Neostigmine antagonism of rocuronium block during anesthesia with sevoflurane, isoflurane or propofol

Purpose: To examine the influence of continuing administration of sevoflurane or isoflurane during reversal of rocuronium induced neuromuscular block with neostigmine. Methods: One hundred and twenty patients, divided into three equal groups, were randomly allocated to maintenance of anesthesia with sevoflurane, isoflurane or propofol. Neuromuscular block was induced with rocuronium and monitored using train-of-four (TOF) stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. Neostigmine was administered when the first response in TOF had recovered to 25%. At this time the volatile agent administration was stopped or propofol dosage reduced in half the patients in each group (n = 20 in each group). The times to attain TOF ratio of 0.8, and the number of patients attaining this end point within 15 min were recorded. Results: The times (mean ± SD) to recovery of the TOF ratio to 0.8 were 12.0 ± 5.5 and 6.8 ± 2.3 min in the sevoflurane continued and sevoflurane stopped groups, 9.0 ± 8.3 and 5.5 ± 3.0 min in the isoflurane continued and isoflurane stopped groups, and 5.2 ± 2.8 and 4.7 ±1.5 min in the propofol continued and propofol stopped groups (P <0.5- 01). Only 9 and 15 patients in the sevoflurane and isoflurane continued groups respectively had attained a TOF ratio of 0.8 within 15 min (P <0.001 for sevoflurane). Conclusions: The continued administration of sevoflurane, and to a smaller extent isoflurane, results in delay in attaining adequate antagonism of rocuronium induced neuromuscular block.

The Dissociative Recombination of Protonated Acrylonitrile, CH2CHCNH+, with Implications for Nitrile Chemistry in Dark Molecular Clouds and the Upper Atmosphere of Titan

Measurements on the dissociative recombination (DR) of protonated acrylonitrile, CH2CHCNH+, have been performed at the heavy ion storage ring CRYRING located in the Manne Siegbahn Laboratory in Stockholm, Sweden. It has been found that at~2meV relative kinetic energy about 50% of the DR events involve only ruptures of X–H bonds (where X=C or N)while the rest leads to the production of a pair of fragments each containing two heavy atoms (alongside H and/or H2). The absolute DR cross section has been investigated for relative kinetic energies ranging from ~1 meV to 1 eV. The thermal rate coefficient has been determined to follow the expression k(T) = 1.78 × 10-6 (T/300)-0.80 cm3 s-1 for electron temperatures ranging from ~10 to 1000 K. Gas-phase models of the nitrile chemistry in the dark molecular cloud TMC-1 have been run and results are compared with observations. Also, implications of the present results for the nitrile chemistry of Titan’s upper atmosphere are discussed.

Highly resolved absolute cross-sections for dissociative electron attachment to SF5CF3

Using two complementary experimental methods, we have measured partial (mass-resolved) cross-sections for dissociative electron attachment to the molecule trifluoromethyl sulfurpentafluoride (SF5CF3) at the gas temperature T-G = 300 K over a broad range of electron energies (E = 0.001-12 eV). The absolute scale for these cross-sections was obtained with reference to the thermal (T = 300 K) rate coefficient for anion formation (8.0(3) x 10(-8) cm(3) s(-1)). Below 1 eV, SF5- is the dominant product anion and formed through the lowest anion state which cuts the neutral SF5CF3 potential close to the S-C equilibrium distance. The highly resolved laser photoelectron attachment data exhibit a downward Wigner cusp at 86meV, indicating that the nu(4)(alpha(1)) vibrational mode is important for the primary attachment dynamics. Both SF5- and F- anions are formed with similar yields through the first excited resonance located near 3.6eV. Towards higher energies, the anions CF3-, SF4-, and SF3- are also produced. Summation of the partial cross-sections yields a total absolute cross-section for anion formation over the energy range 0.001-12 eV. This is used to calculate the dependence of the rate coefficient for dissociative electron attachment over a broad range of electron temperatures for the fixed gas temperature T-G = 300 K; good agreement is found between the calculated values and those obtained in a drift tube experiment. In addition to the experimental work, semiempirical R-matrix calculations have been Carried out for the energy dependence of the cross-section for SF5- formation. The experimental findings are semi-quantitatively recovered. (C) 2008 Elsevier B.V. All rights reserved.

Auditory hallucinations in dissociative identity disorder and schizophrenia with and without a childhood trauma history: Similarities and differences.

Little is known about similarities and differences in voice hearing in schizophrenia and dissociative identity disorder (DID) and the role of child maltreatment and dissociation. This study examined various aspects of voice hearing, along with childhood maltreatment and pathological dissociation in 3 samples: schizophrenia without child maltreatment (n = 18), schizophrenia with child maltreatment (n = 16), and DID (n = 29). Compared with the schizophrenia groups, the DID sample was more likely to have voices starting before 18, hear more than 2 voices, have both child and adult voices and experience tactile and visual hallucinations. The 3 groups were similar in that voice content was incongruent with mood and the location was more likely internal than external. Pathological dissociation predicted several aspects of voice hearing and appears an important variable in voice hearing, at least where maltreatment is present.

Dissociative Recombination of Protonated Formic Acid: Implications for Molecular Cloud and Cometary Chemistry

At the heavy ion storage ring CRYRING in Stockholm, Sweden, we have investigated the dissociative recombination of DCOOD2+ at low relative kinetic energies, from ~1 meV to 1 eV. The thermal rate coefficient has been found to follow the expression k(T) = 8.43 × 10-7 (T/300)^-0.78 cm3 s-1 for electron temperatures, T, ranging from ~10 to ~1000 K. The branching fractions of the reaction have been studied at ~2 meV relative kinetic energy. It has been found that ~87% of the reactions involve breaking a bond between heavy atoms. In only 13% of the reactions do the heavy atoms remain in the same product fragment. This puts limits on the gas-phase production of formic acid, observed in both molecular clouds and cometary comae. Using the experimental results in chemical models of the dark cloud, TMC-1, and using the latest release of the UMIST Database for Astrochemistry improves the agreement with observations for the abundance of formic acid. Our results also strengthen the assumption that formic acid is a component of cometary ices.

Dissociative electron attachment to the highly reactive difluoromethylene molecule–importance of CF2 for negative ion formation in fluorocarbon plasmas

Dissociative electron attachment to the highly reactive difluoromethylene molecule, CF2, produced in a C3F6/He microwave plasma and stepwise via the fast atom reaction CF3I+H?CF3+HI and CF3+H?CF2+HF, has been investigated. The upper limit for the cross section of formation of F- via dissociative electron attachment to CF2 is estimated to be 5×10-4?Å2. This value is four orders of magnitude smaller than the cross section previously predicted from scattering calculations. It is concluded that difluoromethylene plays a negligible role in negative ion formation in fluorocarbon plasmas.

INCIDENCE AND CLINICAL IMPORTANCE OF PERIOPERATIVE HISTAMINE-RELEASE - RANDOMIZED STUDY OF VOLUME LOADING AND ANTIHISTAMINES AFTER INDUCTION OF ANESTHESIA

Although histamine release is recognised as a common event during anaesthesia and surgery, few clinicians judge the resultant cardiorespiratory disturbances serious enough to warrant prophylaxis with antihistamines. We have assessed the incidence and importance of histamine release in a randomised 2 x 2 factorial study.