title: Adverse events in patients with return emergency department visits.
abstract: OBJECTIVE
  This study describes the proportion of emergency department (ED) returns within 7 days due to adverse events, defined as adverse outcomes related to healthcare received.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  We used an electronically triggered adverse event surveillance system at a tertiary care ED from May to June 2010 to examine ED returns within 7 days of index visit.
  
  
  METHODS
  One of three trained nurses determined whether the visit was related to index emergency care. For such records, one of three trained emergency physicians conducted adverse event determinations.
  
  
  METHODS
  We determined adverse event type and severity and analysed the data with descriptive statistics, χ(2) tests and logistic regression.
  
  
  RESULTS
  Of 13,495 index ED visits, 923 (6.8%) were followed by ED returns within 7 days. The median age of all patients was 47 years and 52.8% were women. After nursing review, 211 cases required physician review. Of these, 53 visits were adverse events (positive predictive value (PPV)=5.7%, 95% CI 4.4% to 7.4%) and 30 (56.6%) were preventable. Common adverse event types involved management, diagnostic or medication issues. We observed one potentially preventable death and 58.5% of adverse events resulting in transient disability. The PPV of a modified trigger with a cut-off of return within 72 h, resulting in admission was 11.9% (95% CI 6.8% to 18.9%).
  
  
  CONCLUSIONS
  Our electronic trigger efficiently identified adverse events among 12% of patients with ED returns within 72 h, requiring hospital admission. Given the high degree of preventability of the identified adverse events, this trigger also holds promise as a performance measurement tool.
authors.affiliation: Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: Lisa
authors.initials: L
authors.lastname: Calder
authors.affiliation: Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Anita
authors.initials: A
authors.lastname: Pozgay
authors.affiliation: Department of Emergency Medicine, Queensway Carleton Hospital, Ottawa, Ontario, Canada.
authors.forename: Shena
authors.initials: S
authors.lastname: Riff
authors.affiliation: Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Rothwell
authors.affiliation: Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: Erik
authors.initials: E
authors.lastname: Youngson
authors.affiliation: Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
authors.forename: Naghmeh
authors.initials: N
authors.lastname: Mojaverian
authors.affiliation: Department of Emergency Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Adam
authors.initials: A
authors.lastname: Cwinn
authors.affiliation: Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Alan
authors.initials: A
authors.lastname: Forster
mesh_terms: D000328:Adult; D000368:Aged; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D019300:Medical Errors / Q000706:statistics & numerical data*; D008875:Middle Aged; D011446:Prospective Studies
keywords: Emergency department; Patient safety; Quality improvement