diagnosis and management of acute myocardial infarction and unstable angina pectoris are frequent challenges for emergency department staff. Strategies must quickly and accurately identify all patients requiring admission, monitoring, and reperfusion therapy to maximize outcomes without overdiagnosing. The Acute Cardiac Ischemia Time-Insensitive Predictive Instrument and the Thrombolytic Predictive Instrument are two decision-support tools designed to address this need. The instruments have been shown to improve some measures of the appropriateness of and time to emergency department triage. Prospective trials will be completed soon that will examine their effects on morbidity and mortality.

Acute ischemic syndromes. Chest pain center concept

CPCs have been developed to meet the clinical challenge posed by the diverse group of patients presenting to the ED with findings suggestive of a coronary event. Using a protocol-driven approach, high- and low-risk patients can be identified on presentation, facilitating urgent therapy in the former and triage of the latter to more deliberate management. Most CPCs focus on low-risk patients who are being increasingly managed by accelerated diagnostic protocols. These methods comprise systematic strategies that include innovative diagnostic approaches during a 6 to 12 hour period of observation with serial ECGs, continuous monitoring and cardiac biomarker measurements. A negative evaluation is usually followed by predischarge stress testing, and positive findings mandate admission. An essential aspect of the CPC strategy is continuity of care for patients with negative cardiac evaluations. Current data indicate that management of low-risk patients with chest pain in a CPC is safe accurate, and appears to be cost-effective.

Enoxaparin: a pharmacoeconomic review of its use in the prevention and treatment of venous thromboembolism and in acute coronary syndromes

The pharmacoeconomics of the low molecular weight heparin (LMWH) enoxaparin in the prophylaxis and treatment of venous thromboembolism have mostly been investigated in cost-effectiveness studies that estimated direct costs associated with treatment, using decision analyses and clinical outcome data from randomised controlled trials. These studies have shown enoxaparin to be cost effective compared with unfractionated heparin (UFH) and warfarin in short-term thromboprophylaxis for hospital inpatients undergoing orthopaedic surgery and in thromboprophylaxis following trauma. Outpatient treatment of acute proximal deep vein thrombosis with enoxaparin has also been shown to be cost effective compared with inpatient treatment using UFH. In general surgery, however, it remains to be determined whether enoxaparin is a cost-effective alternative to UFH. The cost effectiveness of enoxaparin compared with UFH in the treatment of unstable angina and non-Q-wave myocardial infarction has also been investigated in several countries using clinical outcomes data from the Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-wave Coronary Events (ESSENCE) randomised trial. ESSENCE demonstrated that enoxaparin was superior to UFH in terms of tolerability and efficacy, and cost saving at both 30-day and 1-year follow-ups. An increasing number of studies indicate enoxaparin to be of economic benefit when used for prevention and treatment of venous thromboembolism and treatment of acute coronary symdromes.

Clinical application of rapid quantitative determination of cardiac troponin-T in an emergency department setting

OBJECTIVES

We analysed the clinical use of Troponin-T compared to creatine kinase MB in a non-trauma emergency department setting.

BACKGROUND

A newly established single specimen quantitative Troponin T assay allows the clinical application of this parameter. METHODS. Five-hundred Troponin T tests were provided for use by emergency physicians who could combine them with the routine laboratory tests without restriction as to the indication or number of tests per patient. The number of tests per patient, time frame, final diagnosis and additional clinical information gained were recorded. All patients were followed for at least 6 months to verify the diagnosis and to assess the occurrence of cardiac events (nonfatal AMI or cardiac death). The ability of Troponin T and creatine kinase MB tests to predict cardiac events within 6 months were compared.

RESULTS

The 500 Troponin T tests were used in 249 patients (median two tests per patient (range 1-5)) within 41 days. The final diagnosis revealed coronary heart disease in 85, non-coronary heart disease in 39, non-cardiac chest pain in 86 and other diagnoses in 39 of the patients. In 14 patients with an elevated creatine kinase MB, myocardial damage could safely be ruled out by a negative Troponin T, in six patients with a normal creatine kinase MB minor myocardial damage could be detected by a positive Troponin T. During follow up 28 cardiac events were recorded. Troponin T had a significantly higher specificity, positive predictive value and proportion of correct prediction for cardiac events within 6 months compared to creatine kinase MB.

CONCLUSIONS

Troponin T has proved to be an useful method for diagnosing myocardial damage in routine clinical use in the non-trauma emergency department.

Identification of chest pain patients appropriate for an emergency department observation unit

There are no perfect tests or algorithms to exclude ACI. Because acute coronary occlusion often occurs in patients with low-grade coronary stenosis, the diagnostic goal of a chest pain diagnostic protocol is not to identify patients with CAD, but rather to identify patients who may be safely discharged home without the development of complications such as MI, unstable angina, death, shock, or CHF over the next 1 to 6 months. There is an advantage to evaluating patients at the time of their symptoms. Patients who have a small plaque that is ruptured, leading to intracoronary thrombosis and ischemia, will manifest ischemia on diagnostic testing that could missed in routine outpatient testing when their plaque were stable. The diagnosis and risk stratification of acute coronary ischemia in the ED depends on a careful history and interpretation of the ECG. Multiple regression models using readily available data (e.g., history, physical examination, and ECG) provide the best tools for risk stratification. If one is deciding how to select patients for an EDOU chest pain evaluation, diagnostic tools that have previously been tested and validated in this setting are preferable. These include the Multicenter Chest Pain Study derived tools (i.e., Goldman, Lee), the ACI and ACI-TIPI tools, and sestamibi risk stratification tools. This is not to say that other tools may not play a role at individual institutions. It is probably better to select a consistent approach and evaluate its performance, rather than to allow random variation to dictate practice. The future direction probably will involve standardization of the ED chest pain population. This allows outcome and cost-effectiveness comparative research of various strategies for patients with normal or nondiagnostic ECGs and normal biomarkers. Although this approach allows more precise stratification, the risk will never be zero, meaning that there will never be a substitute for good clinical judgment and close follow-up care.

Emergency department admissions to inpatient cardiac telemetry beds: a prospective cohort study of risk stratification and outcomes

PURPOSE

Little is known about physicians' use of inpatient cardiac telemetry units among emergency department patients at risk for cardiac complications. We therefore studied the outcomes of patients admitted to inpatient telemetry beds to identify a subset of patients from whom cardiac monitoring could be withheld safely.

SUBJECTS AND METHODS

We conducted a prospective cohort study of 1, 033 consecutive adult patients admitted to an inpatient telemetry unit from the emergency department of a 700-bed urban public teaching hospital. Subjects with or without chest pain were risk-stratified using a prediction rule and observed for in-hospital cardiac complications, acute myocardial infarction, and transfer to an intensive care unit (ICU).

