Cerebral oxygenation monitoring

Abstract

Objectives: To discuss theoretical and practical aspects of cerebral oxygenation, from isolated observational measurements to continuous interventional monitoring.

Data sources: Relevant articles from the pertinent literature, as well as a multivariate physiologic diagram developed in this article.

Study selection: Theoretical, experimental, and clinical information that further clarifies the physiologic relevance of cerebral oxygenation.

Data extraction: All basic concepts of cerebral hemometabolism were used, up to cerebral hemodynamic reserve, and were interrelated accordingly.

Data synthesis: Cerebral perfusion pressure alone does not allow global cerebral hemometabolic optimization. The same situation is true for cerebral blood flow. The reason for this limitation is because these variables lack metabolic information. Cerebral arteriovenous differences do allow global cerebral hemometabolic optimization, because they reflect the exchange between the capillary and the tissue. In addition, cerebral hemodynamic reserve allows quantification of the cerebral microcirculatory tolerance to increases in intracranial "tightness" (decreases in intracranial compliance).

Conclusions: Multivariate optimization of global cerebral oxygenation, primarily based on global cerebral oxygen delivery and extraction, may strongly affect outcome in a variety of predominantly diffuse, acute intracranial disorders. Cerebral hemodynamic reserve may be further explored in experimental and clinical areas, involving not just acute brain trauma.