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Santos PS, Gonzaga MS, Araújo MA, Deschk M, de Siqueira CE, Floriano BP, Cancelli CH. Determination of the minimum alveolar concentration of sevoflurane in Holstein steers. Vet Anaesth Analg 2023; 50:415-420. [PMID: 37407361 DOI: 10.1016/j.vaa.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 06/03/2023] [Accepted: 06/05/2023] [Indexed: 07/07/2023]
Abstract
OBJECTIVE To determine the minimum alveolar concentration (MAC) of sevoflurane in Holstein steers using electric stimulation. STUDY DESIGN Prospective experimental study. ANIMALS A total of 15 Holstein steers aged 7.3 ± 1.2 months and weighing 121 ± 25 kg. METHODS Animals were anesthetized with sevoflurane at 8% in oxygen at 5 L minute-1 via facemask and were intubated with an orotracheal tube of a compatible size. After 15 minutes of stabilization of the initial expired concentration of sevoflurane (Fe'Sevo) at 2.6%, electrical stimulation on the thoracic limb was initiated with a sequence of 2 × 10 ms followed by 2 × 3 second electrical currents of 50 V and 50 Hz, 5 seconds apart. Following each stimulus with a negative response, the Fe'Sevo was decreased by 0.2% and a 15 minute interval was awaited before the next stimulus. The procedure was repeated until the first Fe'Sevo value with a positive motor response was obtained. The Fe'Sevo was then increased by 0.1%, followed by a new stimulus, until a negative response was obtained. The value of MAC was calculated as the arithmetic mean between the lowest Fe'Sevo associated with a negative motor response and the highest Fe'Sevo associated with a positive response. RESULTS The mean MAC for the 15 steers was 2.0 ± 0.3%, which corresponds to 2.1 ± 0.3% at sea level. CONCLUSIONS Based on the proposed methodology, the MAC of sevoflurane for healthy Holstein steers is 2.1 ± 0.3% at sea level. CLINICAL RELEVANCE This Fe'Sevo value can be used to guide depth of anesthesia in steers weighing approximately 120 kg in clinical practice.
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Affiliation(s)
- Paulo Sp Santos
- Department of Animal Clinic, Surgery and Reproduction, Faculty of Veterinary Medicine of Araçatuba, São Paulo State University (UNESP), Araçatuba, SP, Brazil
| | | | - Marcelo A Araújo
- Veterinary Teaching Hospital, Federal University of Mato Grosso do Sul, Campo Grande, MS, Brazil
| | - Mauricio Deschk
- Veterinary Teaching Hospital, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Carlos E de Siqueira
- Department of Animal Clinic, Surgery and Reproduction, Faculty of Veterinary Medicine of Araçatuba, São Paulo State University (UNESP), Araçatuba, SP, Brazil
| | - Beatriz P Floriano
- Department of Small Animal Clinic, Centre of Rural Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil.
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González-Moral ML, Parra S, Gerónimo-Pardo M. In vitro assessment of the direct hemolytic effect of the volatile halogenated anesthetics sevoflurane, isoflurane, and desflurane. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2022; 90:103814. [PMID: 35051617 DOI: 10.1016/j.etap.2022.103814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/11/2022] [Accepted: 01/15/2022] [Indexed: 06/14/2023]
Abstract
Sevoflurane is being repurposed as a topical analgesic for painful wounds. Providing pre-charged sevoflurane syringes to irrigate wounds implies a potential risk of accidental intravenous injections. We assessed the potential of two concentrations (33% and 50% v/v) of three anesthetics, isoflurane, desflurane and sevoflurane, to produce hemolysis in vitro. Spectrophotometric absorbance was read at 576 nm. For both concentrations, the percentage of hemolysis (mean ± SD) was higher for isoflurane (29.7 ± 3.4% and 39.5 ± 5.3%), mild for desflurane (8.0 ± 0.5% and 6.5 ± 0.9%) and negligible for sevoflurane (0.7 ± 0.0% and 0.6 ± 0.1%), respectively. In conclusion, in contrast to isoflurane and desflurane, sevoflurane did not display hemolytic potential in vitro. However, the use of syringes preloaded with sevoflurane may still be problematic if it increases the possibility of inadvertent intravenous administration through increased risk of gas embolism and severe central nervous system depression.
