scholarly journals Preliminary assessment of the AAI Index® during isoflurane anaesthesia in dogs undergoing clinical procedures

2009 ◽  
Vol 80 (3) ◽  
Author(s):  
K.E. Joubert
Keyword(s):  
Evoked Potential ◽  
Polynomial Regression ◽  
Anaesthetic Agent ◽  
Auditory Evoked Potential ◽  
Preliminary Assessment ◽  
Isoflurane Concentration ◽  
Clinical Procedures ◽  
Regression Relationship ◽  
Anaesthetic Depth ◽  
End Tidal

The auditory evoked potential (AEP) is correlated to anaesthetic depth. The AEP has been used in rats, pigs, dogs and humans to assess anaesthetic depth. This study was undertaken to determine whether the AAI Index® derived from the AEP correlated with changes in end tidal isoflurane concentration in dogs. The average AAI Index was 21.8 ± 10.5 and isoflurane concentration was 1.7±0.4 %. Data were divided into 0.5 % intervals of end tidal anaesthetic agent concentration (ETAA). When ETAA values were higher than 2.5 % the AAI values were 2.1-2.5 %, 1.6-2.0 % and 1.1-1.5 % higher than AAI values although not statistically different. The 2.1-2.5 % interval was statistically different from the 1.1-1.5 % and <1.1 % interval. The 1.6-2.0 % interval was statistically different from the 1.1-1.5 % and the <1.1 % intervals. The 1.1-1.5 % interval was statistically different from the <1.1 % interval. The correlation between the AAI Index and isoflurane was -0.176 and was statistically significant (P=0.0009). A linear regression between the AAI Index and isoflurane revealed the following relationship: AAI = 29.074 - (4.2755 × isoflurane) with a power of 0.913. The polynomial regression relationship was AAI = 53.334 - (35.715 x isoflurane) + (10.322 x isoflurane2) - (0.43646 x isoflurane3) with a power of 0.999. The AAI Index was found to correlate with changes in isoflurane concentration

Does the Use of Electroencephalographic Bispectral Index or Auditory Evoked Potential Index Monitoring Facilitate Recovery after Desflurane Anesthesia in the Ambulatory Setting?

2004 ◽  
Vol 100 (4) ◽  
pp. 811-817 ◽  
Author(s):  
Paul F. White ◽  
Hong Ma ◽  
Jun Tang ◽  
Ronald H. Wender ◽  
Alexander Sloninsky ◽  
...  
Keyword(s):  
General Anesthesia ◽  
Evoked Potential ◽  
Auditory Evoked Potential ◽  
Ambulatory Setting ◽  
Control Group ◽  
Maintenance Period ◽  
Quality Of Recovery ◽  
Desflurane Concentration ◽  
End Tidal

Background Analogous to the Bispectral Index (BIS) monitor, the auditory evoked potential monitor provides an electroencephalographic-derived index (AAI), which is alleged to correlate with the central nervous system depressant effects of anesthetic drugs. This clinical study was designed to test the hypothesis that intraoperative cerebral monitoring guided by either the BIS or the AAI value would facilitate recovery from general anesthesia compared with standard clinical monitoring practices alone in the ambulatory setting. Methods Sixty consenting outpatients undergoing gynecologic laparoscopic surgery were randomly assigned to one of three study groups: (1) control (standard practice), (2) BIS guided, or (3) AAI guided. Anesthesia was induced with 1.5-2.5 mg/kg propofol and 1-1.5 microg/kg fentanyl given intravenously. Desflurane, 3%, in combination with 60% nitrous oxide in oxygen was administered for maintenance of general anesthesia. In the control group, the inspired desflurane concentration was varied based on standard clinical signs. In the BIS- and AAI-guided groups, the inspired desflurane concentrations were titrated to maintain BIS and AAI values in targeted ranges of 50-60 and 15-25, respectively. BIS and AAI values, hemodynamic variables, and the end-tidal desflurane concentration were recorded at 5-min intervals during the maintenance period. The emergence times and recovery times to achieve specific clinical endpoints were recorded at 1- to 10-min intervals. The White fast-track and modified Aldrete recovery scores were assessed on arrival in the PACU, and the quality of recovery score was evaluated at the time of discharge home. Results A positive correlation was found between the AAI and BIS values during the maintenance period. The average BIS and AAI values (mean +/- SD) during the maintenance period were significantly lower in the control group (BIS, 41 +/- 10; AAI, 11 +/- 6) compared with the BIS-guided (BIS, 57 +/- 14; AAI, +/- 11) and AAI-guided (BIS, 55 +/- 12; AAI, 20 +/- 10) groups. The end-tidal desflurane concentration was significantly reduced in the BIS-guided (2.7 +/- 0.9%) and AAI-guided (2.6 +/- 0.9%) groups compared with the control group (3.6 +/- 1.5%). The awakening (eye-opening) and discharge times were significantly shorter in the BIS-guided (7 +/- 3 and 132 +/- 39 min, respectively) and AAI-guided (6 +/- 2 and 128 +/- 39 min, respectively) groups compared with the control group (9 +/- 4 and 195 +/- 57 min, respectively). More importantly, the median [range] quality of recovery scores was significantly higher in the BIS-guided (18 [17-18]) and AAI-guided (18 [17-18]) groups when compared with the control group (16 [10-18]). Conclusion Compared with standard anesthesia monitoring practice, adjunctive use of auditory evoked potential and BIS monitoring can improve titration of desflurane during general anesthesia, leading to an improved recovery profile after ambulatory surgery.

Forty-hertz Midlatency Auditory Evoked Potential Activity Predicts Wakeful Response during Desflurane and Propofol Anesthesia in Volunteers 

1999 ◽  
Vol 91 (5) ◽  
pp. 1209-1209 ◽  
Author(s):  
Robert C. Dutton ◽  
Warren D. Smith ◽  
Ira J. Rampil ◽  
Ben S. Chortkoff ◽  
Edmond I Eger
Keyword(s):  
Steady State ◽  
Frequency Spectrum ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Auditory Evoked Potential ◽  
Correct Prediction ◽  
Time Frequency ◽  
Prediction Probability ◽  
End Tidal ◽  
40 Hz

Background Suppression of response to command commonly indicates unconsciousness and generally occurs at anesthetic concentrations that suppress or eliminate memory formation. The authors sought midlatency auditory evoked potential indices that successfully differentiated wakeful responsiveness and unconsciousness. Methods The authors correlated midlatency auditory evoked potential indices with anesthetic concentrations permitting and suppressing response in 22 volunteers anesthetized twice (5 days apart), with desflurane or propofol. They applied stepwise increases of 0.5 vol% end-tidal desflurane or 0.5 microg/ml target plasma concentration of propofol to achieve sedation levels just bracketing wakeful response. Midlatency auditory evoked potentials were recorded, and wakeful response was tested by asking volunteers to squeeze the investigator's hand. The authors measured latencies and amplitudes from raw waveforms and calculated indices from the frequency spectrum and the joint time-frequency spectrogram. They used prediction probability (PK) to rate midlatency auditory evoked potential indices and concentrations of end-tidal desflurane and arterial propofol for prediction of responsiveness. A PK value of 1.00 means perfect prediction and a PK of 0.50 means a correct prediction 50% of the time (e.g., by chance). Results The approximately 40-Hz power of the frequency spectrum predicted wakefulness better than all latency or amplitude indices, although not all differences were statistically significant. The PK values for approximately 40-Hz power were 0.96 during both desflurane and propofol anesthesia, whereas the PK values for the best-performing latency and amplitude index, latency of the Nb wave, were 0.86 and 0.88 during desflurane and propofol (P = 0.10 for -40-Hz power compared with Nb latency), and for the next highest, latency of the Pb wave, were 0.82 and 0.84 (P &lt; 0.05). The performance of the best combination of amplitude and latency variables was nearly equal to that of approximately 40-Hz power. The approximately 40-Hz power did not provide a significantly better prediction than anesthetic concentration; the PK values for concentrations of desflurane and propofol were 0.91 and 0.94. Changes of 40-Hz power values of 20% (during desflurane) and 16% (during propofol) were associated with a change in probability of nonresponsiveness from 50% to 95%. Conclusions The approximately 40-Hz power index and the best combination of amplitude and latency variables perform as well as predictors of response to command during desflurane and propofol anesthesia as the steady-state concentrations of these anesthetic agents. Because clinical conditions may limit measurement of steady-state anesthetic concentrations, or comparable estimates of cerebral concentration, the approximately 40-Hz power could offer advantages for predicting wakeful responsiveness.

scholarly journals Bispectral Index as a Predictor of Sedation Depth during Isoflurane or Midazolam Sedation in ICU Patients

2007 ◽  
Vol 35 (3) ◽  
pp. 348-356 ◽  
Author(s):  
P. V. Sackey ◽  
P. J. Radell ◽  
F. Granath ◽  
C. R. Martling
Keyword(s):  
Clinical Evaluation ◽  
Bispectral Index ◽  
Icu Patients ◽  
Isoflurane Concentration ◽  
Anaesthetic Agents ◽  
Spearman's Rho ◽  
Spearman’S Rho ◽  
Minute Interval ◽  
Anaesthetic Depth ◽  
End Tidal

Bispectral index (BIS) is used for monitoring anaesthetic depth with inhaled anaesthetic agents in the operating room but has not been evaluated as a monitor of sedation depth in the intensive care unit (ICU) setting with these agents. If BIS could predict sedation depth in ICU patients, patient disturbances could be reduced and oversedation avoided. Twenty ventilator-dependent ICU patients aged 27 to 80 years were randomised to sedation with isoflurane via the AnaConDa® or intravenous midazolam. BIS (A-2000 XP, version 3.12), electromyogram activity (EMG) and Signal Quality Index were measured continuously. Hourly clinical evaluation of sedation depth according to Bloomsbury Sedation Score (Bloomsbury) was performed. The median BIS value during a 10-minute interval prior to the clinical evaluation at the bedside was compared with Bloomsbury. Nurses performing the clinical sedation scoring were blinded to the BIS values. End-tidal isoflurane concentration was measured and compared with Bloomsbury. Correlation was poor between BIS and Bloomsbury in both groups (Spearman's rho 0.012 in the isoflurane group and -0.057 in the midazolam group). Strong correlation was found between BIS and EMG (Spearman's rho 0.74). Significant correlation was found between end-tidal isoflurane concentration and Bloomsbury (Spearman's rho 0.47). In conclusion, BIS XP does not reliably predict sedation depth as measured by clinical evaluation in non-paralysed ICU patients sedated with isoflurane or midazolam. EMG contributes significantly to BIS values in isoflurane or midazolam sedated, non-paralysed ICU patients. End-tidal isoflurane concentration appeared to be a better indicator of clinical sedation depth than BIS.

The rat vertex-Middle Latency Auditory-Evoked Potential as indicator of anaesthetic depth: a comparison with evoked-reflex testing

2000 ◽  
Vol 873 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Zainal L Haberham ◽  
Walter E van den Brom ◽  
Anjop J Venker-van Haagen ◽  
Harry N.M de Groot ◽  
Vera Baumans ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Auditory Evoked Potential ◽  
Anaesthetic Depth ◽  
Reflex Testing ◽  
Middle Latency

scholarly journals Does the A-line ARX-Index provide a reasonable assessment of anaesthetic depth in dogs undergoing routine surgery?

