Article

The dynamic relationship between end-tidal sevoflurane concentrations, bispectral index, and cerebral state index in children.

Departamento de Anestesiología, Hospital Clínico U. Católica, Marcoleta 367, Santiago, Chile.
Anesthesia and analgesia (Impact Factor: 3.08). 11/2008; 107(5):1573-8. DOI: 10.1213/ane.0b013e318181ef88
Source: PubMed

ABSTRACT To guide anesthetic administration with electroencephalogram monitors in children, an adequate characterization of the anesthetic effect measured by these monitors in this population is needed. We sought to quantify and compare the dynamic profile of sevoflurane's effect measured with the cerebral state index (CSI) and the bispectral index (BIS) in children.
Fifteen healthy children, aged 3-15 yr, scheduled to undergo minor surgery were prospectively studied. During the simultaneous recording of CSI and BIS, the sevoflurane vaporizer was set at 6 vol % for 5 min and then decreased. End-tidal concentrations (C(ET)) were measured. The C(ET)-sevoflurane effect-site concentration equilibration and pharmacodynamics were modeled. Goodness of fit between models was compared. Data are typical value (coefficient of variation).
Within the anesthetic depth range studied, the rate of change of sevoflurane's effect expressed as the effect-site equilibration half-life (t(1/2) k(e0)) was slower with the CSI [2.0 (14) min] than with BIS [1.2 (53) min] (P < 0.05). The estimated baseline effect of BIS and CSI before sevoflurane administration (E(0)) was 84 (39) for CSI and 87 (7) for BIS (NS). The sensitivity to sevoflurane hypnotic effect expressed in the C(50) [steady-state C(ET) eliciting half of the maximum response (E(max))] was 2.1 (68) % with CSI and 2.1 (16)% with BIS (NS). The E(max) with CSI 45 (0) was higher than that with BIS 27 (39) (P < 0.05). The population prediction error was significantly better for BIS (-0.7 +/- 26.9) than for CSI (-3.0 +/- 178.6) (P < 0.05).
In children, the t(1/2) k(e0) of sevoflurane and the pharmacodynamics of sevoflurane were quantified and the results were entirely dependent on the monitor used to measure its hypnotic effect. Within the anesthetic depth range studied, the rate of change of sevoflurane's effect was slower with the CSI. To adequately guide sevoflurane administration with these monitors in children, these differences should be considered.

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    ABSTRACT: Background Electroencephalogram (EEG) based depth of anesthesia algorithms developed in the adult population have not demonstrated the same reliability when applied to infants. This may be due to frequency changes occurring in the EEG during development. Amplitude-integrated EEG (aEEG) is based primarily in the time domain and hence may have greater utility in infants. Objective To investigate the relationship between age adjusted Minimal Alveolar Concentration (MAC) multiples and aEEG in children under 2 years of age. Methods The aEEG, Spectral Edge Frequency 90% (SEF90) and Bispectral Index™ (BIS) were investigated in a prospective study of children <2 years of age. After anesthetic induction, and caudal block administration, EEG data were collected simultaneously with BrainZ BRM2™ and BIS™ monitors. Using a randomized crossover design, children received up to three age adjusted concentrations of sevoflurane: 0.75, 1 and 1.25 MAC. After 15 min of stable anesthetic delivery EEG readings were obtained. Prediction Probability (Pk) and correlation coefficients were calculated for each EEG parameter. ResultsFrom 51 children 102 stable anesthetics concentrations were obtained. For all age groups Pk of aEEG to multiple of age adjusted MAC was <0.72 indicating a poor predictive power for aEEG. In contrast for the SEF90 and BIS there was evidence for better predictive properties in children aged between 6 months and 2 years, with a Pk >0.81. Conclusion The aEEG is unlikely to be a useful measure of anesthesia depth in young children.
    Pediatric Anesthesia 03/2014; · 2.44 Impact Factor
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    ABSTRACT: Background Although photoplethysmography and cerebral state index (CSI) have been used as indices in monitoring vital signs perioperatively, there are only a few reports comparing the performance of photoplethysmography with CSI in monitoring anaesthesia depth. The aim of the present study was to clarify features of photoplethysmography in monitoring balanced general anesthesia compared with CSI. Material and Methods Forty-five patients undergoing elective operation under general anaesthesia were enrolled in this study. Anaesthesia was induced with target-controlled infusion propofol. The photoplethysmogram, CSI, Modified Observer's Assessment of Alertness/Sedation Scale (MOAAS), and mean arterial pressure (MAP) were continuously monitored and recorded. Finger photoplethysmogram amplitude (PPGA) and pulse beat interval (PBI) were calculated off-line. Results For the period of time from pre-induction to pre-intubation, the coefficient of correlation between MOAAS and CSI was higher than those between MOAAS and PPGA, PBI, and MAP. CSI showed higher prediction probabilities (Pk) to differentiate the levels of MOAAS than did PPGA, PBI, and MAP. PPGA, PBI, and MAP values showed significant differences between before and after intubation, as well as pre- and post-incision (P<0.05), but no significant changes in cerebral state index (P>0.05). Conclusions The present study shows that photoplethysmography-derived parameters appear to be more suitable in monitoring the nociceptive component of balanced general anesthesia, while CSI performs well in detecting the sedation or hypnotic component of balanced general anesthesia.
    Medical science monitor: international medical journal of experimental and clinical research 01/2014; 20:481-6. · 1.22 Impact Factor

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