Variability of cerebral hemoglobin concentration in very preterm infants during the first 6 hours of life.
Cerebral hemoglobin concentration (cHbc), a major determinant of oxygen transport capacity in the brain, shows a considerable variability due to physiological and methodological factors. In order to determine the (relative) contribution of these factors, the cHbc variability within the first 6 hours of life was studied in 28 very preterm infants using near infrared spectrophotometry (NIRS). Mean cHbc values were 46.4 +/- 14.1 micromol/l (2.75 +/- 0.84 ml/100 g). Is the variability in cHbc related to the methodology of cHbc measurements or to physiological variables? A statistical model of stepwise regression (backward selection) with 13 independent variables and with cHbc as a dependent variable showed that, from the total variability of +/- 14.1 micromol/l, only 3.7 micromol/l (26%) were of methodological origin, while the major portion, 9.3 micromol/l (66%) were related to four physiological variables: birth weight, gestational age, blood glucose and transcutaneous carbon dioxide tension. The remaining 1.1 micromol/l (7.8%) were unexplained. We conclude that NIRS, which allows continuous monitoring of cerebral oxygenation and metabolism even in the first hours of postnatal life, is a valid technique to measure cHbc in very preterm infants. The major portion of the large variability of early cHbc registrations can be attributed to physiological factors.
von Siebenthal
Kurt
K
Keel
Matthias
M
Fauchère
Jean-Claude
JC
Dietz
Vera
V
Haensse
Daniel
D
Wolf
Ursula
U
Helfenstein
Urs
U
Bänziger
Oskar
O
Bucher
Hans U
HU
Wolf
Martin
M
D000367:Age Factors; D001921:Brain / Q000098:blood supply* / Q000378:metabolism; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D019102:Infant, Very Low Birth Weight / Q000097:blood*; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D012044:Regression Analysis; D019265:Spectroscopy, Near-Infrared
D006454:Hemoglobins