Development of a shortened state anxiety scale from the Spielberger State-Trait Anxiety Inventory (STAI) for patients receiving mechanical ventilatory support

Anxiety is a common experience for mechanically ventilated patients. There are a number of established instruments available to measure anxiety. However, there are significant limitations with these instruments, particularly the length of many scales when using them with ill persons. An instrument development study was conducted to develop a shortened scale from the 20-item Spielberger State Anxiety Inventory. Two-hundred ventilated patients were recruited from nine ICUs in the urban Midwest. Exploratory factor analysis techniques were used to create a shortened, 6-item scale, which accounted for 66.6 percent of the variance. A Cronbach's alpha of 0.78 with a correlation of 0.92 to the 20-item version resulted based on a 6-item scale, and the shortened scale retained many of the desirable properties of the full-length version. The shortened version of the Spielberger State Anxiety Inventory generally had good psychometric properties. However, additional research is needed to further validate this shortened scale.