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Bezuidenhout E. The blood–gas partition coefficient. SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2020. [DOI: 10.36303/sajaa.2020.26.6.s3.2528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A partition coefficient (λ) describes the relative affinity of a volatile anaesthetic for two phases and how that anaesthetic distributes itself between the two phases when equilibrium has been achieved. The blood–gas partition coefficient (λb/g), or Ostwald coefficient for blood–gas, is a pharmacological term used to describe the solubility of a volatile anaesthetic agent. Volatile agents with a low blood–gas partition coefficient (less soluble) will exert a high partial pressure and produce a more rapid onset and offset of anaesthetic action.
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Williams CJA, Malte CL, Malte H, Bertelsen MF, Wang T. Ectothermy and cardiac shunts profoundly slow the equilibration of inhaled anaesthetics in a multi-compartment model. Sci Rep 2020; 10:17157. [PMID: 33051496 PMCID: PMC7555730 DOI: 10.1038/s41598-020-74014-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/21/2020] [Indexed: 01/08/2023] Open
Abstract
The use of inhalational anaesthesia is ubiquitous in terrestrial vertebrates. Given the dependence of these agents on delivery by the cardiorespiratory system, we developed a new computational model predicting equilibration of inhaled anaesthetics in mammalian and ectotherm conditions including the ability of reptiles to maintain vascular shunts. A multi-compartment model was constructed from simultaneously-solved equations, verified by comparison to the literature for endo and ectotherm physiology. The time to 90% equilibration of anaesthetic in arterial blood (t90) is predicted and used to compare anaesthetics and physiologies. The five to tenfold lower cardiac output and minute ventilation of ectothermic vertebrates is predicted to slow equilibration times by five to ten times leading to 90% equilibration in ectotherm arterial blood of over 200 min, compounded by reduction in body temperature, and the extent of right-to-left vascular shunts. The impact of these findings is also influenced by the solubility coefficient of the anaesthetic, such that at net right-to-left shunt fractions of over 0.8, sevoflurane loses the advantage of faster equilibration, in comparison with isoflurane. We explore clinical strategies to regulate anaesthetic uptake in ectotherms by managing convectional flow especially by supportive ventilation and reduction of the right-to-left shunt.
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Affiliation(s)
- Catherine J A Williams
- Section of Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark. .,Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38, 2000, Frederiksberg, Denmark. .,Ontario Veterinary College, University of Guelph, 50 Stone Road E, Guelph, ON, N1G 2W1, Canada.
| | - Christian Lind Malte
- Section of Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark
| | - Hans Malte
- Section of Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark
| | - Mads F Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38, 2000, Frederiksberg, Denmark
| | - Tobias Wang
- Section of Zoophysiology, Department of Biology, Aarhus University, 8000, Aarhus C, Denmark.,Aarhus Institute of Advanced Sciences, Aarhus University, 8000, Aarhus C, Denmark
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Zhang P, Li Y, Xu T. Development of a simple method for differential delivery of volatile anesthetics to the spinal cord of the rabbit. PLoS One 2020; 15:e0223700. [PMID: 32092080 PMCID: PMC7039460 DOI: 10.1371/journal.pone.0223700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/31/2020] [Indexed: 11/19/2022] Open
Abstract
Emulsified volatile anesthetic can be directly injected into the circulation and eliminated from blood through lungs. Taking advantage of the unique pharmacokinetics of the emulsified volatile anesthetics, we aimed to develop a less traumatic method to differentially deliver them to the spinal cord of rabbit. Sixteen New Zealand White rabbits were randomly assigned to the isoflurane or sevoflurane group. A catheter was placed into the descending aorta, and emulsified isoflurane (8mg/kg/h) or sevoflurane (12mg/kg/h) was given respectively. The concentration and partial pressure of the anesthetics in the jugular and femoral vein were measured. Our results showed that the partial pressure for isoflurane was 3.91±1.11 mmHg and 12.61±1.60 mmHg (1.0MAC), and for sevoflurane was 3.89±1.00 mmHg and 19.92±1.84mmHg (1.0MAC), in the jugular vein and femoral vein, respectively. There was significant difference between jugular and femoral vein partial pressure for both isoflurane and sevoflurane groups (both P < 0.001). In conclusion, a simple and minimally invasive method has been successfully developed to selectively deliver isoflurane and sevoflurane to the spinal cord in the rabbit. Before the anesthetics taking action on the brain, 69% of isoflurane and 81% of sevoflurane were removed through lungs. This method can be used to investigate sites and mechanisms of volatile anesthetic action.
