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Discrepant End-Tidal Concentrations of Sevoflurane at the Same A-Line Autoregressive Index Level during Induction of General Anesthesia: An Observational Study. J Clin Med 2021; 10:jcm10194526. [PMID: 34640546 PMCID: PMC8509407 DOI: 10.3390/jcm10194526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022] Open
Abstract
Background: The A-Line Autoregressive Index (AAI), which is derived from auditory evoked potentials, has been used for determining anesthetic depth. This study verified the correlation between AAI values and the corresponding end-tidal concentrations of sevoflurane during general anesthesia induction. Methods: Thirty young male adults undergoing elective minor orthopedic surgery were sequentially allocated to receive inspiratory 3%, 5%, or 6% sevoflurane for mask induction, followed by mechanical ventilation after tracheal intubation. The inspiratory, end-tidal and estimated jugular bulb concentrations of sevoflurane were recorded at three target AAI values: below 20, below 10, and at the start of burst suppression. Results: The mean time to loss of consciousness in the 6% sevoflurane group was shorter than that in the 5% and 3% groups; however, the groups had comparable AAI values (range: 16–45). The 6% group had a higher end-tidal concentration (4.5% ± 0.2% vs. 3.8% ± 0.2%, p < 0.05) than did the 5% group, despite having the same target anesthetic levels by AAI score ≤10, whereas the estimated jugular bulb concentrations were comparable (1.9% vs. 1.9%) in both groups. Conclusions: Following mechanical ventilation with inspiratory 3%, 5%, or 6% sevoflurane, the end-tidal concentrations were discrepant at the same end points of AAI levels, despite similar estimated jugular bulb concentrations of sevoflurane. Thus, conventional alveolar concentration may overestimate anesthesia depth during rapid wash-in of sevoflurane.
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Wu X, Cao J, Shan C, Peng B, Zhang R, Cao J, Zhang F. Efficacy and safety of propofol in preventing emergence agitation after sevoflurane anesthesia for children. Exp Ther Med 2019; 17:3136-3140. [PMID: 30930979 PMCID: PMC6425276 DOI: 10.3892/etm.2019.7289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 01/30/2019] [Indexed: 11/29/2022] Open
Abstract
Application of propofol in preventing emergence agitation after sevoflurane anesthesia in children was evaluated. Clinical data of 200 children who received sevoflurane anesthesia in Children's Hospital of Xuzhou Medical University were retrospectively analyzed. Among them, 120 patients who received inhaled sevoflurane for pediatric anesthesia and intravenous infusion of propofol (2 mg/kg) were included in observation group. The remaining 80 cases who were directly anesthetized by sevoflurane alone were the control group. T PAED scores, modified Aldrete scores, extubation time, PACU time and adverse reactions (gastrointestinal tract and respiratory response) were analyzed and compared between the control and observation group. PAED scores, extubation time, PACU time and incidence of adverse reactions were significantly lower in observation than in control group, and the modified Aldrete scores were higher in observation than in control group (P<0.05). Spearman's correlation analysis showed that the PAED scores were negatively correlated with modified Aldrete scores and positively correlated with extubation time. There was positive correlation between the PACU time and incidence of adverse reactions and between the PAED scores and extubation time. There was negative correlation between PACU time and incidence of adverse reactions and between Aldrete scores and extubation time (P<0.05). Therefore, we conclude that propofol can be used to prevent agitation after sevoflurane anesthesia in children.
