Cerebral fractional oxygen extraction is inversely correlated with oxygen delivery in the sick, newborn, preterm infant

• Published in: Journal of cerebral blood flow and metabolism Vol. 25; no. 5; pp. 545 - 553
• Main Authors: Kissack, Christopher M, Garr, Rosaline, Wardle, Stephen P, Weindling, A Michael
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-05-2005; Lippincott Williams & Wilkins; Sage Publications Ltd
• Subjects: Biological and medical sciences; Blood Gas Analysis; Brain - blood supply; Brain - metabolism; Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges; Cerebrovascular Circulation - physiology; Female; Fundamental and applied biological sciences. Psychology; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Hemodynamics - physiology; Hemoglobins - metabolism; Humans; Infant, Newborn; Infant, Premature - blood; Infant, Premature - physiology; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Oxygen - analysis; Oxygen Consumption - physiology; Pregnancy; Vascular diseases and vascular malformations of the nervous system; Vertebrates: nervous system and sense organs; cerebral fractional oxygen extraction; near-infrared spectroscopy; cerebral oxygen delivery; preterm neonate; cerebral oxygen consumption; Human; Premature; Oxygen; Nervous system diseases; Oxygen consumption; Infant; Cerebral disorder; Newborn; Central nervous system disease; Cerebrovascular disease
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1038/sj.jcbfm.9600046

Cerebral blood flow (CBF) is known to be low in newborn infants, but this has not been shown to be damaging. The purpose of this study was to investigate the relationships between cerebral haemoglobin flow, blood flow, oxygen delivery, oxygen consumption, venous saturation, and fractional oxygen extraction (OEF) in newborn, preterm infants. Measurements were made by near-infrared spectroscopy in 13 very preterm, extremely low birth weight infants (median gestation 25 weeks) during the first 3 days after birth. There was a negative correlation between cerebral oxygen delivery and OEF (n=13, r=−0.5, P=0.03), which implies that when there is a reduction in cerebral oxygen delivery in sick preterm infants, increased cerebral oxygen extraction may be responsible for maintaining oxygen availability to the brain. During the first 3 days after birth CBF (n=13, r=0.7, P=0.01), oxygen delivery (n=13, r=0.5, P=0.03), and oxygen consumption (n=13, r=0.7, P=0.004) all increased. This increase in oxygen consumption indicates increased cerebral metabolic activity after birth, which is likely to be a normal adaptation to extrauterine life. The increases in blood flow and oxygen delivery may also be normal adaptations that facilitate this increase in metabolic activity. There was a decrease (P=0.04) in mean (±s.d.) cerebral OEF between day 1 (0.37±0.10) and day 2 (0.29±0.09), with no change between day 2 and day 3. Taking into account the negative correlation between OEF and oxygen delivery, this decrease in OEF may be because of increased oxygen delivery during this time.