Abstract
Intraventricular hemorrhage (IVH) in preterm infants is well known to be associated with the high morbidity and mortality of this group. Previous studies have suggested altered cerebral blood flow (CBF) as an important pathologic factor. We measured the CBF in nearterm rabbit fetuses using the hydrogen clearance technique. The local CBF of the rabbit fetuses was significantly low compared with that of the maternal rabbits. The response of CBF to changes in PaCO2 was observed in rabbit fetuses. The CO2 reactivity index of the fetal rabbit was lower than that of the maternal rabbit. This low CO2 reactivity might reflect the immaturity of the fetal brain and its low CBF. We were unable to monitor the fetal blood pressure, but the fetal CBF remained stable when the maternal blood pressure was altered. It is well known that IVH in preterm infants originates from the subependymal germinal matrix and that this has many fragile vessels. Our observation suggests that even a small increase of CBF during hypercapnia might have a large effect towards producing hemorrhage.
Similar content being viewed by others
References
Altman DI, Volpe JJ (1987) Cerebral blood blow in the newborn infant: measurement and role in the pathogenesis of periventricular and intraventricular hemorrhage. Adv Pediatr 34:111–138
Ashwall S, Majcher JS, Vain N, Longo LD (1980) Patterns of fetal lamb regional cerebral blood flow during and after prolonged hypoxia. Pediatr Res 14:1104–1110
Blomstrand S, Karlsson K, Kjellmer I (1978) Measurement of cerebral blood flow in the fetal lamb with a note on the flow-distribution. Acta Physiol Scand 103:1–8
Cavazzuti M, Duffy TE (1982) Regulation of local cerebral blood flow in normal and hypoxic newborn dogs. Ann Neurol 11:247–257
Goddard J, Lewis RM, Alcala H, Zeller RS (1980) Intraventricular hemorrhage-an animal model. Biol Neonate 37:39–52
Goddard J, Lewis RM, Armstrong DL, Zeller RS (1980) Moderate, rapidly induced hypertension as a cause of intraventricular hemorrhage in the newborn beagle model. J Pediatr 96:1057–1060
Goddard-Finegold J, Michael LH (1984) Cerebral blood flow and experimental intraventricular hemorrhage. Pediatr Res 18:7–11
Greisen G (1986) Cerebral blood flow in preterm infants during the first week of life. Acta Paediatr Scand 75:43–51
Greisen G, Trojaborg W (1987) Cerebral blood flow, PaCO2 changes, and visual evoked potentials in mechanically ventilated, preterm infants. Acta Paediatr Scand 76:394–400
Harel S, Watanabe K, Linke I, Schain RJ (1972) Growth and development of rabbit brain. Biol Neonate 21:381–399
Hernandez MJ, Brennan RW, Vannucci RC, Bowman GS (1978) Cerebral blood flow and oxygen consumption in the newborn dog. Am J Physiol 234:209–215
Hernandez MJ, Brennan RW, Bowman GS (1980) Autoregulation of cerebral blood flow in the newborn dog. Brain Res 184:199–202
Kennedy C, Grave GD, Jahle JW, Sokoloff L (1972) Changes in blood flow in the component structures of the dog brain during postnatal maturation. J Neurochem 19:2423–2433
Lorenzo AV, Welch K, Conner S (1982) Spontaneous germinal matrix and intraventricular hemorrhage in prematurely born rabbits. J Neurosurg 56:404–410
Ment LR, Stewart WB, Duncan CC, Lambrecht R (1982) Beagle puppy model of intraventricular hemorrhage. J Neurosurg 57:219–223
Papile L, Rudolph AM, Heymann MA (1985) Autoregulation of cerebral blood flow in the preterm fetal lamb. Pediatr Res 19:159–161
Pasternak JF, Groothuis DR (1985) Autoregulation of cerebral blood flow in the newborn beagle puppy. Biol Neonate 48:100–109
Pasternak JF, Groothuis DR, Fischer JM, Fischer DP (1982) Regional cerebral blood flow in the beagle puppy model of neonatal intraventricular hemorrhage: studies during systemic hypertension. Neurology 33:559–566
Pasternak JF, Groothuis DR, Fischer JM, Fischer DP (1982) Regional cerebral blood flow in the newborn beagle pup: the germinal matrix is a “low-flow” structure. Pediatr Res 16:499–503
Philip AGS, Allan WC, Tito AM, Wheeler LR (1989) Intraventricular hemorrhage in preterm infants: declining incidence in the 1980s. Pediatrics 84:797–801
Purves MJ, James IM (1969) Observation on the control of cerebral blood flow in the sheep fetus and newborn lamb. Circ Res 25:651–667
Reivich M, Brann AW, Rawson J, Sano N (1971) Reactivity of cerebral vessels to CO2 in the newborn rhesus monkey. Eur Neurol 6:132–136
Rosenberg AA, Jones MD, Traystman RJ, Simmons MA, Molteni RA (1982) Response of cerebral blood flow to changes in PCO2 in fetal, newborn, and adult sheep. Am J Physiol 242:862–866
Rudolph AM, Heymann MA (1970) Circulatory changes during growth in the fetal lamb. Cire Res 26:289–299
Shapiro HM, Greenberg JH, Van Horn Naughton K, Reivich M (1980) Heterogeneity of local cerebral blood flow-PaCO2 sensitivity in neonatal dogs. J Appl Physiol 49:113–118
Trommer BL, Groothuis DR, Pasternak JF (1987) Quantitative analysis of cerebral vessels in the newborn puppy: the structure of germinal matrix vessels may predispose to hermorrhage. Pediatr Res 22:23–28
Van De Bor M, Van Bel F, Lineman R, Ruys JH (1986) Perinatal factors and periventricular-intraventricular hemorrhage in preterm infants. Am J Dis Child 140:1125–1130
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Yamashita, N., Kamiya, K. & Nagai, H. CO2 reactivity and autoregulation in fetal brain. Child's Nerv Syst 7, 327–331 (1991). https://doi.org/10.1007/BF00304831
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00304831