Quantitation of cerebral blood volume in human infants by near-infrared spectroscopy.
Current methods for measuring cerebral blood volume (CBV) in newborn infants are unsatisfactory. A new method is described in which the effect of a small change (5-10%) in arterial oxygen saturation (SaO2) on cerebral oxyhemoglobin [HbO2] and deoxyhemoglobin [Hb] concentration is observed by near-infrared (NIR) spectroscopy. Previous experiments in which the NIR absorption characteristics of HbO2 and Hb and the pathlength of NIR light through the brain were defined allowed changes in [HbO2] and [Hb] to be quantified from the Beer-Lambert law. It is shown here that CBV can then be derived from the expression CBV = (delta[HbO2] - delta[Hb])/(2. delta SaO2.H.R.), where H is the large vessel total hemoglobin concentration and R to the cerebral-to-large vessel hematocrit ratio. Observations on 12 newborn infants with normal brains, born at 25-40 wk of gestation and aged 10-240 h, gave a mean value for CBV of 2.22 +/- 0.40 (SD) ml/100 g, whereas mean CBV was significantly higher 3.00 +/- 1.04 ml/100 g in 10 infants with brain injury born at 24 to 42 wk of gestation and aged 4-168 h (P less than 0.05).
Wyatt
J S
JS
Department of Paediatrics, University College London, United Kingdom.
Cope
M
M
Delpy
D T
DT
Richardson
C E
CE
Edwards
A D
AD
Wray
S
S
Reynolds
E O
EO
D001810:Blood Volume; D001930:Brain Injuries / Q000097:blood / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D005069:Evaluation Studies as Topic; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D010108:Oxyhemoglobins / Q000378:metabolism; D012016:Reference Values; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods*
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin