Adverse events among patients registered in high-acuity areas of the emergency department: a prospective cohort study

To enhance patient safety, it is important to understand the frequency and causes of adverse events (defined as unintended injuries related to health care management). We performed this study to describe the types and risk of adverse events in high-acuity areas of the emergency department (ED). This prospective cohort study examined the outcomes of consecutive patients who received treatment at 2 tertiary care EDs. For discharged patients, we conducted a structured telephone interview 14 days after their initial visit; for admitted patients, we reviewed the inpatient charts. Three emergency physicians independently adjudicated flagged outcomes (e.g., death, return visits to the ED) to determine whether an adverse event had occurred. We enrolled 503 patients; one-half (n = 254) were female and the median age was 57 (range 18-98) years. The majority of patients (n = 369, 73.3%) were discharged home. The most common presenting complaints were chest pain, generalized weakness and abdominal pain. Of the 107 patients with flagged outcomes, 43 (8.5%, 95% confidence interval 8.1%-8.9%) were considered to have had an adverse event through our peer review process, and over half of these (24, 55.8%) were considered preventable. The most common types of adverse events were as follows: management issues (n = 18, 41.9%), procedural complications (n = 13, 30.2%) and diagnostic issues (n = 10, 23.3%). The clinical consequences of these adverse events ranged from minor (urinary tract infection) to serious (delayed diagnosis of aortic dissection). We detected a higher proportion of preventable adverse events compared with previous inpatient studies and suggest confirmation of these results is warranted among a wider selection of EDs.