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Temperature gradient between brain tissue and arterial blood mirrors the flow‐metabolism relationship in uninjured brain: an experimental study
Author(s) -
Soukup J.,
Rieger A.,
Holz C.,
Miko I.,
Nemeth N.,
Menzel M.
Publication year - 2007
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.2007.01356.x
Subject(s) - cerebral blood flow , cerebral autoregulation , medicine , cerebral perfusion pressure , autoregulation , blood flow , microdialysis , anesthesia , perfusion , oxygenation , brain tissue , blood pressure , cardiology , central nervous system
Background: The purpose of the present experimental study was to determine the feasibility and usefulness of brain temperature measurement (T br ) and the calculated difference between brain temperature and arterial blood temperature (ΔT br‐a ) in uninjured brain during variations of cerebral perfusion pressure (CPP) and concomitant changes of the regional cerebral blood flow (rCBF). Methods: Nine anaesthetized pigs were subjected to controlled CPP decrease to assess the lower cerebral autoregulation threshold. A parenchymal intracranial pressure (ICP) sensor combined with a microthermistor for temperature measurement, a miniaturized Clark‐type electrode measuring brain tissue oxygenation (p ti O 2 ), a small flexible intraparenchymal thermodilution probe for measuring rCBF and cerebral microdialysis were inserted carefully in the frontal white matter. Results: Analysing the p ti O 2 during controlled CPP decrease, we found significant breakpoints of p ti O 2 at a CPP of 40 mmHg and 20 mmHg, related to an rCBF of 20 ml/100 g/min and approximately 10 ml/100 g/min. Similarly, the relationship between ΔT br‐a , and CPP or rCBF revealed a characteristic increase of ΔT br‐a in the negative direction up to more than –0.30 °C assuming a strong flow dependency. Conclusion: The temperature difference between brain tissue and arterial blood ΔT br‐a mainly reflects the cerebral blood flow–brain tissue oxygenation–metabolism relationship as far as the estimation of the individual lower cerebral autoregulation threshold.