The Minimum Alveolar Concentration (MAC) of Sevoflurane in Humans

Katoh, Takasumi; Ikeda, Kazuyuki

doi:10.1097/00000542-198703000-00006

Cited by 286 publications

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“…In the present experiments, the concentration for Sev-induced maximal inward current was 2 x 10-M (Figure la,b), and for the maximal potentiated effect of Sev on 10-6 M GABA-induced response was 10-M ( Figure 3). In clinical practice, the minimum alveolar anaesthetic concentration (MAV) of Sev is 1.48-2.03%, depending on patient age and methodology (Katoh et al, 1987;Scheller et al, 1988;Lerman et al, 1990;Nakajima et al, 1993;Inomata et al, 1994 andKimura et al, 1994). Thus, above the MAC of Sev used in clinical practice is given a concentration of 3.4-4.7 x 10-M in blood phase.…”

Section: Discussionmentioning

confidence: 99%

“…The pH was adjusted to 7.4 with 95% 02: 5% CO2 gas. The standard external solution contained (in mM): NaCl 150, KCl 5, MgCl2 1, CaCl2 2, glucose 10 and N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid (HEPES) 10 (Katoh et al, 1987;Scheller et al, 1988;Lerman et al, 1990;Nakajima et al, 1993;Inomata et al, 1994;Kimura et al, 1994). Sev was applied every 3 min, at which interval the desensitization of the Sev-induced current was completely removed and constant responses could be repeatedly evoked for more than 1 h. Rapid application of the drugs was performed with the 'Y-tube' method, as described elsewhere (Wu et al, 1994a).…”

Section: Solutionsmentioning

confidence: 99%

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Potentiation by sevoflurane of the γ‐aminobutyric acid‐induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus

Harata

Akaike

1996

British J Pharmacology

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1 The effects of a new kind of volatile anaesthetic, sevoflurane (Sev), on y-aminobutyric acid (GABA)-gated chloride current (IcI) in single neurones dissociated from the rat hippocampal CAI area were examined using the nystatin perforated patch recording configuration under the voltage-clamp condition. All drugs were applied with a rapid perfusion system, termed the 'Y-tube' method. 2 When the concentrations were higher than 3 x lo-M, Sev, itself, induced an inward current (Is,V) at a holding potential (VH) of -40 mV. The concentration-response curve of Isev was bell-shaped, with a suppressed peak and plateau currents at high concentrations (above 2 x l0' M). The reversal potential of I&.v (E&,) was close to the theoretical Cl-equilibrium potential, indicating that Isev was carried mainly by Cl-.3 Is,V was reversibly blocked by bicuculline (Bic), an antagonist of the GABAA receptor, in a concentration-dependent manner with a half-inhibitory concentration (IC50) of 7.2 x 10-7 M. But ISev was insensitive to strychnine (Str), an antagonist of the glycine receptor.4 At low concentrations (between 3 x 10-4 and lo-3 M), Sev markedly enhanced the 10-6 M GABA induced current (IGABA) but reduced the IGABA with accelerating desensitization accompanied by a 'hump' current after washout at high concentrations (higher than 2 x 10' M).5 Sev, 10-3 M potentiated the current induced by low concentrations of GABA (between 10-7 and 3 x 10' M) but reduced the current induced by high concentrations (higher than lo-M) of GABA with a clear acceleration of IGABA desensitization.6 Sev, like pentobarbitone (PB), pregnanolone (PGN) or diazepam (DZP), potentiated the 10-6 M GABA-induced response without shifting the reversal potential of IGABA-7 Ise, was augmented by PB, PGN, or DZP at concentrations that maximally potentiated IGABA, suggesting that Sev enhanced IGABA at a binding site distinct from that for PB, PGN, or DZP. 8 It is concluded that Sev acts on the GABAA receptor complex mimicking the GABA-induced chloride current at high concentrations. At low concentrations, Sev enhances GABA-gated chloride current at a binding site independent of the allosteric modulator sites of barbiturates, benzodiazepines or neurosteroids. The reversible potentiation of the inhibitory GABAA receptor-mediated Cl-current may result in the depressing of postsynaptic excitability and may, at least in part, underlie the anaesthetic action of Sev.

