title: Monitoring surgical and medical outcomes: the Bernoulli cumulative SUM chart. A novel application to assess clinical interventions.
abstract: BACKGROUND
  Monitoring clinical interventions is an increasing requirement in current clinical practice. The standard CUSUM (cumulative sum) charts are used for this purpose. However, they are difficult to use in terms of identifying the point at which outcomes begin to be outside recommended limits.
  
  
  OBJECTIVE
  To assess the Bernoulli CUSUM chart that permits not only a 100% inspection rate, but also the setting of average expected outcomes, maximum deviations from these, and false positive rates for the alarm signal to trigger.
  
  
  METHODS
  As a working example this study used 674 consecutive first liver transplant recipients. The expected one year mortality set at 24% from the European Liver Transplant Registry average. A standard CUSUM was compared with Bernoulli CUSUM: the control value mortality was therefore 24%, maximum accepted mortality 30%, and average number of observations to signal was 500-that is, likelihood of false positive alarm was 1:500.
  
  
  RESULTS
  The standard CUSUM showed an initial descending curve (nadir at patient 215) then progressively ascended indicating better performance. The Bernoulli CUSUM gave three alarm signals initially, with easily recognised breaks in the curve. There were no alarms signals after patient 143 indicating satisfactory performance within the criteria set.
  
  
  CONCLUSIONS
  The Bernoulli CUSUM is more easily interpretable graphically and is more suitable for monitoring outcomes than the standard CUSUM chart. It only requires three parameters to be set to monitor any clinical.
  
  
  METHODS
  the average expected outcome, the maximum deviation from this, and the rate of false positive alarm triggers.
authors.affiliation: Ospedale Gastroentrologico, Castellana Grotte, BA, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Leandro
authors.forename: N
authors.initials: N
authors.lastname: Rolando
authors.forename: G
authors.initials: G
authors.lastname: Gallus
authors.forename: K
authors.initials: K
authors.lastname: Rolles
authors.forename: A K
authors.initials: AK
authors.lastname: Burroughs
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D016031:Liver Transplantation / Q000401:mortality / Q000592:standards*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010043:Outcome and Process Assessment, Health Care / Q000592:standards* / Q000639:trends*; D011785:Quality Assurance, Health Care / Q000592:standards*; D018570:Risk Assessment / Q000379:methods; D016896:Treatment Outcome