Relationship between cerebrovascular dysautoregulation and arterial blood pressure in the premature infant

Objective:to evaluate cerebrovascular autoregulation as a function of arterial blood pressure (abp) in the critically ill, premature infant.study design:a prospective observational pilot study was conducted in two tertiary care neonatal intensive-care units. premature infants (n=23, ⩽30 weeks estimated gestational age with invasive abp monitoring) were enrolled and received routine care while undergoing continuous autoregulation monitoring, using the cerebral oximetry index (cox). the cox is a moving, linear correlation coefficient between cortical reflectance oximetry and abp. cox values were stratified as a function of abp for individual subject recordings and for the cohort.result:the mean duration of autoregulation monitoring was 3.2 days (median: 2.97, range: 0.61–3.99). a total of 10 of 23 (43%) developed intraventricular hemorrhage and 1 of 23 (4%) developed periventricular leukomalacia by head ultrasound. no association was found between neurologic injury and percentage of the monitoring periods with autoregulation impairment (defined as cox>0.5). lower abp was associated with dysautoregulation (higher cox values, p<0.01). the percentage of time with impaired autoregulation was greater with lower abp (p=0.013, spearman r=0.51).conclusion:all infants studied had periods with intact and periods with impaired cerebrovascular autoregulation, measured with the cox. low abp was associated with impaired autoregulation.