2004 ◽  
Vol 75 (3) ◽  
Author(s):  
K.E. Joubert
Keyword(s):  
Objective Assessment ◽  
Subjective Assessment ◽  
Evoked Response ◽  
Auditory Evoked Potential ◽  
Dimensionless Number ◽  
Good Prospect ◽  
Auditory Evoked Response ◽  
Anaesthetic Agents ◽  
Anaesthetic Depth ◽  
End Tidal

The monitoring of anaesthetic depth is usually based on the subjective assessment of the patient. An objective assessment of anaesthesia has only recently become possible. The auditory-evoked response has predictable changes in response to increasing doses of anaesthetic agents. Recent advances have brought about a regression model with exogenous input of the auditory-evoked response, the A-line ARX-Index (AAI Index). The AAI Index is a dimensionless number between 0 and 100. This technology has been incorporated into the AEP(auditory-evoked potential) monitor that is utilised to assess anaesthetic depth in humans. This study was undertaken to determine if the AEP monitor was useful in dogs. Ten dogs were enrolled in the study. After a full clinical and otoscopic examination, dogs were premedicated with acetylpromazine and morphine. Anaesthesia was induced with thiopentone and maintained with halothane. End-tidal carbon dioxide, temperature, pulse oximetry, blood pressure and the electrocardiogram were monitored and recorded every 5 minutes. Anaesthetic depth was assessed as either being adequate or inadequate by the anaesthetist during surgery. An AEP monitor was attached to the patient and automatically collected AAI Index data. The anaesthetist was blinded to the AEP monitor. Following the completion of the surgical procedure, the patient was allowed to wake up with the AEP monitor attached. The AAI Index was analysed to compare adequate with inadequate anaesthesia during the period of surgery and awake with sleep data during recovery. All AAI Index values associated with inadequate anaesthesia were greater than 31 while adequate values were less than 35. The difference between the groups was statistically significant and the power was 0.97. Statistically, the awake and sleep values were significantly different with a power of 0.99. From this study it can be concluded that the AAI Index shows good prospect for the evaluation of anaesthetic depth in dogs undergoing surgery.A larger study is needed to confirm these results.

Auditory Evoked Potential Index Predicts the Depth of Sedation and Movement in Response to Skin Incision during Sevoflurane Anesthesia

2001 ◽  
Vol 95 (2) ◽  
pp. 364-370 ◽  
Author(s):  
Tadayoshi Kurita ◽  
Matsuyuki Doi ◽  
Takasumi Katoh ◽  
Hideki Sano ◽  
Shigehito Sato ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Skin Incision ◽  
Sedation Score ◽  
Auditory Evoked Potential ◽  
Second Phase ◽  
Sevoflurane Anesthesia ◽  
Sevoflurane Concentration ◽  
Potential Index ◽  
Prediction Probability ◽  
End Tidal

Background The auditory evoked potential (AEP) index, which is a single numerical parameter derived from the AEP in real time and which describes the underlying morphology of the AEP, has been studied as a monitor of anesthetic depth. The current study was designed to evaluate the accuracy of AEPindex for predicting depth of sedation and anesthesia during sevoflurane anesthesia. Methods In the first phase of the study, a single end-tidal sevoflurane concentration ranging from 0.5 to 0.9% was assigned randomly and administered to each of 50 patients. The AEPindex and the Bispectral Index (BIS) were obtained simultaneously. Sedation was assessed using the responsiveness portion of the observer's assessment of alertness-sedation scale. In the second phase of the study, 10 additional patients were included, and the 60 patients who were scheduled to have skin incisions were observed for movement in response to skin incision at the end-tidal sevoflurane concentrations between 1.6 and 2.6%. The relation among AEPindex, BIS, sevoflurane concentration, sedation score, and movement or absence of movement after skin incision was determined. Prediction probability values for AEPindex, BIS, and sevoflurane concentration to predict depth of sedation and anesthesia were also calculated. Results The AEPindex, BIS, and sevoflurane concentration correlated closely with the sedation score. The prediction probability values for AEPindex, BIS, and sevoflurane concentration for sedation score were 0.820, 0.805, and 0.870, respectively, indicating a high predictive performance for depth of sedation. AEPindex and sevoflurane concentration successfully predicted movement after skin (prediction probability = 0.910 and 0.857, respectively), whereas BIS could not (prediction probability = 0.537). Conclusions Auditory evoked potential index can be a guide to the depth of sedation and movement in response to skin incision during sevoflurane anesthesia.