RESULTS

There were no significant differences between patients with (n = 677) or patients without chest pain (n = 356) in the rates of major cardiac complications, myocardial infarctions, or transfers to an ICU. Among 318 patients with chest pain who were classified as being very low risk, none suffered major complications (negative predictive value 100%; 95% confidence interval [CI]: 98.8% to 100%). Among 214 very low risk patients without chest pain, 1 (0.5%) had a major complication (negative predictive value 99.5%; 95% CI: 97.4% to 99.9%).

CONCLUSIONS

The prediction rule accurately identified patients with or without chest pain who were at very low risk of major complications, identifying a subset from whom cardiac monitoring could be withheld safely.

The intermediate CCU admission: a preliminary study

In the current health care era, increasing emphasis is being placed on cost reduction. Admitting only high-risk patients to coronary care units (CCU) may reduce hospital costs and charges without adverse clinical outcomes. Recently, guidelines published by the Agency for Healthcare Policy and Research (AHCPR) on suggest that intermediate-risk patients be admitted to an intermediate CCU (ICCU), but the safety and appropriateness of this approach has not been prospectively evaluated. The authors hypothesized that admitting intermediate-risk patients with to an ICCU would be cheaper than admitting to a CCU with comparable safety supporting AHCPR guidelines. To evaluate this, a retrospective cohort study was conducted. Two hundred forty-three intermediate-risk patients consecutively admitted to the CCU (n = 134) and admitted to the ICCU (n = 109) between June 1, 1992 and April 1, 1994 were compared using AHCPR definitions of intermediate risk and a previously published risk prediction model to exclude both very low- and high-risk patients. Extensive demographic, clinical, and diagnostic testing, and treatment, procedural, and outcome data were collected by a trained nurse data collector at the time of admission. Fifty-nine percent of all study patients had at least two coronary risk factors. Twenty-one percent had diabetes. Ninety-eight percent had at least one AHCPR intermediate risk factor for cardiac complications. The two groups (CCU versus ICCU) were quite similar in baseline characteristics: men (56 versus 55%), age (57 +/- 17 versus 60 +/- 17 years), diabetes (22 versus 20%), previous myocardial infarction (30 versus 36%), previous coronary artery surgery (21 versus 21%), and rest pain (78 versus 66%). The use of coronary angiography (44 versus 52%), angioplasty (24 versus 21%), and coronary artery surgery (13 versus 11%) were also similar. The incidence of myocardial infarction or death was similar (3 versus 5%), and length of stay was also similar between groups (6.7 +/- 4.2 versus 6.5 +/- 4.1 days), but cost was less for patients admitted to the ICCU ($13,481 +/- 9,450 versus $10,619 +/- 8,732, P < 0.015). These preliminary data suggest intermediate-risk patients, as identified by AHCPR guidelines, can be treated in an ICCU at lower cost than in a CCU, with reasonable safety. A small incidence of myocardial infarction in ICCU-admitted patients occurs, requiring availability of cardiac resuscitation and continued monitoring of electrocardiographic and enzymatic abnormalities. Admission to ICCU poses no barrier to recommended patient evaluation and management.

Validated risk stratification model accurately predicts low risk in patients with unstable angina

BACKGROUND

In the mid 1990s, two unstable angina risk prediction models were proposed but neither has been validated on separate population or compared.

OBJECTIVES

The purpose of this study was to compare patient outcome among high, medium and low risk unstable angina patients defined by the Agency for Health Care Policy and Research (AHCPR) guideline to similar risk groups defined by a validated model from our institution (RUSH).

METHODS

Four hundred sixteen patients consecutively admitted to the hospital with unstable angina between January 1, 1995, and December 31, 1997, were prospectively evaluated for risk factors. The presence of major adverse events such as myocardial infarction (MI), death and heart failure was assessed for each patient by chart review.

RESULTS

The composite end point of heart failure, MI or death occurred in 3% and 5% of the RUSH and AHCPR low risk categories, respectively, and in 8% and 10% of AHCPR and RUSH high risk categories, respectively. Recurrent ischemic events were best predicted by the RUSH model (high: 24% vs. medium: 12% and low: 10%, p = 0.029), but not by the AHCPR model (high: 14% vs. medium: 13% and low: 9%, p = 0.876). The RUSH model identified five times more low risk patients than the AHCPR model.

CONCLUSIONS

Both models identify patients with low and high event rates of MI, death or heart failure. However, the RUSH model allowed for five times more patients to be candidates for outpatient evaluation (low risk) with a similar observed event rate to the AHCPR model; also, the RUSH model more successfully predicted ischemic complications. We conclude that the RUSH model can be used clinically to identify patients for early noninvasive evaluation, thereby improving cost effectiveness of care.

Determining chest pain patients' suitability for transfer to a general ward following admission to a cardiac care unit

The objective of this study was to assess the performance of a consensus-derived decision algorithm in determining chest pain patients' suitability for early transfer to a lower dependency ward by predicting complications. The sample comprised 516 patients with chest pain presumed to be cardiac in origin, admitted to a cardiac care unit (CCU) in northern England from the community or from the accident and emergency department. A decision algorithm was designed following a review of the literature and amended to take into account a clinical consensus of consultant physicians. Patients were assessed on admission by CCU nurses using the algorithm, and 'triage' decisions recorded (keep on CCU or suitable for early transfer to a general ward). Admission ECGs (electrocardiographs) and baseline clinical data were recorded independently by a researcher 'blinded' to actual clinical course, and applied to the algorithm using statistical software. On discharge or death, patients' case notes were retrieved and the hospital course examined for death or severe complications. Performance of the algorithm and CCU nurses were compared for sensitivity, specificity, positive predictive value and negative predictive value. The main outcome measures were death or severe complications occurring during hospitalization, and during the first 2 days following CCU admission. While sensitivity of both the algorithm (0.98) and CCU nurses (0.95) was high, specificity was low in both groups (0.11 and 0.21, respectively), making it unlikely that the algorithm would prove useful in clinical practice. Further studies are required to develop the optimal triage tool for the assessment of patients with acute chest pain.

Prospective audit of incidence of prognostically important myocardial damage in patients discharged from emergency department

OBJECTIVE

To assess the incidence of prognostically important myocardial damage in patients with chest pain discharged from the emergency department.

DESIGN

Prospective observational study.

SETTING

District general hospital emergency department.

PARTICIPANTS

110 patients presenting with chest pain of unknown cause who were subsequently discharged home after cardiac causes of chest pain were ruled out by clinical and electrocardiographic investigation.

INTERVENTIONS

Patients were reviewed 12-48 hours after presentation by repeat electrocardiography and measurement of cardiac troponin T.

