Evaluating the Construct Validity of the Charité Alarm Fatigue Questionnaire using Confirmatory Factor Analysis

Background. The Charité Alarm Fatigue Questionnaire (CAFQa) is a 9-item Questionnaire that aims to standardize how alarm fatigue (AF) in nurses and physicians is measured. We previously hypothesized that it has two correlated scales, i.e. one on the psychosomatic effects of AF and the other on staff’s coping strategies in working with alarms. Objective. We aimed to validate the hypothesized structure of the CAFQa and thus underpin the instrument's construct validity. Methods. We conducted two independent studies with nurses and physicians from ICUs in Germany (N Study 1 = 265, N Study 2 = 1212). Responses to the questionnaires were analyzed using confirmatory factor analysis with the unweighted least-squares algorithm based on polychoric covariances. Convergent validity was assessed by participants' estimation of their own AF and exposure to false alarms in percent. Results. In both studies the chi-square test reached statistical significance (ꭓ 2 (26) = 44.932, p = 0.012 and ꭓ 2 (26) = 92.416, p < 0.001 for Study 1 and 2, respectively). Other fit indices suggested a good model fit (in both studies RMSEA < 0.05, SRMR < 0.08, RNI > 0.95, TLI > 0.95, and CFI > 0.995). Participants' mean scores correlated moderately with self-reported AF (r Study 1 = 0.45; r Study 2 = 0.53) and weakly with self-perceived exposure to false alarms (r Study 1 = 0.3; r Study 2 = 0.33). Conclusion. The questionnaire measures the construct of alarm fatigue as proposed in our previous study. Researchers and clinicians can rely on the CAFQa to measure the AF of nurses and physicians.