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Affiliation(s)
- Xiaole Wu
- Children's Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Junhua Cao
- Children's Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Chengjing Shan
- Children's Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Bei Peng
- Children's Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Ruidong Zhang
- Shanghai Children's Medical Center, Shanghai 200127, P.R. China
| | - Junli Cao
- Department of Anesthesiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Fengchao Zhang
- Children's Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
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Boboš M, Đurić M, Stevanović V, Nenadić I, Milanović M, Stevanović P. Recovery after laparoscopic anesthesia: Three different anaesthesia techniques: Recovery after laparoscopic anesthesia. SERBIAN JOURNAL OF ANESTHESIA AND INTENSIVE THERAPY 2019. [DOI: 10.5937/sjait1908167b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Messina AG, Wang M, Ward MJ, Wilker CC, Smith BB, Vezina DP, Pace NL. Anaesthetic interventions for prevention of awareness during surgery. Cochrane Database Syst Rev 2016; 10:CD007272. [PMID: 27755648 PMCID: PMC6461159 DOI: 10.1002/14651858.cd007272.pub2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND General anaesthesia is usually associated with unconsciousness. 'Awareness' is when patients have postoperative recall of events or experiences during surgery. 'Wakefulness' is when patients become conscious during surgery, but have no postoperative recollection of the period of consciousness. OBJECTIVES To evaluate the efficacy of two types of anaesthetic interventions in reducing clinically significant awareness:- anaesthetic drug regimens; and- intraoperative anaesthetic depth monitors. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL, ISSUE 4 2016); PubMed from 1950 to April 2016; MEDLINE from 1950 to April 2016; and Embase from 1980 to April 2016. We contacted experts to identify additional studies. We performed a handsearch of the citations in the review. We did not search trial registries. SELECTION CRITERIA We included randomized controlled trials (RCTs) of either anaesthetic regimens or anaesthetic depth monitors. We excluded volunteer studies, studies of patients prior to skin incision, intensive care unit studies, and studies that only randomized different word presentations for memory tests (not anaesthetic interventions).Anaesthetic drug regimens included studies of induction or maintenance, or both. Anaesthetic depth monitors included the Bispectral Index monitor, M-Entropy, Narcotrend monitor, cerebral function monitor, cerebral state monitor, patient state index, and lower oesophageal contractility monitor. The use of anaesthetic depth monitors allows the titration of anaesthetic drugs to maintain unconsciousness. DATA COLLECTION AND ANALYSIS At least two authors independently scanned abstracts, extracted data from the studies, and evaluated studies for risk of bias. We made attempts to contact all authors for additional clarification. We performed meta-analysis statistics in packages of the R language. MAIN RESULTS We included 160 studies with 54,109 enrolled participants; 53,713 participants started the studies and 50,034 completed the studies or data analysis (or both). We could not use 115 RCTs in meta-analytic comparisons because they had zero awareness events. We did not merge 27 of the remaining 45 studies because they had excessive clinical and methodological heterogeneity. We pooled the remaining 18 eligible RCTs in meta-analysis. There are 10 studies awaiting classification which we will process when we update the review.The meta-analyses included 18 trials with 36,034 participants. In the analysis of anaesthetic depth monitoring (either Bispectral Index or M-entropy) versus standard clinical and electronic monitoring, there were nine trials with 34,744 participants. The overall event rate was 0.5%. The effect favoured neither anaesthetic depth monitoring nor standard clinical and electronic monitoring, with little precision in the odds ratio (OR) estimate (OR 0.98, 95% confidence interval (CI) 0.59 to 1.62).In a five-study subset of Bispectral Index monitoring versus standard clinical and electronic monitoring, with 34,181 participants, 503 participants gave awareness reports to a blinded, expert panel who adjudicated or judged the outcome for each patient after reviewing the questionnaires: no awareness, possible awareness, or definite awareness. Experts judged 351 patient awareness reports to have no awareness, 87 to have possible awareness, and 65 to have definite awareness. The effect size favoured neither Bispectral Index monitoring nor standard clinical and electronic monitoring, with little precision in the OR estimate for the combination of definite and possible awareness (OR 0.96, 95% CI 0.35 to 2.65). The effect size favoured Bispectral Index monitoring for definite awareness, but with little precision in the OR estimate (OR 0.60, 95% CI 0.13 to 2.75).We performed three smaller meta-analyses of anaesthetic drugs. There were nine studies with 1290 participants. Wakefulness was reduced by ketamine and etomidate compared to thiopental. Wakefulness was more frequent than awareness. Benzodiazepines reduces awareness compared to thiopental, ketamine, and placebo., Also, higher doses of inhaled anaesthetics versus lower doses reduced the risk of awareness.We graded the quality of the evidence as low or very low in the 'Summary of findings' tables for the five comparisons.Most of the secondary outcomes in this review were not reported in the included RCTs. AUTHORS' CONCLUSIONS Anaesthetic depth monitors may have similar effects to standard clinical and electrical monitoring on the risk of awareness during surgery. In older studies comparing anaesthetics in a smaller portion of the patient sample, wakefulness occurred more frequently than awareness. Use of etomidate and ketamine lowered the risk of wakefulness compared to thiopental. Benzodiazepines compared to thiopental and ketamine, or higher doses of inhaled anaesthetics versus lower doses, reduced the risk of awareness.