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Affiliation(s)
- Peng Zhang
- Department of Anesthesiology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Yao Li
- Department of Anesthesiology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
| | - Ting Xu
- Department of Anesthesiology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan Province, China
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Determination of the minimum alveolar concentration (MAC) and cardiopulmonary effects of sevoflurane in sheep. Vet Anaesth Analg 2018; 45:487-495. [DOI: 10.1016/j.vaa.2018.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 12/12/2017] [Accepted: 01/14/2018] [Indexed: 11/22/2022]
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Effect of Bronchoconstriction-induced Ventilation-Perfusion Mismatch on Uptake and Elimination of Isoflurane and Desflurane. Anesthesiology 2017; 127:800-812. [PMID: 28857808 DOI: 10.1097/aln.0000000000001847] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Increasing numbers of patients with obstructive lung diseases need anesthesia for surgery. These conditions are associated with pulmonary ventilation/perfusion (VA/Q) mismatch affecting kinetics of volatile anesthetics. Pure shunt might delay uptake of less soluble anesthetic agents but other forms of VA/Q scatter have not yet been examined. Volatile anesthetics with higher blood solubility would be less affected by VA/Q mismatch. We therefore compared uptake and elimination of higher soluble isoflurane and less soluble desflurane in a piglet model. METHODS Juvenile piglets (26.7 ± 1.5 kg) received either isoflurane (n = 7) or desflurane (n = 7). Arterial and mixed venous blood samples were obtained during wash-in and wash-out of volatile anesthetics before and during bronchoconstriction by methacholine inhalation (100 μg/ml). Total uptake and elimination were calculated based on partial pressure measurements by micropore membrane inlet mass spectrometry and literature-derived partition coefficients and assumed end-expired to arterial gradients to be negligible. VA/Q distribution was assessed by the multiple inert gas elimination technique. RESULTS Before methacholine inhalation, isoflurane arterial partial pressures reached 90% of final plateau within 16 min and decreased to 10% after 28 min. By methacholine nebulization, arterial uptake and elimination delayed to 35 and 44 min. Desflurane needed 4 min during wash-in and 6 min during wash-out, but with bronchoconstriction 90% of both uptake and elimination was reached within 15 min. CONCLUSIONS Inhaled methacholine induced bronchoconstriction and inhomogeneous VA/Q distribution. Solubility of inhalational anesthetics significantly influenced pharmacokinetics: higher soluble isoflurane is less affected than fairly insoluble desflurane, indicating different uptake and elimination during bronchoconstriction.
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Ng KT, Alston RP, Just G, McKenzie C. Assessing the depth of isoflurane anaesthesia during cardiopulmonary bypass. Perfusion 2017; 33:148-155. [PMID: 28985693 DOI: 10.1177/0267659117735883] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Bispectral index (BIS) and monitoring of end-tidal concentration may be associated with a reduction in the incidence of awareness during volatile-based general anaesthesia. An analogue of end-tidal concentration during cardiopulmonary bypass (CPB) is measuring exhausted isoflurane concentration from the oxygenator as an estimate to blood and, so, brain concentration. The aim of this study was to determine the relationships between oxygenator exhaust and blood concentrations of isoflurane and the BIS score during CPB when administering isoflurane into the sweep gas supply to the oxygenator. METHODS Seventeen patients undergoing elective cardiac surgery using CPB and isoflurane with BIS monitoring were recruited in a single-centre university hospital. Isoflurane gas was delivered via a calibrated vaporiser at the beginning of anaesthetic induction. Radial arterial blood samples were collected after the initiation of CPB and before aortic cross-clamping, which were analysed for isoflurane by gas chromatography and mass spectrometry. The BIS score and the concentration of exhausted isoflurane from the oxygenator membrane, as measured by an anaesthetic gas analyser, were recorded at the time of blood sampling. RESULTS The mean duration of anaesthetic induction to arterial blood sampling was 90 min (95%CI: 80,100). On CPB, the median BIS was 39 (range, 7-43) and the mean oxygenator exhaust isoflurane concentration was 1.24 ± 0.21%. No significant correlation was demonstrated between BIS with arterial isoflurane concentration (r=-0.19, p=0.47) or oxygenator exhaust isoflurane concentration (r=0.07, p=0.80). Mixed-venous blood temperature was moderately correlated to BIS (r=0.50, p=0.04). Oxygenator exhaust isoflurane concentration was moderately, positively correlated with its arterial concentration (r=0.64, p<0.01). DISCUSSION In conclusion, in patients undergoing heart surgery with CPB, the findings of this study indicate that, whilst oxygenator exhaust concentrations were significantly associated with arterial concentrations of isoflurane, neither had any association with the BIS scores, whereas body temperature has moderate positive correlation.
