27 research outputs found

    The influence of propofol, remifentanil and lidocaine on the tone of human bronchial smooth muscle.

    Get PDF
    Bronchoscopy is generally a safe procedure, but the induction of anaesthesia can induce bronchospasm. Consequently we investigated the influence of propofol, remifentanil and lidocaine on the tone of the human bronchial smooth muscle. Materials and methods: The influence of propofol, remifentanil and lidocaine on the contractile response of human bronchial smooth muscle to electrical field stimulation (EFS) has been evaluated. The role of capsaicin-sensitive sensory nerves and of inducible nitric oxide synthase has also been assessed. Furthermore, the interaction between these three dugs has been measured by Bliss Independence (BI) theory. Statistical significance (P < 0.05) was assessed by Student's t test or ANOVA. Results: Propofol (1.3 μg ml-1) and lidocaine (1 mg ml-1) reduced the baseline tone of bronchial rings (-14.45 ± 4.53% and -33.40 ± 1.07%, respectively, P < 0.05), whereas remifentanil had not such effect. Aminoguanidine prevented the relaxant effect of propofol. Propofol did not alter the bronchial contractile response to EFS following 30 min of treatment, whereas remifentanil enhanced the bronchial tension (133.83 ± 9.38%, control 101.93 ± 6.82%, P < 0.05 P < 0.05) and lidocaine completely abolished the contractility at 1 mg ml-1 (P < 0.05). The desensitization of capsaicin-sensitive sensory nerves normalized the hyperresponsiveness induced by remifentanil (-26.77 ± 1.68%, P < 0.05). Significant BI antagonism (P < 0.001) was detected for propofol and lidocaine on the bronchial hyperresponsiveness induced by remifentanil. Conclusion: Propofol and remifentanil may be used safely for bronchoscopy, although remifentanil should be associated with propofol or lidocaine to prevent the potential opioid-mediated bronchospasm

    Stochastic Gravity: Theory and Applications

    Get PDF
    Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel. In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime, compute the two-point correlation functions of these perturbations and prove that Minkowski spacetime is a stable solution of semiclassical gravity. Second, we discuss structure formation from the stochastic gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a black hole and describe the metric fluctuations near the event horizon of an evaporating black holeComment: 100 pages, no figures; an update of the 2003 review in Living Reviews in Relativity gr-qc/0307032 ; it includes new sections on the Validity of Semiclassical Gravity, the Stability of Minkowski Spacetime, and the Metric Fluctuations of an Evaporating Black Hol

    Stochastic Gravity: Theory and Applications

    Get PDF
    Whereas semiclassical gravity is based on the semiclassical Einstein equation with sources given by the expectation value of the stress-energy tensor of quantum fields, stochastic semiclassical gravity is based on the Einstein-Langevin equation, which has in addition sources due to the noise kernel.In the first part, we describe the fundamentals of this new theory via two approaches: the axiomatic and the functional. In the second part, we describe three applications of stochastic gravity theory. First, we consider metric perturbations in a Minkowski spacetime: we compute the two-point correlation functions for the linearized Einstein tensor and for the metric perturbations. Second, we discuss structure formation from the stochastic gravity viewpoint. Third, we discuss the backreaction of Hawking radiation in the gravitational background of a quasi-static black hole.Comment: 75 pages, no figures, submitted to Living Reviews in Relativit

    Measuring Black Hole Formations by Entanglement Entropy via Coarse-Graining

    Full text link
    We argue that the entanglement entropy offers us a useful coarse-grained entropy in time-dependent AdS/CFT. We show that the total von-Neumann entropy remains vanishing even when a black hole is created in a gravity dual, being consistent with the fact that its corresponding CFT is described by a time-dependent pure state. We analytically calculate the time evolution of entanglement entropy for a free Dirac fermion on a circle following a quantum quench. This is interpreted as a toy holographic dual of black hole creations and annihilations. It is manifestly free from the black hole information problem.Comment: 25 pages, Latex, 8 figure

    Entanglement Dynamics between Inertial and Non-uniformly Accelerated Detectors

    Full text link
    We study the time-dependence of quantum entanglement between two Unruh-DeWitt detectors, one at rest in a Minkowski frame, the other non-uniformly accelerated in some specified way. The two detectors each couple to a scalar quantum field but do not interact directly. The primary challenge in problems involving non-uniformly accelerated detectors arises from the fact that an event horizon is absent and the Unruh temperature is ill-defined. By numerical calculation we demonstrate that the correlators of the accelerated detector in the weak coupling limit behaves like those of an oscillator in a bath of time-varying "temperature" proportional to the instantaneous proper acceleration of the detector, with oscillatory modifications due to non-adiabatic effects. We find that in this setup the acceleration of the detector in effect slows down the disentanglement process in Minkowski time due to the time dilation in that moving detectorComment: 20 pages, 15 figures; References added; More analysis given in Appendix C; Typos correcte

    Analogue Gravity

    Full text link

    The influence of propofol, remifentanil and lidocaine on the tone of human bronchial smooth muscle.