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Affiliation(s)
- Anthony G Messina
- School of Management, University of Texas at DallasThe Alliance for Medical Management EducationBox 2331920 N. Coit RoadRichardsonTXUSA75080
| | - Michael Wang
- University of LeicesterClinical Psychology UnitLancaster RoadLeicesterUKLE1 7HA
| | - Marshall J Ward
- Dartmouth‐Hitchcock Medical Center1 Medical Center DrLebanonNHUSA03766
| | - Chase C Wilker
- ARUP LaboratoriesClinical Toxicology IIISalt Lake CityUTUSA
| | - Brett B Smith
- University of UtahUniversity of Utah School of MedicineSalt Lake CityUTUSA84112
| | - Daniel P Vezina
- University of UtahDepartment of Anesthesiology, Department of Internal Medicine, Division of CardiologySalt Lake CityUTUSA
- Veteran's AdministrationEchocardiography LaboratorySalt Lake CityUTUSA
| | - Nathan Leon Pace
- University of UtahDepartment of Anesthesiology3C444 SOM30 North 1900 EastSalt Lake CityUTUSA84132‐2304
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Nishiyama T. The effects of auditory evoked potential click sounds on bispectral index and entropy. Anesth Analg 2008; 107:545-8. [PMID: 18633033 DOI: 10.1213/ane.0b013e318174deed] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The click sounds of auditory evoked potentials (AEP) might have some effect on electroencephalogram indices and Bispectral Index (BIS) but many studies, unconcerned about this effect, have measured both indices simultaneously. In this study, I examined the effects, of AEP click sounds on the BIS, and also on the response entropy (RE) and state entropy (SE) of the entropy monitor. METHODS Forty patients aged 40-70 yr and scheduled for surgery of lower extremities under spinal anesthesia were anesthetized with 0.5% bupivacaine or tetracaine. Patients were sedated with midazolam 1 mg followed by propofol infusion started at 1 mg.kg(-1).h(-1). Propofol infusion was controlled to keep BIS or SE at 80, 60, or 40 for several minutes, and then click sounds (65 dB) of the AEP were given for 60 s. The changes in BIS, RE, and SE were observed continuously for 60 s after the click sounds had stopped. RESULTS BIS, SE, and RE significantly increased during the click sounds. The longest duration of increase was at BIS or SE 60. CONCLUSION AEP monitor click sounds transiently increased the simultaneously measured BIS, RE, and SE during different levels of sedation by propofol infusion during spinal anesthesia. Therefore, the effects of the click sounds should be considered when these monitors are used simultaneously in the same patient.
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Affiliation(s)
- Tomoki Nishiyama
- Department of Anesthesiology, Ofuna Chuo Hospital, Kanagawa, Japan.