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Section: Discussionmentioning

confidence: 99%

Section: Solutionsmentioning

confidence: 99%

Potentiation by sevoflurane of the γ‐aminobutyric acid‐induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus

Harata

Akaike

1996

British J Pharmacology

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“…D Di is sc cu us ss si io on n The current study showed that sevoflurane MAC TT/LMA was 2.63%. Given that the MAC value for sevoflurane in patients aged 30-59 yr has been reported to be 1.71%, 7 the MAC TT/LMA /MAC ratio is 1.54. The ED 95 of sevoflurane for smooth TT/LMA exchange was 2.97%, and the lower limit of the 95% confidence interval of the ED 95 was 2.73%.…”

Section: Méthode : Nous Avons éTudié 21 Hommes D'état Physique Asa Imentioning

confidence: 98%

The ED95 of end-tidal sevoflurane concentration for the smooth exchange of the tracheal tube for a laryngeal mask airway is 2.97%

Takita

Yamane

Morimoto

et al. 2003

Can J Anesth/J Can Anesth

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P Pu ur rp po os se e: : Exchanging the tracheal tube for the laryngeal mask airway (the TT/LMA exchange) while the patient is still anesthetized avoids coughing associated with tracheal extubation. This study was conducted to determine the end-tidal concentration of sevoflurane that prevented response to this exchange in 50% patients (MAC TT/LMA ). M Me et th ho od ds s: :We studied 21 adult male patients, ASA I, aged 21-54 yr. Anesthesia was induced with thiamylal and sevoflurane, and the trachea was intubated following vecuronium neuromuscular blockade. Anesthesia was maintained with sevoflurane and nitrous oxide in oxygen. After surgery, a predetermined end-tidal sevoflurane concentration was achieved and a steady state was maintained for at least 20 min. The concentration at which the TT/LMA exchange was attempted was determined by a modification of Dixon's upand-down method with 0.25% as the step size. At the time of the TT/LMA exchange, no residual nitrous oxide > 3% was detected, and the return to normal neuromuscular function was confirmed. When the TT/LMA exchange was accomplished without coughing, movement, or airway obstruction, it was considered a smooth exchange.R Re es su ul lt ts s: : Sevoflurane MAC TT/LMA determined using the up-anddown method was 2.63% ± 0.14%. The 50% effective dose obtained using a probit analysis was similar [2.53% (95% confidence limits, 2.13-2.82%)].C Co on nc cl lu us si io on n: : Sevoflurane MAC TT/LMA in adult male patients was 2.63% (1.54 MAC) and may be useful for the smooth exchange of the tracheal tube for the LMA in a clinical setting. RACHEAL extubation is often accompanied by coughing. Coughing can cause adverse effects, including an increase in intracranial and intraocular pressures, significant hemodynamic changes, and may threaten the surgical sites. One of the strategies to avoid coughing is tracheal extubation under deep anesthesia, followed by face-mask ventilation. This technique, however, increases the risk of airway obstruction after extubation. Recently, some authors reported that substitution of the laryngeal mask airway (LMA) for the tracheal tube while the patient is still anesthetized prevents the coughing associated with tracheal extubation, and provides a secure airway following tracheal extubation and a smooth recovery period. [1][2][3][4][5] Under light anesthesia, insertion of the LMA and tracheal extubation itself may cause coughing, movement, breath-holding, and/or laryngospasm. Thus, unless the TT/LMA exchange is attempted under adequate anesthesia, this method does not offer any advantage. ObjectifIn the present study, we attempted to determine the sevoflurane MAC TT/LMA in adult male patients where sevoflurane MAC TT/LMA is the end-tidal concentration of sevoflurane at which a smooth exchange of the tracheal tube for the LMA was possible in 50% of patients.M Me et th ho od ds s After obtaining Institutional approval and informed consent, we studied 21 adult male patients, ASA physical status I, aged 21-54 yr, scheduled for general anesth...