MAIN OUTCOME MEASURES

Incidence of missed myocardial damage.

RESULTS

Eight (7%) patients had detectable cardiac troponin T on review and seven had concentrations >/=0.1 microg/l. The repeat electrocardiogram showed no abnormality in any patient.

CONCLUSION

6% of the patients discharged from the emergency department had missed prognostically important myocardial damage. Follow up measurement of cardiac troponin T allows convenient audit of clinical performance in the emergency department.

Modelling for cost-effectiveness analysis

A model creates the framework for a cost-effectiveness analysis, allowing decision makers to explore the implications of using an intervention in different ways and under different conditions. To serve its purpose a model must produce accurate predictions and allow for substantial variation in the factors that influence costs and effects. This paper considers three aspects of modelling: validating effectiveness estimates; modelling costs; and the implications of common statistical forms. Validation procedures similar to those for effectiveness estimates are proposed for costs. Modellers need to pay more attention to ensuring that the pathway of events described by a model represents costs as well as it does effects. Modellers can also help improve the epidemiological and clinical research on which cost-effectiveness analyses depend by showing the implications for resource allocation of the statistical forms conventionally used in these fields.

Assessment of a creatine kinase-MB/myoglobin kit in the prehospital setting in patients presenting with acute nontraumatic chest pain: the "Shahal" experience

OBJECTIVES

To evaluate the usefulness of a novel qualitative, rapid, bedside immunoassay device for the detection of elevated creatine kinase MBmass (CK-MB) and myoglobin as a supportive tool for decision-making by the physician who is evaluating patients who present with chest pain.

DESIGN

Prospective study.

SETTING

Prehospital (mobile intensive care units).

PATIENTS

Three hundred twenty-eight consecutive patients, age 71+/-13 yrs (64% males), who were admitted to the hospital via Shahal's mobile intensive care units.

INTERVENTION

During a 6-month period, based on clinical presentations and electrocardiograms, the mobile's physicians classified patients into groups of high or low probability of having an acute myocardial infarction and, thereafter, used a rapid bedside STATus kit (Spectral Diagnostics, Toronto, Ontario, Canada) to determine blood creatine kinase/MB and myoglobin.

MEASUREMENTS AND MAIN RESULTS

Myocardial infarction was confirmed in 59 (18%) patients. If measured >2 hrs after onset, diagnostic sensitivities, specificities, and positive and negative predictive values for physicians were as follows: 71%, 90%, 46%, and 96%, respectively, compared with 100%, 85%, 44%, and 100%, respectively, if assessed by the kit.

CONCLUSIONS

If used 2 to 12 hrs from the onset of symptoms, this device is a convenient diagnostic aid to prevent a misdiagnosis of acute myocardial infarction or unnecessary hospitalization to exclude infarction. This tool may be a promising cost-cutting factor in these days of escalating expenses and dwindling resources.

Performance and potential impact of a chest pain prediction rule in a large public hospital

PURPOSE

To evaluate the performance of a previously validated prediction rule for patients presenting to the emergency department with chest pain and the potential impact of the rule on triage decisions.

SUBJECTS AND METHODS

In a prospective cohort study, physician investigators interviewed consecutive patients admitted for suspected acute ischemic heart disease (n = 207) by emergency department attending physicians who had not used the prediction rule. We measured the accuracy of the rule in predicting cardiac complications in these patients, and compared actual triage decisions with those that might have been recommended by use of the prediction rule. We also measured comorbid illnesses among patients stratified as very low risk by the prediction rule, as well as the effect of standardizing the definition of unstable angina and interpretation of electrocardiograms (ECG) on the rule's sensitivity and specificity.

RESULTS

Overall, the rate of major cardiac complications (4.3%) was similar to that reported in the original study (3.6%). The prediction rule performed well in predicting these complications in our patients (area under receiver operating characteristic curve 0.84 versus 0.80 in the original study; difference 0.04, 95% confidence interval [CI] -0.07, 0.14). Standardized definitions of unstable angina and interpretation of ECGs improved the specificity of the prediction rule in predicting complications (55% versus 47%; difference 8%, 95% CI 1.5%, 13.7%). The prediction rule recommended admission to telemetry units in 65 fewer patients than actually occurred (31% of the entire cohort). None of these patients had major complications. A substantial minority of "very low risk" patients (27%) had comorbid illnesses requiring inpatient treatment.

CONCLUSIONS

This independent validation of the prediction rule suggests that it can improve triage decisions for patients admitted with suspected acute ischemic heart disease. Additional studies are needed to test prospectively the performance of the prediction rule in actual decision making, its acceptance by clinicians, and its cost effectiveness.

Clinical predictors easily obtained at presentation predict resource utilization in unstable angina

OBJECTIVE

To determine if a risk prediction model for patients with unstable angina would predict resource utilization.

METHODS AND RESULTS

Four hundred sixty-five consecutive patients admitted for unstable angina to a tertiary care university-based medical center were prospectively evaluated from June 1, 1992, to June 30, 1995. The proportion of patients receiving coronary angiography, coronary angioplasty, and coronary artery bypass grafting were analyzed according to four risk groups on the basis of a previously published model: Group 1, <2% risk of major complication; Group 2, 2.1% to 5% risk; Group 3, 5.1 % to 15% risk; and Group 4, >15.1 % risk. Hospital length of stay and estimated cost of hospitalization based on DRG and specific payer ratio of cost-to-charge were also compared between groups. Multiple linear regression analysis was used to determine the influence of estimated risk and procedures on hospital costs. The four groups were well matched for gender, hypertension, tobacco history, and previous percutaneous transluminal coronary angioplasty and myocardial infarction. Group 4 had a higher incidence of previous coronary bypass grafting (35% vs 10%, p=0.001) and triple vessel or left main coronary artery disease compared with Group 1 (44% vs 13%, p=0.041). Group 4 patients were more likely to be admitted to the coronary care unit compared with Group 2 or Group 1 patients (80% vs Group 1: 51% [p= 0.001]; and vs Group 2: 53% [p=0.001]), more likely to receive heparin (87% vs 71%, p=0.007), and more likely to receive a beta-blocker or calcium channel blocker (89% vs 74%, p=0.008) than Group 1. Coronary angioplasty rates were similar for all groups, but Group 4 patients were more likely to receive coronary bypass grafting than Group 2 or Group 1 (27% vs Group 2: 12%, p=0.004 and vs Group 1: 8%, p=0.002). Hospital length of stay was highest in Group 4 and lowest for Group 1. Average hospital costs were significantly less in Group 3 than in Group 4, but higher than in Group 1. Multivariate analysis determined a dependency of costs on risk group with Group 2 having costs 31.4% (95% CI=9.8 to 57.2), Group 3 46.7% (24, 3 to 73.1), and Group 4 75% (46.9 to 110.7) higher than Group 1. The use of procedures also significantly increased costs, with PTCA-treated patients having a 44.9% (26.7 to 65.7) increase in costs compared with medically treated patients, and surgically treated patients having a 204.7% increase in costs.

