title: Detection of postoperative respiratory failure: how predictive is the Agency for Healthcare Research and Quality's Patient Safety Indicator?
abstract: BACKGROUND
  Patient Safety Indicator (PSI) 11, or postoperative respiratory failure, was developed by the US Agency for Healthcare Research and Quality to detect incident cases of respiratory failure after elective operations through use of ICD-9-CM diagnosis and procedure codes. We sought to determine the positive predictive value (PPV) of this indicator.
  
  
  METHODS
  We conducted a retrospective cross-sectional study, sampling consecutive cases that met PSI 11 criteria from 18 geographically diverse academic medical centers on or before June 30, 2007. Trained abstractors from each center reviewed medical records using a standard instrument. We assessed the PPV of the indicator (with 95% CI adjusted for clustering within centers) and conducted descriptive analyses of the cases.
  
  
  RESULTS
  Of 609 cases that met PSI 11 criteria, 551 (90.5%; 95% CI, 86.5-94.4%) satisfied the technical criteria of the indicator and 507 (83.2%; 95% CI, 77.2-89.3%) represented true cases of postoperative respiratory failure from a clinical standpoint. The most frequent reasons for being falsely positive were nonelective hospitalization, prolonged intubation for airway protection, and insufficient evidence to support a diagnosis of acute respiratory failure. Fifty percent of true-positive cases involved substantial baseline comorbidities, and 23% resulted in death.
  
  
  CONCLUSIONS
  Although PSI 11 predicts true postoperative respiratory failure with relatively high frequency, the indicator does not limit detection to preventable cases. The PPV of PSI 11 might be increased by excluding cases with a principal diagnosis suggestive of a nonelective hospitalization and those with head or neck procedures. Removing the diagnosis code criterion from the indicator might also increase PPV, but would decrease the number of true positive cases detected by 20%.
authors.affiliation: Department of Surgery, University of California, Davis, Medical Center, Sacramento, CA, USA. garth.utter@ucdmc.ucdavis.edu
authors.forename: Garth H
authors.initials: GH
authors.lastname: Utter
authors.forename: Joanne
authors.initials: J
authors.lastname: Cuny
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sama
authors.forename: Michael R
authors.initials: MR
authors.lastname: Silver
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Zrelak
authors.forename: Ruth
authors.initials: R
authors.lastname: Baron
authors.forename: Saskia E
authors.initials: SE
authors.lastname: Drösler
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Romano
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality*; D011237:Predictive Value of Tests; D019984:Quality Indicators, Health Care; D015203:Reproducibility of Results; D012131:Respiratory Insufficiency / Q000209:etiology* / Q000401:mortality*; D012189:Retrospective Studies; D013514:Surgical Procedures, Operative / Q000009:adverse effects; D014481:United States; D016270:United States Agency for Healthcare Research and Quality