[The critical threshold of cerebral perfusion pressure in intracranial pressure circumstance of hydrocephalus during infancy].

In cases of brain insults in infants including those who are superimposed with increased intracranial pressure, the importance of management of cerebral hemodynamics has been stressed. As yet, minimal information is available on hydrocephalus. The aim of this clinical study is to clarify the circumstance of intracranial pressure in hydrocephalic infants with cerebrovascular compromise. Polygraphical and continuous intracranial pressure recordings were done in 20 hydrocephalic newborns and infants of various etiologies including 16 hydrocephalus of preshunted state, two cases of shunt dysfunction and two cases of slit ventricle syndrome. Analysis of intracranial pressure circumstance was done both quantitatively and qualitatively using newly devised microcomputer-aided analyzing system. As a cerebrovascularly compromised index of the intracranial pressure circumstance, the transmission ratio of systemic arterial pressure to intracranial pressure defined by Ikeyama, et al.: eta HB (PP of ICP/PP of SABP) was used. There exists bilinear correlation between ICP and eta HB, and more clearly, between CPP and eta HB. Thus, the correlation graph shows the breakpoint of ICP and CPP in relation to eta HB. Abnormal waves similar to Lundberg's A and B are recorded. They appear under the condition of high range of eta HB, and also, below the level of breakpoint of CPP or ICP, and show the characteristic features of pressure waves. During their appearance, the respiratory pattern shows a uniform sequential changes from dysrhythmia, ataxia to hyperventilation. The breakpoint of CPP in relation to eta HB, which is the critical level of CPP where the less tighter intracranial circumstance is maintained above this level, was clarified in hydrocephalus during infancy.(ABSTRACT TRUNCATED AT 250 WORDS)