CONCLUSION

Resource utilization as assessed by the use of revascularization procedures, length of stay, and hospital costs are influenced by patient acuity estimated from a prediction model on the basis of estimated risk of cardiac complications. The model exerts independent influence on cost even after adjustment for various procedures. The use of revascularization procedures, especially coronary artery surgery, remains a large determinant of hospital cost.

Evaluation and risk stratification of patients with chest pain in the emergency department. Predictors of life-threatening events

While assessing chest pain in the emergency department, physicians must first estimate the probability of acute ischemic states in the patient. This first estimate is based on the patient's history, physical examination, and electrocardiogram. Patients who meet the threshold for acute cardiac ischemia are further evaluated to confirm or exclude this diagnosis, while other life-threatening factors are excluded.

Evidence-based medicine and cost-effectiveness analysis

Health care has become increasingly expensive and clinicians have come under increased scrutiny to critically appraise the economic impact of medical programs and interventions. To ensure an equitable allocation of scarce resources and the attainment of maximal clinical benefit, it is vital to adhere to certain basic tenets of economic analysis and to understand the basic approach to cost-effectiveness analysis. These principles are applied to critical care medicine and analogies are made to the methodological rigor of evidence-based medicine.

Evaluation of chest pain in low-risk patients presenting to the emergency department: the role of immediate exercise testing

STUDY OBJECTIVES

To determine the safety and utility of immediate exercise testing in the evaluation of low-risk patients presenting to the emergency department with chest pain and its applicability to a heterogeneous population of men and women.

METHODS

We conducted a prospective study of the safety and utility of immediate exercise testing in low-risk patients, as indicated by clinical and ECG criteria. The study group was large, heterogeneous, and included patients with a history of coronary artery disease. The patients were treated at a large, university medical center. Exercise testing (immediate exercise treadmill testing) was performed by internists, and cardiac serum enzyme levels were not measured before the exercise test.

RESULTS

A total of 212 patients (121 men, 91 women) underwent exercise testing with no adverse effects. Twenty-eight (13%) patients had positive results on exercise ECGs. Twenty-three of the latter had further evaluation that revealed evidence of coronary artery disease in 13 (57%). Fifty-nine percent (125/212) of patients had negative exercise test results and 28% (59/212) had nondiagnostic tests. All patients with negative test results and 93% with nondiagnostic test results were discharged directly from the ED. Thirty-day follow-up was achieved in 201 (95%) patients and revealed no mortality in any of the patients in the three groups. One patient with a positive exercise test result returned to the ED within 30 days with mild congestive heart failure.

CONCLUSION

Our results in this patient population support the safety and utility of immediate exercise testing of low-risk patients who present to the ED.

Biochemical markers of acute myocardial infarction: strategies for improving their clinical usefulness

We investigated the early diagnostic utility, including incremental value, of the serum cardiac markers creatine kinase (CK), CK-MB (mass and activity measurements), cardiac troponin T, and myoglobin in the diagnosis of acute myocardial infarction (AMI) in patients presenting to a major teaching hospital with chest pain and non-diagnostic electrocardiographs (ECG). The reference diagnosis of acute myocardial infarction was made by a single, independent cardiologist using World Health Organization criteria. CK and CK-MB mass were the only significant predictors of AMI at presentation to the Emergency Department. Logistic regression analysis revealed that CK did not significantly predict (P = 0.23) myocardial infarction once CK-MB mass was in the model. Using test results on follow up, in addition to presentation CK-MB mass, change in CK-MB mass was the only other significant independent predictor of AMI. Likelihood ratios for various levels of the significant markers in the logistic regression are given. In conclusion, CK-MB mass measurement was the only useful serum cardiac marker for the diagnosis of AMI in patients presenting with chest pain with non-diagnostic ECGs.

Cost-effectiveness of a hospital-based smoking cessation intervention

OBJECTIVES

This study evaluated the cost-effectiveness of a smoking cessation and relapse-prevention program for hospitalized adult smokers from the perspective of an implementing hospital. It is an economic analysis of a two-group, controlled clinical trial in two acute care hospitals owned by a large group-model health maintenance organization. The intervention included a 20-minute bedside counseling session with an experienced health counselor, a 12-minute video, self-help materials, and one or two follow-up calls.

METHODS

Outcome measures were incremental cost (above usual care) per quit attributable to the intervention and incremental cost per discounted life-year saved attributable to the intervention.

RESULTS

Cost of the research intervention was $159 per smoker, and incremental cost per incremental quit was $3,697. Incremental cost per incremental discounted life-year saved ranged between $1,691 and $7,444, much less than most other routine medical procedures. Replication scenarios suggest that, with realistic implementation assumptions, total intervention costs would decline significantly and incremental cost per incremental discounted life-year saved would be reduced by more than 90%, to approximately $380.

CONCLUSIONS

Providing brief smoking cessation advice to hospitalized smokers is relatively inexpensive, cost-effective, and should become a part of the standard of inpatient care.

Beyond the twelve-lead electrocardiogram: diagnostic tests in the evaluation for suspected acute myocardial infarction in the emergency department, Part II

On a daily basis the emergency physician is faced with the difficult task of determining whether or not a patient with acute chest pain is sustaining an acute myocardial infarction. In most cases this is not a straightforward decision. Although observation units are being used more often for chest pain evaluations, many emergency physicians currently admit such patients to an intensive care setting. Because fewer than one-third of emergency department chest pain patients actually suffer an acute myocardial infarction, expensive resources are, in retrospect, used unnecessarily. Conversely, patients who are infarcting, and are inadvertently discharged home from the emergency department, have a worse prognosis than those admitted. This two-part series reviews the newer modalities available that may help the emergency physician arrive at a more accurate diagnosis. This article, Part II, will review the use of biochemical assays of cardiac proteins and discuss the Chest Pain Observation Unit.

Emergency room triage of patients with acute chest pain by means of rapid testing for cardiac troponin T or troponin I

BACKGROUND

Evaluation of patients with acute chest pain in emergency rooms is time-consuming and expensive, and it often results in uncertain diagnoses. We prospectively investigated the usefulness of bedside tests for the detection of cardiac troponin T and troponin I in the evaluation of patients with acute chest pain.

