title: Predicting cardiac arrest on the wards: a nested case-control study.
abstract: BACKGROUND
  Current rapid response team activation criteria were not statistically derived using ward vital signs, and the best vital sign predictors of cardiac arrest (CA) have not been determined. In addition, it is unknown when vital signs begin to accurately detect this event prior to CA.
  
  
  METHODS
  We conducted a nested case-control study of 88 patients experiencing CA on the wards of a university hospital between November 2008 and January 2011, matched 1:4 to 352 control subjects residing on the same ward at the same time as the case CA. Vital signs and Modified Early Warning Scores (MEWS) were compared on admission and during the 48 h preceding CA.
  
  
  RESULTS
  Case patients were older (64 ± 16 years vs 58 ± 18 years; P = .002) and more likely to have had a prior ICU admission than control subjects (41% vs 24%; P = .001), but had similar admission MEWS (2.2 ± 1.3 vs 2.0 ± 1.3; P = .28). In the 48 h preceding CA, maximum MEWS was the best predictor (area under the receiver operating characteristic curve [AUC] 0.77; 95% CI, 0.71-0.82), followed by maximum respiratory rate (AUC 0.72; 95% CI, 0.65-0.78), maximum heart rate (AUC 0.68; 95% CI, 0.61-0.74), maximum pulse pressure index (AUC 0.61; 95% CI, 0.54-0.68), and minimum diastolic BP (AUC 0.60; 95% CI, 0.53-0.67). By 48 h prior to CA, the MEWS was higher in cases (P = .005), with increasing disparity leading up to the event.
  
  
  CONCLUSIONS
  The MEWS was significantly different between patients experiencing CA and control patients by 48 h prior to the event, but includes poor predictors of CA such as temperature and omits significant predictors such as diastolic BP and pulse pressure index.
authors: Section of Pulmonary and Critical Care, University of Chicago, Chicago, IL.
authors: Matthew M
authors: MM
authors: Churpek
authors: Section of Hospital Medicine, University of Chicago, Chicago, IL.
authors: Trevor C
authors: TC
authors: Yuen
authors: Pritzker School of Medicine, University of Chicago, Chicago, IL.
authors: Michael T
authors: MT
authors: Huber
authors: Department of Health Studies, University of Chicago, Chicago, IL.
authors: Seo Young
authors: SY
authors: Park
authors: Section of Pulmonary and Critical Care, University of Chicago, Chicago, IL.
authors: Jesse B
authors: JB
authors: Hall
authors: Section of Hospital Medicine, University of Chicago, Chicago, IL. Electronic address: dperes@uchicago.edu.
authors: Dana P
authors: DP
authors: Edelson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D016022:Case-Control Studies; D042241:Early Diagnosis; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis* / Q000401:mortality; D006339:Heart Rate; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015996:Survival Rate; D055986:Vital Signs