• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.76-85
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• 2010

In general, anesthetic depth is evaluated by experience of anesthesiologist based on the changes of blood pressure and pulse rate. So it is difficult to guarantee the accuracy in evaluation of anesthetic depth. The efforts to develop the objective index for evaluation of anesthetic depth were continued but there was few progression in this area. Heart rate variability provides much information of autonomic activity of cardiovascular system and almost all anesthetics depress the autonomic activity. Novel monitoring system which can simply and exactly analyze the autonomic activity of cardiovascular system will provide important information for evaluation of anesthetic depth. We investigated the anesthetic depth as following 7 stages. These are pre-anesthesia, induction, skin incision, before extubation, after extubation, Post-anesthesia. In this study, temporal, frequency and chaos analysis method were used to analyze the HRV time series from electrocardiogram signal. There were NN10-NN50, mean, SDNN and RMS parameter in the temporal method. In the frequency method, there are LF and HF and LF/HF ratio, 1/f noise, alphal and alpha2 of DFA analysis parameter. In the chaos analysis, there are CD, entropy and LPE. Chaos analysis method was valuable to estimate the anesthetic depth compared with temporal and frequency method. Because human body was involved the choastic character.

• Korean Journal of Veterinary Research
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• v.46 no.1
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• pp.47-55
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• 2006

To evaluate method for monitoring anesthetic depth with quantitative electroencephalography (q-EEG), we recorded processed EEG (raw EEG) and pain score till 100 minutes in beagle dogs anesthetized for 60 minutes with propofol (n = 5, PRO group), isoflurane (n = 5, ISO group) and propofol-ketaminefentanyl (n = 5, PFK group). Raw EEG was converted into 95% spectral edge frequency (SEF) by fast Fourier transformation (FFT) method. We investigated anesthetic depth by comparing relationship (Pearson's correlation) between q-EEG (95% SEF) and pain score. Pearson's correlation coefficients are +0.2372 (p = 0.0494, PRO group), +0.79506 (p < 0.001, ISO group) and +0.49903 (p = 0.0039, PFK group).

• Journal of Dental Anesthesia and Pain Medicine
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• v.18 no.4
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• pp.235-244
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• 2018

Background: Patients with intellectual disability (ID) often require general anesthesia during oral procedures. Anesthetic depth monitoring in these patients can be difficult due to their already altered mental state prior to anesthesia. In this study, the utility of electroencephalographic indexes to reflect anesthetic depth was evaluated in pediatric patients with ID. Methods: Seventeen patients (mean age, $9.6{\pm}2.9years$) scheduled for dental procedures were enrolled in this study. After anesthesia induction with propofol or sevoflurane, a bilateral sensor was placed on the patient's forehead and the bispectral index (BIS) was recorded. Anesthesia was maintained with sevoflurane, which was adjusted according to the clinical signs by an anesthesiologist blinded to the BIS value. The index performance was accessed by correlation (with the end-tidal sevoflurane [EtSevo] concentration) and prediction probability (with a clinical scale of anesthesia). The asymmetry of the electroencephalogram between the left and right sides was also analyzed. Results: The BIS had good correlation and prediction probabilities (above 0.5) in the majority of patients; however, BIS was not correlated with EtSevo or the clinical scale of anesthesia in patients with Lennox-Gastaut, West syndrome, cerebral palsy, and epilepsy. BIS showed better correlations than SEF95 and TP. No significant differences were observed between the left- and right-side indexes. Conclusion: BIS may be able to reflect sevoflurane anesthetic depth in patients with some types of ID; however, more research is required to better define the neurological conditions and/or degrees of disability that may allow anesthesiologists to use the BIS.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.2
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• pp.63-69
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• 2019

In this study, bispectrum analysis method introduced to reduce variability of SEF(spectral edge frequency) and MF(median frequency), which are the anesthetic depth indexes extracted by EEG spectral analysis. Bispectrum analysis is an analytical method that can confirm the nonlinearity of EEG. Signal measurement and analysis in the surgical environment should take into consideration various external artifact factors. Bispectrum analysis can confirm the presence of externally introduced artifacts, thereby effectively eliminating artifacts that affect the EEG signal. By applying bispectrum parameters, real-time variability of the anesthetic depth parameters SEF, MF could be reduced. Elimination of variability makes it possible to use SEF, MF as a real-time index during surgery.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.287-293
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• 2007

The researchers have studied for a long time about the depth of anesthesia but they don't make criteria for the depth of anesthesia. Anesthetists can't make a prediction about patient's reaction. Therefore, patients have potential risk such as poisonous side effect, late-awake, early-awake and strain reaction. In this study, the distributed characteristics on the bispectrum and bicoherence, the type of nonlinear signal processing, as a result of the coupling of EEG were presented according to depth of anesthesia. These results were consistent with a trend of delta ratio that the index of evaluation for the depth of anesthesia. The higher-order spectrum (HOS), the bispectrum and bicoherence, gives the useful information about depth of anaesthesia than other indexes.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.289-292
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• 2002

