Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Oct 2010
Randomized Controlled TrialDoes nitrous oxide affect bispectral index and state entropy when added to a propofol versus sevoflurane anesthetic?
In earlier studies, nitrous oxide (N2O) did not affect bispectral index (BIS) or state entropy (SE) when administered as the sole anesthetic agent. We investigated the effect of adding N2O to sevoflurane or propofol anesthesia on BIS and SE. ⋯ N2O decreased both BIS and SE when added to sevoflurane, but not propofol. The observed changes in the sevoflurane group were not clinically significant. Decreases in BIS and SE in the sevoflurane group could result from a true additive effect and second-gas effect of N2O that was unaccounted for despite a meticulous titration of sevoflurane using end-tidal gas monitoring.
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J Neurosurg Anesthesiol · Oct 2010
Effect of arterial blood pressure on the arterial to end-tidal carbon dioxide difference during anesthesia induction in patients scheduled for craniotomy.
Before obtaining results of arterial blood gas analysis in mechanically ventilated patients undergoing neurosurgery, the volume of ventilation is primarily adjusted according to endtidal CO2 (EtCO2). We characterized the impact of various arterial blood pressure changes on arterial PCO2 (PaCO2) to EtCO2 differences (PaCO2-EtCO2) in patients anesthetized for craniotomy. ⋯ There was a positive correlation between PaCO2-EtCO2 and MAP decrease shortly after induction of anesthesia. PaCO2-EtCO2 is recommended to be interpreted together with change in MAP during early phase of neuroanesthesia to guarantee optimal mechanical ventilation.