Current opinion in anaesthesiology
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The purpose of this review is to discuss interesting recent developments concerning the use of halogenated agents. Now we are in a new stage of halogen use; we have become alerted to the secondary effects which although not life-threatening are potentially deleterious. ⋯ Based on this new approach, the therapeutic range of the new halogenated agents may be revisited and possibly narrowed.
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To evaluate the relevance of new local anesthetics in pediatric regional anesthesia. ⋯ The goal of anesthetists using regional anesthesia is to use local anesthestics that are as safe and effective as possible, with a rapid onset and a long duration. Even though adequate dose guidelines are available, several toxic effects are reported with the use of bupivacaine in children due to inadvertent intravenous injection, long-term infusion (> 48 h) or administration in newborn babies and infants with reduced metabolism. Ropivacaine and levobupivacaine are new local anesthetics with a wider safety margin that have similar characteristics: both of them are pure S-(-)-enantiomers whose main pharmacological features are less cardio- and neuro-affinity and -toxicity in comparison with the racemic formulae and R-isomers, and a differential neural blockade with less motor than sensory block. Several clinical studies in children compare ropivacaine and levobupivacaine with bupivacaine.
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Recent experimental data from rodent studies have demonstrated accelerated neurodegeneration in rat pups exposed to commonly used anesthetic drugs. These provocative findings certainly question and undermine the safe use of anesthetic drugs, particularly in pediatric anesthesia, and have prompted many to investigate the neurotoxic effect of anesthetic drugs on the developing brain. This review will address the scientific evidence for the anesthetic-induced neurotoxicity and its applicability in humans. ⋯ Taken together, these studies question the applicability of these data to the anesthetic management of the neonate. Further investigations in this area are needed before withholding anesthetics in the anesthetic management of pediatric surgical patients.
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An estimated 0.5-4% of pregnant patients have cardiac disease, such as rheumatic disease, which is decreasing in Western countries, uncorrected congenital heart disease, cardiomyopathy and ischaemic heart disease. There has been an increase in maternal mortality due to cardiac causes. Congenital heart disease is becoming the most common source of cardiac problems in the pregnant patient, because patients are increasingly likely to survive to childbearing age with the improvement of surgery. ⋯ We try to give a brief and comprehensive review on this topic.
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Curr Opin Anaesthesiol · Jun 2005
Current status and clinical relevance of studies of minimum local-anaesthetic concentration (MLAC).
Studies comparing the effects of epidural local anaesthetics have been limited by the lack of knowledge of their relative potencies. In 1995 the concept of the minimum local-anaesthetic concentration (MLAC) was introduced, this has been defined primarily as the median effective analgesic concentration in the first stage of labour. Pharmacologically, this model aims to determine equipotent analgesic concentrations of local anaesthetics, to compare motor effects and to evaluate the relative toxicity during labour. However, results of recent MLAC studies are not uniform and rather confusing, and thus, the basic validity of the MLAC concept for determining local-anaesthetic potency is increasingly discussed. ⋯ Relative differences in local anaesthetics' potencies derived from MLAC examinations are meaningful and correct from the pharmacological point of view, but they cannot simply be transferred to daily clinical practice. Thus, MLAC values should not be misinterpreted as these data are not suggested to be suitable to define and quantify the pharmacodynamics of local anaesthetics, nor to unequivocally predict their toxicological profile in clinically relevant concentrations.