METHODS

In 773 consecutive patients who had had acute chest pain for less than 12 hours without ST-segment elevation on their electrocardiograms, troponin T and troponin I status (positive or negative) was determined at least twice by sensitive, qualitative bedside tests based on the use of specific monoclonal antibodies. Testing was performed on arrival and four or more hours later so that one sample was taken at least six hours after the onset of pain. The troponin T results were made available to the treating physicians.

RESULTS

Troponin T tests were positive in 123 patients (16 percent), and troponin I tests were positive in 171 patients (22 percent). Among 47 patients with evolving myocardial infarction, troponin T tests were positive in 44 (94 percent) and troponin I tests were positive in all 47. Among 315 patients with unstable angina, troponin T tests were positive in 70 patients (22 percent), and troponin I tests were positive in 114 patients (36 percent). During 30 days of follow-up, there were 20 deaths and 14 nonfatal myocardial infarctions. Troponin T and troponin I proved to be strong, independent predictors of cardiac events. The event rates in patients with negative tests were only 1.1 percent for troponin T and 0.3 percent for troponin I.

CONCLUSIONS

Bedside tests for cardiac-specific troponins are highly sensitive for the early detection of myocardial-cell injury in acute coronary syndromes. Negative test results are associated with low risk and allow rapid and safe discharge of patients with an episode of acute chest pain from the emergency room.

Marginally effective medical care: ethical analysis of issues in cardiopulmonary resuscitation (CPR)

Outcomes from cardiopulmonary resuscitation (CPR) remain distressingly poor. Overuse of CPR is attributable to unrealistic expectations, unintended consequences of existing policies and failure to honour patient refusal of CPR. We analyzed the CPR outcomes literature using the bioethical principles of beneficence, non-maleficence, autonomy and justice and developed a proposal for selective use of CPR. Beneficence supports use of CPR when most effective. Non-maleficence argues against performing CPR when the outcomes are harmful or usage inappropriate. Additionally, policies which usurp good clinical judgment and moral responsibility, thereby contributing to inappropriate CPR usage, should be considered maleficent. Autonomy restricts CPR use when refused but cannot create a right to CPR. Justice requires that we define which medical interventions contribute sufficiently to health and happiness that they should be made universally available. This ordering is necessary whether one believes in the utilitarian standard or wishes medical care to be universally available on fairness grounds. Low-yield CPR fails justice criteria. Cardiopulmonary resuscitation should be performed when justified by the extensive outcomes literature; not performed when not desired by the patient or not indicated; and performed infrequently when relatively contraindicated.

Early prediction of risk in patients with suspected unstable angina using serum troponin T

BACKGROUND

One-third of patients with rest angina are reported to have detectable cardiac troponin T in the serum and may be at increased risk of serious cardiac events.

AIM

To investigate whether a single early estimation of serum troponin T was an independent predictor of serious cardiovascular complications in patients with suspected unstable angina.

METHODS

A prospective cohort study in which patients with suspected rest angina had a serum troponin T estimation 14 hours after symptom onset and were classified using discriminator levels of serum troponin T of 0.05 and 0.1 microgram/L as well as a number of other variables. All patients were followed for six months to document any cardiac complications and a stepwise logistic regression analysis was conducted to determine independent risk factors of complications.

RESULTS

One hundred and sixty-four patients were evaluated. Using a discriminator level of 0.05 microgram/L 54 patients (33%) had detectable troponin T. The admission ECG was the only independent predictor of cardiac events in hospital--odds ratio 4.0 (95% CI 1.7-9.6). Detectable troponin T did not appear to be an independent predictor of serious complications. During the six-month follow-up period, detectable troponin T using a discriminator of 0.05 microgram/L was an independent predictor of serious complications--odds ratio 3.7 (95% CI 1.8-7.6).

CONCLUSIONS

In patients with suspected rest angina, detectable serum troponin T > 0.05 microgram/L is an independent predictor of serious cardiac events during the six-month follow-up period although not during hospitalisation. Using a single, early serum troponin T estimation and other variables available at the time of admission, a high risk subgroup who may benefit from early investigation and revascularisation can be identified.

Value of acute rest sestamibi perfusion imaging for evaluation of patients admitted to the emergency department with chest pain

OBJECTIVES

This study sought to determine the ability of early perfusion imaging using technetium-99m sestamibi to predict adverse cardiac outcomes in patients who present to the emergency department with possible cardiac ischemia and nondiagnostic electrocardiograms (ECGs).

BACKGROUND

Evaluation of patients presenting to the emergency department with possible acute coronary syndromes and nondiagnostic ECGs is problematic. Accurate risk stratification is necessary to prevent serious adverse outcomes. Initial results suggest that early perfusion imaging using technetium-99m sestamibi enables reliable risk stratification.

METHODS

Patients presenting to the emergency department with a low to moderate probability of acute coronary syndromes underwent rapid sestamibi injection with gated single-photon emission computed tomographic imaging. Studies showing perfusion defects with associated wall motion abnormalities were considered positive.

RESULTS

A total of 532 consecutive patients underwent serial myocardial marker analysis and rest perfusion imaging. Of these patients, perfusion imaging was positive in 171 (32%). Positive perfusion imaging was the only multivariate predictor of myocardial infarction (MI) (p < 0.0001, odds ratio [OR] 33, 95% confidence interval [CI] 7.7 to 141) and was the most important independent predictor of MI or revascularization (p < 0.0001, OR 14, 95% CI 7.3 to 25), followed by diabetes (p < 0.01, OR 2.8, 95% CI 1.5 to 5.1), typical angina (p = 0.01, OR 2.1, 95% CI 1.2 to 3.7) and male gender (p = 0.03, OR 1.9, 95% CI 1.1 to 3.5). The sensitivity of positive perfusion imaging for MI was 93% (95% CI 77% to 98%), and for MI or revascularization it was 81% (95% CI 71% to 88%), with negative predictive values of 99% (95% CI 98% to 100%) and 95% (95% CI 92% to 97%), respectively.

CONCLUSIONS

Positive rest perfusion imaging accurately identified patients at high risk for adverse cardiac outcomes, whereas negative perfusion imaging identified a low risk patient group. Early perfusion imaging allows for rapid and accurate risk stratification of emergency department patients with possible cardiac ischemia and nondiagnostic ECGs.

A study of unplanned readmissions to a coronary care unit

OBJECTIVE

To determine the cause and frequency of unplanned readmissions to a coronary care unit (CCU) after initial transfer to a general cardiac unit, but before hospital discharge.

DESIGN

Analysis of 1776 admissions to a CCU during a 16-month period.

SETTING

The CCU of a major teaching hospital in South Australia.

PARTICIPANTS

All patients admitted to the CCU during the 16-month period.