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Jankovic MP, Kaufmann M, Kindler CH. Active Research Fields in Anesthesia: A Document Co-Citation Analysis of the Anesthetic Literature. Anesth Analg 2008; 106:1524-33, table of contents. [DOI: 10.1213/ane.0b013e31816d18a1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Pruszkowski O, Dalibon N, Moutafis M, Jugan E, Law-Koune JD, Laloë PA, Fischler M. Effects of propofol vs sevoflurane on arterial oxygenation during one-lung ventilation. Br J Anaesth 2007; 98:539-44. [PMID: 17347180 DOI: 10.1093/bja/aem039] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The inhibitory effect of anaesthetic agents on hypoxic pulmonary vasoconstriction may depend upon their dose, especially when using a volatile agent. The aim of this randomized open study was to compare the effects of sevoflurane and propofol, as primary anaesthetic agents, on oxygenation during one-lung ventilation (OLV), with their administration being adjusted to maintain bispectral index (BIS) values between 40 and 60. METHODS Eighty patients scheduled for a lobectomy, receiving an epidural mixture of ropivacaine and sufentanil, were randomly assigned to Group S (maintenance with sevoflurane) or Group P (maintenance with propofol). After placement of a double-lumen tube, the lungs were ventilated at an inspiratory fraction of oxygen of 1.0, a tidal volume of 6 ml kg(-1), and 12 bpm. Arterial blood gas samples were taken as follows: during two-lung ventilation before OLV, and during the first 40 min of OLV. RESULTS Fifteen patients were excluded (incorrect placement of the tube or BIS outside the desired range). The two groups were comparable in terms of demographic variables, haemodynamic, and BIS levels during the operation. Four patients in each group had a Sp(O2)<90%. Mean of the lowest Pa(O2) was 16.3 (7.5) kPa in Group S and 17.7 (9.3) kPa in Group P (ns). CONCLUSIONS Sevoflurane and propofol had similar effect on Pa(O2) during OLV when their administration is titrated to maintain BIS between 40 and 60.
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Affiliation(s)
- O Pruszkowski
- Department of Anaesthesiology, Université Paris Ile-de-France Ouest, Hôpital Foch, Suresnes, France
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Bould MD, Mahtani DG, Davies R, Roughton M, Hunter DN, Kelleher A. Bispectral index values during elective rigid bronchoscopy: a prospective observational pilot study. Anaesthesia 2007; 62:438-45. [PMID: 17448053 DOI: 10.1111/j.1365-2044.2007.04986.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Rigid bronchoscopy is associated with a high incidence of haemodynamic disturbance and awareness under anaesthesia. Anaesthetic agents are given both to attenuate the sympathetic response to bronchoscopy and to prevent awareness. Use of the Bispectral index to guide anaesthesia has shown to reduce awareness and improve recovery times from general anaesthesia. We undertook a prospective observational study of BIS values in 50 patients during routine anaesthesia for rigid bronchoscopy. BIS values were found to be between 40-60 during bronchoscopy for only 0.5% of the time (0-11.5%[0-98.7%]), median (interquartile range [range]). Patients had a BIS < 40 for 99.6% (87.9-100%[0-100%]) of the duration of bronchoscopy. We identified one case of possible awareness. Few of our patients undergoing general anaesthesia for rigid bronchoscopy had BIS scores in the suggested range of between 40 and 60. BIS < 40 was more frequent than in previous studies of different surgical populations. There was no difference in the BIS values of patients anaesthetised with intermittent boluses or target controlled infusions of propofol.
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Affiliation(s)
- M D Bould
- Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK.
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Wu CC, Mok MS, Chen JY, Wu GJ, Wen YR, Lin CS. Doxapram shortens recovery following sevoflurane anesthesia. Can J Anaesth 2006; 53:456-60. [PMID: 16636029 DOI: 10.1007/bf03022617] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
PURPOSE A randomized, double blind controlled trial was undertaken to investigate the effect of doxapram on recovery times and bispectral index following sevoflurane anesthesia. METHODS Upon completion of surgery under sevoflurane anesthesia, 60 adult patients were randomly allocated to receive either doxapram hydrochloride 1 mg.kg(-1) iv or saline placebo. Clinical recovery from anesthesia was assessed by time to eye opening on verbal command, hand squeezing on command, time to extubation, and the Aldrete recovery score. Bispectral index values, systolic blood pressure, and heart rate were recorded at baseline (before anesthesia), during surgery, and every minute for 15 min after administration of the study drug. RESULTS Time to eye opening was shorter in the doxapram group compared with the control group (6.9 +/- 2.2 min vs 9.9 +/- 3.1 min, P < 0.05). Mean bispectral index scores were also higher in the doxapram group compared with the saline placebo seven to eight minutes following administration of the study medication (P < 0.05). More rapid emergence was associated with a greater increase in heart rate with doxapram (P < 0.05 compared with placebo), but no differences in systolic blood pressure responses were observed in comparison with placebo. CONCLUSION We conclude that doxapram 1 mg.kg(-1) hastens early recovery from sevoflurane anesthesia, and this arousal effect correlates with higher bispectral index values.
