Psychometric evaluation of the Freedman questionnaire to assess sleep in critical patients

Abstract

Aim: A study was made of the psychometric characteristics of the modified Freedman questionnaire to assess sleep in critical patients.

Design: A psychometric study was carried out, with content validity being explored by a group of experts, and internal consistency based on Cronbach's alpha coefficient. Factor analysis was performed to explore construct validity, and stability was assessed by test-retest analysis.

Setting: The Department of Intensive Care Medicine of a reference hospital.

Participants: Patients admitted between 23 February 2016 and 20 December 2017.

Interventions: Questionnaire administration.

Variables: Items of the modified Freedman questionnaire.

Results: Item relevance and definition yielded scores >3 (Likert scale maximum=4). Cronbach's alpha showed a global value of 0.933. The intraclass correlation index was >0.75 for most of the items of the questionnaire. Factor analysis allowed the detection of specific associations between the studied variables and the four factors.

Conclusions: The modified Freedman questionnaire showed good psychometric characteristics. It may be a reliable instrument for assessing the quality of sleep in critically ill patients, as well as the environmental factors.

Keywords: Critical care; Cuidados críticos; Estudios de validación; Privación de sueño; Psicometría; Psychometrics; Sleep deprivation; Validation studies.