Experimental intracerebral hemorrhage: progression of hemodynamic changes after production of a spontaneous mass lesion.

The aim of the study was to determine whether the extent of ischemia produced by an experimental space-occupying lesion changed between 5 minutes and 4 hours after the production of a lesion. In two groups of rats, a 50-microliter balloon was inflated in the right caudate nucleus. Cerebral blood flow (CBF) was determined by 14C-iodoantipyrine quantitative autoradiography, in Group 1 (n = 6) 5 minutes after inflation and in Group 2 (n = 6) 4 hours later. After 5 minutes of inflation, the mean blood flow in the caudate nucleus was reduced to 65% of the contralateral value and 11.5% of the ipsilateral caudate nucleus had a blood flow of below 25 ml/100 g/minute. After 4 hours of inflation, there was a greater fall in the mean CBF of the ipsilateral caudate nucleus to 30% of the contralateral value, and 38.9% of the ipsilateral caudate nucleus had a CBF of less than 25 ml/100 g/minute. The differences between the two groups were significant (mean CBF, P less than 0.01; CBF less than 25 ml/100 g/minute, P less than 0.02). The results show that the initial ischemic lesion produced by a spontaneous intracerebral space-occupying lesion does not remain static, but progresses with time and is significantly greater after 4 hours than after 5 minutes. Interventions that reduce the progression of ischemia may be beneficial in reducing the ultimate amount of ischemic brain damage.