Background and aims Electroencephalographic (EEG) activity may be affected by changes in cerebral perfusion in extremely preterm infants1 so that a reduction in cerebral perfusion may be associated with reduced electrocortical activity. The relationship between invasively measured BP and EEG activity in this group remains to be determined. We hypothesised that systemic BP and cerebral perfusion are directly related to measures of EEG continuity in extremely preterm infants in the first three days of life.
Methods Infants born < 29 weeks gestation was prospectively recruited within 12 h of birth. They had continuous invasive arterial BP and amplitude-integrated EEG (aEEG) recording. Cross cerebral aEEG was assessed for minimum and maximum amplitude, measures of lower and upper aEEG margin, percentage of time minimum amplitude below 5 microvolts and for seizures. Left ventricular output (LVO), common carotid artery blood flow (CCAF) and mean arterial BP (averaged over a 2 h epoch) were related to EEG measures over the same epoch. Non-parametric correlation and multiple linear regression analysis were used for analysis (SPSS v22). Ethics approval (12/LO/1553) and written parental consent were obtained.
Results Median (range) gestation and birthweight were 25.8 (23.4 to 28.9) weeks and 735 (515 to 1470) grams respectively. In simple rank correlation, all EEG parameters were significantly associated with BP on days 1 and 3, and with gestation on day 1. In stepwise multiple regression analysis, only BP was retained.
Conclusions We found a strong relationship between continuous systemic mean arterial BP and measures of EEG continuity, suggesting that at lower BP there is an increase in EEG discontinuity.
Reference 1 West CR. Early low cardiac output is associated with compromised electroencephalographic activity in preterm infants. Pediatric Research 2006