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Affiliation(s)
- Chi-Chen Wu
- Department of Anesthesiology, Taipei Medical University Hospital, 252 Wu-Hsin Street, Taipei, Taiwan 110
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Lewis MC, Gerenstein RI, Chidiac G. Onset Time for Sevoflurane/Nitrous Oxide Induction in Adults Is Prolonged with Increasing Age. Anesth Analg 2006; 102:1699-702. [PMID: 16717312 DOI: 10.1213/01.ane.0000205749.92049.91] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Inhaled induction of anesthesia is occasionally used in adults. Using a modified vital capacity sevoflurane/nitrous oxide (N2O) inhaled induction, we evaluated the effect of increasing age on the onset time of anesthesia. Twenty patients, aged 26-65 yr, performed a vital capacity breath followed by regular tidal breathing from an anesthesia circuit primed with sevoflurane 8%/N2O/O2. The following values were recorded: time to loss of eyelash reflex (LOER); time to bispectral index < or =60 (BIS < or =60); expired fraction of sevoflurane at the time of induction, LOER and BIS < or =60. The mean times and 95% confidence intervals to LOER and BIS < or =60 were 54 s (37-70 s) and 175 s (143-207 s), respectively, and were significantly prolonged by aging (r = 0.65; P = 0.002). Times to LOER and BIS < or =60, predicted from the regression line, were 3.9 and 2 times longer in a 60-yr-old than in a 30-yr-old patient. The expired fraction of sevoflurane measured at time to LOER and BIS < or =60 decreases with increase in age. We conclude that inhaled induction with sevoflurane/N2O is dramatically prolonged with increased age.
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Affiliation(s)
- Michael C Lewis
- Department of Anesthesiology, Miller School of Medicine at the University of Miami, Miami, Florida 33101, USA.
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Wang ZH, Chang MH, Yang JW, Sun JJ, Lee HC, Shyu BC. Layer IV of the primary somatosensory cortex has the highest complexity under anesthesia and cortical complexity is modulated by specific thalamic inputs. Brain Res 2006; 1082:102-14. [PMID: 16500629 DOI: 10.1016/j.brainres.2006.01.070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 01/18/2006] [Accepted: 01/18/2006] [Indexed: 10/25/2022]
Abstract
The system complexity, as calculated from correlation dimension, embedded in each layer and its modulation by specific inputs and general excitatory state are not yet known. The aims of present study were to estimate the system complexity across the cortical layers by analyzing intracortical EEG signals using a nonlinear analytical method, and to identify how layer-related complexity varies with the alteration of thalamic input and brain state. Male Sprague-Dawley rats were anesthetized under l% halothane. Sixteen channels of evoked or spontaneous EEG signals were recorded simultaneously across the six cortical layers in the somatosensory cortex with a single Michigan probe. The system complexity was assessed by computing correlation dimension, D(2), based on the Nonlinear Time Series Analysis data analysis program. Cortical layer IV exhibited a D(2) value, 3.24, that was significantly higher than that of the other cortical layers. The D(2) values in layers IV and II/III were significantly reduced after reversible deactivation of the ventral posterior lateral thalamic nucleus. D(2) decreased with increases in administered halothane concentration from 0.75% to 2.0%, particularly in layer IV. The present findings suggest that cortical layer IV maintains a higher complexity than the other layers and that the complexity of the mid-cortical layers is subject to regulation from specific thalamic inputs and more sensitive to changes in the general state of brain excitation.