OUTCOME MEASURES

CCU readmissions before hospital discharge were categorized as either "planned" or "unplanned." The latter were investigated for determination of casualty and variations in patient characteristics (including age, sex, initial diagnosis, pharmacotherapy, and duration of stay in the CCU).

RESULTS

Of the 1776 CCU admissions examined, 44 (2.5% of total) were unplanned readmissions before hospital discharge. Most of these (39 of 44) were related to "reactivation" of acute myocardial ischemia. Patients whose initial diagnosis was acute myocardial infarction or unstable angina pectoris were more likely to require a further unplanned CCU admission (p < 0.05); those with unstable angina pectoris had a second stay in CCU significantly longer than their first (p < 0.05). Six patients were readmitted within 6 hours of cessation of a heparin infusion (4 of the 6 without aspirin administration), and 11 patients had not received antiplatelet therapy after their initial CCU stay. Overall, a disproportionate number of men were readmitted to CCU (p < 0.05).

CONCLUSIONS

In the current study, unplanned readmissions to the CCU: (1) were relatively infrequent, (2) were more protracted than initial stays in CCU, (3) may have been prevented in 15 of the 44 cases with more appropriate pharmacotherapy, and (4) involved a disproportionate number of male patients.

Are monitored telemetry beds necessary for patients with nontraumatic chest pain and normal or nonspecific electrocardiograms?

We evaluated the frequency of cardiovascular complications in chest pain patients with normal or non-specific electrocardiograms admitted to noncardiac care unit monitored beds and found that none of 261 patients had life-threatening dysrrhythmias requiring treatment.

Assessment of the patient with chest pain in the accident and emergency department

This article will review measures enabling emergency staff to identify patients with chest pain who are likely to need admission to a cardiac care unit, in particular those with manifestations of acute ischaemic heart disease--acute myocardial infarction and unstable angina. Other non-cardiac causes of chest pain will also be discussed.

Evaluation of chest pain in the emergency department

The evaluation of chest pain in the emergency setting should be systematic, risk based, and goal driven. An effective program must be able to evaluate all patients with equal thoroughness under the assumption that any patient with chest pain could potentially be having an MI. The initial evaluation is based on the history, a focused physical examination, and the ECG. This information is sufficient to categorize patients into groups at high, moderate, and low risk. Table 14 is a template for a comprehensive chest-pain evaluation program. Patients at high risk need rapid initiation of appropriate therapy: thrombolytics or primary angioplasty for the patients with MIs or aspirin/heparin for the patients with unstable angina. Patients at moderate risk need to have an acute coronary syndrome ruled in or out expediently and additional comorbidities addressed before discharge. Patients at low risk also need to be evaluated, and once the likelihood of an unstable acute coronary syndrome is eliminated, they can be discharged with further evaluation performed as outpatients. Subsequent evaluation should attempt to assign a definitive diagnosis while also addressing issues specific to risk reduction, such as cholesterol lowering and smoking cessation. It is well documented that 4% to 5% of patients with MIs are inadvertently missed during the initial evaluation. This number is surprisingly consistent among many studies using various protocols and suggests that an initial evaluation limited to the history, physical examination, and ECG will fail to identify the small number of these patients who otherwise appear at low risk. The solution is to improve the sensitivity of the evaluation process to identify these patients. It appears that more than simple observation is required, and at the present time, no simple laboratory test can meet this need. However, success has been reported with a number of strategies including emergency imaging with either radionuclides such as sestamibi or echocardiography. Early provocative testing, either stress or pharmaceutic, may also be effective. The added value of these tests is only in their use as part of a systematic protocol for the evaluation of all patients with acute chest pain. The initial evaluation of the patient with chest pain should always consider cardiac ischemia as the cause, even in those with more atypical symptoms in whom a cardiac origin is considered less likely. The explicit goals for the evaluation of acute chest pain should be to reduce the time to treat MIs and to reduce the inadvertent discharge of patients with occult acute coronary syndromes. All physicians should become familiar with appropriate risk stratification of patients with acute chest pain. Systematic strategies must be in place to assure rapid and consistent identification of all patients and the expedient initiation of treatment for those patients with acute coronary syndromes. These strategies should include additional methods of identifying acute coronary syndromes in patients initially appearing as at moderate or low risk to assure that no unstable patients are discharged. All patients should be followed up closely until the cardiovascular evaluation is completed and, when possible, a definitive diagnosis is determined. Finally, this must be done efficiently, cost-effectively, and in a manner that will result in an overall improvement in patient care.

Early diagnostic efficiency of cardiac troponin I and Troponin T for acute myocardial infarction

OBJECTIVE

To compare the early diagnostic efficiency of the cardiac troponin I (cTn-I) level with that of the cardiac troponin T (cTn-T) level, as well as the creatine kinase (CK), CK-MB, and myoglobin levels, for acute myocardial infarction (AMI) in patients without an initially diagnostic ECG presenting to the ED within 24 hours of the onset of their symptoms.

METHODS

A prospective, observational, cohort study was performed involving chest pain patients admitted to a large urban community hospital. Participants were consecutive consenting ED chest pain patients > or = 30 years of age. Exclusions included duration of symptoms > 24 hours, inability to complete data collection, receipt of CPR, and ST-segment elevation on the initial ECG. Measurements included levels of cTn-I, cTn-T, CK, CK-MB, and myoglobin at the time of presentation and 1, 2, 6, and 12-24 hours after presentation as well as presenting ECG and clinical follow-up. Confirmation of the diagnosis of AMI was based on World Health Organization criteria.

RESULTS

Of the 177 patients included in the study, 27 (15%) were diagnosed as having AMIs. The sensitivities of all 5 biochemical markers for AMI were poor at the time of ED presentation (3.7-33.3%) but rose significantly over the study period. The sensitivity of cTn-T was significantly better than that of cTn-I over the initial 2 hours, but both markers' sensitivities were low (< 60%) during this time frame. The cTn-I was significantly more specific for AMI than was the cTn-T, but not significantly better than CK-MB or myoglobin. Likelihood ratio analysis showed that the biochemical markers with the highest positive likelihood ratios for AMI during the first 2 hours following ED presentation were myoglobin and CK-MB. From 6 through 24 hours, the positive likelihood ratios for cTn-I, CK-MB, and myoglobin were superior to those of CK and cTn-T.

CONCLUSIONS

cTn-I, CK-MB, and myoglobin are significantly more specific for AMI than are CK and cTn-T. Myoglobin is the biochemical marker having the highest combination of sensitivity, specificity, and negative predictive value for AMI within 2 hours of ED presentation. Neither cTn-I nor cTn-T offers significant advantages over myoglobin and CK-MB in the early (< or = 2 hours) initial screening for AMI. The cardiac troponins are of benefit in identifying AMI > or = 6 hours after presentation.

