CEREBRAL BLOOD-FLOW IS INDEPENDENT OF MEAN ARTERIAL BLOOD-PRESSURE INPRETERM INFANTS UNDERGOING INTENSIVE-CARE

Objective. Preterm infants axe often presumed to have a pressure passi ve cerebral circulation implying that a low mean arterial blood pressu re (MABP) results in reduced cerebral perfusion. The aim of this study was to determine whether cerebral blood flow (CBF) was compromised in preterm infants whose MABP fell below 30 mm Hg (4 kPa). Methods. Thir ty preterm infants undergoing intensive care were studied within the f irst 24 hours of life. CBF was measured using near infrared spectrosco py. The infants were analyzed in two groups on the basis of their MABP at the time of study: group 1 had a MABP below 30 mm Hg and group 2 m ore than 30 mm Hg. CBF in the two groups was compared. Results. There was no significant difference in the mean CBF between the two groups. In group 1 the median MABP was 27.2 mm Hg (range, 23.7-29.9 mm Hg) and CBF was 13.9 (standard deviation, +/- 6.9) mL.100 g(-1).min(-1). In g roup 2 the median MABP was 35.3 mm Hg (range, 30.1-39.3 mm Hg) and CBF was 12.3 (standard deviation, +/- 6.4) mL.100 g(-1).min(-1). Mortalit y and incidence of cranial ultrasound scan abnormalities were also not significantly different. Conclusion. These results indicate that pret erm infants undergoing intensive care are able to maintain adequate ce rebral perfusion at a MABP in the range of 23.7 to 39.3 mm Hg.