title: Determining delayed admission to intensive care unit for mechanically ventilated patients in the emergency department.
abstract: BACKGROUND
  The adverse effects of delayed admission to the intensive care unit (ICU) have been recognized in previous studies. However, the definitions of delayed admission varies across studies. This study proposed a model to define "delayed admission", and explored the effect of ICU-waiting time on patients' outcome.
  
  
  METHODS
  This retrospective cohort study included non-traumatic adult patients on mechanical ventilation in the emergency department (ED), from July 2009 to June 2010. The primary outcomes measures were 21-ventilator-day mortality and prolonged hospital stays (over 30 days). Models of Cox regression and logistic regression were used for multivariate analysis. The non-delayed ICU-waiting was defined as a period in which the time effect on mortality was not statistically significant in a Cox regression model. To identify a suitable cut-off point between "delayed" and "non-delayed", subsets from the overall data were made based on ICU-waiting time and the hazard ratio of ICU-waiting hour in each subset was iteratively calculated. The cut-off time was then used to evaluate the impact of delayed ICU admission on mortality and prolonged length of hospital stay.
  
  
  RESULTS
  The final analysis included 1,242 patients. The time effect on mortality emerged after 4 hours, thus we deduced ICU-waiting time in ED > 4 hours as delayed. By logistic regression analysis, delayed ICU admission affected the outcomes of 21 ventilator-days mortality and prolonged hospital stay, with odds ratio of 1.41 (95% confidence interval, 1.05 to 1.89) and 1.56 (95% confidence interval, 1.07 to 2.27) respectively.
  
  
  CONCLUSIONS
  For patients on mechanical ventilation at the ED, delayed ICU admission is associated with higher probability of mortality and additional resource expenditure. A benchmark waiting time of no more than 4 hours for ICU admission is recommended.
authors.forename: Shih-Chiang
authors.initials: SC
authors.lastname: Hung
authors.forename: Chia-Te
authors.initials: CT
authors.lastname: Kung
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Hung
authors.forename: Ber-Ming
authors.initials: BM
authors.lastname: Liu
authors.forename: Jien-Wei
authors.initials: JW
authors.lastname: Liu
authors.forename: Ghee
authors.initials: G
authors.lastname: Chew
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Chuang
authors.forename: Wen-Huei
authors.initials: WH
authors.lastname: Lee
authors.forename: Tzu-Chi
authors.initials: TC
authors.lastname: Lee
mesh_terms: D018806:APACHE; D000368:Aged; D016001:Confidence Intervals; D003422:Critical Care; D003953:Diagnosis-Related Groups; D004636:Emergency Service, Hospital / Q000458:organization & administration* / Q000706:statistics & numerical data; D005260:Female; D015600:Glasgow Coma Scale; D006742:Hospital Bed Capacity; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units / Q000191:economics / Q000458:organization & administration / Q000706:statistics & numerical data*; D007902:Length of Stay / Q000191:economics / Q000706:statistics & numerical data*; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D010343:Patient Admission / Q000191:economics / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D012121:Respiration, Artificial / Q000401:mortality* / Q000592:standards; D012131:Respiratory Insufficiency / Q000209:etiology / Q000401:mortality* / Q000628:therapy; D012189:Retrospective Studies; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors; D014218:Triage / Q000458:organization & administration / Q000592:standards