British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Developmental pharmacokinetics of morphine and its metabolites in neonates, infants and young children.
Descriptions of the pharmacokinetics and metabolism of morphine and its metabolites in young children are scant. Previous studies have not differentiated the effects of size from those related to age during infancy. ⋯ M3G is the predominant metabolite of morphine in young children and total body morphine clearance is 80% that of adult values by 6 months. A mean steady-state serum concentration of 10 ng ml(-1) can be achieved in children after non-cardiac surgery in an intensive care unit with a morphine hydrochloride infusion of 5 micro g h(-1) kg(-1) at birth (term neonates), 8.5 micro g h(-1) kg(-1) at 1 month, 13.5 micro g h(-1) kg(-1) at 3 months and 18 micro g h(-1) kg(-1) at 1 year and 16 micro g h(-1) kg(-1) for 1- to 3-yr-old children.
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Randomized Controlled Trial Comparative Study Clinical Trial
Entropy of EEG during anaesthetic induction: a comparative study with propofol or nitrous oxide as sole agent.
The search continues for an anaesthetic monitor that can define the level of anaesthesia in an individual patient irrespective of anaesthetic agent(s) used. Studies of available monitors based on bispectral analysis or evoked auditory potentials show the complexity of the problem. We assessed a new monitor, based on the entropy of the EEG, during induction of anaesthesia with either propofol or nitrous oxide. ⋯ The entropy monitor of anaesthetic depth shows a successive decrease with propofol but loss of consciousness with nitrous oxide is not associated with change in entropy indices.
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Randomized Controlled Trial Clinical Trial
Unconscious learning during surgery with propofol anaesthesia.
Learning during anaesthesia has been demonstrated, but little is known about the circumstances under which it may occur. This study investigated the hypothesis that learning during anaesthesia occurs during, but not before, surgical stimulation. ⋯ Learning during anaesthesia seems more likely to occur during rather than before surgical stimulation at comparable anaesthetic depth. We hypothesize that surgical stimulation facilitates learning during anaesthesia, independently of its effects on anaesthetic depth.
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Multicenter Study Clinical Trial
Pharmacokinetics of levobupivacaine 0.25% following caudal administration in children under 2 years of age.
Levobupivacaine, the S(-)enantiomer of racemic bupivacaine is less cardiotoxic than racemic bupivacaine and the R(+)enantiomer dexbupivacaine, while retaining similar local anaesthetic properties and potency to racemic bupivacaine. The pharmacokinetic profiles of the two bupivacaine enantiomers differs and that of racemic bupivacaine may be age dependent. We examined the pharmacokinetics of levobupivacaine after its single shot caudal epidural administration in children. ⋯ After the caudal epidural administration of levobupivacaine 2 mg kg(-1) in children less than 2 yr of age, C(max) was within the accepted safe range for racemic bupivacaine. T(max) varied and occurred later in some children, particularly those aged less than 3 months. Sampling in future pharmacokinetic studies in this age group should extend beyond 60 min.
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It may be clinically useful to predict the depth of the epidural space. ⋯ We conclude that the preoperative abdominal CT is helpful in prediction of the distance for low-thoracic epidural insertion using the paramedian approach.