Abstracts and Programme: EUROANAESTHESIA 2011: The European Anaesthesiology Congress: Monitoring: Equipment and Computers
A xenon depth of anesthesia monitor
Background and Goal of Study: Xenon is a noble gas with anesthetic properties supposedly mediated by antagonism of N-methyl-D-aspartate receptors, and experimental data indicate that xenon has cardioprotective and neuroprotective effects. Monitoring the state of hypnosis during general anesthesia is an standard in anesthetic care. The objective of the study was to study the performance of Biespectral index (BIS) and Auditory evoked potentials (AEP) in xenon anesthesia in patients undergoing knee replacement.
Materials and Methods: We planned a prospective study, approved by ethical committee, in 10 patients undergoing knee replacement surgery, ASA I-II and older than 65 years.The maintenance of anesthesia was done with xenon 65% in oxygen and epidural analgesia.Bis and AEP were monitored every 5 minutes. Data are presented as mean and standard deviation (SD).
Results and Discussion: Ten patients (7 women and 3 men), ASA physical status I or II were studied. They had a mean of age of 75 (range 65-83) years, weighed 75 (13) and were 164 (7) cm tall. The awake mean values for BIS were 95 (2.5) and 65 (2.82) for EAP. After the induction of anesthesia, BIS values decreased to 33 (9.01) and EAP to 19(6.79). When the administration of xenon was started,mean values for BIS were 44(10.67) and 21 (3.25) for EAP. During maintenance of anesthesia mean BIS values were between 36.6 and 51.4, mean EAP values were between 14.33 and 35.20. During surgery, BIS values between 40 and 60 is suggested. In case of AEP, the surgical anaesthesia range is between 15 and 25. In our study we can see that during xenon anesthesia an increase in depth of anesthesia indicated by BIS monitoring is accompanied by a decreased in AEP values.In both cases the main values during xenon anesthesia were situated in the surgical anesthesia range.
Conclusion(s): During xenon anesthesia the changes in depth of anesthesia are indicated by changes in BIS and AEP values. Both monitors show its values in the surgical anesthesia range.© 2011 European Society of Anaesthesiology