Reliability and Validity of Shortened State Trait Anxiety Inventory in Spanish Patients Receiving Mechanical Ventilation

Background In order to measure anxiety in physically and cognitively debilitated patients, such as patients receiving invasive mechanical ventilation, the use of reliable and valid instruments is recommended; however, these instruments should be short. Objective To analyze the reliability and validity of a short version of the state subscale from the Spielberger State-Trait Anxiety Inventory, developed by Chlan and colleagues and translated into Spanish (STAI-E6), in patients receiving invasive mechanical ventilation. Methods An instrumental study was conducted of 80 patients receiving invasive mechanical ventilation in the intensive care unit at the Hospital of Alicante (Spain). The patients completed the 6-item STAI-E6 scale. Before the patients completed the scale, the interviewers indicated their impression of each patient's level of anxiety by using a linear scale. Internal consistency, construct validity, and convergent validity of the scale were analyzed. Results The scale did not present a floor/ceiling effect, the Cronbach α was 0.79, and the single-factor structure of the original scale was maintained. Scores on the scale correlated positively with the subjective assessment of the health professional. Significant differences were found only between anxiety level and duration of intubation. Conclusions The 6-item version of the state subscale from the STAI-E6 shows satisfactory reliability and validity for Spanish patients receiving invasive mechanical ventilation.This study was funded by the Ministry of Health and Consumer Affairs (Spanish government), through the program of grants for studies to assess health technology and research on health services (ref. PI06/90476-90492)