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

Abstract

Background: The Charité Alarm Fatigue Questionnaire (CAFQa) is a 9-item questionnaire that aims to standardize how alarm fatigue in nurses and physicians is measured. We previously hypothesized that it has 2 correlated scales, one on the psychosomatic effects of alarm fatigue 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 2 independent studies with nurses and physicians from intensive care units in Germany (study 1: n=265; study 2: n=1212). Responses to the questionnaire 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 alarm fatigue and exposure to false alarms as a percentage.

Results: In both studies, the χ2 test reached statistical significance (study 1: χ226=44.9; P=.01; study 2: χ226=92.4; P<.001). Other fit indices suggested a good model fit (in both studies: root mean square error of approximation <0.05, standardized root mean squared residual <0.08, relative noncentrality index >0.95, Tucker-Lewis index >0.95, and comparative fit index >0.995). Participants' mean scores correlated moderately with self-reported alarm fatigue (study 1: r=0.45; study 2: r=0.53) and weakly with self-perceived exposure to false alarms (study 1: r=0.3; study 2: r=0.33).

Conclusions: 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 alarm fatigue of nurses and physicians.

Keywords: ICU; alarm; alarm fatigue; alarm management; alarm system; alarm system quality; alarms; care; clinical alarms; factor analysis; intensive; intensive care unit; medical devices; patient monitoring; patient safety; questionnaire; questionnaires; safety; validation; validity; warning.

Figure 1.. Diagram of the final model from each study. Factors are shown in circles (factor 1: alarm stress; factor 2: alarm coping), and items 1‐9 in squares. In both studies, the variance of the factors was constrained to 1. The arrows connecting the factors with the items are the factor loadings and arrows pointing toward the items show the residuals. The arrows between the factors show their correlation.