British journal of anaesthesia
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We have studied the pharmacokinetics and distribution of ketamine and its biotransformation products in dogs after extradural administration of ketamine at L4-5. The mean apparent uptake rate constants of ketamine for plasma and CSF were 4.17 (SD 1.84) and 5.15 (2.50) h-1, respectively. The concentrations of ketamine in CSF were greater than those found in plasma. ⋯ The concentrations decreased in concert with the increase in polarity of the metabolites. A specific distribution for all compounds was observed. Ketamine showed a greater affinity for brainstem, while norketamine and dehydronorketamine were distributed mostly in cerebellum and kidney, respectively.
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The benefits, risks and resource implications of providing an Acute Pain Service were assessed during the first year of the service. Six hundred and sixty patients recovering from major surgery were treated with patient-controlled analgesia (510 patients) or extradural infusion analgesia (150 patients). ⋯ Eight patients developed potentially serious complications including respiratory depression and hypotension; the diagnosis and management of these problems on general wards is discussed. Retrospective analysis of the incidence of postoperative chest infection in surgical patients showed a marked reduction during the first year of the service (1.3% in 1988, 0.4% in 1989-90 (P less than 0.01].