[Relationship between cardiovascular circulation and intracranial pressure--analyses of polygraphic recordings during cardiac surgery in congenital heart diseases].
Few reports have appeared in regard to cerebral perfusion pressure (CPP) accompanying fluctuations in intracranial pressure (ICP), arterial pressure (BP) and central venous pressure (CVP) as well as autoregulation of cerebral circulation in neonates and infants. Therefore, we report here on interesting findings we obtained from monitoring ICP, BP, and CVP during operations in 30 neonates or infants with congenital heart disease as our subjects. i) ICP fluctuates depending on arterial pressure and venous pressure, but changes in the latter display a clearer effect. ii) On inducing anesthesia the amplitude of ICP pulsating waves became gradually larger, but following intubation intracranial pressure was somewhat reduced and became stable. iii) Following thoracotomy CVP rose and at the same time intracranial pressure also increased somewhat. Before thoracotomy ICP pulsating waves resembled arterial pressure wave forms, but after thoracotomy they resembled central venous pressure wave forms. iv) In cases with two-peak ICP pulsating waves, when we conducted a study by blocking venous return from the internal carotid vein during the operation by the Queckenstedt method, ICP rose by increasing its amplitude, but the pulsating wave forms lost their venous component, and changed into a single peak consisting of an arterial component. v) In order to observe the relationship between changes in arterial pressure and ICP, when we looked at changes in ICP accompanying partial blockage of the descending aorta (DAo), simultaneously with the partial blocking of the DAo both AP and CVP rose, and ICP also rose accordingly. Also, when arterial blockage was relaxed, BP, CVP, and ICP immediately recovered completely to the status quo prior to the blocking procedure. This finding indicates that by blocking of the DAo, intracranial arterial and venous blood volume abruptly rapidly increase and since CVP also rises, therefore ICP rises to maintain a balance with these. As a result, this brings about the effect of normally maintaining the cerebral perfusion volume. vi) If we look at changes in ICP brought about by partial blocking of the ascending aorta, blockage of the artery brought about a further reduction in BP, and in this case since the arterial blood flow into the cranium also fell off markedly, we found that ICP also was reduced. The above results suggest that in the normal brains of neonates and infants even when under various conditions various fluctuations in corporeal circulation develop, cerebral perfusion volume adjusts itself in response to this, and thus autoregulation of cerebral blood flow is able to act in an adequate way.
Hayashi
T
T
Departement of Neurosurgery, St. Mary's Hospital, Kurume, Japan.
Anegawa
S
S
Torigoe
R
R
D001794:Blood Pressure; D002560:Cerebrovascular Circulation; D006330:Heart Defects, Congenital / Q000503:physiopathology / Q000601:surgery*; D006706:Homeostasis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007427:Intracranial Pressure; D016343:Monitoring, Intraoperative; D010477:Perfusion; D014690:Venous Pressure