Electrophysiologic Correlates of Attention versus Distraction in Young and Elderly Listeners

2002 ◽  
Vol 13 (07) ◽  
pp. 383-391 ◽  
Author(s):  
Albert R. De Chicchis ◽  
Michael Carpenter ◽  
Jerry L. Cranford ◽  
Murvin R. Hymel
Keyword(s):  
Selective Attention ◽  
Evoked Potential ◽  
The Elderly ◽  
Auditory Evoked Potential ◽  
Competition Effect ◽  
Specific Target ◽  
Attention Effect ◽  
Competition Effects ◽  
Significant Attention ◽  
Versus Stimulus

This study examined the effects of selective attention versus stimulus competition on the late auditory evoked potential (LAEP) in 20 young and 20 elderly listeners. In a series of test runs, different oddball tonal sequences were presented to one or both ears, and listeners were instructed to attend to tones at a specific target ear. Peak amplitudes were recorded for the N1, P2, and the early and late N2 components of the LAEP. Significant attention effects were found for all four components. N1 amplitudes increased significantly when participants attended to the target stimuli, whereas the amplitudes of P2, N2e, and N2l decreased. For all LAEP components except N2l, the attention effect did not differ between young and elderly listeners. Significant competition effects also were found for all four components. Amplitudes were significantly larger in monaural than binaural conditions for all components except N2l. The magnitude of this competition effect also was significantly larger for the young listeners than the elderly for all components except N1. These results suggest that the ability to attend selectively to sounds may be more resistant to normal aging than are effects related to stimulus competition.

scholarly journals The effect of early versus late lipid infusion in parenteral nutrition on the biochemical and cortical auditory evoked potential parameters in preterm neonates

2019 ◽  
Vol 67 (1) ◽  
Author(s):  
Rania Mohamed Abdou ◽  
Hoda Mahmoud Ibrahim Weheiba
Keyword(s):  
Weight Gain ◽  
Parenteral Nutrition ◽  
Biochemical Parameters ◽  
Evoked Potential ◽  
Demographic Data ◽  
Auditory Evoked Potential ◽  
Preterm Neonates ◽  
Lipid Infusion ◽  
Significant Difference ◽  
Cortical Auditory Evoked Potential

Abstract Background As brain activity depends greatly on the functions provided by lipid membranes, dietary fat in early life can affect the developing nervous system. Despite the adoption of an early more aggressive parenteral nutrition approach with amino acid infusions still reluctance to the early use of intravenous lipids in neonates. Aim To compare the effect of delayed versus early introduction of intravenous lipid in preterm on the biochemical parameters and on brain development by the cortical auditory evoked potential (CAEP) latency and amplitude. Methods This is a comparative study included 49 neonates admitted at the ain shams university NICUs. Participants were divided into two groups: 26 in group of early lipid infusion and 23 in late lipid infusion, Demographic data, and biochemical parameters were documented during the 1st 2 weeks of life. The CAEP was performed at age of 6 months. The latency and amplitude of P1 were recorded and compared between both groups. Results In the present work we found that group of early lipid infusion had reach their full oral intake earlier with shorter duration of parenteral nutrition and length of stay. They had better weight gain and significantly better glucose level control than group of late lipid infusion. There was no significant difference in the other chemical parameters between both groups expect for the higher incidence of cholestasis in the group of late lipid infusion. At 6 months of age, the group of early lipid infusion had significantly shorter latency and amplitude of P1 than the group of late lipid infusion. Conclusion Early effective nutrition positively affect feeding tolerance and weight gain and maturation of higher brain centers brain.

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