A study of electroencephalographic descriptors and end-tidal concentration in estimating depth of anesthesia

Jitendran Muthuswamy; Rob Roy; Ashutosh Sharma

doi:10.1007/bf02077633

End Tidal Anesthetic Concentration in Different Anesthesia Techniques Where Depth of Anesthesia Adjusted With Entropy

Case Medical Research ◽

10.31525/ct1-nct04203290 ◽

2019 ◽

Author(s):

Keyword(s):

Depth Of Anesthesia ◽

Anesthetic Concentration ◽

End Tidal

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Comparison between Bispectral Index and Patient State Index as Measures of the Electroencephalographic Effects of Sevoflurane

Anesthesiology ◽

10.1097/aln.0b013e3181895fd0 ◽

2008 ◽

Vol 109 (5) ◽

pp. 799-805 ◽

Cited By ~ 34

Author(s):

Martin Soehle ◽

Richard K. Ellerkmann ◽

Matthias Grube ◽

Matthias Kuech ◽

Stefan Wirz ◽

...

Keyword(s):

Bispectral Index ◽

Pharmacodynamic Modeling ◽

Depth Of Anesthesia ◽

Sevoflurane Anesthesia ◽

Effect Site ◽

Effect Site Concentration ◽

Patient State ◽

State Index ◽

Patient State Index ◽

End Tidal

Background The Bispectral Index (BIS) and the Patient State Index (PSI) quantify depth of anesthesia by analyzing the electroencephalogram. The authors examined the response of BIS and PSI to sevoflurane anesthesia. Methods In 22 patients, sevoflurane anesthesia was induced by inhalation with a tight-fitting facemask and was maintained via a laryngeal mask. Sevoflurane concentrations were increased until burst suppression occurred and subsequently decreased until BIS recovered to values above 60. This procedure was repeated twice until patients underwent intubation for subsequent surgery. End-tidal sevoflurane concentrations, BIS, and PSI were recorded simultaneously. The performance of PSI and BIS to predict the estimated sevoflurane effect site concentration, as derived from simultaneous pharmacokinetic and pharmacodynamic modeling, was compared by determination coefficients (rho(2)) and prediction probabilities (P(K)). Results A significant (P < 0.001) correlation between BIS and PSI was found (r(2) = 0.75), and a close sigmoid relation between sevoflurane effect site concentration and both BIS (rho(2) = 0.84 +/- 0.09) and PSI (rho(2) = 0.85 +/- 0.15) was observed. The maximum sevoflurane electroencephalographic effect resulted in PSI values (1.3 +/- 4.3) that were significantly (P = 0.019) lower than BIS values (7.9 +/- 12.1), and the effect site efflux constant k(e0) was significantly smaller (P = 0.001) for PSI (0.13 +/- 0.08 min(-1)) than for BIS (0.24 +/- 0.15 min(-1)). The probability of BIS (P(K) = 0.80 +/- 0.11) to predict sevoflurane effect site concentration did not differ (P = 0.76) from that of PSI (P(K) = 0.79 +/- 0.09). Conclusions The BIS reacted faster to changes in sevoflurane concentrations, whereas the PSI made better use of the predefined index range. However, despite major differences in their algorithms and minor differences in their dose-response relations, both PSI and BIS predicted depth of sevoflurane anesthesia equally well.

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Epidural Lidocaine Decreases Sevoflurane Requirement for Adequate Depth of Anesthesia as Measured by the Bispectral Index ® Monitor

Anesthesiology ◽

10.1097/00000542-200105000-00018 ◽

2001 ◽

Vol 94 (5) ◽

pp. 799-803 ◽

Cited By ~ 109

Author(s):

Peter S. Hodgson ◽

Spencer S. Liu

Keyword(s):

