title: Monitoring sedation status over time in ICU patients: reliability and validity of the Richmond Agitation-Sedation Scale (RASS).
abstract: BACKGROUND
  Goal-directed delivery of sedative and analgesic medications is recommended as standard care in intensive care units (ICUs) because of the impact these medications have on ventilator weaning and ICU length of stay, but few of the available sedation scales have been appropriately tested for reliability and validity.
  
  
  OBJECTIVE
  To test the reliability and validity of the Richmond Agitation-Sedation Scale (RASS).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Adult medical and coronary ICUs of a university-based medical center.
  
  
  METHODS
  Thirty-eight medical ICU patients enrolled for reliability testing (46% receiving mechanical ventilation) from July 21, 1999, to September 7, 1999, and an independent cohort of 275 patients receiving mechanical ventilation were enrolled for validity testing from February 1, 2000, to May 3, 2001.
  
  
  METHODS
  Interrater reliability of the RASS, Glasgow Coma Scale (GCS), and Ramsay Scale (RS); validity of the RASS correlated with reference standard ratings, assessments of content of consciousness, GCS scores, doses of sedatives and analgesics, and bispectral electroencephalography.
  
  
  RESULTS
  In 290-paired observations by nurses, results of both the RASS and RS demonstrated excellent interrater reliability (weighted kappa, 0.91 and 0.94, respectively), which were both superior to the GCS (weighted kappa, 0.64; P<.001 for both comparisons). Criterion validity was tested in 411-paired observations in the first 96 patients of the validation cohort, in whom the RASS showed significant differences between levels of consciousness (P<.001 for all) and correctly identified fluctuations within patients over time (P<.001). In addition, 5 methods were used to test the construct validity of the RASS, including correlation with an attention screening examination (r = 0.78, P<.001), GCS scores (r = 0.91, P<.001), quantity of different psychoactive medication dosages 8 hours prior to assessment (eg, lorazepam: r = - 0.31, P<.001), successful extubation (P =.07), and bispectral electroencephalography (r = 0.63, P<.001). Face validity was demonstrated via a survey of 26 critical care nurses, which the results showed that 92% agreed or strongly agreed with the RASS scoring scheme, and 81% agreed or strongly agreed that the instrument provided a consensus for goal-directed delivery of medications.
  
  
  CONCLUSIONS
  The RASS demonstrated excellent interrater reliability and criterion, construct, and face validity. This is the first sedation scale to be validated for its ability to detect changes in sedation status over consecutive days of ICU care, against constructs of level of consciousness and delirium, and correlated with the administered dose of sedative and analgesic medications.
authors.affiliation: Department of Medicine, Center for Health Services Research, Vanderbilt University School of Medicine, Tennessee Valley Veteran's Affairs Healthcare System, Geriatric Research Education and Clinical Center, Nashville 37232, USA. wes.ely@vanderbilt.edu
authors.forename: E Wesley
authors.initials: EW
authors.lastname: Ely
authors.forename: Brenda
authors.initials: B
authors.lastname: Truman
authors.forename: Ayumi
authors.initials: A
authors.lastname: Shintani
authors.forename: Jason W W
authors.initials: JW
authors.lastname: Thomason
authors.forename: Arthur P
authors.initials: AP
authors.lastname: Wheeler
authors.forename: Sharon
authors.initials: S
authors.lastname: Gordon
authors.forename: Joseph
authors.initials: J
authors.lastname: Francis
authors.forename: Theodore
authors.initials: T
authors.lastname: Speroff
authors.forename: Shiva
authors.initials: S
authors.lastname: Gautam
authors.forename: Richard
authors.initials: R
authors.lastname: Margolin
authors.forename: Curtis N
authors.initials: CN
authors.lastname: Sessler
authors.forename: Robert S
authors.initials: RS
authors.lastname: Dittus
authors.forename: Gordon R
authors.initials: GR
authors.lastname: Bernard
mesh_terms: D000368:Aged; D000700:Analgesics / Q000008:administration & dosage; D016292:Procedural Sedation / Q000592:standards / Q000706:statistics & numerical data; D003243:Consciousness; D003422:Critical Care / Q000592:standards / Q000706:statistics & numerical data; D004569:Electroencephalography; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007362:Intensive Care Units / Q000592:standards / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000592:standards / Q000706:statistics & numerical data; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D012121:Respiration, Artificial
chemical_list: D000700:Analgesics; D006993:Hypnotics and Sedatives