Autoregulation of cerebral blood flow in the newborn dog

Local Cerebral Blood Flow in the Newborn Rabbit: An Autoradiographic Study of Changes during Development

“…Similar to that in the adult, cerebral blood flow has been found to be maintained near constant during moderate changes in perfusion pressure in various newborn animals and in human subjects (2,(29)(30)(31). Because, in the present study, within each age group and for each region there appeared to be a different basal level of blood flow, it is likely that autoregulation of cerebral blood flow adapts to elevated levels of flow and blood pressure during development.…”

“…Because, in the present study, within each age group and for each region there appeared to be a different basal level of blood flow, it is likely that autoregulation of cerebral blood flow adapts to elevated levels of flow and blood pressure during development. Indeed, in a study of cerebral blood flow autoregulation in the newborn dog, there appeared to be a shift in the pressure limits of autoregulation of global cerebral blood flow to a lower pressure range compared with the adult (29). A similar effect has been observed during chronic hypertension where there is an adaptation of the cerebral autoregulatory range to the chronic higher blood pressure levels (32).…”

Pathogenesis of hypoxic-ischemic brain injury

“…First, the curve is narrower, particularly at the upper limit, in the less mature animal, and second the normal mean arterial blood pressure in the less mature animal is only marginally above the lower limit of the curve. 16,17 Autoregulation may be disrupted with hypoxia, hypo/hypercarbia or acidosis. 14,[18][19][20][21] Under such conditions, the cerebral circulation becomes pressure passive and directly reflects systemic blood pressure changes.…”

Brain Interstitial Adenosine and Sagittal Sinus Blood Flow during Systemic Hypotension in Piglet

“…At 40 and 30 mm Hg, sagittal sinus blood flow decreased fur ther but CVR remained steady, whereas interstitial fluid adenosine rose 10-and 16-fold, respectively. In group 2 (n = 7), an abrupt reduction of MABP from 80 to 47 mm Hg It is well established that neonates exhibit auto regulation of CBF to maintain constant CBF over a range of systemic blood pressure (Hernandez et al, 1980;Laptook et aI., 1982;Leffler et aI., 1986). While the precise mechanism for the autoregulation of CBF remains unclear, in the adult it has been explained primarily by myogenic and metabolic theories (Bayliss, 1902;Kontos et aI., 1978).…”