| 1. |
- Kantonen, Oskari, et al.
(författare)
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Decreased thalamic activity is a correlate for disconnectedness during anesthesia with Propofol, Dexmedetomidine and Sevoflurane but not S-ketamine
- 2023
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Ingår i: Journal of Neuroscience. - : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 43:26, s. 4884-4895
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Tidskriftsartikel (refereegranskat)abstract
- Establishing the neural mechanisms responsible for the altered global states of consciousness during anesthesia and dissociating these from other drug-related effects remains a challenge in consciousness research. We investigated differences in brain activity between connectedness and disconnectedness by administering various anesthetics at concentrations designed to render 50% of the subjects unresponsive. One hundred and sixty healthy male subjects were randomized to receive either propofol (1.7 μg/ml; n = 40), dexmedetomidine (1.5 ng/ml; n = 40), sevoflurane (0.9% end-tidal; n = 40), S-ketamine (0.75 μg/ml; n = 20), or saline placebo (n = 20) for 60 min using target-controlled infusions or vaporizer with end-tidal monitoring. Disconnectedness was defined as unresponsiveness to verbal commands probed at 2.5-min intervals and unawareness of external events in a postanesthesia interview. High-resolution positron emission tomography (PET) was used to quantify regional cerebral metabolic rates of glucose (CMRglu) utilization. Contrasting scans where the subjects were classified as connected and responsive versus disconnected and unresponsive revealed that for all anesthetics, except S-ketamine, the level of thalamic activity differed between these states. A conjunction analysis across the propofol, dexmedetomidine and sevoflurane groups confirmed the thalamus as the primary structure where reduced metabolic activity was related to disconnectedness. Widespread cortical metabolic suppression was observed when these subjects, classified as either connected or disconnected, were compared with the placebo group, suggesting that these findings may represent necessary but alone insufficient mechanisms for the change in the state of consciousness.
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| 2. |
- Kantonen, Oskari, et al.
(författare)
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Decreased Thalamic Activity Is a Correlate for Disconnectedness during Anesthesia with Propofol, Dexmedetomidine and Sevoflurane But Not S-Ketamine
- 2023
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Ingår i: Journal of Neuroscience. - : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 43:26, s. 4884-4895
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Tidskriftsartikel (refereegranskat)abstract
- Establishing the neural mechanisms responsible for the altered global states of consciousness during anesthesia and dissociating these from other drug-related effects remains a challenge in consciousness research. We investigated differences in brain activity between connectedness and disconnectedness by administering various anesthetics at concentrations designed to render 50% of the subjects unresponsive. One hundred and sixty healthy male subjects were randomized to receive either propofol (1.7 μg/ml; n = 40), dexmedetomidine (1.5 ng/ml; n = 40), sevoflurane (0.9% end-tidal; n = 40), S-ketamine (0.75 μg/ml; n = 20), or saline placebo (n = 20) for 60 min using target-controlled infusions or vaporizer with end-tidal monitoring. Disconnectedness was defined as unresponsiveness to verbal commands probed at 2.5-min intervals and unawareness of external events in a postanesthesia interview. High-resolution positron emission tomography (PET) was used to quantify regional cerebral metabolic rates of glucose (CMRglu) utilization. Contrasting scans where the subjects were classified as connected and responsive versus disconnected and unresponsive revealed that for all anesthetics, except S-ketamine, the level of thalamic activity differed between these states. A conjunction analysis across the propofol, dexmedetomidine and sevoflurane groups confirmed the thalamus as the primary structure where reduced metabolic activity was related to disconnectedness. Widespread cortical metabolic suppression was observed when these subjects, classified as either connected or disconnected, were compared with the placebo group, suggesting that these findings may represent necessary but alone insufficient mechanisms for the change in the state of consciousness.
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| 3. |
- Scheinin, Annalotta, et al.
