S.R. Podolsky

Does Pneumatic Tube System Transport Contribute to Hemolysis in ED Blood Samples

Introduction Our goal was to determine if the hemolysis among blood samples obtained in an emergency department and then sent to the laboratory in a pneumatic tube system was different from those in samples that were hand-carried. Methods The hemolysis index is measured on all samples submitted for potassium analysis. We queried our hospital laboratory database system (SunQuest®) for potassium results for specimens obtained between January 2014 and July 2014. From facility maintenance records, we identified periods of system downtime, during which specimens were hand-carried to the laboratory. Results During the study period, 15,851 blood specimens were transported via our pneumatic tube system and 92 samples were hand delivered. The proportions of hemolyzed specimens in the two groups were not significantly different (13.6% vs. 13.1% [p=0.90]). Results were consistent when the criterion was limited to gross (3.3% vs 3.3% [p=0.99]) or mild (10.3% vs 9.8% [p=0.88]) hemolysis. The hemolysis rate showed minimal variation during the study period (12.6%–14.6%). Conclusion We found no statistical difference in the percentages of hemolyzed specimens transported by a pneumatic tube system or hand delivered to the laboratory. Certain features of pneumatic tube systems might contribute to hemolysis (e.g., speed, distance, packing material). Since each system is unique in design, we encourage medical facilities to consider whether their method of transport might contribute to hemolysis in samples obtained in the emergency department.

Acute Coronary Syndrome Screening and Diagnostic Practice Variation

BACKGROUND In the absence of the existing acute coronary syndrome (ACS) guidelines directing the clinical practice implementation of emergency department (ED) screening and diagnosis, there is variable screening and diagnostic clinical practice across ED facilities. This practice diversity may be warranted. Understanding the variability may identify opportunities for more consistent practice. METHODS This is a cross-sectional clinical practice epidemiology study with the ED as the unit of analysis characterizing variability in the ACS evaluation across 62 diverse EDs. We explored three domains of screening and diagnostic practice: 1) variability in criteria used by EDs to identify patients for an early electrocardiogram (ECG) to diagnose ST-elevation myocardial infarction (STEMI), 2) nonuniform troponin biomarker and formalized pre-troponin risk stratification use for the diagnosis of non-ST-elevation myocardial infarction (NSTEMI), and 3) variation in the use of noninvasive testing (NIVT) to identify obstructive coronary artery disease or detect inducible ischemia. RESULTS We found that 85% of EDs utilize a formal triage protocol to screen patients for an early ECG to diagnose STEMI. Of these, 17% use chest pain as the sole criteria. For the diagnosis of NSTEMI, 58% use intervals ≥4 hours for a second troponin and 34% routinely risk stratify before troponin testing. For the diagnosis of noninfarction ischemia, the median percentage of patients who have NIVT performed during their ED visit is 5%. The median percentage of patients referred for NIVT in hospital (observation or admission) is 61%. Coronary CT angiography is used in 66% of EDs. Exercise treadmill testing is the most frequently reported first-line NIVT (42%). CONCLUSION Our results suggest highly variable ACS screening and clinical practice.