A Visual Analog Scale to assess anxiety in children during anesthesia induction (VAS-I): Results supporting its validity in a sample of day care surgery patients.

BACKGROUND: The modified Yale Preoperative Anxiety Scale is widely used to assess children's anxiety during induction of anesthesia, but requires training and its administration is time-consuming. A Visual Analog Scale, in contrast, requires no training, is easy-to-use and quickly completed.

AIM: The aim of this study was to evaluate a Visual Analog Scale as a tool to assess anxiety during induction of anesthesia and to determine cut-offs to distinguish between anxious and nonanxious children.

METHODS: Four hundred and one children (1.5-16 years) scheduled for daytime surgery were included. Children's anxiety during induction was rated by parents and anesthesiologists on a Visual Analog Scale and by a trained observer on the modified Yale Preoperative Anxiety Scale. Psychometric properties assessed were: (i) concurrent validity (correlations between parents' and anesthesiologists' Visual Analog Scale and modified Yale Preoperative Anxiety Scale scores); (ii) construct validity (differences between subgroups according to the children's age and the parents' anxiety as assessed by the State-Trait Anxiety Inventory); (iii) cross-informant agreement using Bland-Altman analysis; (iv) cut-offs to distinguish between anxious and nonanxious children (reference: modified Yale Preoperative Anxiety Scale ≥30).

RESULTS: Correlations between parents' and anesthesiologists' Visual Analog Scale and modified Yale Preoperative Anxiety Scale scores were strong (0.68 and 0.73, respectively). Visual Analog Scale scores were higher for children ≤5 years compared to children aged ≥6. Visual Analog Scale scores of children of high-anxious parents were higher than those of low-anxious parents. The mean difference between parents' and anesthesiologists' Visual Analog Scale scores was 3.6, with 95% limits of agreement (-56.1 to 63.3). To classify anxious children, cut-offs for parents (≥37 mm) and anesthesiologists (≥30 mm) were established.

CONCLUSIONS: The present data provide preliminary data for the validity of a Visual Analog Scale to assess children's anxiety during induction.