title: Measuring nausea in emergency department patients via the use of exploratory factor analysis.
abstract: OBJECTIVE
  The objective was to evaluate the applicability of a previously studied multifactorial nausea scale in the emergency department (ED) setting via exploratory factor analysis (EFA).
  
  
  METHODS
  Two studies evaluated the validity and factor structure of 18 nausea descriptors scored on 11-point Likert scales. Trained research volunteers administered the scale to 83 men and 123 women in the first sample and to 100 men and 230 women in the second sample. All patients were assessed at enrollment and again at 90 minutes to detect changes in symptom severity. An EFA in the first study used a maximum likelihood estimation method with a principal factor analysis. The second study narrowed the descriptors and evaluated the factor structure with a confirmatory factor analysis (CFA).
  
  
  RESULTS
  Two factors were retained in the solution; one contained five items with descriptors of physical symptoms, and a second contained five items with psychological symptoms. CFA determined that the two five-item scales were stable and reliable measures of patient nausea experience.
  
  
  CONCLUSIONS
  The scales measure both physical and psychological symptoms of nausea, indicating that the experience is multidimensional.
authors.affiliation: Department of Emergency Medicine, Oregon Health and Science University, Portland, OR, USA. cloutier@ohsu.edu
authors.forename: Robert L
authors.initials: RL
authors.lastname: Cloutier
authors.forename: Bret E
authors.initials: BE
authors.lastname: Fuller
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hendrickson
authors.forename: Nikolas
authors.initials: N
authors.lastname: Jones
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004636:Emergency Service, Hospital; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D025341:Principal Component Analysis; D012720:Severity of Illness Index; D055815:Young Adult