(författare)
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Foundations of human consciousness : Imaging the twilight zone
- 2021
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Ingår i: Journal of Neuroscience. - : The Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 41:8, s. 1769-1778
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Tidskriftsartikel (refereegranskat)abstract
- What happens in the brain when conscious awareness of the surrounding world fades? We manipulated consciousness in two experiments in a group of healthy males and measured brain activity with positron emission tomography. Measurements were made during wakefulness, escalating and constant levels of two anesthetic agents (Experiment 1, n=39) and during sleep-deprived wakefulness and Non-Rapid Eye Movement sleep (Experiment 2, n=37). In Experiment 1, the subjects were randomized to receive either propofol or dexmedetomidine until unresponsiveness. In both experiments, forced awakenings were applied to achieve rapid recovery from an unresponsive to a responsive state, followed by immediate and detailed interviews of subjective experiences during the preceding unresponsive condition. Unresponsiveness rarely denoted unconsciousness, as the majority of the subjects had internally generated experiences. Unresponsive anesthetic states and verified sleep stages, where a subsequent report of mental content included no signs of awareness of the surrounding world, indicated a disconnected state. Functional brain imaging comparing responsive and connected vs. unresponsive and disconnected states of consciousness during constant anesthetic exposure revealed that activity of the thalamus, cingulate cortices and angular gyri are fundamental for human consciousness. These brain structures were affected independent from the pharmacologic agent, drug concentration and direction of change in the state of consciousness. Analogous findings were obtained when consciousness was regulated by physiological sleep. State-specific findings were distinct and separable from the overall effects of the interventions, which included widespread depression of brain activity across cortical areas. These findings identify a central core brain network critical for human consciousness. SIGNIFICANCE STATEMENT Trying to understand the biological basis of human consciousness is currently one of the greatest challenges of neuroscience. While the loss and return of consciousness regulated by anesthetic drugs and physiological sleep are employed as model systems in experimental studies on consciousness, previous research results have been confounded by drug effects, by confusing behavioral "unresponsiveness" and internally generated consciousness, and by comparing brain activity levels across states that differ in several other respects than only consciousness. Here, we present carefully designed studies that overcome many previous confounders and for the first time reveal the neural mechanisms underlying human consciousness and its disconnection from behavioral responsiveness, both during anesthesia and during normal sleep, and in the same study subjects.
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| 4. |
- Cajander, Per, 1976-, et al.
(författare)
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Effects of dexmedetomidine on pharyngeal swallowing and esophageal motility : A double-blind randomized cross-over study in healthy volunteers
- 2023
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Ingår i: Neurogastroenterology and Motility. - : Wiley-Blackwell Publishing Inc.. - 1350-1925 .- 1365-2982. ; 35:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Sedative agents increase the risk of pulmonary aspiration, where an intact swallowing function is an important defense mechanism. Dexmedetomidine is an α2 -adrenoceptor agonist widely used during procedural sedation due to beneficial properties with minimal respiratory effects. The effects of dexmedetomidine on pharyngeal swallowing and esophageal motility are not known in detail.METHODS: To determine the effects of dexmedetomidine on pharyngeal swallowing and esophageal motility, nineteen volunteers were included in this double-blinded, randomized placebo-controlled cross-over study. Study participants received target-controlled dexmedetomidine and placebo infusions. Recordings of pressure and impedance data were acquired using a manometry and impedance solid-state catheter. Data were analyzed from three bolus swallows series: baseline, during dexmedetomidine/placebo infusion at target plasma concentrations 0.6 ng ml-1 and 1.2 ng ml-1 . Subjective swallowing difficulties were also recorded.KEY RESULTS: On pharyngeal swallowing, dexmedetomidine affected the upper esophageal sphincter with decreased pre- and post-swallow contractile pressures and an increase in residual pressure during swallow-related relaxation. On esophageal function, dexmedetomidine decreased contractile vigor of the proximal esophagus and increased velocity of the peristaltic contraction wave. Residual pressures during swallow-related esophagogastric junction (EGJ) relaxation decreased, as did basal EGJ resting pressure. The effects on the functional variables were not clearly dose-dependent, but mild subjective swallowing difficulties were more common at the higher dose level.CONCLUSIONS AND INFERENCES: Dexmedetomidine induces effects on pharyngeal swallowing and esophageal motility, which should be considered in clinical patient management and also when a sedative agent for procedural sedation or for manometric examination is to be chosen.
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| 5. |
- Cajander, Per, 1976-, et al.