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Affiliation(s)
- Ka Ting Ng
- 1 Department of Anaesthesiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - R Peter Alston
- 2 Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - George Just
- 3 Clinical Research Facility Mass Spectrometry Core Centre for Cardiovascular Research, Queens Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Chris McKenzie
- 2 Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK
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Maier KL, McKinstry-Wu AR, Palanca BJA, Tarnal V, Blain-Moraes S, Basner M, Avidan MS, Mashour GA, Kelz MB. Protocol for the Reconstructing Consciousness and Cognition (ReCCognition) Study. Front Hum Neurosci 2017; 11:284. [PMID: 28638328 PMCID: PMC5461274 DOI: 10.3389/fnhum.2017.00284] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/15/2017] [Indexed: 01/07/2023] Open
Abstract
Important scientific and clinical questions persist about general anesthesia despite the ubiquitous clinical use of anesthetic drugs in humans since their discovery. For example, it is not known how the brain reconstitutes consciousness and cognition after the profound functional perturbation of the anesthetized state, nor has a specific pattern of functional recovery been characterized. To date, there has been a lack of detailed investigation into rates of recovery and the potential orderly return of attention, sensorimotor function, memory, reasoning and logic, abstract thinking, and processing speed. Moreover, whether such neurobehavioral functions display an invariant sequence of return across individuals is similarly unknown. To address these questions, we designed a study of healthy volunteers undergoing general anesthesia with electroencephalography and serial testing of cognitive functions (NCT01911195). The aims of this study are to characterize the temporal patterns of neurobehavioral recovery over the first several hours following termination of a deep inhaled isoflurane general anesthetic and to identify common patterns of cognitive function recovery. Additionally, we will conduct spectral analysis and reconstruct functional networks from electroencephalographic data to identify any neural correlates (e.g., connectivity patterns, graph-theoretical variables) of cognitive recovery after the perturbation of general anesthesia. To accomplish these objectives, we will enroll a total of 60 consenting adults aged 20-40 across the three participating sites. Half of the study subjects will receive general anesthesia slowly titrated to loss of consciousness (LOC) with an intravenous infusion of propofol and thereafter be maintained for 3 h with 1.3 age adjusted minimum alveolar concentration of isoflurane, while the other half of subjects serves as awake controls to gauge effects of repeated neurobehavioral testing, spontaneous fatigue and endogenous rest-activity patterns.
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Affiliation(s)
- Kaitlyn L. Maier
- Department of Pharmacology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States
| | - Andrew R. McKinstry-Wu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States
| | - Ben Julian A. Palanca
- Department of Anesthesiology, Washington University School of Medicine, Washington University in St. LouisSt. Louis, MO, United States
| | - Vijay Tarnal
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States
| | | | - Mathias Basner
- Department of Psychiatry, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States,Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States
| | - Michael S. Avidan
- Department of Anesthesiology, Washington University School of Medicine, Washington University in St. LouisSt. Louis, MO, United States
| | - George A. Mashour
- Department of Anesthesiology, University of MichiganAnn Arbor, MI, United States
| | - Max B. Kelz
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States,Center for Sleep and Circadian Neurobiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, United States,*Correspondence: Max B. Kelz
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Ng KT, Alston RP, Just G, McKenzie C. Coronary Sinus Isoflurane Concentration in Cardiac Surgery. J Cardiothorac Vasc Anesth 2017; 31:2035-2041. [PMID: 28506542 DOI: 10.1053/j.jvca.2017.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Volatile anesthetic agents such as isoflurane may be associated with fewer adverse myocardial events compared with total intravenous anesthesia in cardiac surgery. The authors aimed to determine whether reasonable isoflurane concentrations at tissue level were being achieved to protect the myocardium using this agent. The isoflurane concentration in myocardium has never been measured. The primary aim was to sample coronary sinus (CS) blood and measure its isoflurane concentration. Secondary aims were to determine whether the CS blood concentration would equilibrate with the arterial blood concentration and the relationship of CS blood concentration with oxygenator exhaust isoflurane concentrations during cardiopulmonary bypass (CPB). DESIGN Prospective, observational study. SETTING Single-center university hospital. PARTICIPANTS The study comprised 23 patients undergoing cardiac surgery using CPB and isoflurane. MEASUREMENTS AND MAIN RESULTS Shortly after initiation of CPB and insertion of a CS retrograde cardioplegia catheter but before aortic cross-clamping, CS blood was aspirated, followed by radial artery blood, which then were analyzed for isoflurane with gas chromatography and mass spectrometry. The oxygenator exhaust isoflurane level was measured with an anesthetic gas analyzer. The mean arterial and CS isoflurane concentrations were 87.7 ± 50.1 and 73.0 ± 42.9 μg/mL, respectively. There was a significant mean difference of 14.7 μg/mL (95% confidence interval 6.7-22.8) between CS and arterial isoflurane concentrations. Oxygenator exhaust isoflurane levels were correlated positively with those in the CS blood (r = 0.68, p < 0.001) and arterial blood (r = 0.72, p < 0.001). CONCLUSIONS This was the first study in which CS blood was sampled and measured for isoflurane concentration. The CS isoflurane concentration could be estimated from the isoflurane concentration in the oxygenator exhaust gas. However, the value of this relationship is limited because the CS isoflurane concentration does not accurately represent its myocardial levels during CPB.
