title: Assessing the accuracy of algorithm-derived cardiorespiratory fitness in surgical patients: a prospective cohort study.
abstract: OBJECTIVE
  To determine if a non-exercise algorithm-derived assessment of cardiorespiratory fitness (CRFA) accurately predicted estimated values obtained using a six-minute walk test (CRF6MWD) and the Duke Activity Status Index (CRFDASI).
  
  
  METHODS
  Following research ethics board approval, an observational cohort study was conducted in selected, consenting patients undergoing elective surgery. Participants completed questionnaires assessing their self-reported exercise capacity. Their height, weight, waist circumference, and vital signs were measured. A six-minute walk test was performed twice with a 45-min rest interval between tests. The correlation between CRFAand both CRF6MWDand CRFDASIwas determined.
  
  
  RESULTS
  Two hundred forty-two participants were included. Mean age was 62 (range 45-88 yr); 150 (62%) were male, 87 (36%) self-reported walking or jogging > 16 km per week, and 49 (20%) were current smokers. The CRFAand CRF6MWDwere highly correlated (Pearson r = 0.878; P < 0.001). CRFAand CRFDASIwere less strongly correlated (Pearson r = 0.252; P < 0.001). Among patients capable of walking > 427 m in the six-minute walk test, CRFA, CRF6MWD, and CRFDASIwere equivalent.
  
  
  CONCLUSIONS
  A non-exercise algorithm can estimate cardiorespiratory fitness in patients presenting for elective surgery. The variables required to compute CRFAcan be obtained in a clinic setting without the need to engage in formal exercise testing. Further evaluation of CRFAas a predictor of long-term outcome in patients is warranted.
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Alberta, 2-150 Clinical Sciences Building, Edmonton, AB, T6G2G3, Canada.
authors.forename: Fadi
authors.initials: F
authors.lastname: Hammal
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Alberta, 2-150 Clinical Sciences Building, Edmonton, AB, T6G2G3, Canada.
authors.forename: Tanis
authors.initials: T
authors.lastname: Quaife
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Alberta, 2-150 Clinical Sciences Building, Edmonton, AB, T6G2G3, Canada.
authors.forename: Kieran
authors.initials: K
authors.lastname: Purich
authors.affiliation: Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Haennel
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Alberta, 2-150 Clinical Sciences Building, Edmonton, AB, T6G2G3, Canada.
authors.forename: Ferrante S
authors.initials: FS
authors.lastname: Gragasin
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Alberta, 2-150 Clinical Sciences Building, Edmonton, AB, T6G2G3, Canada.
authors.forename: Daniella San
authors.initials: DS
authors.lastname: Martin-Feeney
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Alberta, 2-150 Clinical Sciences Building, Edmonton, AB, T6G2G3, Canada. bfinegan@ualberta.ca.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Finegan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D015331:Cohort Studies; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D013514:Surgical Procedures, Operative; D011795:Surveys and Questionnaires