(författare)
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Response to Letter to the Editor
- 2023
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Ingår i: Neurogastroenterology and Motility. - : Wiley-Blackwell. - 1350-1925 .- 1365-2982. ; 35:8
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Tidskriftsartikel (refereegranskat)abstract
- It is crucial to consider the possible influence of anesthetic agents on esophageal function testing. Dexmedetomidine has been shown to affect primary peristalsis during esophageal manometry. In the two case reports presented by Toaz et al., secondary peristalsis during FLIP panometry was also affected. This may be attributed to an alternate pharmacodynamic effect, with a transient direct α2-mediated effect on esophageal smooth muscle, associated with a high plasma concentration following bolus injection, prior to the onset of sympathetic inhibition.
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| 6. |
- Kallioinen, Minna, et al.
(författare)
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The influence of dexmedetomidine and propofol on circulating cytokine levels in healthy subjects
- 2019
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Ingår i: BMC Anesthesiology. - : BioMed Central. - 1471-2253 .- 1471-2253. ; 19:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Surgery and diseases modify inflammatory responses and the immune system. Anesthetic agents also have effects on the human immune system but the responses they induce may be altered or masked by the surgical procedures or underlying illnesses. The aim of this study was to assess how single-drug dexmedetomidine and propofol anesthesia without any surgical intervention alter acute immunological biomarkers in healthy subjects. Methods: Thirty-five healthy, young male subjects were anesthetized using increasing concentrations of dexmedetomidine (n = 18) or propofol (n = 17) until loss of responsiveness (LOR) was detected. The treatment allocation was randomized. Multi-parametric immunoassays for the detection of 48 cytokines, chemokines and growth factors were used. Concentrations were determined at baseline and at the highest drug concentration for each subject. Results: The changes in the concentration of eotaxin (decrease after dexmedetomidine) and platelet-derived growth factor (PDGF, increase after propofol) were statistically significantly different between the groups. Significant changes were detected within both groups; the concentrations of monocyte chemotactic protein 1, chemokine ligand 27 and macrophage migration inhibitory factor were lower in both groups after the drug administration. Dexmedetomidine decreased the concentration of eotaxin, interleukin-18, interleukin-2Ra, stem cell factor, stem cell growth factor and vascular endothelial growth factor, and propofol decreased significantly the levels of hepatocyte growth factor, IFN-.-induced protein 10 and monokine induced by IFN-gamma, and increased the levels of interleukin-17, interleukin-5, interleukin-7 and PDGF. Conclusions: Dexmedetomidine seemed to have an immunosuppressive effect on the immune system whereas propofol seemed to induce mixed pro- and anti-inflammatory effects on the immune system. The choice of anesthetic agent could be relevant when treating patients with compromised immunological defense mechanisms. Trial registration: Before subject enrollment, the study was registered in the European Clinical Trials database (EudraCT number 2013-001496-21, The Neural Mechanisms of Anesthesia and Human Consciousness) and in ClinicalTrials.gov (Principal Investigator: Harry Scheinin, number NCT01889004, The Neural Mechanisms of Anesthesia and Human Consciousness, Part 2, on the 23rd of June 2013).
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| 7. |
- Kallionpää, Roosa E., et al.