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Affiliation(s)
- Ka Ting Ng
- University of Edinburgh, Edinburgh, United Kingdom.
| | - R Peter Alston
- Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - George Just
- Clinical Research Facility Mass Spectrometry Core Centre for Cardiovascular Research, Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Chris McKenzie
- Department of Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh, United Kingdom
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Brosnan RJ, Fukushima FB, Pham TL. Anesthetic synergy between two n-alkanes. Vet Anaesth Analg 2017; 44:577-588. [PMID: 28583773 DOI: 10.1016/j.vaa.2016.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 06/28/2016] [Accepted: 07/03/2016] [Indexed: 11/17/2022]
Abstract
OBJECTIVE N-butane and n-pentane can both produce general anesthesia. Both compounds potentiate γ-aminobutyric acid type A (GABAA) receptor function, but only butane inhibits N-methyl-d-aspartate (NMDA) receptors. It was hypothesized that butane and pentane would exhibit anesthetic synergy due to their different actions on ligand-gated ion channels. STUDY DESIGN Prospective experimental study. ANIMALS A total of four Xenopus laevis frogs and 43 Sprague-Dawley rats. METHODS Alkane concentrations for all studies were determined via gas chromatography. Using a Xenopus oocyte expression model, standard two-electrode voltage clamp techniques were used to measure NMDA and GABAA receptor responses in vitro as a function of butane and pentane concentrations relevant to anesthesia. The minimum alveolar concentrations (MAC) of butane and pentane were measured separately in rats, and then pentane MAC was measured during coadministration of 0.25, 0.50 or 0.75 times MAC of butane. An isobole with 95% confidence intervals was constructed using regression analysis. A sum of butane and pentane that was statistically less than the lower-end confidence bound isobole indicated a synergistic interaction. RESULTS Both butane and pentane dose-dependently potentiated GABAA receptor currents over the study concentration range. Butane dose-dependently inhibited NMDA receptor currents, but pentane did not modulate NMDA receptors. Butane and pentane MAC in rats was 39.4±0.7 and 13.7±0.4 %, respectively. A small but significant (p<0.03) synergistic anesthetic effect with pentane was observed during administration of either 0.50 or 0.75×MAC butane. CONCLUSIONS Butane and pentane show synergistic anesthetic effects in vivo consistent with their different in vitro receptor effects. CLINICAL RELEVANCE Findings support the relevance of NMDA receptors in mediating anesthetic actions for some, but not all, inhaled agents.
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Affiliation(s)
- Robert J Brosnan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Fabíola B Fukushima
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Trung L Pham
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
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Sayre RS, Lepiz MA, Horsley KT, Pashmakova MB, Barr JW, Washburn SE. Effects of oxymorphone hydrochloride or hydromorphone hydrochloride on minimal alveolar concentration of desflurane in sheep. Am J Vet Res 2016; 76:583-90. [PMID: 26111087 DOI: 10.2460/ajvr.76.7.583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To establish the minimum alveolar concentration (MAC) of desflurane and evaluate the effects of 2 opioids on MAC in sheep. ANIMALS 8 adult nulliparous mixed-breed sheep. PROCEDURES A randomized crossover design was used. Each sheep was evaluated individually on 2 occasions (to allow assessment of the effects of each of 2 opioids), separated by a minimum of 10 days. On each occasion, sheep were anesthetized with desflurane in 100% oxygen, MAC of desflurane was determined, oxymorphone (0.05 mg/kg) or hydromorphone (0.10 mg/kg) was administered IV, and MAC was redetermined. Physiologic variables and arterial blood gas and electrolyte concentrations were measured at baseline (before MAC determination, with end-tidal desflurane concentration maintained at 10%) and each time MAC was determined. Timing of various stages of anesthesia was recorded for both occasions. RESULTS Mean ± SEM MAC of desflurane was 8.6 ± 0.2%. Oxymorphone or hydromorphone administration resulted in significantly lower MAC (7.6 ± 0.4% and 7.9 ± 0.2%, respectively). Cardiac output at MAC determination for desflurane alone and for desflurane with opioid administration was higher than that at baseline. No difference was identified among hematologic values at any point. Effects of oxymorphone and hydromorphone on durations of various stages of anesthesia did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE MAC of desflurane in nulliparous adult sheep was established. Intravenous administration of oxymorphone or hydromorphone led to a decrease in MAC; however, the clinical importance of that decrease was minor relative to the effect in other species.