Improving the early diagnosis of acute myocardial infarction

The diagnosis of early myocardial infarction, especially in association with atypical clinical presentations, can be difficult to establish. Continued observation of high-risk patients, with multiple serial electrocardiographs and the use of other diagnostic modalities as available, is essential to prevent the inadvertent premature discharge of patients with evolving myocardial infarcts from the accident and emergency department.

Admission decisions in emergency department chest pain patients at low risk for myocardial infarction: patient versus physician preferences

STUDY OBJECTIVE

Patient involvement in medical decisionmaking is accepted as an ethical and a legal imperative. Medical decisions are based in part on individuals' knowledge and acceptance of risk of adverse consequences. It is unclear whether actions taken to protect against low risk of poor outcome reflect patient or physician preferences. We sought to test the hypothesis that emergency department chest pain patients presented with a hypothetical situation involving a low risk of myocardial infarction are more willing than ED physicians to accept the risk associated with discharge from the hospital.

METHODS

We prospectively surveyed 89 ED patients with chest pain and a cohort of physicians in the ED who had been presented a hypothetical case in which the risk of AMI was quoted as 5% and the risk of death or disability if the patient was discharged was 1% and .2% if the patient was admitted. All the patients had presented to the ED with a chief complaint of chest pain; the 31 physicians, all residents, were approached at a teaching conference separate from their clinical duties.

RESULTS

Twenty-eight patients (31%), compared with 2 physicians (6%), chose discharge for the hypothetical patient with chest pain (25% difference; 95% confidence interval [CI], 6% to 41%). Forty-four patients (49%), compared with 30 physicians (97%), correctly identified the risks associated with admission and discharge (46% difference; 95% CI, 29% to 63%). Of the subjects who correctly identified the risks, 19 patients (43%) preferred discharge, compared with 1 physician (3%) (40% difference; 95% CI, 18% to 60%).

CONCLUSION

ED patients with chest pain appear to be more likely than physicians to accept a small risk of poor outcome in a hypothetical circumstance. Many patients cannot identify the risks associated with their decision.

Planning patient services for intermediate care units: insights based on care for intensive care unit low-risk monitor admissions

OBJECTIVE

To describe the technology and nursing services that would be required to care for intensive care unit (ICU) low-risk monitor admissions in an intermediate unit.

DESIGN

Prospective, multicenter, inception cohort analysis.

SETTING

Forty U.S. hospitals with > 200 beds, including 26 hospitals that were randomly selected and 14 that volunteered for the study.

PATIENTS

A sample of 8,040 ICU patients admitted to the ICU for monitoring, who received no active life-support treatment on ICU day 1.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic, physiologic, and treatment information were obtained during ICU days 1 to 7. A previously validated multivariate equation was used to identify 6,180 monitor admissions at low (< 10%) risk for receiving active treatment during their entire ICU stay. We used daily Therapeutic intervention Scoring System (TISS) data to identify the equipment, type and amount of nursing care, and the types of active treatment that would have been used had these ICU patients been admitted to an intermediate care unit. Mean day-1 ICU TISS scores were as follows: 16.4 for all patients; 18.3 for surgical patients; and 13.5 for medical admissions. Concentrated nursing care accounted for 89% and technologic monitoring for 11% of day-1 TISS points. Surgical admissions had a 2.8-day mean ICU length of stay and received an average of 16.5 TISS points per patient per day. Medical admissions had a 2.7-day mean ICU length of stay and received an average of 12.3 TISS points per patient per day. Subsequent active life-support therapy was received by 4.4% of these ICU low-risk monitor admissions.

CONCLUSIONS

The services received by ICU low-risk monitor admissions provide insight regarding the equipment and nursing care that might be required, and the kinds of emergencies that might occur, if these patients were cared for in medical and surgical intermediate care units. Our data suggest that if ICU low-risk monitor patients were admitted to an intermediate care unit, they would mainly require concentrated nursing care (nurse/patient ratio of 1:3 to 1:4) and limited technologic monitoring.

Cost-effectiveness of a coronary care unit versus an intermediate care unit for emergency department patients with chest pain

BACKGROUND

Guidelines are not available for which patients with acute chest pain should be admitted to the coronary care unit and which patients can be reasonably triaged to monitored beds in lower levels of care.

METHODS AND RESULTS

Clinical and resource utilization data from 12 139 emergency department patients with acute chest pain were used in a decision-analytic model to identify cost-effective guidelines for the admission to a coronary care unit versus an intermediate care unit for initially uncomplicated patients without other indications for intensive care. The probability of clinical complications and death were derived from data on age-specific subsets of the population. Resource utilization estimates were based on cost data from a subset of 901 patients and length of stay data for the entire cohort. The survival benefit associated with initial triage to the coronary care unit instead of an intermediate care unit was assumed to be 15%. In the baseline analysis for 55- to 64-year-old patients, the probability of acute myocardial infarction (AMI) at which the coronary care unit had an incremental cost-effectiveness below $50 000 per year-of-life-saved was 29%. Triage to the coronary care unit was somewhat more cost-effective in elderly patients because their higher early complication rate more than offset their shorter life expectancy.

CONCLUSIONS

This analysis indicates that the coronary care unit usually should be reserved for patients with a moderate (21% or more, depending on the patient's age) probability of AMI unless patients need intensive care for other reasons. Clinical data suggest that only patients with ECG changes of ischemia or infarction not known to be old have a probability of AMI this high. Intermediate care units are appropriate for patients whose risks are not high enough for a coronary care unit to be cost-effective but too high for other alternatives to be recommended for safety and effectiveness.

An emergency department-based protocol for rapidly ruling out myocardial ischemia reduces hospital time and expense: results of a randomized study (ROMIO)

OBJECTIVES

We tested the hypothesis that an emergency department-based protocol for rapidly ruling out myocardial ischemia would reduce hospital time and expense but maintain diagnostic accuracy.

BACKGROUND

Patients with a missed diagnosis of myocardial infarction have a high mortality rate; however, providing routine hospital care to low risk patients may not be time- or cost-effective.

METHODS

One hundred low risk patients were entered into the study and randomized either to an emergency department-based rapid rule-out protocol (n = 50) or to routine hospital care (n = 50). Patients receiving routine care were managed by their attending physicians. The rapid protocol included serum enzyme testing at 0, 3, 6 and 9h, serial electrocardiograms with continuous ST segment monitoring and, if results were negative, a predischarge graded exercise test. Study patients were also compared with 160 historical control subjects.

