INTRAVENOUS-INFUSION ANESTHESIA AND DELIVERY DEVICES

During the past decade, major advances have taken place with regard to intravenous infusion anaesthesia. New opioid analgesics, iv anaesthetics, and muscle relaxants have become available, which are characterized by a rapid onset of action, short duration of clinical effect, and favourable side effect profiles. Optimal administration of these drugs is often best achieved by continuous infusion, rather than a more traditional technique of intermittent bolus administration. New concepts in pharmacokinetic modelling also provide an enhanced appreciation of the factors which determine rates of recovery upon discontinuation of an intravenous infusion. Pharmacokinetic principles guide rational selection of the iv anaesthetic drugs according to both procedure and patient-specific requirements. In addition, improvements in the new programmable syringe infusion pumps provide a degree of simplicity and accuracy in operation, which make iv infusion of one, two or three components of the anaesthetic state a simple and practical reality for most procedures. In this CME article, these issues will be reviewed according to the following outline: Historical considerations; Rationale for continuous infusion of iv anaesthetic drugs; Pharmacokinetic and pharmacodynamic considerations; Infusion schemes; New techniques, new indications; IV anaesthetic delivery systems; Pharmacoeconomic considerations; Conclusions.