Elsevier

Annals of Emergency Medicine

Volume 44, Issue 3, September 2004, Pages 199-205
Annals of Emergency Medicine

Cardiology
Effects of neural network feedback to physicians on admit/discharge decision for emergency department patients with chest pain,☆☆,

https://doi.org/10.1016/j.annemergmed.2004.02.037Get rights and content

Abstract

Study objective

Neural networks can risk-stratify emergency department (ED) patients with potential acute coronary syndromes with a high specificity, potentially facilitating ED discharge of patients to home. We hypothesized that the use of “real-time” neural networks would decrease the admission rate for ED chest pain patients.

Methods

We conducted a before-and-after trial. Consecutive ED patients with chest pain were evaluated before and after implementation of a neural network in an urban university ED. Data included 40 variables used in neural networks for acute myocardial infarction and acute coronary syndrome. Data were obtained in real time, and neural network outputs were provided to the treating physician while patients were in the ED. On hospital discharge, attending physicians received feedback, including neural network output, their initial clinical impression, cardiac test results, and final diagnosis. The main outcome was the actual admit/discharge decision made before versus after the implementation of the neural network.

Results

Before implementation, 4,492 patients were enrolled; after implementation, 432 patients were enrolled. Implementation of the neural network did not decrease the hospital admission rate (before: 62.7% [95% confidence interval (CI) 61.3% to 64.1%] versus after: 66.6% [95% CI 62.2% to 71.0%]). Additionally, the ICU admission rates were not different (11.4% [95% CI 10.5% to 12.3%] versus 9.3% [95% CI 6.6% to 12.0%]). Physician query found that the neural network changed management in only 2 cases (<1%).

Conclusion

The use of real-time neural network feedback did not influence the admission decision for ED patients with chest pain, most likely because the neural network output was delayed until the return of cardiac markers, and the disposition decision had already been made by that time.

Introduction

Rapid and accurate identification of low-risk emergency department (ED) patients with chest pain syndromes remains problematic.1., 2. Clinical and computer algorithms can successfully risk-stratify patients; however, they are not able to identify a group of patients at such low risk that they could be safely and immediately released from the ED.3., 4., 5., 6., 7., 8., 9., 10., 11., 12.

A number of approaches have been developed to assist physicians in improving their diagnostic accuracy for myocardial infarction.8., 9., 13., 14., 15. It has been suggested that physicians will not use any method that purports to improve diagnostic accuracy unless it is easy to use and dramatically and consistently improves their performance.16., 17. Most approaches developed to aid in the diagnosis of myocardial infarction have not met these requirements. Many of them have failed when applied in the field,17 in part because they depend on complete and accurate data to maintain optimum performance, which in real-time application is rarely possible.

The artificial neural network is a powerful modality for the recognition of complex patterns that can maintain accuracy when some input data are missing.10 The network maps a complex multidimensional space defined by the constellation of input information, characterizing patterns that are provided during training. During testing, the network determines the goodness of fit of unknown patterns to that mapped space. Network function allows for an infinite variability of input information weighting. It is thought that the network's ability to assign the weight given to a specific input variable being determined by the values of all other input variables is what enables it to perform more accurately than other statistical approaches.

A number of studies have revealed that the artificial neural network can accurately identify the presence of myocardial infarction in patients with chest pain.10., 11., 18., 19., 20., 21. The artificial neural network achieves better diagnostic accuracy for acute myocardial infarction and acute coronary syndrome than other widely accepted risk-stratification tools.22 Despite data showing the superiority of neural networks over other risk-stratification algorithms, they have yet to be used in “real time.” We sought to determine the impact of real-time artificial neural network use on ED chest pain patient disposition and physician decisionmaking.

Section snippets

Study design

We performed a before-and-after trial to assess the impact of neural network feedback on physician decisionmaking for ED patients with chest pain, as assessed by their admit/discharge decision. At the conclusion of the study, we queried physicians to assess their satisfaction and trust with the neural network.

Setting

Patients were enrolled at an urban, tertiary care hospital ED with an annual census of approximately 53,000 adult visits. The “before” portion of the study was conducted between July 1999

Results

There were 4,492 patient visits for whom data collection instruments were completed before implementation of the neural network. After neural network implementation, an additional 432 patient visits were evaluated. Patients in both portions of the study were generally similar with respect to demographic, historical, and other clinical characteristics used for computation by the neural networks (Table). Neural network outputs were produced for 100% of patients in the neural network phase of the

Limitations

There are several limitations to our study. Although patients in both portions of our trial appeared similar with respect to demographic and clinical characteristics at presentation, the group that presented after implementation of the neural network was less likely to sustain an acute myocardial infarction or have a discharge diagnosis of acute coronary syndrome, which, however, should have biased the “after” group toward a lower admission rate.

We did not conduct a comprehensive instructional

Discussion

One of the strengths of the neural network is that its accuracy is not compromised when some input data are missing. Despite requiring more input data (and therefore being more likely to have occasional missing data), the neural network outperforms other risk-stratification algorithms, such as the Goldman and acute cardiac ischemia time-insensitive predictive instrument algorithms, 11., 23. which makes it a potentially valuable tool in the ED, where the emergency physician rarely has access to

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    Author contributions: JEH designed the study, developed the data collection instrument, oversaw all study-related procedures, wrote the first draft of the paper, and assisted with data analysis. KLS and DMS assisted with coordination of the data collection, performed data entry, and oversaw the day-to-day operations of the study. KLS, DMS, FDS, FSS, and WGB critically reviewed the manuscript. FDS, FSS, and WGB assisted with study design. FDS assisted with study design and development of the data collection instrument, coordinated the data collection and data entry, and performed patient follow-up in the hospital. FSS performed the statistical analysis. WGB designed the neural network and wrote sections of the manuscript. JEH takes responsibility for the paper as a whole.

    ☆☆

    The authors report this study did not receive any outside funding or support.

    Reprints not available from the authors.

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