title: Delays in service for non-emergent patients due to arrival of emergent patients in the emergency department: a case study in Hong Kong.
abstract: BACKGROUND
  In Hong Kong Emergency Departments (EDs), the timeliness of providing high-quality services has been compromised by the increasing attendance of non-emergent patients in addition to the unpredictable arrival of emergency patients.
  
  
  OBJECTIVE
  We sought to quantify the impact of the presence of emergent patients and other related factors on the delay in service for non-emergent patients.
  
  
  METHODS
  We conducted a retrospective study in patients who visited the ED of a large hospital in Hong Kong from July 1, 2009 to June 30, 2010. We estimated waiting and length of stay (LOS) for individual non-emergent patients registered during day and evening shifts. Using multiple linear regression, we estimated waiting time and LOS as a function of the presence of emergent patients and other related factors such as patient demographics and clinical factors. In particular, we evaluated the influence of the arrival or presence of emergent patients on the odds of violating the 120-min waiting time target for semi-urgent patients.
  
  
  RESULTS
  The arrival of a new emergent patient prolonged the waiting time and LOS of a non-emergent patient by 14.9% (95% confidence interval [CI] 14.2-15.5) and 10.8% (95% CI 10.6-11.0), respectively. An additional patient-hour needed for an emergent patient increased the probability of violating the waiting time target for non-emergent patients (odds ratio 2.3, 95% CI 2.2-2.4).
  
  
  CONCLUSIONS
  The arrival of an emergent patient significantly prolonged the waiting time and LOS for non-emergent patients. Discouraging non-urgent ED utilization and building a real-time decision-support system are critical methods needed to relieve staff pressure and guide contingent resource reallocation when emergent patients arrive.
authors.affiliation: Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong SAR.
authors.forename: Mai
authors.initials: M
authors.lastname: Xu
authors.forename: Tse Chiu
authors.initials: TC
authors.lastname: Wong
authors.forename: Shui Yee
authors.initials: SY
authors.lastname: Wong
authors.forename: Kwai Sang
authors.initials: KS
authors.lastname: Chin
authors.forename: Kwok Leung
authors.initials: KL
authors.lastname: Tsui
authors.forename: Renee Y
authors.initials: RY
authors.lastname: Hsia
mesh_terms: D000328:Adult; D000368:Aged; D003441:Crowding; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004638:Emergency Treatment / Q000706:statistics & numerical data; D005260:Female; D006723:Hong Kong; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D014850:Waiting Lists
keywords: Emergency Department; emergent patients; length of stay; non-emergent patients; overcrowding; waiting times