(författare)
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Alpha band frontal connectivity is a state-specific electroencephalographic correlate of unresponsiveness during exposure to dexmedetomidine and propofol
- 2020
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Ingår i: British Journal of Anaesthesia. - : Elsevier. - 0007-0912 .- 1471-6771. ; 125:4, s. 518-528
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Tidskriftsartikel (refereegranskat)abstract
- Background herent alpha electroencephalogram (EEG) rhythms in the frontal cortex have been correlated with the hypnotic effects of propofol and dexmedetomidine, but less is known about frontal connectivity as a state-specific correlate of unresponsiveness as compared with long-range connectivity. We aimed to distinguish dose- and state-dependent effects of dexmedetomidine and propofol on EEG connectivity. thods rty-seven healthy males received either dexmedetomidine (n=23) or propofol (n=24) as target-controlled infusion with stepwise increments until loss of responsiveness (LOR). We attempted to arouse participants during constant dosing (return of responsiveness [ROR]), and the target concentration was then increased 50% to achieve presumed loss of consciousness. We collected 64-channel EEG data and prefrontal–frontal and anterior–posterior functional connectivity in the alpha band (8–14 Hz) was measured using coherence and weighted phase lag index (wPLI). Directed connectivity was measured with directed phase lag index (dPLI). sults efrontal–frontal EEG-based connectivity discriminated the states at the different drug concentrations. At ROR, prefrontal–frontal connectivity reversed to the level observed before LOR, indicating that connectivity changes were related to unresponsiveness rather than drug concentration. Unresponsiveness was associated with emergence of frontal-to-prefrontal dominance (dPLI: –0.13 to –0.40) in contrast to baseline (dPLI: 0.01–0.02). Coherence, wPLI, and dPLI had similar capability to discriminate the states that differed in terms of responsiveness and drug concentration. In contrast, anterior–posterior connectivity in the alpha band did not differentiate LOR and ROR. nclusions cal prefrontal–frontal EEG-based connectivity reflects unresponsiveness induced by propofol or dexmedetomidine, suggesting its utility in monitoring the anaesthetised state with these agents. inical trial registration
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| 8. |
- Kallionpää, Roosa E., et al.
(författare)
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Single-subject analysis of N400 event-related potential component with five different methods
- 2019
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Ingår i: International Journal of Psychophysiology. - : Elsevier. - 0167-8760 .- 1872-7697. ; 144, s. 14-24
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Tidskriftsartikel (refereegranskat)abstract
- There are several different approaches to analyze event-related potentials (ERPs) at single-subject level, and the aim of the current study is to provide information for choosing a method based on its ability to detect ERP effects and factors influencing the results. We used data from 79 healthy participants with EEG referenced to mastoid average and investigated the detection rate of auditory N400 effect in single-subject analysis using five methods: visual inspection of participant-wise averaged ERPs, analysis of variance (ANOVA) for amplitude averages in a time window, cluster-based non-parametric testing, a novel Bayesian approach and Studentized continuous wavelet transform (t-CWT). Visual inspection by three independent raters yielded N400 effect detection in 85% of the participants in at least one paradigm (active responding or passive listening), whereas ANOVA identified the effect in 68%, the cluster-method in 59%, the Bayesian method in 89%, and different versions of t-CWT in 22–59% of the participants. Thus, the Bayesian method was the most liberal and also showed the greatest concordance between the experimental paradigms (active/passive). ANOVA detected significant effect only in cases with converging evidence from other methods. The t-CWT and cluster-based method were the most conservative methods. As we show in the current study, different analysis methods provide results that do not completely overlap. The method of choice for determining the presence of an ERP component at single-subject level thus remains unresolved. Relying on a single statistical method may not be sufficient for drawing conclusions on single-subject ERPs.
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| 9. |
- Nummela, Aleksi, et al.
(författare)
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Circulating oxylipin and bile acid profiles of dexmedetomidine, propofol, sevoflurane, and S-ketamine : a randomised controlled trial using tandem mass spectrometry
- 2022
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Ingår i: BJA Open. - : Elsevier. - 2772-6096. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThis exploratory study aimed to investigate whether dexmedetomidine, propofol, sevoflurane, and S-ketamine affect oxylipins and bile acids, which are functionally diverse molecules with possible connections to cellular bioenergetics, immune modulation, and organ protection.MethodsIn this randomised, open-label, controlled, parallel group, Phase IV clinical drug trial, healthy male subjects (n=160) received equipotent doses (EC50 for verbal command) of dexmedetomidine (1.5 ng ml−1; n=40), propofol (1.7 μg ml−1; n=40), sevoflurane (0.9% end-tidal; n=40), S-ketamine (0.75 μg ml−1; n=20), or placebo (n=20). Blood samples for tandem mass spectrometry were obtained at baseline, after study drug administration at 60 and 130 min from baseline; 40 metabolites were analysed.ResultsStatistically significant changes vs placebo were observed in 62.5%, 12.5%, 5.0%, and 2.5% of analytes in dexmedetomidine, propofol, sevoflurane, and S-ketamine groups, respectively. Data are presented as standard deviation score, 95% confidence interval, and P-value. Dexmedetomidine induced wide-ranging decreases in oxylipins and bile acids. Amongst others, 9,10-dihydroxyoctadecenoic acid (DiHOME) –1.19 (–1.6; –0.78), P<0.001 and 12,13-DiHOME –1.22 (–1.66; –0.77), P<0.001 were affected. Propofol elevated 9,10-DiHOME 2.29 (1.62; 2.96), P<0.001 and 12,13-DiHOME 2.13 (1.42; 2.84), P<0.001. Analytes were mostly unaffected by S-ketamine. Sevoflurane decreased tauroursodeoxycholic acid (TUDCA) –2.7 (–3.84; –1.55), P=0.015.ConclusionsDexmedetomidine-induced oxylipin alterations may be connected to pathways associated with organ protection. In contrast to dexmedetomidine, propofol emulsion elevated DiHOMEs, oxylipins associated with acute respiratory distress syndrome, and mitochondrial dysfunction in high concentrations. Further research is needed to establish the behaviour of DIHOMEs during prolonged propofol/dexmedetomidine infusions and to verify the sevoflurane-induced reduction in TUDCA, a suggested neuroprotective agent.Clinical trial registrationNCT02624401.