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Ye BO, Ji Y, Yuan Q, Zhang GR, Fan Q, Wei G, Yin Z, Tao L. Sevoflurane inhibits the antioxidant capacity of erythrocytes. Exp Ther Med 2015; 11:650-654. [PMID: 26893661 DOI: 10.3892/etm.2015.2938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 09/29/2015] [Indexed: 01/14/2023] Open
Abstract
The aim of the present study was to observe the effects of sevoflurane on the antioxidant capacity, endothelial nitric oxide synthase (eNOS) content and lifespan of erythrocytes. A 2% erythrocyte suspension was prepared from whole blood collected from healthy volunteers and then treated with sevoflurane at different concentrations (group A, 0%; group S1, 1%; group S3, 3%; and group S5, 5%), in the presence or absence of 200 µmol/l hydrogen peroxide (H2O2, or H in group names). In order to evaluate the effects of sevoflurane on the antioxidant capacity and NO metabolism of erythrocytes, the hemolysis rate, catalase (CAT) content and eNOS content were determined, while the labeled phosphatidylserine rate and forward scatter of erythrocytes were detected using flow cytometry. Group S3 showed the highest hemolysis rate in the absence H2O2, while treatment with H2O2 increased the hemolysis rate of groups S1 and S3 (P=0.027). The CAT content in groups treated with sevoflurane was significantly lower compared with that in the control (group A, air group). The CAT content in groups S1+H, S3+H and S5+H remained significantly lower compared with group A+H (P<0.05). The eNOS content of group A was similar to that of group S3, while the content in group S1 was similar to that in group S5. In addition, the eNOS content of groups A and S3 increased, while that of groups S1 and S5 was reduced upon H2O2 treatment (P<0.05). The results indicated that sevoflurane reduced the antioxidative activity of erythrocytes, decreasing the resistant ability to H2O2 damage and increasing the hemolysis rate. The underlying mechanism may be associated with the inhibitory effect on the CAT activity of erythrocytes. Sevoflurane also inhibited the generation of nitric oxide in erythrocytes and reduced the tolerance of erythrocytes against oxidative stress damage due to H2O2.
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Affiliation(s)
- B O Ye
- Department of Anesthesia, Air Force General Hospital, PLA, Beijing 100142, P.R. China
| | - Yun Ji
- Department of Anesthesia, Air Force General Hospital, PLA, Beijing 100142, P.R. China
| | - Quan Yuan
- Outpatient Department, Shanghai Campus, PLA Nanjing Institute of Politics, Shanghai 200433, P.R. China
| | - Guo-Rong Zhang
- Department of Pain, Air Force General Hospital, PLA, Beijing 100142, P.R. China
| | - Qin Fan
- Department of Anesthesia, Air Force General Hospital, PLA, Beijing 100142, P.R. China
| | - Guo Wei
- Department of Anesthesia, Air Force General Hospital, PLA, Beijing 100142, P.R. China
| | - Zhe Yin
- Department of Anesthesia, Air Force General Hospital, PLA, Beijing 100142, P.R. China
| | - Lei Tao
- Department of Anesthesia, Air Force General Hospital, PLA, Beijing 100142, P.R. China
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Bronchoconstriction induced by inhaled methacholine delays desflurane uptake and elimination in a piglet model. Respir Physiol Neurobiol 2015; 220:88-94. [PMID: 26440992 DOI: 10.1016/j.resp.2015.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 09/22/2015] [Accepted: 09/27/2015] [Indexed: 12/11/2022]
Abstract
Bronchoconstriction is a hallmark of asthma and impairs gas exchange. We hypothesized that pharmacokinetics of volatile anesthetics would be affected by bronchoconstriction. Ventilation/perfusion (VA/Q) ratios and pharmacokinetics of desflurane in both healthy state and during inhalational administration of methacholine (MCh) to double peak airway pressure were studied in a piglet model. In piglets, MCh administration by inhalation (100 μg/ml, n=6) increased respiratory resistance, impaired VA/Q distribution, increased shunt, and decreased paO2 in all animals. The uptake and elimination of desflurane in arterial blood was delayed by nebulization of MCh, as determined by Micropore Membrane Inlet Mass Spectrometry (wash-in time to P50, healthy vs. inhalation: 0.5 min vs. 1.1 min, to P90: 4.0 min vs. 14.8 min). Volatile elimination was accordingly delayed. Inhaled methacholine induced severe bronchoconstriction and marked inhomogeneous VA/Q distribution in pigs, which is similar to findings in human asthma exacerbation. Furthermore, MCh-induced bronchoconstriction delayed both uptake and elimination of desflurane. These findings might be considered when administering inhalational anesthesia to asthmatic patients.
