Maayke Hunfeld

206 Chapter 7 Statistical analyses Outcomes of participants and non-participants were compared with independent sample t-tests for normally distributed continuous data, Mann–Whitney U tests for non-normally continuous data and Fisher’s exact test for dichotomous data. Normality of all data was examined with the Shapiro-Wilk test. Neuropsychological outcome standard scores were converted into Z-scores by calculating the difference with the test-mean, divided by the test-SD. A negative Z-score reflects a worse score compared with the norm (for comparable interpretation, BRIEF z-scores were multiplied by -1). One-sample t-tests were performed to compare neuropsychological outcomes of OHCA survivors with the normative Z-score = 0. Repeated measures of participants at 3-6 and 24 months were compared with non-parametric paired tests (Wilcoxon signed rank tests) for continuous Z-scores. Due to the explorative design of this study, no correcting for multiple testing was performed. Correlations between PCPC and intellectual functioning were analyzed using Kendall’s tau-b. All analyses were performed with SPSS 25.0 for Windows. Results were considered statistically significant at p values < 0.05. Results Between January 2012 and December 2017, 113 children were admitted to the PICU following ROC post-OHCA (Fig. 1). Of these 113 children, 51 (45%) survived to hospital discharge. Two were excluded due to pre-arrest PCPC > 3. In the eligible sample of 49 children, the most common causes of OHCA were (33%) arrhythmia and near-drowning (31%) (supplementary file 3). At time of OHCA, median age was 48 months (IQR 17-166) and 67% were males. SES was low in 20%, middle in 61% and high in 16%, which was significantly lower than the SES distribution in the Netherlands (26) . Median PCPC score at hospital discharge was 2 [IQR 1-3], with good outcome in 73%. Demographical and OHCA variables between neuropsychological tested and non- tested children were overall comparable (supplementary file 4). Except that tested OHCA children were significantly older than non-tested children at 3-6 months ( p =0.03).