CJEM Articles: acute coronary syndrome

Ojective:

To achieve our goal of excellent emergency cardiac care, our institution embarked on a Lean process improvement initiative. We sought to examine and quantify the outcome of this project on the care of suspected acute coronary syndrome (ACS) patients in our emergency department (ED).

Methods:

Front-line ED staff participated in several rapid improvement events, using Lean principles and techniques such as waste elimination, supply chain streamlining, and standard work to increase the value of the early care provided to patients with suspected ACS. A chart review was also conducted. To evaluate our success, proportions of care milestones (first electrocardiogram [ECG], ECG interpretation, physician assessment, and acetylsalicylic acid [ASA] administration) meeting target times were chosen as outcome metrics in this before-and-after study.

Results:

The proportion of cases with 12-lead ECGs completed within 10 minutes of patient triage increased by 37.4% (p < 0.0001). The proportion of cases with physician assessment initiated within 60 minutes increased by 12.1% (p = 0.0251). Times to ECG, physician assessment, and ASA administration also continued to improve significantly over time (p values < 0.0001). Post-Lean, the median time from ECG performance to physician interpretation was 3 minutes. All of these improvements were achieved using existing staff and resources.

Conclusions:

The application of Lean principles can significantly improve attainment of early diagnostic and therapeutic milestones of emergency cardiac care in the ED.

Objective: We derived a clinical decision rule to determine which emergency department (ED) patients with chest pain and possible acute coronary syndrome (ACS) require chest radiography.

Methods: We prospectively enrolled patients over 24 years of age with a primary complaint of chest pain and possible ACS over a 6 month period. Emergency physicians completed standardized clinical assessments and ordered chest radiographs as appropriate. Two blinded investigators independently classified chest radiographs as "normal," "abnormal not requiring intervention" and "abnormal requiring intervention," based on review of the radiology report and the medical record. The primary outcome was abnormality of chest radiographs requiring acute intervention. Analyses included interrater reliability assessment (with κ statistics), univariate analyses and recursive partitioning.

Results: We enrolled 529 patients during the study period between Jul. 1, 2007, and Dec. 31, 2007. Patients had a mean age of 59.9 years, 60.3% were male, 4.0% had a history of con gestive heart failure and 21.9% had a history of acute myocardial infarction. Only 2.1% (95% confidence interval [CI] 1.1%-3.8%) of patients had radiographic abnormality of the chest requiring acute intervention. The κ statistic for chest radiograph classification was 0.81 (95% CI 0.66-0.95). We derived the following rule: patients can forgo chest radiography if they have no history of congestive heart failure, no history of smoking and no abnormalities on lung auscultation. The rule was 100% sensitive (95% CI 32.0%-40.4%) and 36.1% specific (95% CI 32.0%-40.4%).

Conclusion: This rule has potential to reduce health care costs and enhance ED patient flow. It requires validation in an independent patient population before introduction into clinical practice.

Objective: We sought to determine the diagnostic accuracy of clinical prediction rules to exclude acute coronary syndrome (ACS) in the emergency department (ED) setting.

Methods: We searched MEDLINE, EMBASE, Web of Science and the Cochrane Database of Systematic Reviews. We contacted content experts to identify additional articles for review. Reference lists of included studies were hand searched. We selected articles for review based on the following criteria: 1) enrolled consecutive ED patients; 2) incorporated variables from the history or physical examination, electrocardiogram and cardiac biomarkers; 3) did not incorporate cardiac stress testing or coronary angiography into prediction rule; 4) based on original research; 5) prospectively derived or validated; 6) did not require use of a computer; and 7) reported sufficient data to construct a 2 × 2 contingency table. We assessed study quality and extracted data independently and in duplicate using a standardized data extraction form.

Results: Eight studies met inclusion criteria, encompassing 7937 patients. None of the studies verified the prediction rule with a reference standard on all or a random sample of patients. Six studies did not report blinding prediction rule assessors to reference standard results, and vice versa. Three prediction rules were prospectively validated. Sensitivities and specificities ranged from 94% to 100% and 13% to 57%, and positive and negative likelihood ratios from 1.1 to 2.2 and 0.01 to 0.17, respectively.

Conclusion: Current prediction rules for ACS have substantial methodological limitations and have not been successfully implemented in the clinical setting. Future methodologically sound studies are needed to guide clinical practice.