RESULTS

Myocardial infarction or unstable angina occurred in 6% of patients within 30 days; no diagnoses were missed. By intention to treat analysis (n = 50 in each group), the hospital stay was shorter and charges were lower with the rapid protocol than with routine care (p = 0.001). Among patients in whom ischemia was ruled out, those assigned to the rapid protocol had a shorter hospital stay (median 11.9 vs. 22.8 h, p = 0.0001) and lower initial ($893 vs $1,349, p = 0.0001) and 30-day ($898 vs. $1,522, p = 0.0001) hospital charges than did patients given routine care. In historical control subjects, the hospital stay was longer (median 34.5 h, p = 0.001 vs. either group) and charges greater (median $2,063, p = 0.001, vs rapid protocol, p = 0.02, vs. routine care group).

CONCLUSIONS

In low risk patients who present to the emergency department with chest pain, the rapid protocol ruled out myocardial infarction and unstable angina more quickly and cost-effectively than did routine hospital care.

Prediction of the need for intensive care in patients who come to emergency departments with acute chest pain

BACKGROUND

Patients who come to the emergency department with chest pain are a heterogeneous group. Some have ischemic heart disease that may lead to serious complications, whereas others have minor disorders. We performed a study to identify clinical factors that predict which patients will have complications requiring intensive care.

METHODS

We first studied 10,682 patients with acute chest pain at seven hospitals between 1984 and 1986 (derivation set) to identify potential clinical predictors of the development of major complications. We then validated these predictors in a separate set of 4676 patients at one hospital between 1990 and 1994 (validation set).

RESULTS

In the derivation set of patients, we identified the following set of clinical features, which, if present in the emergency department, were associated with an increased risk of complications: ST-segment elevation or Q waves on the electrocardiogram thought to indicate acute myocardial infarction, other electrocardiographic changes indicating myocardial ischemia, low systolic blood pressure, pulmonary rales above the bases, or an exacerbation of known ischemic heart disease. On the basis of these criteria, the patients in the validation set were stratified into four groups, with the risk of major complications in the first 12 hours ranging from 0.15 to 8 percent. After 12 hours, the probability of a major complication could be updated on the basis of whether the patient had already had a complication of major severity, a complication of intermediate severity, or a myocardial infarction (independent relative risks, 18.9, 7.7 and 4.0, respectively, as compared with patients without prior complications or myocardial infarction).

CONCLUSIONS

The risk of major complications in patients with acute chest pain can be estimated on the basis of the clinical presentation and new clinical observations made during the hospital course. These estimates of risk help in making rational decisions about the appropriate level of medical care for patients with acute chest pain.

Non-ICU care of hemodynamically stable mechanically ventilated patients

OBJECTIVE

To analyze a 4 1/2-year experience caring for hemodynamically stable mechanically ventilated patients on a nonmonitored respiratory care floor (RCF) for therapeutic outcome, utilization, and costs.

DESIGN

A retrospective medical records review.

SETTING

ICUs and an RCF of a university-affiliated tertiary care center.

PARTICIPANTS

Two hundred twenty-four patients requiring more than 24 h of mechanical ventilation cared for on the RCF.

RESULTS

The mean age of patients was 67 +/- 17 years. Of the admissions, 58% were from the medical ICU, 28% were from surgical ICUs, and 9.4% were from general medical floors. Patients spent 50 +/- 66 days mechanically ventilated on the RCF. Overall survival was 50.4% with 93.8% of surviving patients successfully weaned from mechanical ventilation. Survival by diagnostic group demonstrated highest probability of survival in patients with trauma and lowest in patients with multisystem failure. Of the survivors, 39% were discharged home, 34% to a rehabilitation unit, and 24% to a skilled nursing facility. Savings based on differential of costs between the ICU and RCF, primarily from reduced staffing requirements, were estimated at $4.1 million.

CONCLUSION

Use of a nonmonitored RCF for the care of hemodynamically stable mechanically ventilated patients yields acceptable therapeutic outcomes while providing the institution with increased flexibility in critical care bed management and significant financial savings.

Test of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) for prehospital use

STUDY OBJECTIVES

To test diagnostic performance for acute cardiac ischemia (ACI) in a manually calculated and in a computerized, ECG-calculated ACI time-insensitive predictive instrument (ACI-TIPI) in prehospital chest pain patients.

METHODS

We carried out prospective inclusion and data acquisition with retrospective analysis. Over a 6-month period, 439 adult emergency medical services patients with chest pain underwent prehospital electrocardiography. Because of incomplete data, 77 cases were excluded, leaving a study sample of 362 patients. Excluded patients did not differ significantly with respect to age, sex, final diagnosis, or history of myocardial infarction, heart surgery, diabetes, or stroke. ACI-TIPI probabilities of ACI were computed on the basis of the prehospital ECGs as interpreted retrospectively and independently by two study investigators blinded to patient outcome, with a specially programmed electrocardiograph, and with a computer algorithm further modified by logistic-regression analysis.

RESULTS

Diagnostic performance on the basis of receiver operating characteristic (ROC) curve areas of the ACI-TIPI was scored, by the two physician readers, .73 and .74; and by ECG, .75. Patients with low ACI-TIPI probability (0% to 9%) had no acute myocardial infarctions, a 2.3% incidence of angina, and no prehospital life-threatening events.

CONCLUSION

ACI-TIPI probabilities of ACI as generated by a specially programmed electrocardiograph are comparable to those based on physician ECG interpretations and may be useful in the prehospital evaluation of chest pain.

Role of telemetry monitoring in the non-intensive care unit

To determine the outcomes of patients admitted to a non-intensive care telemetry unit and to assess the role of telemetry for guiding patient management decisions, data from 2,240 patients admitted to a telemetry unit were collected prospectively during 7 months. Physicians recorded the outcomes (intensive care unit transfer and mortality) and assessed whether telemetry assisted in guiding patient management. Indications for admission to the telemetry unit included chest pain syndromes (55%), arrhythmias (14%), heart failure (12%), and syncope (10%). Telemetry led to direct modifications in management in 156 patients (7%; 95% confidence interval [CI] 5.9% to 8%). Telemetry was perceived as useful but did not alter management for 127 patients (5.7%; 95% CI 4.7% to 6.6%). Two hundred forty-one patients were transferred to an intensive care unit from the telemetry unit (10.8%; 95% CI 9.5% to 12%). Nineteen patients (0.8% of all admissions; 95% CI 0.5% to 1.2%) were transferred because of an arrhythmia identified by telemetry. Routine transfer after cardiac revascularization or surgery accounted for 134 transfers; clinical deterioration accounted for 88 transfers. There were 20 deaths in the unit (0.9%; 95% CI 0.5% to 1.3%): 4 of the 20 deaths occurred while patients were being monitored. The role of telemetry in guiding patient management may be overestimated by physicians, since it detected significant arrhythmias that led to change in medications or urgent interventions in a small fraction of patients.