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Affiliation(s)
- Zi-Hao Wang
- Computing Centre, Academia Sinica, Taipei 11529, Taiwan, ROC
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Alpiger S, Helbo-Hansen HS, Vach W, Ording H. Efficacy of A-line AEP Monitor as a tool for predicting acceptable tracheal intubation conditions during sevoflurane anaesthesia. Br J Anaesth 2005; 94:601-6. [PMID: 15749734 DOI: 10.1093/bja/aei111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND It is essential for the clinical anaesthetist to know whether patients are sufficiently anaesthetized to tolerate direct laryngoscopy and endotracheal intubation. Because of the lack of an accurate objective method to determine the level of general anaesthesia, under- or overdosing of anaesthetics may occur. Auditory evoked potential (AEP) is one of several physiological parameters under investigation. We aimed to determine the clinically required depth of anaesthesia, measured by the A-line AEP Monitor and expressed as A-Line ARX Index (AAI) for 90% probability of acceptable conditions for endotracheal intubation. METHODS We studied 108 patients anaesthetized by mask with increasing concentration of sevoflurane in 30% oxygen and 70% nitrous oxide. Fentanyl 1.5 microg kg(-1) and glycopyrrolate 0.2 mg were administered intravenously immediately before starting induction of anaesthesia. The monitor was programmed to give an alarm at AAI 10, 15, 20, 25 or 30 according to randomization. When the alarm sounded, the end-expiratory sevoflurane concentration was registered and endotracheal intubation was attempted. Intubation conditions were assessed by an observer blinded to the AAI. RESULTS At AAI 10 we found acceptable conditions in 91% (confidence interval [CI 72-99%]) of patients. The prediction probability value P(K) of AAI was 0.69 (CI 0.59-0.79) and the P(K) of end-expiratory sevoflurane concentration was 0.93 (CI 0.87-0.99). ED(90) (the AAI with a 90% probability of acceptable intubation conditions) was calculated as 8.5 (CI 0-17.5). CONCLUSIONS AAI indicates the depth of anaesthesia necessary for acceptable endotracheal intubation conditions. Under the conditions of the present study, end-expiratory sevoflurane concentration was a better predictor and may turn out to be more useful in the clinical setting.
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Affiliation(s)
- S Alpiger
- Department of Anaesthesiology, Vejle Hospital, Vejle, Denmark.
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Alpiger S, Helbo-Hansen HS, Vach W, Ording H. Efficacy of the A-line AEP monitor as a tool for predicting successful insertion of a laryngeal mask during sevoflurane anesthesia. Acta Anaesthesiol Scand 2004; 48:888-93. [PMID: 15242435 DOI: 10.1111/j.0001-5172.2004.00425.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The use of clinical signs for assessing depth of anesthesia is unreliable during periods with little noxious stimulation. A patient may appear adequately anesthetized at one moment at a given level of stimulation, but may later, when facing other more intense stimuli, show signs of insufficient anesthesia. In order to prevent under- or overdosing of anesthetics, an anesthesia depth monitor that is able to predict responses to noxious stimulation would therefore be useful. Auditory evoked potentials (AEP) is one of several physiological parameters under investigation. The method has been improved by rapid extraction and conversion of the AEP curve into an index (A-Line ARX Index = AAI). We aimed to determine the clinically required depth of anesthesia, measured by the A-line AEP Monitor, for at least 90% probability of acceptable insertion conditions for a laryngeal mask airway (LMA). METHODS We studied 112 patients anesthetized by mask with increasing concentration of sevoflurane in oxygen. The monitor was programmed to give an alarm at AAI between 15 and 40 according to randomization. When the alarm sounded, the end-expiratory sevoflurane concentration was recorded and the LMA inserted. Insertion conditions were assessed by an observer blinded to the AAI. RESULTS The ED(95) and prediction probability (P(K)) for AAI were 14.5 (CI 7.4-21.6) and 0.76 (0.66-0.86), respectively, while the ED(95) and P(K) for expiratory sevoflurane concentration were 4.36% (CI 3.73-4.98) and 0.95 (0.91-0.99). CONCLUSIONS AAI indicates the level of depth of anesthesia necessary for acceptable laryngeal mask insertion conditions. End-expiratory sevoflurane concentration was the better predictor.
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Affiliation(s)
- S Alpiger
- Department of Anesthesiology, Vejle Hospital, Vejle, Denmark.
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