    No full text
    Background: Bronchoscopy is generally a safe procedure, but the induction of anaesthesia can induce bronchospasm. Consequently we investigated the influence of propofol, remifentanil and lidocaine on the tone of the human bronchial smooth muscle. Materials and methods: The influence of propofol, remifentanil and lidocaine on the contractile response of human bronchial smooth muscle to electrical field stimulation (EFS) has been evaluated. The role of capsaicin-sensitive sensory nerves and of inducible nitric oxide synthase has also been assessed. Furthermore, the interaction between these three dugs has been measured by Bliss Independence (BI) theory. Statistical significance (P < 0.05) was assessed by Student's t test or ANOVA. Results: Propofol (1.3 mu g ml(-1)) and lidocaine (1 mg ml(-1)) reduced the baseline tone of bronchial rings (-14.45 +/- 4.53% and -33.40 +/- 1.07%, respectively, P < 0.05), whereas remifentanil had not such effect. Aminoguanidine prevented the relaxant effect of propofol. Propofol did not alter the bronchial contractile response to EFS following 30 min of treatment, whereas remifentanil enhanced the bronchial tension (133.83 +/- 9.38%, control 101.93 +/- 6.82%, P < 0.05 P < 0.05) and lidocaine completely abolished the contractility at 1 mg ml(-1) (P < 0.05). The desensitization of capsaicin-sensitive sensory nerves normalized the hyperresponsiveness induced by remifentanil (-26.77 +/- 1.68%, P < 0.05). Significant BI antagonism (P < 0.001) was detected for propofol and lidocaine on the bronchial hyperresponsiveness induced by remifentanil. Conclusion: Propofol and remifentanil may be used safely for bronchoscopy, although remifentanil should be associated with propofol or lidocaine to prevent the potential opioid-mediated bronchospasm. (C) 2013 Elsevier Ltd. All rights reserved

    The influence of propofol, remifentanil and lidocaine on the tone of human bronchial smooth muscle.

    No full text
    Bronchoscopy is generally a safe procedure, but the induction of anaesthesia can induce bronchospasm. Consequently we investigated the influence of propofol, remifentanil and lidocaine on the tone of the human bronchial smooth muscle. Materials and methods: The influence of propofol, remifentanil and lidocaine on the contractile response of human bronchial smooth muscle to electrical field stimulation (EFS) has been evaluated. The role of capsaicin-sensitive sensory nerves and of inducible nitric oxide synthase has also been assessed. Furthermore, the interaction between these three dugs has been measured by Bliss Independence (BI) theory. Statistical significance (P < 0.05) was assessed by Student's t test or ANOVA. Results: Propofol (1.3 μg ml-1) and lidocaine (1 mg ml-1) reduced the baseline tone of bronchial rings (-14.45 ± 4.53% and -33.40 ± 1.07%, respectively, P < 0.05), whereas remifentanil had not such effect. Aminoguanidine prevented the relaxant effect of propofol. Propofol did not alter the bronchial contractile response to EFS following 30 min of treatment, whereas remifentanil enhanced the bronchial tension (133.83 ± 9.38%, control 101.93 ± 6.82%, P < 0.05 P < 0.05) and lidocaine completely abolished the contractility at 1 mg ml-1 (P < 0.05). The desensitization of capsaicin-sensitive sensory nerves normalized the hyperresponsiveness induced by remifentanil (-26.77 ± 1.68%, P < 0.05). Significant BI antagonism (P < 0.001) was detected for propofol and lidocaine on the bronchial hyperresponsiveness induced by remifentanil. Conclusion: Propofol and remifentanil may be used safely for bronchoscopy, although remifentanil should be associated with propofol or lidocaine to prevent the potential opioid-mediated bronchospasm
    corecore