Validation of the Parents' Postoperative Pain Measure in Finnish children aged 1-6 years

The Canadian Parents' Postoperative Pain Measure (PPPM) is a behavioural pain measure for children. The purpose of this study was to test validity and reliability of this measure in 1-6-year-old Finnish children at home after minor day surgery. Children (n = 85) and their parents from four hospitals were included in the sample. The parents, mostly mothers (93%), filled in at home a questionnaire including PPPM during the day of operation, and the first and second postoperative days. Parents (n = 85) rated the presence or absence of behavioural changes from a checklist and also the child's worst pain during each day (using a Visual Analogue Scale, VAS). The response rate was 58. Principal component factor analysis, testing of correlation coefficient, cross-tabulations and Cronbach's alpha were used to test the instrument. The findings showed that construct validity of the measure was satisfactory. The PPPM was successful in discriminating between children who had no/low pain and children who had a clinically significant pain measured by VAS (convergence validity). Scores on the PPPM decreased from days 0 to 1 and from days 1 to 2 (predictive validity). Internal consistency of the measure and correlations with the pain scores on VAS were high on all days following surgery (equivalence). Sensitivity was satisfactory only when specificity was weaker. The findings of this study can be utilized in the development of children's postoperative pain assessment at home. However, further studies are needed to test the instrument in larger samples.