Determination and Applications of MAC

Quasha, Arthur L.; Eger, Edmond I.; Tinker, John H.

doi:10.1097/00000542-198010000-00008

Cited by 548 publications

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“…Não foi empregada medicação pré-anestésica e opióides durante a anestesia para evitar efeito aditivo na CAM dos agentes inalatórios, com conseqüente interferência nos parâme-tros avaliados durante a indução e recuperação da anestesia 3, [16][17][18] .…”

Section: Discussionunclassified

“…Patients were not premedicated and opioids were not used during anesthesia to avoid an additive effect on inhalational agents MAC, with the consequent interference in the parameters evaluated during induction and anesthesia recovery 3, [16][17][18] . Previous saturation of the respiratory circuit and the increase of halogenate concentration by MAC fractions each 3 respiratory movements were planned to decrease the interference of alveolar ventilation and of the rate of increase of the inspired concentration.…”

Section: Discussionmentioning

confidence: 99%

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Influência do óxido nitroso na velocidade de indução e de recuperação do halotano e do sevoflurano em pacientes pediátricos

Tardelli

Iwata

Amaral

et al. 2001

Rev. Bras. Anestesiol.

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Section: Discussionunclassified

Section: Discussionmentioning

confidence: 99%

Influência do óxido nitroso na velocidade de indução e de recuperação do halotano e do sevoflurano em pacientes pediátricos

Tardelli

Iwata

Amaral

et al. 2001

Rev. Bras. Anestesiol.

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“…The most common measure of in vivo volatile anesthetic potency is minimum alveolar concentration (MAC), the partial pressure of volatile anesthetic in the lungs required to produce immobility in response to a noxious stimulus in 50% of trials (Eger et al, 1965;Quasha et al, 1980). Potencies of inhaled convulsants are often defined as the concentration that elicits convulsions in 50% of animals (Koblin et al, 1981).…”

Section: Conversion Of Flurothyl and Iso-flurothyl Concentrations Expmentioning

confidence: 99%

“…The aqueous equivalent concentration reflects the concentration of inhaled compound in the aqueous phase that is in equilibrium with a particular partial pressure in the gas phase. It is believed that the lungs and brain are in equilibrium with respect to anesthetic concentration following induction of volatile anesthesia (Eger et al, 1965;Quasha et al, 1980). In contrast, a caveat to bear in mind is that the partial pressure of flurothyl in the lungs may not always to be in equilibrium with the concentration of flurothyl in the brain, especially at high concentrations of inspired flurothyl (Koblin et al, 1981).…”

Section: Conversion Of Flurothyl and Iso-flurothyl Concentrations Expmentioning

confidence: 99%

Differential modulatory actions of the volatile convulsant flurothyl and its anesthetic isomer at inhibitory ligand-gated ion channels

Krasowski

2000

Neuropharmacology

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A challenge for theories of general anesthesia is the existence of compounds predicted to be anesthetics but which, instead, do not produce anesthesia and often elicit other behavioral effects such as convulsions. This study focused on flurothyl (bis[2,2,2-trifluoroethyl] ether), a potent volatile convulsant, and its anesthetic isomer, 'iso-flurothyl' (1,1,1,3,3,3-hexafluoro-2-methoxypropane). The effects of flurothyl and iso-flurothyl were studied using the whole-cell patch-clamp technique on agonist activated chloride currents in human GABA A , glycine, and GABA c ρ 1 receptors expressed in HEK 293 cells. GABA A and glycine receptors are promising molecular targets for the actions of inhaled ether general anesthetics. Flurothyl acted as a non-competitive antagonist at GABA A α 2 β 1 and α 2 β 1 γ 2s receptors, but had no effect at glycine α 1 receptors. Flurothyl had biphasic actions on GABA responses at GABA C ρ 1 receptors. In contrast, iso-flurothyl enhanced ('potentiated') submaximal agonist responses at GABA A and glycine receptors, but had no effect on GABA responses at GABA C ρ 1 receptors. Point mutations in GABA A and glycine receptor subunits, which have been previously shown to abolish potentiation of agonist responses by the ether anesthetics enflurane and isoflurane, also ablated potentiation of agonist responses by iso-flurothyl. These same mutations in the GABA A receptor had only modest effects on the inhibitory actions of flurothyl. GABA A receptors with mutations conferring insensitivity to antagonism by picrotoxin were still inhibited by flurothyl, suggesting that picrotoxin and flurothyl antagonize GABA responses by distinct sites or mechanisms of action. In summary, antagonism of GABA A receptors is likely to account for the convulsant effects of flurothyl, while the general anesthetic actions of iso-flurothyl, like those of other ether anesthetics, may be related to positive modulation of GABA A and/or glycine receptors.