General Anesthesia ◽

Epidural Anesthesia ◽

Bispectral Index ◽

Depth Of Anesthesia ◽

Intravenous Lidocaine ◽

Lidocaine Group ◽

Plasma Lidocaine ◽

Intravenous Saline ◽

End Tidal ◽

To Receive

Background Epidural anesthesia potentiates sedative drug effects and decreases minimum alveolar concentration (MAC). The authors hypothesized that epidural anesthesia also decreases the general anesthetic requirements for adequate depth of anesthesia as measured by Bispectral Index (BIS). Methods After premedication with 0.02 mg/kg midazolam and 1 microg/kg fentanyl, 30 patients aged 20-65 yr were randomized in a double-blinded fashion to receive general anesthesia with either intravenous saline placebo or intravenous lidocaine control (1-mg/kg bolus dose; 25 microg x kg(-1) x min(-1)). A matched group was prospectively assigned to receive epidural lidocaine (15 ml; 2%) with intravenous saline placebo. All patients received 4 mg/kg thiopental and 1 mg/kg rocuronium for tracheal intubation. After 10 min of a predetermined end-tidal sevoflurane concentration, BIS was measured. The ED50 of sevoflurane for each group was determined by up-down methodology based on BIS less than 50 (MAC(BIS50)). Plasma lidocaine concentrations were measured. Results The MAC(BIS50) of sevoflurane (0.59% end tidal) was significantly decreased with lidocaine epidural anesthesia compared with general anesthesia alone (0.92%) or with intravenous lidocaine (1%; P < 0.0001). Plasma lidocaine concentrations in the intravenous lidocaine group (1.9 microg/ml) were similar to those in the epidural lidocaine group (2.0 microg/ml). Conclusions Epidural anesthesia reduced by 34% the sevoflurane required for adequate depth of anesthesia. This effect was not a result of systemic lidocaine absorbtion, but may have been caused by deafferentation by epidural anesthesia or direct rostral spread of local anesthetic within the cerebrospinal fluid. Lower-than-expected concentrations of volatile agents may be sufficient during combined epidural-general anesthesia.

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A Crossover Comparison of the Sensitivity and the Specificity between BIS and AEP in Predicting Unconsciousness in General Anesthesia

Scientific Programming ◽

10.1155/2020/8899957 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Haitao Yang ◽

Guan Wang ◽

Jinxia Gao ◽

Jie Liu

Keyword(s):

General Anesthesia ◽

Sensitivity And Specificity ◽

Auditory Evoked Potentials ◽

High Sensitivity ◽

Anesthetic Technique ◽

Depth Of Anesthesia ◽

Anesthetic Depth ◽

Sevoflurane Group ◽

Anesthetic Drugs ◽

End Tidal

Background. There is an increasing concern of awareness and recall during general anesthesia for both the patient and the anesthetist. The bispectral index (BIS) is used to assess the level of sedation and depth of anesthesia and detect consciousness in different anesthetic drugs. Middle-latency auditory evoked potentials (AEPs) also quantify action of anesthetic drugs and detect the transition from consciousness to unconsciousness. We aim to compare the sensitivity and specificity between BIS and AEP in predicting unconsciousness in inhalational sevoflurane anesthesia and intravenous propofol anesthesia. Methods. Totally, 40 patients were randomly allocated into two groups: propofol or sevoflurane group. In the propofol group, anesthesia was induced with target-controlled infusion propofol. In the sevoflurane group, anesthesia was induced by increasing concentrations of sevoflurane. There were 3 end points during induction: sedation, unconsciousness, and anesthesia. Target and effect-site concentrations of propofol, end-tidal concentration of sevoflurane, and BIS and AEP were recorded at each stage. Results. We obtained good EC50 with both monitors, at which there is a 50% chance that the patient has reached the end point, but the index variation was affected by the anesthetic technique. Propofol had higher correlations with stage of anesthesia, BIS, and AEP than sevoflurane. BIS had higher correlations with depth of anesthesia than AEP, but we did not find an anesthetic depth monitor that had high sensitivity and specificity and is not affected by the anesthetic technique. Conclusions. The prediction powers of BIS and AEP do not seem as good as some papers mentioned.

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