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15
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Effects of anesthesia on the respiratory system. Best Pract Res Clin Anaesthesiol 2015; 29:273-84. [DOI: 10.1016/j.bpa.2015.08.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 08/20/2015] [Indexed: 11/21/2022]
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16
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Valente ACS, Brosnan RJ, Guedes AGP. Desflurane and sevoflurane elimination kinetics and recovery quality in horses. Am J Vet Res 2015; 76:201-7. [DOI: 10.2460/ajvr.76.3.201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Esper T, Wehner M, Meinecke CD, Rueffert H. Blood/Gas Partition Coefficients for Isoflurane, Sevoflurane, and Desflurane in a Clinically Relevant Patient Population. Anesth Analg 2015; 120:45-50. [DOI: 10.1213/ane.0000000000000516] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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18
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Becker LF, Schwarz DH, Wenz G. Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs. Beilstein J Org Chem 2014; 10:2920-7. [PMID: 25550759 PMCID: PMC4273231 DOI: 10.3762/bjoc.10.310] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/23/2014] [Indexed: 01/03/2023] Open
Abstract
Methyl and ethyl thioether groups were introduced at all primary positions of α-, β-, and γ-cyclodextrin by nucleophilic displacement reactions starting from the corresponding per-(6-deoxy-6-bromo)cyclodextrins. Further modification of all 2-OH positions by etherification with iodo terminated triethylene glycol monomethyl ether (and tetraethylene glycol monomethyl ether, respectively) furnished water-soluble hosts. Especially the β-cyclodextrin derivatives exhibit very high binding potentials towards the anaesthetic drugs sevoflurane and halothane. Since the resulting inclusion compounds are highly soluble in water at temperatures ≤37 °C they are good candidates for new aqueous dosage forms which would avoid inhalation anaesthesia.
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Affiliation(s)
- Lisa F Becker
- Organic Macromolecular Chemistry, Saarland University, Campus C4.2, 66123 Saarbrücken, Germany
| | - Dennis H Schwarz
- Organic Macromolecular Chemistry, Saarland University, Campus C4.2, 66123 Saarbrücken, Germany
| | - Gerhard Wenz
- Organic Macromolecular Chemistry, Saarland University, Campus C4.2, 66123 Saarbrücken, Germany
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Equipotent Subanesthetic Concentrations of Sevoflurane and Xenon Preventing Cold-stimulated Vocalization of Neonatal Rats. Anesthesiology 2014; 121:1194-202. [DOI: 10.1097/aln.0000000000000423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract
Background:
The effects of inhaled anesthetics on the developing brain are studied using neonatal rodents exposed to fractions of minimum alveolar concentration (to avoid cardiorespiratory compromise). However, these fractions cannot be assumed to be equipotent. Xenon’s anesthetic and neuroprotective properties warrant investigation in these models. Therefore, equipotent, subanesthetic concentrations of inhaled anesthetics are needed.
Methods:
Forty-eight Wistar rats (Charles River Laboratories, Kent, United Kingdom) on postnatal day 9 were randomized to eight concentrations of inhaled anesthetics: isoflurane, sevoflurane, or xenon. Exposure was closely monitored in individual metal-based chambers resting on a 35°C mat to maintain normothermia. A 25°C mat was used to stimulate vocalization and a sound recording made (1 min, 1 to 100 kHz). Rectal temperature or partial pressure of carbon dioxide and pH of mixed arteriovenous blood were measured immediately after the exposure. Concentration–response models were constructed using logistic regression (dependent variable: vocalization and explanatory variable: concentration). The effects of all other explanatory variables were assessed by inserting them individually into the model.
Results:
The effective inhaled concentrations preventing cold-stimulated vocalization in 50 and 95% of neonatal rats (EiC50 and EiC95) on postnatal day 9 were 0.46 and 0.89% sevoflurane and 20.15 and 34.81% xenon, respectively. The effect on the EiC50 of all other explanatory variables, including duration, was minimal. Stability of EiC50 isoflurane was not achieved over three durations (40, 80, and 120 min exposure). Partial pressure of carbon dioxide and pH in mixed arteriovenous blood appeared normal.
