We conducted a survey of the incidence of Postoperative Residual Curarisation (PORC) in two groups of patients following the use of atracurium or vecuronium. In the first group (B) the neuromuscular blocking drugs were administered by bolus dosing, and in the second group (I) by continuous fusion. On arrival in the recovery room, neuromuscular function was assessed both by compound evoked electromyogram (EMG) in a train of four pattern and also clinically, by the ability to sustain a headlift for > 5 seconds, and to cough. Results were obtained from 150 patients (100 in group B and 50 in group I). The incidence of PORC, as defined by a train of four ratio of < 0.7, on arrival in the recovery room was 12% in group B, and 24% in group I. Clinical criteria of adequate neuromuscular reversal revealed different results, with the majority of patients being unable to perform either clinical test on arrival in recovery. Those patients in whom a peripheral nerve stimulator was used intra-operatively did not have a reduced incidence of PORC. We have demonstrated that PORC is still a common occurrence even with intermediate duration of action neuromuscular blocking drugs.

An analysis of multiple competing reactions is presented for one or more reactants with arbitrary electrode kinetics. Criteria are established for selectivity enhancement and control and mr electrochemical reactor design based on electrode potential, temperature, conversion, and transport processes. The strongest effect arises from the potential, which can offset the selectivity dependence on other operating variables. Diffusion transport in porous electrodes can also improve reaction specificity, depending on kinetics. The role of reactor design on selectivity is examined ~or two extreme reactors with channel flow or with thorough mixing. The former operates under nonuniform current and selectivity distribution along the working electrode and may result in apparent limiting currents. Although discussion focuses on two irreversible paralml electroorganic reactions, results are also applicable to reversible, coupled or uncoupled reactions of ionic, dissolved, and gas-phase reactants at thin porous flow-by, gas-diffusion, thin-gap, and slurry electrodes.Reductions and oxidations of organic molecules in solution, in the presence of an electric potential field, yield a variety of important chemicals. Despite extensive mechanistic and exploratory studies (1-3), however, few electroorganic reactions have reached large scale application (4-6). This slow evolution of electrochemicaI processing has partly resulted from inadequate understanding of the coupling of complex chemical, kinetic, and physical steps or of the effect of cell design on reaction specificity and rate. The latter constitute basic parameters in process feasibility evaluation. In view of recent interest for industrial electroorganic processing (6-8) an examination of design criteria for electrochemical reactors (cells) is warranted.In this analysis we examine the rational choice of flow reactors, contact patterns, and operating conditions for optimal selectivity and rate control of competing organic electrocatalytic reactions. For a rational design, knowledge of the kinetic parameters, including the transfer coefficients, of each reaction is essential. The discussion here presents a methodology for a detailed kinetic characterization of coupled, simultaneous electrochemical reactions.Electrocatalytic processes are considered because of the unusual effects that the electrode material and its potential have on selective promotion of complex reaction paths (9). The development of efficient catalytic electrodes and cell configurations and the advent of novel, energy-saving schemes, such as electrogenerative catalytic processes (10, 11), are expected to improve the feasibility of conventional processes (7, 8).With parallel or competing reactions, one reactant may undergo reduction or oxidation via two or more different routes. This is particularly the case with electrocatalytic reactions, which involve surface adsorption on one or more active sites, possible reorganization of the reactant or a reaction intermediate, and surface reaction with one or several el...

No abstract

A methodology is outlined for the analysis of multiple parallel electro‐organic reactions of arbitrary, simple electrode kinetics on solid or porous electrodes, in the absence and in the presence of slow mass transport processes. The analysis is further used to predict the selectivity and rate of two model electrochemical reactors under potentiostatic, channel plug‐flow or complete mixing. The product yield of both reactors depends strongly on the electrode potential, with reductions of low transfer coefficients favoured by positive, electrogenerative potentials. Channel flow reactors result in non‐uniform rate, current and selectivity distributions and exhibit apparent limiting currents before the onset of slow mass transport. With multipath competing reactions or in the presence of slow external transport, both reactors are amenable to maximisation of desirable product yields.

The Laryngotracheal Instillation of Topical Anaesthetic (LITA) tracheal tube has an additional pilot tube through which local anaesthetic can be instilled into the larynx via 10 small holes above and below the cuff We studied 40 patients undergoing supratentorial craniotomy. They were premedicated with two oral doses of propranolol 1 mg.kg(-1). The anaesthetic consisted of infusions of remifentanil, propofol and vecuronium. On insertion of the first skin clip at the end of surgery, 5 ml of either saline or 2% lidocaine was injected into the appropriate lumen of the tracheal tube. There was no difference between the groups in the degree of coughing or the haemodynamic response to tracheal extubation.