Arterial blood and end-tidal concentrations of sevoflurane during the emergence from anesthesia in gynecologic patients

et al. 2021

JCM

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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.

Section: Introductionmentioning

confidence: 99%

Discrepant End-Tidal Concentrations of Sevoflurane at the Same A-Line Autoregressive Index Level during Induction of General Anesthesia: An Observational Study

et al. 2021

JCM

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“…(5) For inhalational anaesthetics, however, a time lag between end-tidal and brain concentrations has been identi ed and physiologically modelled through measurement of the inspiratory, end-tidal, and jugular bulb concentrations. (6)(7)(8) Accordingly, the body's uptake and elimination (9) of anaesthetics across the alveolar membrane and blood-brain barrier depend on the partition coe cient, (10)(11)(12) ventilation, (13) and cardiac output. (7) Sevo urane requires nearly 40 min to achieve a pharmacokinetic equilibrium between arterial and jugular bulb concentrations, indicating that no further brain uptake of inspiratory 3.5% sevo urane occurs after general anaesthesia induction.…”

Section: Introductionmentioning

confidence: 99%

Discrepant End-Tidal Concentrations of Sevoflurane at the Same A-Line Autoregressive Index Level During Induction of General Anaesthesia: An Observational Study

et al. 2020

Preprint

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Background: The A-Line Autoregressive Index (AAI), which is derived from auditory evoked potentials, has been used for determining anaesthetic depth. This study verified the correlation between AAI values and the corresponding end-tidal concentrations of sevoflurane during general anaesthesia induction.Methods: Thirty young male adults undergoing elective minor orthopaedic 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 anaesthetic 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 anaesthesia depth during rapid wash-in of sevoflurane.

“…[16] Ideally, detecting the actual brain or alternative arterial blood concentrations of an inhaled anesthetic is advantageous to ensure awakening in a smooth manner. However, these data are currently only available for desflurane [17] and sevoflurane [18] but not for isoflurane. The present study was designed to determine the arterial blood concentrations of isoflurane at awakening as well as to clarify the reliability of the end-tidal concentration for representing the arterial blood concentration during emergence from various durations of isoflurane anesthesia in gynecologic patients.…”

Section: Introductionmentioning

confidence: 99%

Awakening arterial blood and end-tidal concentrations of isoflurane in female surgical patients

Lin

et al. 2016

Medicine

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Delayed extubation occurs after isoflurane anesthesia, especially following prolonged surgical duration. We aimed to determine the arterial blood concentrations of isoflurane and the correlation with end-tidal concentrations for predicting emergence from general anesthesia.Thirty-four American Society of Anesthesiologists physical status class I–II gynecologic patients were included. General anesthesia was maintained with a fixed 2% inspiratory isoflurane in 6 L/minute oxygen, which was discontinued after surgery. One milliliter of arterial blood was obtained for the determination of isoflurane concentration by gas chromatography at 20 and 10 minutes before and 0, 5, 10, 15, and 20 minutes after discontinuation, in addition to the time of eye opening to verbal command, defined as awakening. Inspiratory and end-tidal concentrations were simultaneously detected by an infrared analyzer.The mean awakening arterial blood concentration of isoflurane was 0.20%, which was lower than the simultaneous end-tidal concentration 0.23%. The differences between arterial and end-tidal concentrations during emergence fell into an acceptable range (±1.96 standard deviation). After receiving a mean time of 108-minute general anesthesia, the time to eye opening after discontinuing isoflurane was 18.5 minutes (range 11–30, median 18 minutes), without statistical significance with anesthesia duration (P = 0.078) and body mass index (P = 0.170).We demonstrated the awakening arterial blood concentration of isoflurane in female patients as 0.20%. With well-assisted ventilation, the end-tidal concentration could be an indicator for the arterial blood concentration to predict emergence from shorter duration of isoflurane anesthesia.