In this study, we measure and analyzed variation of EEG signal by anesthesiologist progress step. In an experiment, the EEG signal was acquired and analyzed as 5 steps(prior surgical operation, during induction, surgical operation, awakening, posterior surgical operation). As a result, we confirm the anesthesiologist progress phase, concluded the possibility of anesthesia depth because using SEF and MF, and Delta ratio confirmed that can presume operating patient's consciousness state.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.81-91
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• 1991

This study was carried out to investigate the effects of intravenous drip with ketamine hydrochloride and its application for control depth and maintenance of anesthesia in dogs. Changes of blood pressure, vital signs, blood gas and anesthetic state were observed in this study. The obtained were summerized as follows ; 1. Changes of blood pressure and heart rate after intravenous drip anesthesia with ketamine hydrochloride were observed with significant increase in all group ; group II (0.135m81k9/min), group III (0.269mg/kg/min) and group IV(0.538mg/kg/min). These conditions were maintained unchangeably until 160 minutes after administration in all group. This may be indicated that there were no side effects on account of ketamine accumulation. 2. There were irregular respiration, pain reflex, Jaw tone reflex and vomition probability in the anesthetic conditions of group II The anesthetic conditions of group III were rarely shown as mentioned above. Awakening time and recovery time of group H were more prolonged 21 minutes and 27 minutes respectively than those of group III. These experimental data suggested that the optimal dosage of intravenous drip anesthesia of ketamine Hcl was 0.269mg/kg/min.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.278-290
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• 1997

The purposes of this study were to evaluate and compare the pulpal anesthesia induced by an inferior alveolar nerve block and that by Gow-Gates technique, and to investigate the relationship between pulpal anesthesia and intraoral soft tissue responses. After one side of mandibule was anesthetized with inferior alveolar nerve block or Gow-Gates technique using 2 % lidocaine with 1 : 100,000 epinephrine in 19 volunteers of ages between 24 and 29 (16 males and 3 females, average age 25.9 yrs.), electric pulp tests were done on the canine teeth of the anesthetized side and contralateral one before, at 1 min, continued at every 5 minutes until 60 min, and every 10 minutes until 100 min after completion of local anesthetic injection. Degree of pulpal anesthesia was classified as anesthetic failure, possible anesthesia and complete anesthesia by the criteria based on the thresholds to electric pulp test of contralateral canine and the currents of the electric pulp tester. Subjective signs on the lower lip and tongue were checked and prick-pin tests were done on the buccal gingiva of the first molar, buccal and lingual gingiva of the canine tooth at 5, 10 and 20 min after the completion of anesthetic injection. Thresholds to electric pulp test, degree of pulpal anesthesia and relationship between the pulpal anesthesia and soft tissue responses were analyzed with SPSS, paired t-test, Wilcoxon matched-pairs signed-ranks test and correlation analysis. The results were as follows : No significant differences were found in the peak thresholds to electric pulp test, in the induction time to it and in the depth of pulpal anesthesia between inferior alveolar nerve block and Gow-Gates technique (p>0.05). There was no significant relationship between pulpal anesthesia and soft tissue responses in both inferior nerve block and Gow-Gates technique.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.194-197
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• 2005

This study was performed to investigate the anesthetic effects of intramuscularly administered medetomidinetiletamine/zolazepam ($Zoletil^{(R)}$) in the green iguana. The doses of medetomidine were 50, 100 and 150 ${\mu}g/kg$ in each groups and tiletamine/zolazepam was administered at doses of 10 mg/kg in all groups. Heart rate, respiratory rate and body temperature were measured. Anesthetic depth was evaluated by righting reflex. In all study groups, heart rate and respiratory rate significantly decreased at 5 minutes after anesthetic administration, and gradually increased after 30 minutes. The present study suggested that the combination of 100 ${\mu}g/kg$ of medetomidine and 10 mg/kg of tiletamine/zolazepam provided rapid, safe, and effective anesthesia for the green iguana.

• The Korean Journal of Pain
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• v.10 no.1
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• pp.73-76
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• 1997

Background : Epidural anesthesia is now accepted as a popular technique for pain relief and anesthesia. However, accidental dural puncture may occur during placement of the epidural needle. This study was undertaken to evaluate difference of the epidural depth between parturients and non-parturients. Method : Eighty non-parturients receiving epidural anesthesia were assigned to group I, and eighty parturients whose body weight had not yet increased over 15 kg from pregnancy were assigned to group II. With patients in lateral decubitus position, 18 guage Tuohy needle was punctured by approaching at $L_{3-4}$ interspace. Epidural space was identified using loss-of-resistance to air technique. Result : Epidural depth was 4.18 cm and 4.25 cm in group I and group II respectively. There was no significant statistical difference in body mass index(BMI) and ponderal index(PI) (p<0.05), nor in epidural depth between the two groups. Conclusion : Epidural needle need not be placed deeper in parturients than in nonparturients.