title: Relationship between two anxiety instruments in patients receiving mechanical ventilatory support.
abstract: OBJECTIVE
  The primary aim of this paper is to discuss the relationship between the Visual Analog Scale-Anxiety (VAS-A) and the Spielberger State Anxiety Inventory (SAI) in patients receiving mechanical ventilatory support. A secondary aim is to provide suggestions for the nurse-researcher to consider when selecting an instrument to measure anxiety.
  
  
  BACKGROUND
  Anxiety is a common experience for critically ill patients receiving mechanical ventilatory support. It is a challenge, however, for nurse-researcher to select an instrument to measure anxiety that is valid and reliable yet does not cause great response burden for participants. Visual analog scales may reduce response burden, but lack sound validation in research participants receiving mechanical ventilatory support.
  
  
  METHODS
  This study used a correlational design. A convenience sample of critically ill patients receiving mechanical ventilatory support (n = 200) were asked to rate their current level of anxiety on the 20-item Spielberger SAI and a 100-mm VAS-A.
  
  
  RESULTS
  Eight participants were unable to complete the Spielberger SAI; 100% completed the VAS-A. The two instruments were found to be significantly correlated at r = 0.50; P = 0.01.
  
  
  CONCLUSIONS
  The VAS-A was found to be less burdensome for research participants than the Spielberger SAI, resulting in no missing data on the VAS-A. Findings from this study provide initial validation of the VAS-A as a justifiable instrument to measure anxiety in patients receiving mechanical ventilatory support. Researchers are advised to balance reliability and validity properties with response burden when selecting an instrument to measure anxiety in patients with communication challenges and energy limitations.
authors.affiliation: School of Nursing, University of Minnesota, Minneapolis, Minnesota 55455, USA. chlan001@umn.edu
authors.forename: Linda L
authors.initials: LL
authors.lastname: Chlan
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001007:Anxiety / Q000175:diagnosis* / Q000209:etiology; D003422:Critical Care; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011581:Psychological Tests / Q000592:standards*; D011594:Psychometrics / Q000592:standards; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000523:psychology*