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“…The anatomical unit o f gas exchange in reptiles is the faveolus (Maina, 2000) and while minimum faveolar concentration or MFC may repre sen t m ore a c c u ra te term in o lo g y , m in im u m a lv e o la r concentration is traditionally adopted in prior reptilian anes th e tic s tu d ie s an d w ill be u sed h ere fo r co n sisten cy . Minimum alveolar concentration values should be consistent across mammalian species (Quasha, et al, 1980), but seem to be more variable across reptile species even when maintained within their respective preferred optimal temperature range (Mosley, et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Minimum Alveolar Concentration of Isoflurane and Arterial Blood Gas Values in Anesthetized Green Iguanas, Iguana iguana

Hess

Gj²,

Grimm

et al. 2007

Journal of Herpetological Medicine and Surgery

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A b s t r a c t : The minimum alveolar concentration o f isoflurane ( M A C is o f lu r a n e ) was determined in seven green iguanas, Iguana iguana, using a standard double bracketing technique. Following chamber induction, anesthe sia was maintained with isoflurane in 100% O2 using mechanical ventilation o f 25 ml/kg body weight, at a rate o f two breaths per minute. Following an equilibration period o f 25 min at each percentage o f isoflurane tested, response to a supramaximal electrical stimulus applied to the ventral portion o f the tail was assessed. Arterial blood was collected from the right carotid artery for determining blood gas values in iguanas main tained at 1.5 times their individual M A C is o flu ra n e -As measured by time to loss o f righting reflex, chamber induction time was 23 ± 7 min (range 1 8 -3 5 min). M ean (±SD) M A C is o f lu ra n e was 1.62 ± 0.40%, median MAC was 1.60 %, with a range o f 1.10 to 2.15%. Values for pH, partial pressure o f carbon dioxide (PaC02) in kPa (mmHg), partial pressure o f oxygen (Pa02) in kPa (mmHg), bicarbonate concentration (HCO3') mmol L: * base excess (mmol L '1), oxygen saturation (%), concentrations o f sodium (Na+) (mmol L '1), calcium (Ca ) (mmol L_1), potassium (K+) (mmol L '1,), and chloride (C l') (mmol L '1), and anion Gap (mmol L_1) were 7.49 ± 0 .0 3 , 4.75 ± 0.13 (34.6 ± 2 .7 ), 14.2 ± 1 .6 (106.7 ± 12.0), 25.7 ± 1.2, 2.4 ± 1 .4 , 94.4 ± 5.2, 151.1 ± 2.6, 1.03 ± 0.15, 2.0 ± 0.6, 123.8 ± 4.4, and 3.6 ± 1.7 respectively. The MAC o f isoflurane was lower than minimum alveolar concentration values previously published for green iguanas. The pH, oxygen saturation, and Pa02 were higher than reported in prior publications in which blood was collected from the femoral artery or ventral coccygeal vessels, and the mean Pa02 was lower than in a previous publication in which blood was collected from the left carotid artery.K e y w o r d s : green iguana, Iguana iguana, minimum alveolar concentration, arterial blood gases, isoflurane.

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Determination and Applications of MAC

Cited by 548 publications

References 0 publications

Influência do óxido nitroso na velocidade de indução e de recuperação do halotano e do sevoflurano em pacientes pediátricos

Influência do óxido nitroso na velocidade de indução e de recuperação do halotano e do sevoflurano em pacientes pediátricos

Differential modulatory actions of the volatile convulsant flurothyl and its anesthetic isomer at inhibitory ligand-gated ion channels

Minimum Alveolar Concentration of Isoflurane and Arterial Blood Gas Values in Anesthetized Green Iguanas, Iguana iguana

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