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“…Sevofluorane is a halogenated volatile anaesthetic with a low blood gas solubility [7]. This facilitate smooth and rapid induction of anesthesia, allow easear titration of anesthetic dose to the desired effect during the maintenance period and permit rapid emergency and recovery at the end of the anesthesia [8,9]. Because a biological process like anesthesia has a nonlinear, timevarying structure and time-varying parameters, modeling it suggests the use of rule-based controllers like fuzzy controllers.…”

Section: Iipatients and Applicationmentioning

confidence: 99%

“…This type of controller is widely used and is the most applicable control type in anesthesia [13,14,15,16,17]. In anesthetic practice, the systolic pressure has greater significance than the diastolic pressure, which isn't frequently recorded, particularly if access to the arm is difficult No "normal" blood pressure can be specified for the anaesthetized patient; in general the systolic pressure should be stable in the range 90-140 mmHg (12.0-18.7 kPa) [9,18]. Blood pressure value always contrast to depth of anesthesia.…”

Section: Iipatients and Applicationmentioning

confidence: 99%

Depth control of sevofluorane anesthesia with microcontroller based fuzzy logic system

Yardımcı

Ferikoğlu²,

Hadimioğlu³

2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Abstract-This system was designed for anesthetic agent, sevofluorane, which is among the first choices of anesthesiologist for inhalation anesthesia. Sevofluorane is a halogenated volatile anaesthetic with a low blood gas solubility. This facilitate smooth and rapid induction of anesthesia, allow easear titration of anesthetic dose to the desired effect during the maintenance period and permit rapid emergency and recovery at the end of the anesthesia.In this study, sevofluorane depth of anesthesia was examined through a microcontroller-based fuzzy logic control system according to the blood pressure and heart rate taken from the patient. The potential benefits of the systems are as follows: 1)To increase patients' safety and comfort, 2)To direct anesthesiologist' attention to other physiological variables which they have to keep under control by abating their tasks, 3)To make the optimum in the area of anesthetic agent, 4)To help protect the environment by using optimum anesthetic agent, 5)To economize by lessening the costs of an operation. This study will serve as a guide in developing new anesthesia control systems for patients who are in different agent and different risk groups. All the details concerning the system design were given in paper. Keywords -FLC, Biomedical, Control of Anesthesia I.INTRODUCTIONSince the 1980s new techniques have appeared from which fuzzy logic has been applied extensively in medical systems. The last couple of decades have witnessed a significant developments in control systems theory. In the meantime, developments in electronics and computers have resulted in many application areas of control theory. Although medicine is a science which isn't related to control engineering, it is being affected to such an extent that it is now possible to use available control techniques for on-line devices, especially during surgical operations and in intensive care units [1,2].General anesthesia is the most common type of anesthetic performed at hospitals. There are several different ways to start the anesthetic, a process referred to as "induction of anesthesia." One of the most common types of anesthetic induction used at hospitals is an inhalation induction. This simply means that the patient breathes himself to sleep. The patient, will accompany the anesthesiologist to the operating room. There, after attaching monitors, the anesthesiologist will help hold a clear plastic mask over the patient's nose and mouth. The mask is attached to the anesthesia machine which delivers oxygen and anesthetic gases. The advantage of an inhalation induction is that there are no needles or anything else that is painful until after the patient is completely anesthetized [3,4,5].In this study a fuzzy logic controller was used to control depth of sevofluorane anethesia, which was taken as a measure of the systolic blood pressure and hearth rate. The main reason for automating the control of depth anesthesia is to release the anesthesiologist so that he or she can devote attention to other tasks as well (contr...

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The Minimum Alveolar Concentration (MAC) of Sevoflurane in Humans

Cited by 286 publications

References 0 publications

Potentiation by sevoflurane of the γ‐aminobutyric acid‐induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus

Potentiation by sevoflurane of the γ‐aminobutyric acid‐induced chloride current in acutely dissociated CA1 pyramidal neurones from rat hippocampus

The ED95 of end-tidal sevoflurane concentration for the smooth exchange of the tracheal tube for a laryngeal mask airway is 2.97%

Depth control of sevofluorane anesthesia with microcontroller based fuzzy logic system

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