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| 10. |
- Nummela, Aleksi J., et al.
(författare)
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Effects of dexmedetomidine, propofol, sevoflurane and S-ketamine on the human metabolome : A randomised trial using nuclear magnetic resonance spectroscopy
- 2022
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Ingår i: European Journal of Anaesthesiology. - : Wolters Kluwer. - 0265-0215 .- 1365-2346. ; 39:6, s. 521-532
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pharmacometabolomics uses large-scale data capturing methods to uncover drug-induced shifts in the metabolic profile. The specific effects of anaesthetics on the human metabolome are largely unknown.OBJECTIVE: We aimed to discover whether exposure to routinely used anaesthetics have an acute effect on the human metabolic profile.DESIGN: Randomised, open-label, controlled, parallel group, phase IV clinical drug trial.SETTING: The study was conducted at Turku PET Centre, University of Turku, Finland, 2016 to 2017.PARTICIPANTS: One hundred and sixty healthy male volunteers were recruited. The metabolomic data of 159 were evaluable.INTERVENTIONS: Volunteers were randomised to receive a 1-h exposure to equipotent doses (EC50 for verbal command) of dexmedetomidine (1.5 ng ml-1; n = 40), propofol (1.7 μg ml-1; n = 40), sevoflurane (0.9% end-tidal; n = 39), S-ketamine (0.75 μg ml-1; n = 20) or placebo (n = 20).MAIN OUTCOME MEASURES: Metabolite subgroups of apolipoproteins and lipoproteins, cholesterol, glycerides and phospholipids, fatty acids, glycolysis, amino acids, ketone bodies, creatinine and albumin and the inflammatory marker GlycA, were analysed with nuclear magnetic resonance spectroscopy from arterial blood samples collected at baseline, after anaesthetic administration and 70 min postanaesthesia.RESULTS: All metabolite subgroups were affected. Statistically significant changes vs. placebo were observed in 11.0, 41.3, 0.65 and 3.9% of the 155 analytes in the dexmedetomidine, propofol, sevoflurane and S-ketamine groups, respectively. Dexmedetomidine increased glucose, decreased ketone bodies and affected lipoproteins and apolipoproteins. Propofol altered lipoproteins, fatty acids, glycerides and phospholipids and slightly increased inflammatory marker glycoprotein acetylation. Sevoflurane was relatively inert. S-ketamine increased glucose and lactate, whereas branched chain amino acids and tyrosine decreased.CONCLUSION: A 1-h exposure to moderate doses of routinely used anaesthetics led to significant and characteristic alterations in the metabolic profile. Dexmedetomidine-induced alterations mirror α2-adrenoceptor agonism. Propofol emulsion altered the lipid profile. The inertness of sevoflurane might prove useful in vulnerable patients. S-ketamine induced amino acid alterations might be linked to its suggested antidepressive properties.TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02624401. URL: https://clinicaltrials.gov/ct2/show/NCT02624401.
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