Statistical methods
cerebral desaturation, ischemia, hypotension, seizures
REGRESSION, ISCHEMIA
We estimated that a sample of 46 patients would provide 90% power to detect a relative LP ratio reduction of 35% in the high MAP group, compared with the low MAP group, using a patient-to-patient variation with standard deviation (SD) of 15 [The mean between-group difference in blood pressure during the intervention period was calculated by mixed effects linear regression. Dynamic changes of MD variables were compared between treatment groups by linear mixed effects linear regression (Supplementary Methods).Time-averaged means of MD parameters in intervals of 12 h ensured statistical robustness in contrast to point values. Note that all hourly measurements were included in the mixed models, and only aggregated in the parametrization of the model, not in the measurements themselves.The mixed model fitting procedure handled missing values, assumed to be missing completely at random. Missing MD data rates were less than 5% and imputation where not used. Missing measurements were taken into account by the maximum likelihood estimation of the mixed models. Associations between MD variables, episodes of hypotension, EEG-verified seizures, cerebral desaturation, and neurological outcome were assessed with chi-square-test and logistic regression. Statistical comparison of episodes with ischemia and cerebral desaturation between outcome groups was performed using Mann–Whitney 