title: The relationship between emergency department crowding and patient outcomes: a systematic review.
abstract: OBJECTIVE
  Emergency department (ED) crowding is a significant patient safety concern associated with poor quality of care. The purpose of this systematic review is to assess the relationship between ED crowding and patient outcomes.
  
  
  METHODS
  We searched the Medline search engine and relevant emergency medicine and nursing journals for studies published in the past decade that pertained to ED crowding and the following patient outcome measures: mortality, morbidity, patient satisfaction, and leaving the ED without being seen. All articles were appraised for study quality.
  
  
  RESULTS
  A total of 196 abstracts were screened and 11 articles met inclusion criteria. Three of the eleven studies reported a significant positive relationship between ED crowding and mortality either among patients admitted to the hospital or discharged home. Five studies reported that ED crowding is associated with higher rates of patients leaving the ED without being seen. Measures of ED crowding varied across studies.
  
  
  CONCLUSIONS
  ED crowding is a major patient safety concern associated with poor patient outcomes. Interventions and policies are needed to address this significant problem.
  
  
  CONCLUSIONS
  This review details the negative patient outcomes associated with ED crowding. Study results are relevant to medical professionals and those that seek care in the ED.
authors.affiliation: Doctoral Student, Columbia University School of Nursing, New York, NY, USA.
authors.forename: Eileen J
authors.initials: EJ
authors.lastname: Carter
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Pouch
authors.forename: Elaine L
authors.initials: EL
authors.lastname: Larson
mesh_terms: D003441:Crowding; D004636:Emergency Service, Hospital; D006801:Humans; D063868:Patient Outcome Assessment; D061214:Patient Safety; D011787:Quality of Health Care
keywords: Emergency department crowding; patient outcomes