Conclusions:
The authors report equipotent subanesthetic concentrations of sevoflurane and xenon in neonatal rats with preserved cardiopulmonary function. This may be useful in designing neonatal rodent models of anesthesia.
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The volatile anesthetic methoxyflurane protects motoneurons against excitotoxicity in an in vitro model of rat spinal cord injury. Neuroscience 2014; 285:269-80. [PMID: 25446348 DOI: 10.1016/j.neuroscience.2014.11.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/21/2014] [Accepted: 11/13/2014] [Indexed: 11/23/2022]
Abstract
Neuroprotection of the spinal cord during the early phase of injury is an important goal to determine a favorable outcome by prevention of delayed pathological events, including excitotoxicity, which otherwise extend the primary damage and amplify the often irreversible loss of motor function. While intensive care and neurosurgical intervention are important treatments, effective neuroprotection requires further experimental studies focused to target vulnerable neurons, particularly motoneurons. The present investigation examined whether the volatile general anesthetic methoxyflurane might protect spinal locomotor networks from kainate-evoked excitotoxicity using an in vitro rat spinal cord preparation as a model. The protocols involved 1h excitotoxic stimulation on day 1 followed by electrophysiological and immunohistochemical testing on day 2. A single administration of methoxyflurane applied together with kainate (1h), or 30 or even 60 min later prevented any depression of spinal reflexes, loss of motoneuron excitability, and histological damage. Methoxyflurane per se temporarily decreased synaptic transmission and motoneuron excitability, effects readily reversible on washout. Spinal locomotor activity recorded as alternating electrical discharges from lumbar motor pools was fully preserved on the second day after application of methoxyflurane together with (or after) kainate. These data suggest that a volatile general anesthetic could provide strong electrophysiological and histological neuroprotection that enabled expression of locomotor network activity 1 day after the excitotoxic challenge. It is hypothesized that the benefits of early neurosurgery for acute spinal cord injury (SCI) might be enhanced if, in addition to injury decompression and stabilization, the protective role of general anesthesia is exploited.
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Elias KM, Kang S, Liu X, Horowitz NS, Berkowitz RS, Frendl G. Anesthetic selection and disease-free survival following optimal primary cytoreductive surgery for stage III epithelial ovarian cancer. Ann Surg Oncol 2014; 22:1341-8. [PMID: 25287437 DOI: 10.1245/s10434-014-4112-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Indexed: 12/23/2022]
Abstract
BACKGROUND Previous studies have offered conflicting results regarding an association between perioperative epidural analgesia and disease-free survival (DFS) following optimal primary cytoreductive surgery for stage III epithelial ovarian cancer. A possible separate role for inhalational anesthetics has not been assessed. METHODS We conducted a historical cohort study of all women undergoing optimal primary cytoreduction (<1 cm residual disease) for Stage III epithelial ovarian cancer between January 1, 2007, and December 31, 2011, at Brigham and Women's Hospital. Cohorts were defined by exposure to perioperative epidural analgesia or exposure to specific volatile anesthetics. The primary outcome was DFS. RESULTS A total of 194 patients met study inclusion criteria. Addition of epidural analgesia was associated with a lower overall rate of ovarian cancer recurrence compared with general anesthesia alone (72 vs. 85 %, p = 0.028). Longer median DFS was associated with more than 48 h of epidural use (14.9 months) compared with fewer than 24 h (10.9 months) or 24-48 h of epidural use (10.0 months; p = 0.025). Use of desflurane was associated with a lower overall rate of ovarian cancer recurrence compared with sevoflurane (63 vs. 84 %, p = 0.01). In multivariate analysis, use of desflurane was independently associated with improved DFS (hazards ratio 0.563; 95% confidence interval 0.33-0.962). CONCLUSIONS For patients with Stage III ovarian cancer, use of desflurane is associated with improved DFS following primary cytoreductive surgery compared with other volatile anesthetics. If epidural analgesia offers additional benefit, this effect appears limited to patients with more than 48 h of postoperative epidural use.
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Affiliation(s)
- Kevin M Elias
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology and Reproductive Biology, Brigham and Women's Hospital, Boston, MA, USA,
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Abstract
Inhaled agents represent an important and useful class of drugs for equine anesthesia. This article reviews the ether-type anesthetics in contemporary use, their uptake and elimination, their mechanisms of action, and their desirable and undesirable effects in horses.
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Affiliation(s)
- Robert J Brosnan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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