Continuous estimation of cerebral metabolic changes.

The purpose of the present research has been to estimate rapid metabolic changes. By means of mass spectrometry, the partial pressure of physiological gases are continuously analyzed in a local area of the brain tissue. The method we have developed allows quantitative measurement of the variables with a response time of less than 1 min. When coupled with continuous measurement of(1) PaO2 and PaCO2 by means of mass spectrometry, and (2) cerebral blood flow by thermoclearance, this method is able to indicate rapid metabolic changes when quantitative methods of determining metabolism are not usable.