Selective reduction of blood flow to white matter during hypotension in newborn dogs: a possible mechanism of periventricular leukomalacia.

The cerebrovascular response of newborn animals to hypotension has not been defined on a regional basis. Using an autoradiographic technique employing 14C-iodoantipyrine as indicator, we studied the cerebral physiological responses of newborn dogs to hypotension induced by exsanguination or by administration of Escherichia coli endotoxin. Regional cerebral blood flow (rCBF) to all gray matter structures was preserved, even at mean arterial pressures as low as 20 mm Hg. In contrast, rCBF to periventricular and occipital white matter decreased significantly during severe hypotension. The selective hypoperfusion of cerebral white matter during severe hypotension may provide a mechanistic explanation for the pathogenesis of periventricular leukomalacia.