RESUMEN
(1) Background: This research presents the CUCEQS© (Spanish acronym for Questionnaire of Perioperative Nursing Safety Competencies), which evaluates the perception of perioperative nurses about their competencies related to surgical patient safety. The aim of the present study was to design, validate, and analyze the psychometric properties of the CUCEQS©. (2) Methods: We devised an instrumental, quantitative, and descriptive study divided into two phases: in the first, the questionnaire was designed through a Delphi method developed by perioperative nurses and experts in patient safety. In the second, the reliability, validity, and internal structure of the tool were evaluated. (3) Results: In the first phase, the items kept were those that obtained a mean equal to or higher than four out of five in the expert consensus, and a Content Validity Index higher than 0.78. In the second phase, at the global level, a Stratified Cronbach's Alpha of 0.992 was obtained, and for each competency, Cronbach's Alpha values between 0.81 and 0.97 were found. A first-order confirmatory factor analysis of the 17 subscales (RMSEA 0.028, (IC 90% = 0.026-0.029) and its observed measures was performed for the 164 items, as well as a second-order analysis of the four competencies (RMSEA = 0.034, (IC90% = 0.033-0.035). (4) Conclusions: The questionnaire is a valid tool for measuring the perceived level of competency by the perioperative nurses in surgical patient safety. This is the first questionnaire developed for this purpose, and the results obtained will facilitate the identification of areas to be improved by health professionals in patient safety.